Healing of dense regular connective tissue, due to a high fiber-to-cell ratio and low metabolic activity and regeneration potential, frequently requires surgical implantation or reconstruction with high risk of reinjury. An alternative to synthetic implants is using bioscaffolds obtained through decellularization, a process where the aim is to extract cells from the tissue while preserving the tissue-specific native molecular structure of the ECM. Proteins, lipids, nucleic acids and other various extracellular molecules are largely involved in differentiation, proliferation, vascularization and collagen fibers deposit, making them the crucial processes in tissue regeneration. Because of the multiple possible forms of cell extraction, there is no standardized protocol in dense regular connective tissue (DRCT). Many modifications of the structure, shape and composition of the bioscaffold have also been described to improve the therapeutic result following the implantation of decellularized connective tissue. The available data provide a valuable source of crucial information. However, the wide spectrum of decellularization makes it important to understand the key aspects of bioscaffolds relative to their potential use in tissue regeneration. Connective tissue (CT) is an omnipresent and versatile tissue representing a wide spectrum of functions. One of the functions is forming attachments between components of motor skills through creating ligaments, tendons, fasciae and aponeurosis. These four structures are representatives of dense regular connective tissue (DRCT), which is tissue rich in collagen fibers. The regeneration of DRCT is challenging because of the molecular composition of those structures. Its relatively low cell-to-fiber ratio favors disorganized fibrotic scarring around the wound . It may One of the potential therapies is the tissue-specific wound dressings obtained by tissue decellularization. Removing cells produces an immunologically neutral material with protein composition and fibers organization as in the target tissue that can be used as an efficient and safe wound dressing, also in xenogeneic transplants . The decThe physical properties of the ECM are mainly determined by the number and distribution of fibers. The molecular composition of proteins in the ECM is dominated by collagen fibers, especially type I collagen fibers. In DRTC, it establishes over 80% of the tissue dry mass . FurtherVIM) or platelet-derived growth factor receptor alpha (PDGFRA), as shown in Fibroblasts synthesize a wide spectrum of proteins, and they are the main architects of the synthesis and remodeling of the ECM structure . One of Due to the ubiquity of DRCT tissue, it suffers in many injuries to and pathologies of the musculoskeletal system. The most common injuries of DRCT are Achilles tendon rupture , injury SOX9 and GLI1 genes is involved. Because of bone elongation, some junctions have to migrate to reach the target position on mature bone. During entheses, the migrating population of Sox9+ cells are replaced by Gli1+ cells which form mature connections. In stationary junctions, Sox9+ cells inhibit the enthesis structure during the whole process of bone elongation and ossification, with only some Sox9+ cells expressing Gli1 [A crucial element in the tendon/ligament/fascia functioning is enthesis at the point of its junction to the bone, shown in ing Gli1 . Increasing Gli1 , which iing Gli1 . Stiffening Gli1 , which ming Gli1  and alsoing Gli1 . One of ing Gli1 . In conclusion, DRCT regeneration requires comprehensive support. It is especially necessary to concentrate on the aspects of providing the undisturbed orientation and distribution of collagen fibers, efficient inter-tissue connections and preventing ossification and fibrous scarring.The most important aspects of the decellularization process are its efficiency of cell extraction and preservation of the ECM fibrous structure. Universally described criteria for the safety and efficiency of decellularization are DNA and nucleus residues. Crapo et al. suggest implementing three quantitative indicators of effective decellularization: (1) less than 50 ng dsDNA in 1 mg of ECM dry weight; (2) residual fragments of DNA shorter than 200 bp; (3) lack of visible nuclear material in tissue sections stained with 4′,6-diamidino-2-phenylindole (DAPI) or hematoxylin and eosin . ApproprThe DRCT decellularization protocols exhibit plenty of different techniques, shown in Electroporation-induced decellularization employs high-magnitude electric pulses to reduce integrity of the cell membrane. The electric field crossing through the cells destabilizes the electric potential of cell membranes and results in the formation of nanoscale pores. Homeostasis of cells is destabilizing, which is the direct cause of cell death. Modifications of the voltage or pulses frequency allow adjustment of the decellularization conditions in relation to the desired effects. The most commonly used type of electroporation is NTIRE , which minimizes thermal damages of the ECM . This teSonication-induced decellularization uses high-frequency sound waves to form and collapse microbubbles to generate shear forces, microstreaming and shock waves. These forces disrupt cell membranes, leading to the release of cellular contents, and also induce ECM net looseness. The induction of waves can be generated using a direct sonicator or an undirected ultrasonic bath. The use of the indirect method, due to its global effect, enables the decellularization of larger samples and exhibits improved perseverance of the ECM structure but requires more time . In the The procedure of freezing samples induces intracellular ice crystal formation, causing mechanical disruption of cell membranes, leading to cell death. This technique most often involves the manual use of liquid nitrogen and an incubator, but there is a possibility of automating the process, which can be used in manufacturing processes . The freHigh Hydrostatic Pressure (HHP) involves applying elevated pressure to a sample immersed in a liquid medium. High pressure leads to irreversible loosening of the phospholipid bilayer, which causes cell membrane permeability and ultimately results in cell death. Using an HHP-involving methodology, the periodontal ligament was successfully decellularized, resulting in a cell-free ECM with high mechanical strength and low residual DNA content, suggesting the technique can be used as an efficient decellularization tool . The decIn conclusion, a significant portion of physical methods, especially sonication and electroporation, demonstrate low efficiency of cell extraction, and they should constitute only a stimulus initiating a decellularization process in a multi-step protocol. The procedure with them should be enriched with other cell extraction agents. Sonication, although not well studied in the context of DRCT, leads to significant loosening of ECM fibers and may be precluded from use with this tissue. Electroporation, despite promising results, has not been sufficiently evaluated for its effects on DRCT. All of the above methods do not require extensive specialized equipment, and FT shows the most promising results.A commonly utilized non-ionic surfactant used as a component of decellularization protocols is Triton-X 100. It extracts the cells through lipid bilayer disruption, a crucial factor in the breakdown of cell membranes and subsequent release of cellular contents. Triton X-100 should preserve protein structure and maintain the structural integrity and composition of ECM. A significant relaxation of collagen fibers occurs in Triton-X-treated tendons . ResearcThe ionic detergent SDS is one of the common supplements in the decellularization protocol. Its mechanism of action is based on the dissolution of cell membranes and also on disruption of protein interactions and structure. SDS is an extremely effective molecule for decellularization but is also dangerous for the surrounding proteins . ApplyinSodium azide is a well-known inhibitor of cytochrome C oxidase in the mitochondria. It causes disruption of cellular function and cell death by reducing ATP synthesis. It is a commonly used component of DRCT decellularization protocols, acting as a bacteriostatic agent . Due to The functionality of Latrunculin macrolide produced by the marine sponge relies on depolymerization of actin filaments, which are one of the major structural components of the cell cytoskeleton. It is also a major ingredient of the structure of muscles, which is a reason why that the agent is commonly used for muscle decellularization. Furthermore, Latrunculin B was described once as a valuable agent of safe tendon cell extraction . The advEthylenediaminetetraacetic acid (EDTA) is a chelating agent whose mechanism of decellularization is based on separating the cells from the surrounding ECM by binding to divalent metal cations at the site of cell adhesion. Protocols using EDTA alone are described as insufficient . Therefow/v) trypsin caused significant slackness of ECM fibers. Therefore, the enzyme is commonly used in multi-step protocols with other agents, especially in DRCT, where ECM preservation is a priority [Trypsin is a pancreatic enzyme that shows robust enzymatic activity in digesting membrane proteins, often leading to cell death. The mechanism of trypsin action is based on targeting the bonding with the C-terminal side of arginine and lysine, resulting in cleaving peptides. Trypsin treatment should be precisely balanced between effective decellularization and protein preservation in DRCT. Incubation of porcine myocardial tissue for 5 h  or porcipriority ,120. In priority . The purpriority , the conpriority .DNase and RNase are endonucleases whose role is to cleave DNA or RNA in the extracellular space. Important for DNase activity is the presence of calcium and magnesium ions . Due to A plentiful number of scientific papers describe the action of decellularization agents. However, there is a dearth of direct comparisons of procedures in terms of DRCT treatment. Various tissues respond differently to the same protocol of decellularization , which mDecellularized ECM (dECM) can be used in various ways, as shown in The structure of dECM can be modified in many possible ways. One of the possibilities is to leave the native structure and shape of the collected sample. This solution is a common way of processing ligament and tendons from small animals , where tOther strategies rely on the disruption of the primary cross-linking during the remodeling of the dECM form. A common transformation of the dECM is the formation of a hydrogel. The first stage of its production is lyophilization and fragmentation of dECM into a powder . The nexForming the scaffold shape can also be achieved by 3D printing technology. This technique uses a pre-gel with or without cells which is cross-linked during the time of printing. The most commonly used technique of printing with dECM hydrogels uses a head with a mechanical extrusion and incubating system for pre-gel staining. Toprakhisar et al. used a system with a glass capillary tube, aspirating the pre-gel from a cool reservoir and incubating it at 37 °C for 6 min to transform the liquid into a gel. After incubation, the gel was extruded from the glass capillary on the printing area . This prBFGF) expression during DRCT healing. Supplementation of l-ascorbic acid (vitamin C) has a significant impact on collagen production and also on mechanical resistance of DRCT [Considering the most important aspects of DRCT treatment, the efficiency of wound dressings and implants can be increased by manipulating composition with supplements. Biomaterial can be supplemented at any point of time during the preparations. Ingredients can be added during the decellularization protocol , after d of DRCT . Coating of DRCT . Evidenc of DRCT  suggestsMMP expression [Oxidative stress (OS) is a forceful disturber of proper DRCT recovery. Excessive production of reactive oxygen species causes the reduction of fiber production and the weakening of tendons and ligaments . The prepression . There apression , nicotinpression , β-lactopression  and N-acpression .SOX9 expression in differentiating cells of injured tissue, affecting the development of cartilage tissue, potentially contributing to the regeneration of entheses [SOX9 during cartilage healing is even higher when using tendon dECM [The crucial aspect of any regenerating tissue is cell differentiation, which also can be improved by dECM supplements. In equine tendon samples, differentiation was assured by Transforming Growth Factor Beta 3 (TGFβ3), which led to tenogenic differentiation of adipose-derived stromal cells (ASCs) . Growth entheses . Expressdon dECM . HoweverExtracellular vesicles (EVs) seem to have a comprehensive supplementary effect. The cargo of EVs includes lipids, nucleic acids and proteins, with a broad spectrum of activity . ExosomeAfter the decellularization process, despite cell extraction, most of the extracellular molecules remain in the dECM. These molecules, among others, take part in the aspects discussed above, such as the proliferation, differentiation or inflammation process. Nevertheless, supplementation can be an effective way to increase or decrease the intensity of some processes and to boost efficiency of injuries healing. Additionally, it can ensure proper regeneration when healing proceeds with a scaffold obtained from a source other than the target tissue.The current state of the research advancement of the DRCT decellularization process enables the use of bioscaffolds in preclinical studies and, above all, in in vivo trials. Due to the functions and localizations of DRCT structures, the experiments are divided into two parts. One of the parts is the research about tendons and ligament, which have a similarity in shape and composition that allows application of the process interchangeably in tendon/ligament healing . AnotherThere is a significant disproportion between these two areas of research, as there are few studies on decellularized flat DRCT. Abdominal wall reconstruction is commonly performed with synthetic meshes, replacing native tissues . As provBiomechanical aspects of tendon/ligament provide promising results; the bioscaffolds show similar strength and stiffness to the native tissue ,168. In The high collagenic composition of DRCT structures ensures an impressive mechanical resistance but also contributes to low metabolic activity and poor regeneration abilities. A promising method to replace ligaments seems to be using implants, which also faces difficulties. The best results appear to be with autogenic implants , but theDecellularization of DRCT structures seems to be a universal and promising tool whose potential is not yet fully understood. The material obtained in this process is very simple to modify, and, at the same time, it is a strong structure that achieves results similar to native tissue. The decellularized tissue is not only an immunologically neutral scaffold, but also, due to the high content of extracellular molecules, has an active effect on the metabolism of the surrounding cells. Decellularization promotes regeneration of the injured tissue. The native molecular structure of the scaffold promotes integration of healing tissues and also preserves mechanical resistance, preventing reinjuries, which are a common complication at the tendon, ligament or fascia healing process. It shows superior regenerative potential compared to commercially available synthetic scaffolds but also faces the challenges. Multiple methods of decellularization have been developed. However, protocols combining multiple methods show greater potential than single-component procedures. Using several components, with other mechanisms of action, enlarges the decellularization effect, but also allows minimization of the doses of various agents. The destructive effect of decellularization is intensified when applying higher amounts of single components. In addition, crucial to operating with the physical decellularization methods seems to be one of its abilities, that of loosening the collagen fibers without dissolving them, which not only improves cell extraction, but also promotes and expedites cell reseeding. The development of a simple and efficient decellularization protocol will make it possible to automate this process as quickly as possible and make it widely available in various forms, such as in universal DRCT implants, wound dressing, hydrogels or filaments for 3D bioprinting.Many experiments remain necessary to fully understand the potential of decellularization and, above all, to analyze and optimize currently available solutions. However, the current techniques provide promising results for therapeutic use.


Fungi represent a large portion of the biodiversity on Earth and they are key players in soils where they provide numerous ecosystem functions. Soil fungi play important ecological roles influencing plant health as symbionts, pathogens and decomposers. Soil fungal biodiversity is increasingly recognized as providing benefits to soil health as they participate in numerous ecosystem processes. Continued research on the identity, abundance and distribution of soil fungi, their various roles in soil microbiome community are thus fundamental to better understand all dimensions of fungal biodiversity, their impact on plant health as well as the prevention of diseases.This Research Topic aimed at collecting contributions that provide taxonomic, physiological and ecological characterizations of soil fungal communities that will aid to the understanding of their biology, interrelationships and the mechanisms that underpin the various ecosystem functions they provide in the soil. The volume focuses at environmental mycology and reports sensitive, accurate and fast methods for the detection, identification and distribution of fungi. We were interested in metagenomic, metatranscriptomic and metabolomic approaches, as they increasingly reveal the impact of fungal biodiversity on soil and plant health.Frąc et al.). They can be rapid or subtle, depending on the applied factor. In this volume of Frontiers in Microbiology we have concentrated on mycobiome, which is much less popular in soil microbiome studies than bacteria. Wolińska et al. focused their research on identification of the core fungal mycobiome and found fungi linked to the sensitivity and resistance to long-term monocultures of maize, which is one of the most popular crop plants grown in monocultures worldwide. The study clearly demonstrated mycobiome changes depending on the seasons and agricultural practices. Even short breaks in the monoculture, caused by intercropping, greatly increased soil mycobiome biodiversity. Similarly, the soil mycobiome dramatically changed after the use of cover crops, in the soil of continuous cucumber cultivation under plastic shed systems , mainly due to the increase of beneficial fungi. The study indicated positive sides of cover crops in creating plant-protective mycobiome in the soil.Monoculture farming is a fascinating testing ground for studies of soil mycobiome. The use of various cultivars, application of agronomic methods, pesticides, fertilizers and biological compounds at different stages of plant development cause changes in the structure and dynamics of soil microbiome . However, in most plants there are only fragmentary results concerning the effects of planting patterns on the fungal community structure in the rhizospheric soil. The results obtained by Cai et al. indicated that fertilization alters the fungal community structure in soil rhizosphere of cassava, increase the potentially beneficial fungi and decrease the pathogenic species. Moreover, the results showed that both full-dose and reduced fertilization significantly increased plant yield. The authors paid attention to the need of maintaining the stability of ecological niches in crop plant rhizosphere and they suggested to use specific microbial-based fertilizers. Jin et al. underlined that the decrease of chemical fertilizer application in combination with bio-organic amendments can be effective in reducing the overuse of mineral fertilizers in agriculture without the loss of soil fertility. Soil mycobiome was more responsive than bacterial microbiome to chemical fertilizer reduction combined with bio-organic amendments applied to lettuce. This fertilization strategy improved soil fertility, as well as plant yield and quality, giving valuable implications for vegetable safety, and environmental sustainability development.Soil microbes play numerous functions in the ecosystem and interact with plants improving their growth, development, fitness and production .Soil mycobiome  is essential, but still neglected, component of soil microbiome. Soil fungi are very important for agricultural, horticultural and forest ecosystems supporting functioning and environmental services to plant health, soil quality, fertility, and ecological stability. Soil functionality can be improved by managing the soil mycobiome. However, fungi can also cause plant diseases, decrease yield, and affect human health. Therefore, there is a need to study the possibility of different mycobiome-based solutions and tools for sustainable and regenerative agriculture, including prediction of plant disease occurrence and control of mycobiome shift in soils. Metagenomic, metatranscriptomic, and metaproteomic methods combined with bioinformatic analyses may help to protect crops in modern agriculture. Moreover, there is a necessity to monitor environmental effects of newly developed microbial-based solutions. Although the knowledge on soil fungal community and mycobiomes is increasing, there is still a big black box concerning the future aspects of its influence on the environment.MF, EH, and MJ wrote drafted, read, corrected, improved, revised, and accepted the last version of manuscript. All authors contributed to the article and approved the submitted version.


Claviceps fungus was later shown to synthesize ergot alkaloid mycotoxins in the sclerotia, after which time the control of mycotoxins in agricultural products has become an important issue for ensuring food safety. In the light of the importance of microbial metabolism in such double-edged ways, the present Research Topic accepted five original research papers and one perspective paper , which have expanded the scientific knowledge of the relevant microorganisms by using advanced modern technology, as outlined below.Microorganisms are closely associated with agriculture and food industries in both beneficial and detrimental ways. As the beneficial use of microorganisms, humans have taken advantage of their activities for preserving, flavoring, and enriching the agricultural products through fermentation. Since the early ages of crop cultivation, yeasts and molds inhabiting raw materials in the environment have been used for processing, which has led to the emergence of indigenous food cultures with unique tastes and odors. Despite the long history of traditional fermentation, it was not until the mid-19th century, when Louis Pasteur elucidated the chemical processes associated with life and structural integrity of yeast cells, that alcoholic fermentation has come to be recognized as the result of microbial activity Barnett, . In contSake is a traditional Japanese rice wine made by advanced parallel double fermentation that involves starch saccharification of steamed rice grains by Aspergillus oryzae  and simultaneous alcoholic fermentation by the yeast Saccharomyces cerevisiae. Other than the common eukaryotic fermenting microorganisms used in sake production, bacteria inhabiting the sake breweries (described as kuratsuki in Japanese) have been identified by using massive parallel DNA sequencing, revealing the diversity of microbial flora during sake production in different breweries. This finding has led to the hypothesis that the specific flavor and taste of sake products possibly arose from interactions between brewery-specific kuratsuki bacteria and yeasts , such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which have numerous health benefits throughout human life. For the production of PUFAs, Schizochytrium is considered as one of the alternative sources to fish oils, as this eukaryotic heterotrophic microalagae can produce high levels of such functional food ingredients , AoCcsA (a copper chaperone that introduces copper ions into AoSod1), and EcdR (a transcription factor for AobrlA expression) in the copper regulation of these reproductive structures. In addition to the molecular mechanism underlying sterility, the presumed occurrence of galactofuranose -containing glycans in A. oryzae cell walls  and showed the UgmA-dependent synthesis of Galf-containing glycoproteins in the koji mold. Although the amount of the Galf-containing glycoproteins in the cell wall fraction was significantly smaller than that in other Aspergillus species, the incorporation of Galf side chains into the core mannan backbone was required for the maintenance of cell wall integrity; i.e., as revealed by the temperature and calcofluor white sensitivities of the A. oryzae ΔugmA disruptant. Given that such fungal-type galactomannan (FTGM) is a remnant of the ancestral pathogenic Aspergillus species and is antigenic in humans, it is intriguing to assume that some health-promoting benefits, such as immunostimulatory effects and intestinal eubiosis, occur through habitual ingestion of koji-fermented foods (Kitagaki, Apart from the applied aspects of microorganisms used for the production of fermented foods and beverages, two basic studies on the cell structure and gene functions of Fusarium graminearum and other closely related Fusarium phytopathogenic fungi infect wheat and barley, and accumulate trichothecene mycotoxins in the grains (Kimura et al., Fusarium species have recently been found to have a potential ability to glucosylate the side chains of the trichothecene skeleton, raising the possibility of producing diverse variations of “masked” mycotoxins (Matsui et al., F. graminearum has been the subject of intensive studies, and several hypotheses and models have been proposed. Liew et al. discuss several issues that previous researchers had not noticed, presenting original unpublished results, and proposing a revision of the current understanding of the mechanism of trichothecene biosynthesis regulation. Finally, the perspective paper shares a strategy for establishing a regulatory model of transcription of Tri6 and Tri10 in F. graminearum, which are trichothecene transcription factor and regulatory protein genes, respectively, located at the core region of the gene cluster (Maeda et al., In summary, this Research Topic highlights recent advances that explore applied aspects of microorganisms for the production of fermented foods and beverages, as well as basic research into the genetic and biochemical mechanisms underlying the growth, development, and metabolism of microorganisms that affect the quality, safety, and functionality of agricultural products.All authors listed have made a substantial, direct, and intellectual contribution to the work and approved it for publication.


EGFR and ALK) are associated with poor response to immunotherapy, and failing to identify such patients results in poor outcomes [KEAP1 or STK11, as well as other molecules involved in tumor microenvironment, are becoming a subject of interest in immunotherapy research, and might eventually reach relevance for introduction in clinical practice [Non-small-cell lung cancer (NSCLC) is the major cause of cancer-related deaths worldwide, due to its high incidence and mortality . The chaoutcomes ,6; on thpractice ,8. Previpractice ,10. The The first consideration based on the current context is that the technology for the detection of molecular alterations is rapidly and constantly improving, with increasing sensitivity in terms of gene detection, including both acknowledged and novel, uncommon mutations; the second consideration takes into account the increasing availability of targeted therapies, with a non-negligible degree of variation among the different regulatory agencies. These improvements pose further challenges: on the one hand, pathologists and molecular biologists must continuously make efforts in terms of training and upgrades of laboratory tools; on the other hand, medical oncologists are required to make clinical decisions for patients with uncommon molecular alterations (including uncommon mutations in both acknowledged targets and uncommon novel targets), for which limited research is available so far, and targeted agents may exist while not being readily available through national healthcare services. An emerging approach to address these potential issues is represented by the institution of molecular tumor boards, which are expected to include personnel with the skills and resources needed for the optimal management of patients whose tumor harbors a complex molecular profile .MET alterations during treatment with EGFR inhibitors, the former approach appears more suitable when various, singularly uncommon, acquired mutations occur. One major limit to this approach is the necessity to re-characterize the tumor at progression, with potential discomfort for the patient and perception of time loss, especially when new actionable drivers are not identified. One possible answer to this issue is represented by the employment of liquid biopsy to detect novel mutations from peripheral blood. This emerging approach is rapidly evolving in terms of accuracy, and its potential applications are currently being explored in the translational and clinical setting. In particular, by making the molecular characterization more accessible compared with conventional biopsy, blood-based liquid biopsy allows for repeated sample collection from each patient, thus providing an unprecedented opportunity for longitudinal monitoring. Furthermore, the nature of liquid biopsy should make its molecular profile representative of the whole neoplasm, hence overcoming the limits of conventional biopsy due to tumor heterogeneity. Notably, while liquid biopsy is extremely promising, histology-based assessments, such as histotype diagnosis and the identification of morphologic shift during targeted therapy  are still beyond the possibilities of liquid biopsy [Another concept, strictly linked with the development of molecular biology and targeted therapy, is represented by the study of resistance mechanisms developed during treatment with targeted agents, which result in clinical disease progression. Notably, the identification of said mechanisms is expected to result in the development of novel therapeutic strategies designed to either manage and counteract resistance-based progression, or to prevent the occurrence of acquired resistance in first place . While td biopsy ,15,16.EGFR [Similar to other fields of medicine, molecular oncology is expected to benefit from the increasing applications of artificial intelligence (AI). In this context, predictive algorithms can provide a large amount of information able to aid in histomolecular diagnosis; two major examples of these applications are represented by digital pathology and radiomics. In digital pathology, AI-based algorithms are applied to scanned tumor slides in order to detect features invisible to the human eye and predictive of specific molecular profiles . In radiEGFR . The devIn conclusion, molecular oncology and precision medicine have made a huge leap in the last few years, resulting in significant survival advantages in different malignancies, and particularly in NSCLC. However, in spite of the impressive achievements, there is still huge room for improvement. The continuous study of emerging molecular alterations and the development of novel treatments capable of exploiting oncogenic drivers remain major objective in thoracic oncology.


Strain-based condition evaluation has garnered as a crucial method for the structural health monitoring (SHM) of large-scale engineering structures. The use of traditional wired strain sensors becomes tedious and time-consuming due to their complex wiring operation, more workload, and instrumentation cost to collect sufficient data for condition state evaluation, especially for large-scale engineering structures. The advent of wireless and passive RFID technologies with high efficiency and inexpensive hardware equipment has brought a new era of next-generation intelligent strain monitoring systems for engineering structures. Thus, this study systematically summarizes the recent research progress of cutting-edge RFID strain sensing technologies. Firstly, this study introduces the importance of structural health monitoring and strain sensing. Then, RFID technology is demonstrated including RFID technology’s basic working principle and system component composition. Further, the design and application of various kinds of RFID strain sensors in SHM are presented including passive RFID strain sensing technology, active RFID strain sensing technology, semi-passive RFID strain sensing technology, Ultra High-frequency RFID strain sensing technology, chipless RFID strain sensing technology, and wireless strain sensing based on multi-sensory RFID system, etc., expounding their advantages, disadvantages, and application status. To the authors’ knowledge, the study initially provides a systematic comprehensive review of a suite of RFID strain sensing technology that has been developed in recent years within the context of structural health monitoring. Engineering structures may be damaged due to various natural and human factors during service life. Structural damage can be defined as the change of material and geometric properties of the whole structure or some structural component, e.g., the decay or decline of the structure in stiffness, boundary, strength, and connection conditions, which will affect the future performance for the whole structural system ,4,5,6,7.In recent years, engineering structure collapse accidents occur frequently due to various natural and human factors. Structural health monitoring (SHM) plays a significant role in structural damage identification and reliability evaluation for in-service engineering structures. They can resort to sensor systems, data acquisition and processing systems, and computer software to monitor, diagnose and analyze the structural condition and safety performance of in-service engineering structures. Furthermore, a real-time health monitoring system for major engineering structures is established to timely identify structural damage and make corresponding early warning mechanisms, so as to give early warning to possible disasters.In the context of structural health monitoring and structural state evaluation, the strain can reflect the local damage of the structure, and based on the strain monitoring data, the damage location, fatigue failure, and reliability evaluation of the structure can be carried out. Through the strain monitoring and state assessment of structures, strain and stress distribution can be obtained rapidly and effectively, and stress concentration area can be derived as soon as possible, which can help to realize the structural strength analysis, and evaluate the structure service condition to provide early diagnosis. The traditional strain monitoring techniques mainly include three methods: the resistance strain sensor method, the vibrating string strain sensor method, and the FBG optical sensor method. The resistance strain sensor is a resistance sensor with the resistance strain gauge as the conversion element. The elastic sensing element can be deformed caused by external excitation, and the attached resistance strain gauge will be deformed together. The resistance strain gauge can transfer the deformation into the resistance change so that a variety of physical quantities such as strain, acceleration, displacement, and temperature can be measured.In the vibrating string strain sensor method, a certain length of adding a hyphen is tensioned between two installation blocks, and the installation block is fixed on the surface of the structure. When the structure is deformed, it causes a change in the steel string tension in the vibrating strain sensor, which leads to a change in the inherent collar of the steel. The electromagnetic wire solid excitation of the steel tension will produce food and reduce vibration because of the quota rate, and the structural strain can be obtained by reading only the changes of the steel tensioned inherent whisker. The fiber Bragg grating (FBG) sensor can change the light wavelength according to the change of strain and temperature. FBG exposes a small part of light-sensitive fiber under a light wave, and the fiber refractive index will change permanently according to the intensity of the light wave being irradiated.However, in practical engineering applications, such traditional strain sensors have many weaknesses: the sensors need to be connected to each other by wired means and also the monitoring data are transmitted through wired methods. Thus, there needs more wiring, and the wiring operation is complicated and time-consuming. For instance, for the resistance strain sensor, the resistance change caused by strain is usually small, and the transmission of weak resistance changes requires a high-quality wire, so the wire cost is greatly increased. At the same time, too-long wires are susceptible to noise when they transmit weak resistance changes, which greatly reduces the accuracy of the signal. In addition, data acquisition equipment for traditional strain sensors is generally expensive. Therefore, in civil engineering applications, with the aim to overcome the shortcomings of the traditional strain sensors, strain sensing technology based on radio frequency identification (RFID) came into being. This technology can not only make up for the shortcomings of traditional monitoring methods such as complex wiring and high cost, but also overcome the shortcomings of other wireless sensor systems such as cumbersome, low efficiency, and large energy consumption, which can realize the low-cost, passive, and wireless strain measurement. This study reviews a suite of the fundamental literature to demonstrate the recent development of RFID strain sensing technologies. The RFID technology is first introduced in detail, and the basic principle of the RFID technique for wireless strain sensing is also described. Further, the design and application of various kinds of RFID strain sensors in SHM are presented, expounding their advantages, disadvantages and application status.The organization of this article is as follows. The research background is presented in An RFID system is generally composed of an RFID electronic tag, an RFID reader, and an RFID tag antenna ,9,10. RFRegarding the working principle of RFID, RFID belongs to one of the wireless communication technology, utilizing radio frequency signals to achieve the transmission of information and the acquisition of relevant data wirelessly. Specifically, the RFID reader is employed to identify the radio frequency signals, and the RFID tag is carried with the encoded information and responds through the built-in antenna. The RFID reader will transmit radio frequency signals of a specific frequency. When the RFID tag entering the identification range receives the radio frequency signals, the RFID tag is endowed with energy to activate the work. The RFID reader will collect radio frequency signals from the RFID tag by the receiving antenna and sends the signals to the host equipment after the demodulation processing. The tag number and other information can be identified by the host system, which will execute the corresponding instructions according to different settings.As a non-contact identification and communication technology, an RFID electronic tag can identify the target and acquires data through RF signals automatically . The encThe RFID electronic tag generally comprised a tag antenna and coupling components . AccordiRFID readers can identify RFID electronic tags and can realize wireless communication technology. As RFID technology matures and is widely used, the demand for RFID readers is also increasing . CurrentRFID readers can realize the RFID tag identification, as well as the read or write operation for monitoring data. The RFID reader plays an important role in the RFID system. Firstly, the working frequency of the whole RFID system is determined by the frequency of RFID readers. Secondly, the transponder is passive and its working energy is extracted from the RF signal sent out from RFID readers, so the RFID reader power directly affects the distance of the radio frequency identification .The RFID reader generally comprises an RFID transmitter and receiver, an RFID reader antenna, and a control system. The control system is mainly realized by the microprocessor . The comThe strain sensor based on passive RFID technology is a relatively common type, with the advantage that it can realize completely infinite passive strain sensing without an external power supply. However, the transmission distance is relatively short. Dey investigated a chipless passive RFID strain sensor tag with a traditional planar antenna, which can be used in the SHM applications areas such as soil strain monitoring, where the object or structure is exposed to less external traction force. Khan et al.  introducCarbon nanotubes have good performance and the use of this material can make the sensor detection range larger and the effect better. Benchirouf et al.  proposedWith the aim to verify the measurement reliability of passive RFID sensors, Ahmed et al.  proposedRegarding passive RFID technology, many studies investigated communication and data storage algorithms for efficient wireless data collection. Also, much research focused on improving transmission distances for better engineering applications. Gonek et al.  proposedCompared with passive RFID sensors, the active RFID strain sensor has a higher working frequency, generally equipped with external power. Correspondingly, active RFID sensors also consume more energy. The advantage of this active RFID strain sensing technology is the long transmission distance, which is especially suitable for practical engineering applications. Cho and Baek  proposedIn the context of sensing technology, wireless sensor networks have the advantages of low energy consumption, inexpensive hardware, and small size of wireless multifunctional sensor devices. There is a significant interrogation range for the active UHF RFID tags, which directly obtain the energy from the radiated radio frequency power. The design of the RFID tag antenna has a critical importance on the final interrogation range . Active Semi-passive RFID strain sensing technology incorporates the advantages of both active and passive RFID tags. The semi-passive RFID tags are in a dormant state for most cases with extremely low power consumption. Only when the tag enters the activation signal range, the semi-passive RFID tag is activated, and the tag will start to work. The advantages of this technology are longer transmission distance, low power consumption, and longer service life, but the disadvantage is that the design is more complex. Wang et al.  proposedRegarding the semi-active RFID tag circuit design, Zou and his research team  presenteUHF RFID techniques have the advantage of long transmission distance, but the overall sensing system has high energy consumption. This section will present some examples to show the achievements made in the field of UHF RFID strain sensing technology. Yang et al.  proposedA near-field UHF RFID reader antenna was designed by Qian et al.  with a lWhile chipped RFID technology is well developed, current research is focused on finding solutions providing a superiority with respect to lower cost, a coping strategy is to eliminate the use of RFID chips in the RFID tag design, generating a device which is named “chipless RFID” ,50. ChipWith the improvement of RFID sensor technology, single sensing function has been difficult to meet the engineering requirements. Therefore, engineers are exploring the integration of multiple physical quantity monitoring in one RFID tag to form a multi-sensory RFID system. This multi-sensory RFID system shares one RFID tag, which can reduce the cost of the sensor, in addition, it can measure multiple physical quantities at the same time, and the integration is higher. However, this kind of sensor design is more complex and difficult to design. This section will introduce the RFID-based multi-sensor system which is able to simultaneously record strain and other structural responses. As shown in For most multi-sensory RFID systems, two or more types of structural responses are generally usually monitored simultaneously . For other cases, structural responses and environmental parameters may be monitored simultaneously . As shown in In addition to the aforementioned RFID strain sensing technologies, many researchers have explored other different types of RFID strain sensing technologies, including wireless strain sensing based on reusable RFID technology, metallic environments RFID technology, virtual RFID technology, etc. Regarding the wireless strain sensing based on reusable RFID technology, as shown in In metallic environments, the RFID tag performance will degrade. In order to enhance the RFID sensor performance in harsh metallic environments, an RFID tag antenna design with a ground plane can be adopted. Thus, Zawodniok et al.  used douRegarding wireless strain sensing based on virtual RFID technology, Lee et al.  proposedIn order to introduce the reviewed RFID sensors in more detail, the following table has been summarized to describe the test performance, technical data, and features of every RFID solution, as well as the maturity level. It can be concluded from The influencing factors that restrict the application of RFID sensors in the field of structural health monitoring mainly include the following aspects: the wireless transmission distance of RFID sensors is relatively short; battery life technology restricts the development of active RFID sensors; and, in terms of electromagnetic interference, there are many influencing factors affecting electromagnetic wave in the real environment, so it is hard to extract stable and accurate electromagnetic information for sensing and detection. The sampling frequency and test accuracy of the RFID sensing system still need to be improved for SHM field applications.This study reviews a suite of the fundamental literature to demonstrate the recent development of RFID strain sensing technologies. The RFID technology is first introduced in detail, and the basic principle of the RFID technique for wireless strain sensing is also described. Further, the design and application of different kinds of RFID strain sensors in SHM are presented including passive RFID strain sensing technology, active RFID strain sensing technology, semi-passive RFID strain sensing technology, Ultra-High-Frequency RFID strain sensing technology, chipless RFID strain sensing technology, and wireless strain sensing based on multi-sensory RFID system, etc. Compared with traditional monitoring technologies, the RFID strain sensor avoids large-scale tedious wiring, and also the operation process is simple and the monitoring efficiency can be improved. With the comprehensive and thorough review, it can be concluded that there exists a prominent trend in employing wireless RFID strain sensing technology for monitoring, damage detection, and structural control. Although these RFID strain sensors have begun to generate wireless and passive strain monitoring for engineering structures, there still exists a high need for investigating the reliability and robustness of the RFID sensing technology with regard to real-time and online monitoring of the large engineering structures. Generally, the continuous long-term data acquisition capability of RFID sensors is insufficient compared to traditional wired strain sensors. In addition, the wireless transmission distance of current RFID strain sensors cannot be too far. For completely passive RFID strain sensors, its wireless transmission distance is small, generally within a range of a few or a dozen meters, which limits its application in practical engineering. For semi-passive or active RFID strain sensors, the wireless transmission distance can reach a range of 100 m. Therefore, for continuous and long-distance strain monitoring, RFID wireless strain sensing technology still has its limitations in practical real-world engineering applications. The use of chipless RFID sensing technology, and multi-sensory RFID system to harness the utility of low-cost and highly efficient sensors for strain monitoring is still in the nascent stage. In the field of chipless RFID strain sensing research, emerging smart materials  need to be developed to improve the gain of RFID tag antennas and improve electromagnetic characteristics. In addition, the RFID reading range and the 3D printing technology of RFID tags need to be further investigated to improve the field performance for on-site practical engineering.


Micro-optics based on the artificial adjustment of physical dimensions, such as the phase, polarization, and wavelength of light, constitute the basis of contemporary information optoelectronic technology. As the main means of optical integration, it has become one of the important ways to break through the future bottleneck of microelectronic technology. Geometric phase optical components can precisely control the polarization, phase, amplitude and other properties of the light field at the sub-wavelength scale by periodically arranging nanometer-sized unit structures. It has received extensive attention in the fields of holographic imaging and polarization optics. This paper reviews the physical mechanism of micro-nano structure modification, research progress of femtosecond laser direct-writing photoresist, femtosecond laser ablation of metal thin films, femtosecond laser-induced nanograting, and other methods for preparing polarization converters and geometric phase optics. The challenges of fabricating ultrafast optical devices using femtosecond laser technology are discussed. Micro-nano structures have unique optical, electrical, magnetic and thermal properties. Research on the preparation of micro and nano structures has considerable value and broad development prospects. The preparation of micro and nano structured materials is inseparable from the advanced micro and nano processing technology ,2. A femSince the birth of geometric optics, researchers have designed the contours of natural materials to change the optical path difference and realize the regulation of light transmission behavior, such as lenses. Geometric optical devices have simple design and stable functions, but it is difficult to realize certain functions, such as phase distribution regulation through simple design, and it is difficult to achieve miniaturization due to the lack of certain precision. Wave optical devices based on diffraction principle, such as flat-top beam generator and beam homogenizer, are widely used in laser processing, biomedicine, communication and sensing due to their high-energy efficiency and accuracy ,9,10. WiIn 1892, Poincare proposed a useful method to describe polarization, that is, in spherical coordinates, the basic polarization state is mapped by Stokes parameters to the surface of a sphere, which is called the Poincare sphere. The geometric phase can be easily observed in such condition: a circular polarized light goes through a geometric phase device, which mostly consists of spatial-distributed anisotropy/birefringence elements, and the phase retardance of the orthogonal-polarized components is determined by the orientation angle of anisotropy elements. It can be proved by the Jones matrix calculation that when a circular polarized light passes through a birefringence structure  in a specific optical axis direction, an orthogonal polarization state will be generated with twice the phase change as the optical axis angle. For example, the grating structure shown in Therefore, spatially varying polarization state and phase modulation can be realized by the design of spatially varying birefringence structure . Structures such as gratings and liquid crystals have birefringent properties and are often used as basic elements to form polarization converter and geometric phase devices. By designing the orientation and other parameters of the spatial distribution, the integrated devices are fabricated on different materials with excellent performance.The geometrical phase plane lens fabricated by Harvard University has the capability of chiral imaging and spatially resolved chiral spectrum. The diagram for chiral imaging is shown in With the development of science and technology, the material structure enters the micro and nano scale when endowed with new properties different from those of individual materials. Advanced micro-nano processing technology is involved in the preparation of micro-nano structured materials, especially femtosecond laser processing, which has been proven to be a micro and nano processing technology with superior performance. Femtosecond laser micro-nano machining has the following advantages: (1) simpler equipment—no need to have clean room facilities; (2) ability to process almost all types of materials; (3) this process is applicable to the surface of any three-dimensional object; and (4) different micro-nano structures can be easily obtained by adjusting the respective parameters. Nowadays, femtosecond laser manufacturing is widely used in almost all types of materials and has attracted extensive attention due to its unique three-dimensional (3D) processing capability, high manufacturing resolution, and scalability.Light can carry both energy and momentum, and the momentum of light includes both linear and angular components. Near the paraxial axis, the angular momentum of light has two parts: one is the spin angular momentum related to the circular polarization, and the other is the orbital angular momentum related to the wave vector or phase wavefront direction. There is an interaction between the spin of light and the orbital angular momentum, and the change in the orbit is always accompanied by a lateral spin-dependent deflection. The orbital angular momentum of light endows more dimensional manipulation of light, and researchers have witnessed the remarkable development of vortex light in many fields. A beam of light or a photon can carry two different angular momentums. The orbital angular momentum arises from spin-orbit interactions induced by polarization manipulation. The spin-orbit angular momentum coupler is designed in terms of spin angular momentum (SAM) and orbital angular momentum (OAM) exchange, which occurs in heterogeneous anisotropic media, and its most direct application is the ordinary Gaussian beam starts to generate an OAM-bearing beam . AccordiAs shown in The femtosecond laser, undoubtedly, has become a common fabrication method for nano structures in photoresist. Wang and his team used femtosecond laser direct writing to fabricate geometric phase optical elements in photoresist for structured light generation . A serieAn optical vortex generator  produces a beam with a helical wavefront, which can be used for the structural processing of materials and optical polymerization ,29,30. TAs shown in Xu et al. further studied the influence of the thermal annealing process on structure preparation by combining the advantages of efficient processing and the thermal smoothing effect . Blazed Using this technique, as shown in Since Birnbaum first observed nanostripes in 1965, nanostripes have attracted people’s attention, no matter from the perspective of a physical mechanism or practical application. By adjusting the wavelength and irradiation conditions of the laser, people can partially control the morphology of nanostripes produced by self-organization. The material is irradiated with linearly polarized nanosecond or femtosecond laser pulses to form periodic surface structures. It is understood that such structures are formed by the interference of incident laser light with reflected light. Therefore, fringes are usually oriented perpendicular to the incident polarization.2 glass is ~65% lower than that in fused silica [2 glass is in the sub picosecond region, usually around 500 fs, while the fused silica is at the picosecond level, about 1–2 ps. 2 content in the glass. Finally, polarized vortex beam microconverters were prepared on AF32 glasses that can be used in the near-infrared spectral range. Recently, many researchers have focused on the processing of solid transparent materials by femtosecond laser. Owing to its higher durability and damage threshold, the geometric phase optical element that has been fabricated in solid materials is of great potential in many prospects, in which, an ultrafast laser also plays an important role. The interaction between transparent materials (such as silica glass) and an ultrafast laser leads to different types of modification, including self-assembly nano-gratings with unique birefringence. Beresna et al. demonstrated the fabrication of spatially varying polarization converters by femtosecond laser-induced, self-assembled nanogratings . The mand silica . Under t−4). At Np = 200 or so, the nanopores form the nanoplane.Sakakura et al. report a novel ultrafast laser-induced structure (Type X) in silica glass, which consists of randomly distributed nanopores extending perpendicular to the polarization direction of laser, which is also a controlled birefringence structure; however, with the transmittance of up to 99% in the visible and near-infrared, and over 90% in the UV range down to 330 nm . To findAn interesting phenomenon is that the diameter of the modified region in the retardance images (1 μm) is much smaller than the diameter of the beam spot at the focal point (~5 μm). This shows that the modification only happens in the central part of the focused beam because of multiphoton absorption, which is a characteristic of Type X. While using femtosecond laser-induced nanogratings for applications, researchers are also actively exploring their forming mechanisms. Physical models such as plasmonic interference, asymmetric evolution of nano-plasmons, and exciton-pole self-trapping interference are considered to be the reasons for nanograting formation ,47,48,4923Sb7S70 glass [The transmission ranges of specialty glasses, such as chalcogenide glasses, have been synthesized with broad transmission ranges. It has unique physical and chemical properties and a transparent window well beyond the 2–5 μm spectral range of conventional glass. It offers particular advantages for various photonic applications, including space optical communication. Yves Bellouard et al. used a femtosecond laser to induce self-organized nanostructures on and near the surface of Ge70 glass . Figure Li et al. proposed a nanowire generation and stretching model by 2020, which could explain the formation mechanism of nanogratings to some extent . First, Femtosecond laser induced nanograting structures on the surface and inside of materials have attracted much attention in the field of femtosecond laser-matter interaction research. It is reported that material properties and their dependence on laser excitation determine the morphology of nanogratings. Sapphire is a widely used material in extreme conditions, such as aerospace and chemical industries. As shown in The birefringence intensity also varies significantly at different stages of nanogrid formation. The induced birefringence intensity increases gradually with the number of pulses before the nanoscale pores will undergo a self-organized joint growth phase. After the appearance of regular nano-gratings, the birefringence intensity slowly increases to a certain value and then tends to saturate. Since sapphire is a crystalline material, the range of formation parameters of nanograting is much narrower compared to that of glass materials, and the formation region of nanograting is also accompanied by the appearance of larger stresses, and the material is prone to losses, such as cracks, and the birefringence properties generated by nanograting are much smaller than those of the stresses that accompany it.In order to achieve the target retardation of 633 nm/4 = 158 nm, a five-layer structure was fabricated. During this process, a huge stress-induced birefringence appeared on the boundary, the retardance of which of was 1.5 times that of the scanned area in a single layer (exceeded 266 nm in five layers). To solve the problem of excessive edge stress, the thermal annealing has been adopted to reduce the stress at the edge of the device, and it greatly improves the phase distribution F.In conclusion, this review illustrates a broad spectrum of materials that researchers applied in femtosecond laser direct-writing fabrication, for instance, femtosecond laser direct-writing photoresists, femtosecond laser ablation of thin metal films, and femtosecond laser-induced nanogratings. The polarization converter and geometric phase devices, including low-loss Type X structure, were fabricated based on the properties of different materials thanks to the high-precision characteristics of femtosecond laser direct-writing technology. Achromatic feature of polarization converter, speed, and precision of glass internal processing, and the problem of debris are also key issues to improve the fabrication efficiency and performance of devices. When fabricating devices using femtosecond laser-induced nanogratings, the researchers also proposed various formation theories through experimental observations. However, there is still a lack of enough evidence to explain the mechanism, which needs to be further explored to boost the future femtosecond lasers fabrication technique.


Precise control of the structure of metallic nanomaterials is critical for the advancement of nanobiotechnology. As DNA (deoxyribonucleic acid) can readily modify various moieties, such as sulfhydryl, carboxyl, and amino groups, using DNA as a directing ligand to modulate the morphology of nanomaterials is a promising strategy. In this review, we focus on the use of DNA as a template to control the morphology of metallic nanoparticles and their biomedical applications, discuss the use of DNA for the metallization of gold and silver, explore the factors that influence the process, and outline its biomedical applications. This review aims to provide valuable insights into the DNA-guided growth of nanomaterials. The challenges and future directions are also discussed. The use of nanomaterials has brought significant advances in various fields, including biomedical applications. However, the synthesis of these materials often involves complex and expensive processes. Metallic nanomaterials are typically synthesized by wet chemistry or photolithography. However, metallic materials with complex shapes cannot be prepared by traditional wet chemical methods . AlthougIn 1998, Braun et al.  proposedContinuous development has shown that DNA sequence combinations can control the different morphologies of nanoparticles during their growth, and that these effects can be synergistic or competitive. The DNA used to guide the growth of nanomaterials is stable and retains its biological recognition capabilities . As a reThe unique properties of these DNA-guided metal nanomaterials have led to their exploration in a range of biomedical applications. Metal nanoparticles have unique optical, electronic and magnetic properties . DNA-dirIn this review, we provide an overview of the current state of research in this field, with a focus on the synthesis and characterization of DNA-guided metal nanomaterials, as well as their biomedical applications. We highlight the progress made in the development of novel synthetic strategies and the optimization of existing methods to improve the control and precision of the resulting nanostructures. Furthermore, we discuss the potential of DNA-guided metal nanomaterials in various biomedical applications, including drug delivery, imaging, and sensing. We describe the strategies employed to enhance the biocompatibility and stability of these nanomaterials. Lastly, we outline the challenges that remain in the development and application of DNA-guided metal nanomaterials in biomedicine, such as their scalability for large-scale production, long-term stability, and precise control over their morphology. We also discuss the potential avenues for future research, such as the exploration of new biomedical applications and the integration of multiple functions into a single DNA-guided metal nanomaterial. Overall, DNA-guided metallization of nanomaterials holds significant promise in the field of biomedicine, and this review provides a comprehensive overview of the current state of research and the future directions of this exciting area.The formation of metal nucleation sites depends on the binding of metal ions or complexes to DNA and their subsequent reduction to form metal clusters, or on the binding of small metal particles to DNA.In the DNA-directed assembly of nanoparticles, chemical bonds are commonly used to connect DNA to nanoparticles, such as the Au-S bond commonly used in gold nanoparticles ,15,16. SIn this section, we mainly focus on the use of DNA to guide the metallization of metallic nanomaterials. So far, the main discussion has been on the functionalization of nanomaterials using DNA after their synthesis, where the morphology of the nanomaterials is already determined and DNA cannot influence it. The method of seed-mediated synthesis using DNA as a director can be used to prepare nanomaterials with controlled morphology . The suc4, ascorbic acid), UV light, and electricity ,5739,57]Graphdiyne (GD) is a novel two-dimensional carbon material that was used as a substrate to synthesize single-crystal gold nanostructures with tunable morphology at room temperature by Chen and co-workers . The groIn addition to using single-stranded DNA, double-stranded DNA can also be employed to engineer the controlled crystallization of gold and other metal nanomaterials ,64. Comp4). In bottom-up synthesis, it is easier to manipulate the crystallization of atoms in a guided direction when structurally controlling the morphology of nanomaterials, compared to using metalized molecular templates where the expansion of metal clusters only amplifies the initial shape of the template. This approach allows the formation of gold nanocrystals with different structures, such as asymmetric structures such as pegs, stars, and biconcave discs, as well as more complex jellyfish and flower-like structures, by using different arrangements to anchor the DNA to the gold nanoseeds [Ma et al.  immobilianoseeds . It is wanoseeds . Gao et anoseeds  successfDNA origami is a technique that allows DNA molecules to be folded into specific shapes using complementary base-pairing. This method involves using DNA-origami structures as templates to direct the synthesis of metallic structures. These DNA origami structures can be used as templates to guide the synthesis of metallic structures with precise control of their size and shape. For example, DNA origami structures can be designed to be a specific shape, such as a triangle or square, and then used as a template to guide the synthesis of metal nanoparticles of that shape ,67,68,69+ to the host strand through the surface site resistance effect, resulting in the site-specific formation of silver nanocrystals (AgNCs) with specific fluorescence wavelengths. Furthermore, the excitation/emission properties of AgNCs could be regulated by adjusting the distance between the nucleation site and the template, the template conformation, and the position of the nucleation site on the template.Nanomaterials composed of other materials, such as silver, can be prepared using DNA origami as a template to obtain finely-structured nanostructures. In their research, Wang et al.  utilizedIn addition to homogeneous structures, DNA origami can also be utilized for heterogeneous structural junctions. Uprety et al.  investigIn summary, the electrostatic interactions between metal ions and phosphate groups of DNA facilitate the homogeneous metallization of the DNA structure, allowing for the direct growth of inorganic nanocrystals on the DNA template. However, this approach lacks addressability and does not allow for the fabrication of arbitrary forms of inorganic nanostructures. Selective metallization at specific sites on DNA origami can address this limitation. Sequential selective metallization can provide the necessary microenvironment to confine and control the mineralization process, thus enabling the precise preparation of fine metal nanostructures.The biomedical applications of DNA-guided metallized nanomaterials are diverse and promising, with potential applications in biosensing, bioimaging, and therapy ,71.4 reduction of AgNO3  and computed tomography (CT). By attaching metal nanoparticles to DNA templates, contrast agents with high specificity and sensitivity can be designed for use in diagnostic imaging. Zhang et al.  produced+ binding and the formation of stable supramolecular structures such as i-motifs and G-quadruplexes are two important prerequisites for the formation of bright photoluminescent AgNC [Silver nanoclusters (AgNCs) prepared using DNA as a template have become an important tool for the development of biomarkers and molecular sensors because of their good fluorescence properties, excellent photostability, sub-nanometer size, and low cytotoxicity ,77. The ent AgNC . Based oent AgNC  reportedent AgNC  used mulS nucleating sequences, and complementary sequences (CDNAs) that can hybridize with target DNA or RNA to alter the fluorescent properties of AgNCS. In addition, DNA-AgNCs combined with other nanomaterials can be combined to design FRET-based fluorescent probes for the fluorescent labeling of folate receptors on cancer cells [The versatility of DNA can also be exploited to combine different functional DNAs in a single structure for bioimaging. Li et al.  designeder cells .The use of DNA-guided metallized nanomaterials in therapy has the potential to improve efficacy and specificity. By attaching drugs to the surface of metal nanoparticles guided by DNA templates, targeted drug delivery to specific tissues or cells can be achieved . AdditioThe nanoparticles obtained by the metallization of DNA can be used in combination with other materials for photothermal therapy. Wang et al.  combinedDNA-templated metallized materials can be used to act as gatekeepers for drug delivery systems. Mesoporous silica is often used to deliver drugs; however, its porous structure is prone to drug leakage. Liu et al.  proposedOverall, these recent examples demonstrate the potential of DNA-guided metallized nanomaterials in various biomedical applications and provide a foundation for further research and development in this field.The use of DNA templates in metallization has several advantages. First, DNA is a highly specific and versatile biomolecule that can be easily synthesized and modified to provide a variety of templates for different metals and applications. Second, DNA provides a high degree of control over the shape and size of the metal nanoparticles, which is critical for many applications, particularly in biomedicine. Thirdly, DNA is biocompatible and biodegradable, making it an attractive material for use in biomedical applications . FinallyThere are also limitations in DNA-guided metallization. One major limitation is the requirement for specialized DNA sequences and metal ions, which can limit the range of possible applications. The DNA-guided metallization method may not be suitable for the synthesis of certain types of nanoparticles that require more complex chemical reactions or processing steps . When DNFinally, While DNA is generally considered non-toxic, the metal nanoparticles used in DNA-guided metallization may be toxic to cells and tissues . MoreoveAlthough there have been significant advances in the field of DNA-guided metallized nanomaterials, there is still much research that needs to be conducted to advance the field. Emerging trends and new directions in the field of DNA-guided metallization of nanomaterials are focused on expanding the range of applications and developing multifunctional nanomaterials .Current methods for synthesizing DNA-guided metallized nanomaterials are often time-consuming and produce small quantities of nanoparticles. There is a need for more efficient and scalable synthesis methods to enable the production of larger quantities of nanomaterials for use in biomedical applications. Advances in computer simulations and modeling have enabled the rational design of DNA-guided metallized nanomaterials with specific properties and functions. By simulating the interactions between DNA molecules and metal ions, researchers can predict the size, shape, and properties of the resulting nanoparticles and optimize their performance. The standardization of DNA-guided metallized nanomaterials is important to ensure reproducibility and comparability of results across different research groups. The development of standardized protocols for synthesis, characterization, and evaluation of DNA-guided metallized nanomaterials is needed to facilitate the translation of these materials into clinical applications.There is a growing interest in developing DNA-guided metallized nanomaterials that have multiple functions, such as targeted drug delivery, imaging, and biosensing. Further research is needed to optimize the design of multifunctional nanomaterials and to evaluate their performance in vitro and in vivo. The biocompatibility of DNA-guided metallized nanomaterials needs to be thoroughly evaluated to ensure that they are safe for use in biomedical applications. More research is needed to determine the long-term effects of exposure to these nanomaterials and to develop strategies to mitigate any potential risks.The field of DNA-guided metallization of nanomaterials has emerged as a promising strategy for the synthesis of nanomaterials with well-defined sizes, shapes, and compositions. This approach involves using DNA molecules as templates to guide the nucleation and growth of metal ions into nanoscale structures. In this review, we focus on the morphology control of gold and silver nanostructures using DNA, which can be modified on the surfaces of different nanomaterials through covalent or non-covalent binding . SignifiThe process of nanomaterials morphology control is influenced by several factors, including the shape of the nanoparticles, the density of DNA grafting, and the secondary structure of DNA. The shape of the nanoparticles strongly affects the interaction between the nanoparticles, which determines the orientation and assembly structure of the nanoparticles. The size, shape, and composition of precious metal nanoparticles  also affect their properties. When DNA oligonucleotides are in the single-stranded state, they are highly flexible and can be curled at will, while the double-stranded DNA structures formed after hybridization are very rigid. Hence, it is crucial to explore and control the multiple influencing factors in the future.Further research is needed to advance the field of DNA-guided metallized nanomaterials and to fully realize their potential for biomedical applications. This includes the development of more efficient and scalable synthesis methods, the exploration of new biomedical applications, and the thorough evaluation of biocompatibility and safety. Additionally, it is still necessary to address how to translate the preparation method of DNA-guided metallization of nanomaterials into large-scale industrial production to meet the demands of biomedical applications.Overall, DNA-guided metallization is a promising approach for the synthesis of metal nanoparticles and nanostructures with precise control over their size, shape, and composition. The use of DNA templates provides a powerful tool for the development of new materials with a wide range of biomedical applications.


Critical illness is often accompanied by a hemodynamic imbalance between macrocirculation and microcirculation, as well as mitochondrial dysfunction. Microcirculatory disorders lead to abnormalities in the supply of oxygen to tissue cells, while mitochondrial dysfunction leads to abnormal energy metabolism and impaired tissue oxygen utilization, making these conditions important pathogenic factors of critical illness. At the same time, there is a close relationship between the microcirculation and mitochondria. We introduce here the concept of a “critical unit”, with two core components: microcirculation, which mainly comprises the microvascular network and endothelial cells, especially the endothelial glycocalyx; and mitochondria, which are mainly involved in energy metabolism but perform other non-negligible functions. This review also introduces several techniques and devices that can be utilized for the real-time synchronous monitoring of the microcirculation and mitochondria, and thus critical unit monitoring. Finally, we put forward the concepts and strategies of critical unit-guided treatment. Regarding patients with acute stroke, neurologists often say, “time is brain” or “time is neuron”. Then, what should intensive care physicians pay attention to when dealing with critically ill patients? With the in-depth study and understanding of critical illness, the answer to this question has gradually become clear and specific. Critical illness is often accompanied by a hemodynamic imbalance between macrocirculation and microcirculation, as well as mitochondrial dysfunction, both of which are directly related to organ dysfunction and poor prognosis . MicrociMicrocirculation encompasses a vascular network that is less than 150 mm in diameter and is composed of arterioles, capillary networks, and venules. It is important for transporting oxygen, neutral molecules, and immune cells; removing carbon dioxide and metabolic waste; and maintaining the fluid balance between tissues , and it One of the most important features of microcirculation dysfunction is the heterogeneity of regional perfusion within a few microns of proximity . Tissue Endothelial cells are the most important functional cells in microcirculation. Endothelial cells exist in all blood vessels, which mediate and regulate many important physiological functions of the microcirculation, including perfusion, permeability, local coagulation, and immune response . It has The endothelial glycocalyx (EGC) of the surface layer of endothelial cells plays important roles in regulating vascular permeability, leukocyte and platelet adhesion, shear force, and inflammation. EGC damage is considered an early and sensitive marker of endothelial injury . After aThese observations are not limited to animal experiments. Indeed, many clinical studies support the key role of endothelial cell injury in sepsis-induced organ failure. Deng et al.  demonstrIn addition, extensive endothelial cell dysfunction may be an important part of the pathogenesis of coronavirus disease 2019) [ [19]. EnMitochondria are double membrane-bound organelles found in almost all eukaryotes. One of their most important functions is to meet the energy needs of cells in tissues, which is accomplished largely through the oxidative phosphorylation process of aerobic respiration . The oxiDecreased mitochondrial respiratory activity is an essential part of organ dysfunction under critical conditions, especially in shock, similar to the potential effects of impaired microcirculatory perfusion and tissue oxygenation . The proNotably, in addition to affecting the development of critical illness by regulating cellular energy metabolism, mitochondria also play key roles in many other aspects of cellular signal transduction, regulating gene expression and cellular calcium levels and activating the cell death pathway . For exaThe mutual influence and interaction between microcirculation and mitochondria are not difficult to understand. Oxygen is transported to tissue cells through microcirculation. Ischemia-induced or hypoxia-induced cell injuries that disturb the microcirculation lead to mitochondrial dysfunction, and even the heterogeneity of tissue cell function stems, to some extent, from the heterogeneity of microcirculatory perfusion . Layec eThe conditions of sepsis are instructive for studying the interaction between microcirculation and mitochondria in critically ill patients. Macrocirculatory failure is indeed common in sepsis patients; however, many such patients die despite resuscitation of the macrocirculation perfusion and improvement in cardiac output. What leads to the life-threatening organ dysfunction in sepsis are microcirculatory abnormalities. With the decrease of oxygen and glucose delivery in microcirculation, mitochondrial respiration is gradually difficult to maintain the production of ATP and even leads to mitochondrial function damage. This idea was confirmed in a clinical study by Fredriksson et al. , who fouMitochondria and the endothelium also share a very close relationship. Mitochondria are important organelles that produce large amounts of ATP through electron transport chains . MitochoThe production of mitochondria-derived DAMPs (mtDAMPs) by damaged mitochondria triggers sterile inflammation . These mClearly, both microcirculation and mitochondria are vital energy-supplying apparatuses whose dysfunction is involved in critical illnesses. Because microcirculation and mitochondria mutually influence and interact in the occurrence and development of critical illness, with both playing a pivotal role, we combined them as the critical unit. Damage to the critical unit includes microcirculatory and endothelial dysfunction, as well as mitochondrial dysfunction and disrupted energy metabolism .With the ultimate goal of macrocirculatory hemodynamic optimization being to improve the critical unit, it is extremely important to monitor the critical unit itself. However, the ability to monitor the critical unit in clinical practice is relatively limited, in part because of the lack of real-time synchronous monitoring technology to assess microcirculatory perfusion and mitochondrial function. Although no high-quality randomized controlled trials have confirmed that monitoring techniques improve the prognosis of critically ill patients, effective monitoring is an important prerequisite for accurate, targeted treatment. For this reason, intensive care physicians actively seek practical monitoring technologies and promote innovations to existing devices. The emergence of several new technologies and devices is expected to solve the initial problem of critical unit monitoring .2) in the skin, which reflects mitochondrial oxygen utilization and function [2 in human skin and has been tested in clinical studies of healthy volunteers and patients in perioperative and intensive care settings [2 in the skin but also to evaluate mucosal oxygenation in the gastrointestinal system through endoscopy [2 was approximately 40–60 mmHg in the physiological state, further enhancing the applicability of this technique.The balance between the supply and demand of oxygen in microcirculation is also affected by mitochondrial function, but the currently available indicators or techniques used to evaluate microcirculation, such as lactate, capillary refill time (CRT), sublingual dark-field imaging, and near-infrared spectroscopy, lack the capacity to directly assess mitochondrial function . The recfunction . Wefers function  confirmefunction . COMET isettings ,50,51. Indoscopy . Recentlndoscopy  establis2 also reflects the oxygen supply and demand of the microcirculation to a certain extent, although there are some limitations at present [2 with other microcirculation indicators, such as lactate and CRT, to reflect the condition of the critical unit. Although there remains a lack of effective means to integrate these parameters systematically, this combination may provide a feasible approach for monitoring the critical unit.Skin mitoPO present . As the Mitochondria are the energy factories of cells. Mitochondrial nicotinamide adenine dinucleotide (NADH) is the most sensitive indicator of the supply-demand balance of oxygen. A previous study confirmed that monitoring the changes in NADH fluorescence could be utilized to reflect the functioning of mitochondrial energy metabolism in cells . KatarzyMayevsky et al.  developeWith more and more experts and clinicians realizing the close connection between microcirculation and mitochondria, the integral nature of the critical unit is gaining attention and leading to the rapid development and improvement of novel technologies and devices. Such developments are encouraging and indicate that the potential of systematic, real-time monitoring of the critical unit will soon be realized. Accordingly, a new era of monitoring that is becoming ever closer to the true nature of tissue perfusion is fast approaching—the era of critical unit monitoring.In critical illness, there is often an obvious separation between macrocirculatory hemodynamics and microcirculatory function that typically results in a hemodynamic imbalance between macrocirculation and the microcirculation . NotablyImproving microcirculatory perfusion is the core and foundation of critical unit-guided treatment. In microcirculation-guided treatments, the improvement of endothelial function and the heterogeneity of microcirculatory perfusion are two aspects that cannot be ignored. Thus, many new understandings of fluid resuscitation and drug intervention have been generated.The resuscitation strategy in critical illness, especially in patients with shock, has been widely discussed. Fluid resuscitation is one of the most commonly used interventions in hemodynamic therapy . Based oVarious commonly used clinical drugs, such as nitroglycerin and dobutamine, have also attracted much attention. In theory, using vasodilators may improve microcirculatory perfusion by increasing the microvascular driving pressure. However, at present, there are often contradictory results in related studies. As early as 2003, Spronk et al.  found th2 consumption in a swine model of fecal peritonitis. Recently, however, Chommeloux et al. [Dobutamine also has a partial vasodilatory effect. However, due to the few studies evaluating the effect of dobutamine on microcirculation in critically ill patients and related studies also having contradictory results, whether dobutamine could improve microcirculatory perfusion needs to be confirmed by further high-quality studies . In a prx et al.  found th2 analog, could improve renal perfusion in endotoxemic rats, but clinical data are lacking [In addition, animal experiments by He et al.  confirme lacking . Depret  lacking  found th lacking  conducteIt is not difficult to see that there is no strong evidence that any drug could significantly improve microcirculatory perfusion, nor have studies demonstrated the benefits of one drug over another.Based on an in-depth understanding of the relationship between critical illness and mitochondria, mitochondria-guided treatment strategies have also attracted much attention. Of course, it is worth noting that although several promising mitochondria-guided treatments exist, none of them have been clinically approved.In a controlled clinical trial, Murray et al.  recentlyThe ANS regulates both microcirculation and mitochondria, and abnormalities in ANS functioning are often present in patients with critical illness . The ANSIt is well established that untimely or inappropriate intervention can cause reinjury, thus promoting the occurrence and development of critical illness, a concept that is reflected in critical unit-guided treatment. For example, fluid resuscitation remains an important strategy of critical unit-guided treatment, with current guidelines recommending crystalloids, mostly balanced crystalloids, as the first choice for fluid therapy in septic patients ,97. HoweImproving microcirculatory perfusion and mitochondrial function is a central issue following macrocirculation resuscitation, and there is growing evidence that microcirculatory and mitochondrial dysfunction are closely related to prognosis in critically ill patients. In this review, we highlighted the significant roles of microcirculation, especially endothelial cells, and mitochondria in critical illness and explained the inseparable relationship between the two. This concept of the critical unit, comprising microcirculation and mitochondria as the core, emphasizes the importance of maintaining the integrity of the critical unit to improve the status of microcirculation and mitochondria in critical illness. We also introduced several technologies and devices that function on the basis of this concept and may soon realize the achievement of critical unit monitoring. Innovations in treatment strategies that emphasize the importance of critical unit-guided monitoring and treatment are expected to further improve the concept of the critical unit. We anticipate that this review will enable more and more clinicians to understand the critical unit concept, further promoting the continuous development of critical unit monitoring and treatment.


Pain is a complex multidimensional experience, defined by the International Association for the Study of Pain (IASP) as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage” . It has Domínguez-Oliva et al. wrote a review on pain neurobiology in rodents and the possibility of detecting pain via the use of facial action units (FAU). Facial expressions have been shown to be a feasible non-invasive method to evaluate pain in acute, chronic, surgical, and neuropathic pain models, and to constitute a useful complementary tool for refining the use of rodents in research. Sylvain et al. tried to correlate intraoperative nociception with some respiratory parameters, hypothesizing that nociception may influence the rate of inspiratory gas flow  and the fraction of inspiratory time (Ti/Ttot) in anesthetized dogs. However, the large differences found among individuals suggest that these respiratory parameters may not be a proper target to correctly discriminate between the presence or absence of intraoperative nociception.In this Special Issue, seven papers have been published which deal with different aspects of pain. Cavaco et al. evaluated the efficacy of this technique in dogs undergoing ovariectomy. In the study, 0.2 mL/kg of bupivacaine 0.25% was infiltrated bilaterally using both preiliac and retrocostal approaches. In agreement with previous literature, the TAP block allowed to reduce the signs of intraoperative nociception and to guarantee a lower analgesic demand in the post-operative period.In the last decade, loco-regional anesthesia has allowed a breakthrough in the management of perioperative pain in veterinary species. To date, numerous techniques have been studied and applied in clinical practice. A great importance has been gained by interfascial blocks, aiming at depositing the local anesthetic in a fascial plane where neural targets are located. The TAP block (Transversus Abdominis Plane block) is one of these, and it is performed to provide analgesia of the abdominal wall, skin, subcutis and parietal peritoneum. Sambugaro et al. performed a retrospective study comparing the intra- and postoperative efficacy of extradural versus systemic analgesia in dogs undergoing cholecystectomy. In agreement with what has been previously published, the requirement for intra and post-operative rescue analgesia was lower and the voluntary feed intake higher in patients receiving neuraxial anesthesia.Despite the numerous loco-regional techniques developed in the last years, neuraxial anesthesia still remains one of the cornerstones when visceral analgesia is needed . Stabile et al. compared the duration of a sciatic-femoral block performed with lidocaine, either associated with a constant rate infusion of dexmedetomidine or alone. The results obtained showed that the sensory block lasted longer in patients receiving dexmedetomidine, while no differences in recovery of patellar and tibial reflexes, proprioceptive function, and ability to walk were found among groups. The authors hypothesized that dexmedetomidine also inhibits delayed rectifier K+ and Na+ currents, reducing neuronal activity, and blocking the hyperpolarized activated cation current.One of the main limitations described in the use of loco-regional blocks is their duration of action. In order to prolong the sensory but not the motor blockade, several drugs have been studied, either injected together with the local anesthetics or administered systemically. Miranda-Cortés et al. conducted a review to summarize the pharmacokinetic and pharmacodynamic characteristics of cannabinoids, and highlighted their possible use in the treatment of acute, chronic and neuropathic pain, thanks to their ability in preventing both peripheral and central sensitization. Despite these promising results, non-steroidal anti-inflammatory drugs (NSAIDs) still remain the cornerstone of many pathological conditions, among which osteoarthritis (OA) in dogs. However, their use is often correlated with gastrointestinal ulceration, and it is contraindicated in the presence of renal insufficiency. Various combinations of nutraceuticals, as glucosamine hydrochloride and chondroitin sulfate, have also been described to improve OA signs, but the evidence of their effectiveness is variable. Kampa et al. have shown that dogs receiving PCSO-524 (compound of marine based fatty acids) and EAB-277 (combination of phospholipids extracted from krill oil together with lipid fractions of the green lipped mussel), but not those receiving glucosamine/chondroitin, resulted in significant improvements in peak vertical force within a few weeks, to a similar degree compared to carprofen.Unfortunately, incorrect analgesic treatment often leads to development of chronic pain, whose treatment is certainly more complex. Cannabinoids are widely studied for the management of chronic pain. In summary, the results of the aforementioned studies and reviews include new and interesting data related to the diagnosis and treatment of acute and chronic pain in veterinary species. The aspects covered and the results achieved show how a constant update in the field is needed and how new therapeutic targets could improve our current clinical practice.All authors listed have made a substantial, direct, and intellectual contribution to the work and approved it for publication.