Breath analysis for non-invasive clinical diagnostics and treatment progression has penetrated the research community owing to the technological developments in novel sensing nanomaterials. The trace level selective detection of volatile organic compounds (VOCs) in breath facilitates the study of physiological disorder and real-time health monitoring. This review focuses on advancements in chemiresistive gas sensor technology for biomarker detection associated with different diseases. Emphasis is placed on selective biomarker detection by semiconducting metal oxide (SMO) nanostructures, 2-dimensional nanomaterials (2DMs) and nanocomposites through various optimization strategies and sensing mechanisms. Their synergistic properties for incorporation in a portable breathalyzer have been elucidated. Furthermore, the socio-economic demands of a breathalyzer in terms of recent establishment of startups globally and challenges of a breathalyzer are critically reviewed. This initiative is aimed at highlighting the challenges and scope for improvement to realize a high performance chemiresistive gas sensor for non-invasive disease diagnosis. Breath analysis for non-invasive clinical diagnostics and treatment progression has penetrated the research community owing to the technological developments in novel sensing nanomaterials. Among other non-invasive sources  for disease diagnosis, exhaled breath analysis seems feasible as the ancient Greek physicians had predicted that the aroma of breath provides a certain clue about diagnosis.4 Usually, this mixture of vapors along with approximately 3500 chemical species existing in human exhaled breath have been identified by various analytical techniques including gas chromatography-mass spectrometry (GC-MS), flame ionization spectrometry (FIS) and photo ionization detection (PID).5–11 However, these methods are inadequate for routine breath biomarker monitoring as they rely on sophisticated laboratory equipment, trained technicians, and time consuming and complex sample preparation procedures leading to the lack of real time quantitative data. Thereby limiting the portability and so eliminates the possibility of point of care real time diagnosis. Hence the global scientific community had focused their efforts on developing a portable instrumentation for the real-time quantification of biomarkers for the disease diagnosis through exhaled breath.The advent of modern breath analysis came into existence when Pauling and his team in 1971 discovered more than 200 VOCs in human breath due to the biochemical pathways resulting through the physiological process.12 These VOCs may originate from cellular levels due to their fundamental body processes13 and metabolisms in blood14 that plays a vital role in altering the concentration of VOCs. Other sources include inhaled atmospheric air, airway surfaces and tissues throughout the body. As the blood collects all the compounds during bodily metabolism and interacts with lung, they appear in breath.15 54 VOCs at elevated concentration indicates several health risks related to gastrointestinal, respiratory systems and metabolic disorders such as halitosis, renal failure, diabetes, chronic liver and kidney diseases few of them listed in 31,32 An increased concentration of ammonia is closely associated with renal disease, acetone with diabetes mellitus (DM) and nitric oxide with chronic obstructive pulmonary disease (COPD).33 Since all this VOC appear in the breath because of certain body metabolisms, these endogenous gases resolve practical information on the possible disease and hence it is the perfect indication of any disease. Accurate quantification of these biomarkers provides the feasibility of non-invasive disease detection through exhaled breath.The composition of VOCs range between parts per million (ppm) to parts per billion (ppb) that varies quantitatively and qualitatively for every individual similar to unique fingerprints.34,35 Whereas, other non-invasive sources such as saliva, sweat, urine and feces need human intervention limiting the diagnostic capabilities at the situation of emergencies. While the biomarkers from each source originate from the fundamental body metabolism, exhaled breath is reliable as it eliminates the social awkwardness or an embarrassment to the patients during sample collection. Apart from social consideration, other non-invasive sources possess certain issues in terms of stability of the sample.36 Moreover with the capability of repeated and self sampling, breath analysis are considered to be truly non-invasive and can be performed easily without any embarrassment or discomfort.37 Also, it does not present burden to the subject being tested and the ease of sampling offers the advantage of delivering result on spot instead of the traditional laboratory sample preparation and analysis.38 Hence, the significance of breath analysis lies on eliminating the pre-analytical and post-analytical procedure along with the mailing of test reports to the concerned subject. Furthermore, as the biomarkers in breath appear due to the fundamental body metabolism at cellular level, diseases may be identified at early stage which is the need of the decade for different cancers that could be cured, if identified at preliminary stage.39,40 Breath analysis may permit bedside and personalized home care monitoring, thus could be inexpensive and allows frequent testing for proper control of the disease progression and the effect of medications.41 Thus offers an inexpensive replacement for the traditional laboratory analytical tests.The availability of unlimited sample quantity even during unconsciousness may become vital in emergency situations, for continuous monitoring of disease progression and the effect of medication in short time period.42 The exhaled biomarkers not only emanate from fundamental body processes but also from the exogenous production by different sources. Breath sampling procedure is not yet standardized leading to the unawareness of sample collection from either nasal or oral cavity. Even though, after the collection of idealized sample, extrinsic factors such as temperature and humidity may influence the outcome of the diagnosis. Furthermore, the level of data interpretation needs standardization to develop a cloud of breathprint database from laboratories across the globe representing a reference standard for clinical practices.43However, there are numerous challenges to be addressed to bring a portable breathalyzer to the commercial market. The high complexity of breath samples leads to misinterpretation of results.Helicobacter pylori and hydrogen breathalyzer for small intestine bacterial overgrowth are currently in research practices.44–48 Nevertheless, there is no single breath test act as stand-alone diagnostic test and only act as a pre-screening tool.Although, limited number of breathalyzer were recognized by international guidelines and used in patients. Among them ethanol breath test, nitric oxide breath test to diagnose asthma, urea breath test for the diagnosis of 49Incorporation of nanomaterials in gas sensors has attracted research interests owing to their unique physic-chemical properties. Gas sensor technologies are classified based on their differences in working principle and device structures. Broadly it is categorized into technologies that rely on the change in electrical and other properties including optical, calorimetric and acoustic properties. The reliability of technologies based on variations in electrical properties such as field effect transistors (FET), surface work function transistors (SWF) and chemiresistors are suitable for exact quantification of breath biomarkers in the range of parts per billion to parts per million. Among them, chemiresistors are widely explored due to their ease in fabrication and miniaturization, simplicity in operation and demands low power.Hence, the international breath research community is focusing on nanostructured chemi-resistive gas sensors for sensitive and selective detection of breath biomarkers. Herein, we will review SMO and 2DM nanocomposites in chemi-resistive gas sensing device configuration for the development of breathalyzers. Their corresponding sensing mechanisms and performance to various biomarkers was highlighted along with the social demands, challenges and regulatory aspects in the hope of directing future research towards non-invasive disease diagnosis through portable breathalyzers.2.50 This gas sensor device configuration was explored in sensing various biomarkers including acetone, nitrous oxide, ammonia etc. and put to use for clinical trials.51–5354 The change in electrical properties of the sensors depends on the concentration of target biomarker. Various SMOs of different nanostructures have received a steady growth for their low cost fabrication process, reliable measuring electronics that demand very low power consumption.55,56 Indeed, the non-invasive sensing devices for clinical applications must possess satisfactory portability and affordable cost in addition to their demonstrated sensor performances. Hence it has spurred the interest of the international breath research community to develop an economical hand-held chemi-sensor that is capable of monitoring biomarkers in exhaled breath. The nanomaterials based chemi-resistive sensors' parameters such as sensitivity, selectivity, repeatability, response and recovery time can be optimized by altering the characteristics of the sensing material and their definition were given as follows:Chemiresistors consists of a sensing film supported on an inert substrate where interdigitated or two metallic electrodes on their either side are deposited and a heater printed at the backside.Relative response: ratio of resistance of the sensor in the ambient atmosphere to the resistance to the exposure of acetone of varying concentration.57Sensitivity: change in relative response with respect to the change in gas concentration.57Selectivity: measure of the relative response of other interfering biomarkers with respect to acetone.Repeatability: measure of variation in relative response for the same gas concentration under the same experimental conditions.Stability: measure of depreciation in sensor performance over a period of 1 month.Response and recovery time: time taken by the sensor to reach 90% resistance change of the final equilibrium value.5859 n-type SMOs resistance decreases for reducing gas and increase for oxidizing gas from the baseline resistance. Meanwhile, a vice versa phenomenon occurs for p-type SMOs, where resistance decrease for oxidizing gases and increase for reducing gases.59 Commonly, chemiresistors exhibit a change in its electrical resistance in the presence of specific target analyte it is engineered to, based on the following mechanisms.The basic sensing mechanism of these SMOs depends on the change in carrier concentration of the sensing material during gas interaction. This interaction may result in an increase or decrease in electrical resistance or conductivity.2.1−, O2− and O2− by gaining electrons from the conduction band of the sensing film leading to oxidation, causing changes in its electrical resistance termed as baseline  and acceptor (CO), where green region represents charge accumulation and red region shows charge depletion regions. The free electrons in the donor vapor (NH3) donates electron onto the MoS2 monolayer leading to an increase in charge carrier thus decrease in resistance. On the contrary, charge transfer from the conduction band of the n-type MoS2 to the acceptor vapor (CO) causes the charge density to decrease and increase in electrical resistance of n-type MoS2.65 Unlike, the oxygen ion mechanism, physisorption dominates the adsorption of target analyte in two dimensional nanomaterials.66 Physisorption being a weak force and un-directional, strong and selective binding of analyte is hindered and lead to sluggish recovery, respectively.The gas sensing mechanism of 2D layered nanomaterial such as graphene, MoS2.3E) leading to accumulation and depletion region at the interface. The vicinity of target analyte near the heterojunction leads to the equalization of Fermi level due to band bending. 2 before and after vapor infusion. Hybridization of SnO2 and RGO with a work function of 4.5 eV and 5.32 eV respectively causes a difference in Fermi energy levels (2) to higher work function (RGO) tending to equalize the Fermi energy levels .72–78Important milestones had been achieved in the way of non-invasive diseases diagnosis through portable breath analyzers by the discussed sensing mechanisms. Peng With the advancements of data acquisition instruments, the response to breath input from gas sensors can be digitized and transmitted to a computer for further signal preprocessing and feature extraction. Furthermore recent development of machine learning techniques provides better classification accuracy between healthy and diseased subjects. Hence, there is scope for improvement in each block represented in 3.79 The motivation in the following section is to discuss these optimization strategies of promising nanomaterials as potential gas sensors incorporated in a breathalyzer for the detection of various disease biomarkers in exhaled breath.VOCs exhaled from human breath provide information about the fundamental cellular mechanism which when detected quantitatively and qualitatively favors early detection of disease limiting further complications. This way of disease diagnosis had its footprint from the ancient times associating fruity like breath odor with diabetes mellitus, fishy with liver complications and urine like breath odor with renal failure. After the advent of modern equipment, approximately 30 VOCs with elevated concentrations in breath have been associated with halitosis, diabetes mellitus, kidney malfunction, asthma and different cancers. Over the past decades considerable efforts have been focused on nanostructured materials for the detection of various VOCs with better sensing performances. Materials at nanoscale possess peculiar property compared to their bulk counterpart. Exploiting these properties by controlling their size and shape in the form of nanorods, nanowires, nanosphere improved the gas sensing performance. Moreover, their working conditions including the operating temperature were found to significantly improve the detection capabilities selective to breath biomarkers.3.180 Moreover, as they are simple in operation and demands low power, SMOs were largely applied in gas and solvent leak detectors in semiconductor industries, environmental monitoring, food processing, agricultural industry and medical diagnosis.81 The first commercial SMO sensor at the beginning of 1970s used amorphous SnO2. Sensors made of SnO2 nanoparticles possess numerous advantages that include higher sensitivity, ability to operate at lower working temperature and thermally stable structure. This gas sensor was fabricated and patented by Taguchi which was later commercialized by Figaro Inc. The sensor was used for gas leak alarms in factories and residences to prevent fire accidents.82 The demand for high performance gas sensors for various applications with low power consumption had diverted the research efforts towards SMOs as gas sensors. Moreover, these SMOs can be altered to deliver high sensing performance by varying the concentration of dopant incorporated, controllable morphology, methodology of sensing material preparation and tailoring physical/chemical properties.83–86 However, sensitivity and selectivity being a primary sensing performance, various above mentioned optimization trials have been best possibly utilized.Several different categories of material exhibit chemiresistive property. Among them, SMOs dominate as a superior gas sensing materials due to their capability to sense a wide variety of gases (oxidizing and reducing gases) and availability of numerous material choices.87,88 Numerous SMO nanostructures such as SnO2, WO3, In2O3, NiO, ZnO, CuO, Co3O4 has been utilized as standalone materials for the detection of various biomarkers.89 Jiang et al., optimized 3 variations of the preparation procedure to synthesize SnO2 hollow nanotube observed from the TEM image shown in 2 were explored towards asthma biomarker (NOx). The sensors were capable of sensing NOx at room temperature in the concentration ranging between 9.7 ppb to 97 ppm well below breath NOx concentration with a faster response time of 20 s for 9.7 ppb and 6 s for 9.7 ppm .90 The dependence of sensing performance on the morphology was further established by Xu et al., where they studied the acetone, isopropanol and ethanol sensing properties of SnO2 nanorods at room temperature. They found the difference in sensing pattern with respect to the length of the synthesized nanorods shown in 91 However, SnO2 nanosheets were found to be selective to ethane, propane and 1-butene compared to all other alkenes  favors more interaction sites for target biomarkers. Thus, leading to better sensing performances by optimizing their morphology and tailoring its physico-chemical properties. The permeable and porous structures of metal oxide are explored beneficial for the efficient gas diffusion and entire electron depletion accordingly. The high sensing performances of metal oxides are defined by low detection limits and short recovery times. 9.7 ppm . These s alkenes .92 Simil94–96 SENSOR Lab at Bresica  has addressed the issue of selectivity tuning by modulating the operating temperature of ZnO nanoparticles. They found the sensor was selective to NO2 at 300 °C, H2 at 400 °C and CH4 at 500 °C and attributed to the thermodynamics of gas adsorption on the sensor surface including decomposition of gases on the surface.97 This strategy was also exhibited on the commercial sensors from Figaro Inc.98,99Concurrently, the peculiar strategy of modulating the operating temperature for selectivity tuning towards a specific VOCs were studied. A SMO sensor operating at different temperature may behave like a distinct sensor with different performance to specific VOC.100,101,103 Yet, ZnO nanosheets showed high sensitivity to formaldehyde and acetaldehyde with a lower detection limit of 50 ppb working at 220 °C.102 Likewise, In2O3 nanowires detected acetone at 400 °C, whereas thick wires detected low concentration (500 ppb) of NO2 at temperature less than 300 °C.110 Yet, In2O3 nanobricks detected 500 ppb of NO2 at a significantly lower operating temperature of 50 °C.112 These discussions illustrated the capability of tuning the selectivity by various optimization strategies. However, the response to exhaled concentration range tend to be poor due to lack in enhanced surface area for analyte interaction. In addition, meager conductivity of SMOs hinders the reproduction of the electrical change before and after analyte interaction to the outer world.Similarly, many other metal oxide nanostructure were utilized for sensing different biomarkers as listed in 3.2115–118 The defects induced by surface functionalization may influence the gas adsorption and desorption by the increase in number of reactive sites causing high sensitivity. Numerous review articles on graphene based gas sensors with a special focuses on its application in different fields, transduction principles, functionalization with metals and polymers were presented.119–126On the other hand, 2DMs has intriguing properties such as high surface area, high conductivity and high carrier mobility at room temperature with low noise that facilitates better response for target analytes. Exploiting these merits, graphene and its derivatives were the most explored carbon materials for gas sensor application in the past decade. The transparent and flexible characteristics of graphene were utilized for different configuration gas sensing devices.2, where M denotes the transition metals like Mo, W, Hf, Ti, Zr, V, Nb, Ta, Re, etc. and X denotes the chalcogens .127 However, only certain transition metal disulfides (TMDs) such as MoS2, WS2 and SnS2 have been utilized as a sensing film for the detection of various disease biomarkers in exhaled breath as listed in 136 Among other chalcogens, TMDs are widely explored due to its abundant presence in nature, less toxic and stable in atmosphere compared to metal selenides and metal tellurides. Their gas sensing performances were illustrated in 2 sensing performance of atomic layered MoS2 nanosheet at low concentration of 120 ppb have not shown a complete recovery to the baseline and same occurrence was observed for subsequent concentrations  as shown in 129 Similar performance was witnessed by SnS2 nanosheets with a high response (∼170 s) and recovery time (∼140 s) to 10 ppm NO2 . Moreover, its enhanced optical, electrical and electrochemical properties were suitable in various gas sensing device configurations. However, its capability of selectively detecting gas concentration as low as in parts per billion among diverse environment was hindered for real time breath analysis application. Hence, numerous efforts have been made to composite it with 2DMs for the detection of variety of breath biomarkers under varying structural morphology of the nanocomposite and working conditions of the sensor.140As discussed in the previous section, SnO2 nanocomposite showed selective sensing to NO2 at 150 °C achieving a lower detection limit of 1 ppm with a response of 24.7  showed highest response of 18.7 to 5 ppm NO2. Moreover the response time, complete recovery, long term stability and selectivity of the composite was significantly improved. The authors speculated the enlargement of surface area by the incorporation of SnO2 on MoS2 nanosheets and the p–n heterojunction changed the electronic properties locally.145 The humidity sensing property of WS2/SnO2 revealed the importance of 2DM/SMO composites, where a significant improvement in sensing performances (862.8 times) were observed compared to standalone SMO or 2DM.146 Moreover, with much electronegative in nature, SnS2 was made composite with SnO2 to improve the selectivity towards ammonia and NO2.147 The study by Li et al. showed significant selectivity to ammonia with a response of 2.48 for 100 ppm at room temperature among other breath biomarkers  to improve the selectivity of WS2 2DM towards ammonia at room temperature. The composite with a molar ratio of 0.44 TiO2 QD/WS2 exhibited fast response and high selectivity to 500 ppm ammonia.163 Furthermore, tungsten was also used in combination with WS2 to detect ammonia, H2 and NO2. They optimized the working temperature at 150 °C and achieved a lower detection limit of 1 ppm to ammonia.168 These discussions provide a notion that different combination of SMO/2DMs with varying optimization strategies such as morphology, nanosheet's layer thickness and operating temperature would tune the sensing system towards specific biomarker with enhanced sensitivity. Similarly many other binary and ternary nanocomposites with 2DMs can be explored for elucidating the peculiar properties and explore them for the detection of various breath biomarkers. Incorporation of these sensors in handheld portable breath analyzer may possibly favor the underprivileged community in the poor healthcare resource setting. The biomarker concentration displayed on the system or rather transmitted wirelessly could pave way for universal use, for its effortless sample collection procedures. In the future, SMO/2DM based nanosensors could be miniaturized on a single lab-on-chip and could be used as a pocket device or an add-on to the mobile phones.Similarly, many other combinations of SMO/2DM were exploited for the detection of various exhaled biomarkers listed in  ethanol . These ranalysis . Furthertability .156 Mean4.169–171 Meanwhile with low power demand resulting in the reduction of device dimension on a single lab-on-chip, nanosensors are the choice of technology for incorporation in portable breathalyzers for disease diagnosis. Also, an array of cross-reactive nanosensors incorporated in the breathalyzer would mimic the mammalian olfactory and detect various gases emanating from breath probing the metabolic processes at the fundamental cellular levels favoring early detection of diseases. Accurate detection of these trace level gases would pave way for non-invasive, user friendly, personalized home care diagnostic equipment which lead to better control of diseases and monitor the effect of medication. Moreover, the instant display of results may avoid pre-analytical and post-analytical processes such as sample collection, preparation and test report dispatch. Also it enables mass screening during pandemic leading to reduced transmission rate of the disease.172 These processes eliminate consumables thus considerably reduce the global health expenditure. The merits of nanosensors create a demand for breathalyzers in global market demanding a socio-economic balance. Hence researchers across the globe are having high hopes and making strides on startups for disease diagnosis through breath analysis by various technologies. For instance, SpiroNose® developed by Breathomix utilizes 7 different SMO sensors that capture real-time breath profiles. The between-days repeatability of asthmatic and healthy subjects was precise and was even better when compared to the routine standard test (spirometry).173 Moreover, it satisfactorily discriminated healthy subjects and patients with COPD, asthma and lung cancer.174 Similarly, Aeonose® developed by The Enose Company, Netherlands have been found suitable for the prescreening of prostate, lung and collateral cancer proving it suitability for personalized home care.175–179 Also, AmBeR® was designed and developed by BreathDX consists of an array of sensors fabricated by inkjet printing functional nanomaterials capable of ammonia measurement in ppb concentration range.180,181 Each of the startup listed in Nanosensors based on chemi-resistive principle for breath analysis has seen progress in recent years in terms of sensitive and selective detection of specific breath biomarkers amidst various interference including exogenous gases and humidity in breath.5.etc.Even though with the high socio-economic demand, inception of startups, research and development across the globe with the state-of-the-art technologies, there are numerous challenges needs to be addressed. For the commercial deployment of breathalyzer for non-invasive disease diagnosis in clinical setup and for personalized homecare utilization, much care must be provided in designing a nanomaterial based chemi-resistive sensor. Sensors should possess accurate detection capabilities as the breath sample is highly complex and informative due to the changes in breath volatolomics that occurs on the fundamental cellular processes. Moreover, the biomarker is in parts per million which demands the sensor to possess high sensitivity and selective to detect the trace level amount among other interfering biomarkers along with the strong influence of relative humidity in exhaled breath. Thus the sensor incorporated in breathalyzer should possess superior gas sensing performances such as sensitivity and selectivity towards specific disease biomarkers, humidity-resistive property, faster response and recovery time 182 Moreover, as only the alveolar breath contains information about the cellular processes, the sensor chamber should be designed in such a way to accommodate the whole of alveolar breath and avoid sharp edges to eliminate recirculation zones. There is still no standardization on the collection of sample from either oral or nasal cavity. Hence, influence of exogenous production and presence of the biomarker as a pollutant in the atmosphere may hinder the exact quantification of endogenous production of biomarker.However, desiccants and pre-concentrators are crucially important, if the sensors do not satisfy the humidity-resistive property and selectivity, respectively.183,184 The mentioned issues in standardization lead to huge variations in results between different studies and are hard to replicate.185 Further, the sensors work in harsh environment (humidity and temperature) leading to eventual degradation in sensor performance. Hence, as there are opportunities and demand for a breathalyzer, corresponding challenges and improvements are necessary.More importantly, the biomarkers associated with specific diseases by the analytical techniques such as GC-MS is questionable as the pathophysiology of a single disease may diffuse numerous VOCs. Therefore, a global library of VOCs with corresponding diseases needs establishment to develop a cloud of breath database which may act as a reference standard. Further, the measuring electronics requires proper optimization to avoid instrumentation errors after proper breath sample collection and sensor design. The lack of standardization of library of VOCs, breath sample collection procedure, chamber design, sensor positioning and measuring electronics causes an insignificant criterion for reproducibility of the diagnostic outcomes.186,187The use of nanomaterials for medical devices and implant materials has been successfully explored. Particularly in USA and Taiwan, nanomaterial incorporated products were widely seen that exhibits better performance compared to their bulk counterpart. However, safety and security being a primary concern, the considerable change in properties of the nanomaterial used in a medical device requires detailed study on their adverse effects on human body including toxicity. The dimensions of the nanoparticle decide its hazardous nature. Smaller particles may enter the human body through respiratory tract during inhalation, skin or oral ingestion due to the poor immune system of human body towards nanoparticle. For instance, nanoparticles less than 30 nm in size may damage the central nervous system, the defective mechanism of lung cells is not capable of handling nanoparticle with the size lesser than 70 nm and nanoparticle size less than 50 nm may enter the nucleus of human cells.188 Hence, regulatory requirements are good manufacturing procedures, labeling and warning, approval procedures and post market follow up.Hence, nanomaterial based medical devices have raised the concern for health authorities to develop certain regulatory aspects for safety assessment that does not develop any temporary or permanent discomfort to the users. The risks associated with the absorption or distribution of nanomaterial in human body must be established. Along with these safety assessments, no compromise in the quality must be ensured by the manufacturer by focusing on repeated validation on the manufactured nano medical device.6.Non-invasive disease diagnosis through breath analysis is one of the foreseen healthcare services. Their tendency to replicate the fundamental cellular process makes it more attractive for early diagnosis leading to the increases in survival by adopting effective treatment methodologies. To this direction, chemi-resistive VOC sensors with a well understood sensing mechanisms for simple, fast and accurate detection of breath biomarkers were presented in this current review. These chemi-resistive gas sensors possess miniaturization capabilities with no trade-off on the performance, which pose as a primary requirement for point-of-care medical devices. As mentioned in this review, numerous SMO nanostructures, 2D nanosheets and their composites have been utilized for the detection of various disease biomarkers. Their demonstrated performances were favorable for diagnosis of disease from exhaled breath with an easy sampling procedure and instant display of the outcome. Besides, their mass-screening competency during COVID-19 pandemic has found a new market for portable breathalyzers.Whilst, the strength of the technology remains weak and inconclusive. This reflects the lack of standardization of breath sampling, sensor technologies and sample sizes across the spectrum of studies. Under-powering alongside difficulties including inference by numerous other external sources of VOCs and complexity of breath have both contributed to the setback of the technology for regular clinical trial. It seems that the implementation of gas sensors for breath analysis application has not reached the maturity for the widespread acceptance and usage. Nonetheless, SMO/2DM nanocomposites are amongst the few materials that enhance geometrical, chemical and electronic properties for gas sensing applications to tune its selective binding with a single biomarker at lower concentration. Further, placement of cross reactive sensors and coupling of breath sample to sensors through pre-concentrator devices on a single lab-on-chip may realize the dream of non-invasive disease diagnosis through breath analysis.However, with the rapid advancements in the field of nanotechnology, regulatory aspect of these medical devices essentially takes care of all the relevant issues. The quality and safety of these devices must be enforced by the regulatory authorities in order to protect the manufacturing staffs and the end-users. Meanwhile, frequent updates are necessary with respect to the emerging applicability of nanomaterials and devices.The authors declare no conflict of interest, financial or otherwise.


The highly conserved Nonsense-mediated mRNA decay (NMD) pathway is a translation dependent mRNA degradation pathway. Although NMD is best known for its role in degrading mRNAs with premature termination codons (PTCs) generated during transcription, splicing, or damage to the mRNAs, NMD is now also recognized as a pathway with additional important functions. Notably, NMD precisely regulates protein coding natural mRNAs, hence controlling gene expression within several physiologically significant pathways. Such pathways affected by NMD include nutritional bio-metal homeostasis and metal ion detoxification, as well as crosstalk between these pathways. Here, we focus on the relationships between NMD and various metal homeostasis and detoxification pathways. We review the described role that the NMD pathway plays in magnesium, zinc, iron, and copper homeostasis, as well as cadmium detoxification. Saccharomyces cerevisiae, Drosophila melanogaster, Arabidopsis, Caenorhabditis elegans, and humans (Cheng and Maquat The highly conserved Nonsense-mediated mRNA degradation (NMD) pathway is a translation dependent mRNA degradation pathway. Although it is best known as a surveillance pathway that degrades mRNAs with premature termination codons (PTCs) due to errors during transcription, splicing, or damage to the mRNA, NMD is now also recognized to possess additional functions. Previous studies have elucidated NMD as a regulatory pathway for gene expression through controlling the expression of fully functional protein-coding natural mRNAs. The targeting of natural mRNAs by NMD has been observed in multiple organisms including S. cerevisiae  factors (Pulak and Anderson The proteins that are required for NMD to function are three highly conserved up-frameshift (UPF) factors: Upf1, Upf2 and Upf3 proteins.  with a median size of ~ 121 nts  in the 5′-UTR that inactivate NMD  may generate mRNAs with distinct 5′-UTRs that could include uORFs. uORFs are potent regulatory elements located in 5′-UTRs of transcripts that can inhibit the translation of the downstream main ORF, but some uORFs enhance expression. If the uORF of an mRNA is translated, the stop codon can be recognized as a PTC, resulting in degradation of the mRNA by NMD. However, several naturally occurring uORF-containing transcripts are resistant to NMD. For example, yeast In addition to containing NMD-targeting features that activate their degradation, regulation of natural mRNAs occurs in specific cellular contexts and environmental conditions. Multiple conditions affect NMD-mediated degradation of mRNAs. Here we focus on NMD-mediated control of genes involved in bio-metal homeostasis and metal ion detoxification. We review the described role NMD plays in magnesium, zinc, iron, and copper homeostasis and cadmium detoxication.2+) is an essential metal that serves as a cofactor for many cellular enzymes and is required for normal cellular growth. Yeast cells regulate cytoplasmic magnesium levels and store magnesium in the vacuole and mitochondria. In yeast, magnesium homeostasis is regulated by the controlled activity of magnesium uptake transporters in the plasma membrane and transporters responsible for intracellular magnesium storage. ALR1 and ALR2 were the first magnesium transporters identified on the plasma membrane  for oxidative stress protection Karlin . As copp2+) is an essential element for all eukaryotes and functions as a cofactor for many enzymes involved in cellular functions including DNA replication and repair, cellular respiration, photosynthesis, oxygen transport, lipid metabolism and translation  which control chromatin modification marks at these genes  produced from cryptic upstream transcription. Transcription of these CD-CUTs mediates repression at promoters by preventing premature binding of RNA polymerase II in conditions of metal repletion. CD-CUTs are targeted by cytoplasmic turnover pathways that include the exoribonuclease Xrn1p and the core NMD factor Upf1p. Importantly, CD-CUT transcription or accumulation also interferes with binding of the transcriptional activators AFT1 and ZAP1, which modulate transcriptional accumulation of metal homeostasis mRNAs such as FIT3 and ZRT1  close to protein coding genes has been shown to function as a mode of transcriptional control  promoter elements of target genes and activates the high-affinity copper uptake systems encoded by CTR1 and CTR3 . The PCA1 allele found in most common lab yeast strains possess a missense mutation in the ATP-binding residue conserved in P1B -type ATPases [hereafter referred as PCA1 970R; , a vacuolar transporter, sequesters cadmium and other heavy metals as well as glutathione into the vacuole to counter cell stress  is a non-essential and toxic environmental contaminant , which is involved in ribosome biogenesis and recycling, is required for maintaining regulatory pathways including NMD  in the 3′-UTR of mRNAs, such as Cth1p and Cth2p resulting in mis-regulation of iron homeostasis , are involved in ribosome biogenesis and recycling and are required for maintaining regulatory pathways including NMD. Further studies investigating the extent to which NMD regulates mRNAs involved in the adaptation of yeast cells to changes in levels of metal ions and the role these metals ions play in translation and its reliability will elucidate metal ion homeostasis and NMD. Additionally, there are likely other metal ion homeostatic mechanisms impacted by NMD that need to be explored.The importance of NMD in metal ion homeostasis and toxic metal detoxification is highlighted here. The NMD pathway regulates select mRNAs involved in magnesium, zinc, iron, and copper homeostasis, as well as cadmium detoxication. NMD is a translation dependent process that ensues once translation is terminated aberrantly, and metal ions can affect the reliability of translation. Bio-metal homeostasis is related to NMD mediated regulation of gene expression in the case of magnesium homeostasis (Johansson and Jacobson CRS5 and CUP1, CRS5 is regulated by NMD while CUP1 is not. Moreover, mRNAs encoded by different alleles are differentially regulated by NMD based on environmental conditions. For example, PCA1 970G and PCA1 970R mRNAs are differentially regulated by NMD in the presence of cadmium. It would be significant to understand how prevalent this environmentally specific differential regulation of mRNAs by NMD is.In terms of specific mRNA targets regulated by NMD and involved in metal ion homeostasis, one of the questions that have arisen leads inquiries as to why there is variability in NMD-mediated regulation of the mRNAs that encode proteins with similar functions. For example, of the two copper binding metallothionein in yeast


Cerebrovascular aneurysms of the supraclinoid region are a technical challenge and can be particularly difficult to treat when greater than 25 mm in diameter. Such giant aneurysms can be approached with various skull-based and endovascular surgical techniques, and the advent of the Pipeline embolization stent presents a new treatment modality. Previously used for the treatment of small aneurysms, the Pipeline embolization device (PED) is a flow diverter device that has more recently been investigated in its use for the treatment of giant aneurysms with few studies to date published about its procedural outcomes. Here, we highlight the case of three patients (two elderly and one middle-aged) presenting symptomatically with giant supraclinoid aneurysms of the cavernous internal carotid artery (ICA) and posterior communicating artery treated with the Pipeline stent and monitored on follow-up visits. We further review the most current case reports and the two clinical trials to date investigating the utility of the Pipeline stent in the treatment of large and giant cerebral aneurysms, highlighting the emerging evidence of its efficacy and long-term patient outcomes. We report successful resolution of symptoms and radiographic evidence of aneurysm size reduction on all patient follow-ups and suggest the Pipeline embolization device as a novel technique that can be utilized for the treatment of giant cerebrovascular aneurysms with emerging evidence of immediate and long-term success. Cerebrovascular aneurysms pose a challenge in treatment and symptom management to date. Traditionally, aneurysm clipping by way of craniotomy demonstrates a long-standing history of excellent treatment and prevention of recurrence approach. However, this is not without significant risk posed to patients, particularly when involving skull-based aneurysms in anatomically challenging locations such as the cavernous sinus. At the margin of the supraclinoid segment where internal carotid arteries (ICA) enter the subarachnoid space, aneurysms in this area can be technically challenging to access. With the advent of endovascular neurosurgery, treatment options such as endovascular coiling, onyx embolization, and ICA parent artery occlusion now exist as alternative approaches for treatment. Flow diverter devices including the Pipeline embolization device (PED)  and SILK  are new innovations providing the option for implanting a thrombogenic stent to establish flow diversion away from the aneurysm while allowing for the formation of a neointimal layer of the inner blood vessel lumen. The PED is a flexible stent composed of 25% platinum-tungsten and 75% cobalt-chromium-nickel alloy with a stent porosity of 70%, providing the flexibility of vessel conformity and appropriate metal coverage of the vessel . In the PED use for the treatment of giant and large aneurysms was FDA-approved in 2011 and has since been used for the treatment of aneurysms of various sizes, types, and locations, including off-label uses for dissecting aneurysms, carotid-cavernous fistulas, pseudoaneurysms, and ruptured aneurysms . Its useCase 1Our first patient is a 69-year-old patient with a medical history of hyperlipidemia and hypertension and a 50-pack year tobacco smoking history presenting with left-sided facial hemiparesis and left-sided upper and lower extremity hemiparesis. CT angiography demonstrated an 18 mm multi-lobular, irregular, broad-based right posterior communicating artery aneurysm extending to the right carotid terminus. The patient was started on aspirin 81 mg and atorvastatin 80 mg without the need for acute intervention. Stroke etiology was determined to be secondary to small vessel disease, and the patient was discharged with an NIHSS of 2 and mRS of 3. The patient was instructed to return for endovascular therapy at a three-month follow-up. The patient underwent Pipeline stent placement with coiling of the 25 × 14 × 7 mm supraclinoid aneurysm without any intra-procedural complications , 35 patients were enrolled, of which 30 underwent PED placement and five with SILK. Only one patient had a giant aneurysm, and six had large aneurysms. Similar to our patients, the majority were supraclinoid ICA aneurysms, and complete occlusion was attained in 35 of the 38 total aneurysms, with the remaining three achieving partial occlusion within six months [4, 35 patPEDs have also been demonstrated to be used effectively in patients presenting with a giant fusiform aneurysm in the cavernous ICA, with aneurysmal shrinkage at two-year follow-up, indicating its utility in such aneurysms . In caseTwo clinical trials and one large multicenter retrospective analysis exist to date examining the use of PEDs in the treatment of large and giant cerebral aneurysms: the Pipeline for Uncoilable or Failed Aneurysms (PUFS) trial and the Surpass IntraCranial Aneurysm Embolization System Pivotal Trial (SCENT) trial, highlighted in Table The PUFS trial examined 108 patients in total, with 57% of the patients presenting with aneurysms of the cavernous segment, 25% in supraclinoid, and 27% in the paraophthalmic segment. Among the 39 patients with deficits in presentation, 25 (64%) demonstrated improvement after stenting, with 21 of these patients having complete aneurysm occlusion at six months postoperatively. In total, 80 patients (82%) with aneurysms treated in the PUFS trial and evaluated at six months showed occlusion of the aneurysm, 8% with a neck remnant, 8% with a residual aneurysm, and 2% with indeterminate changes [Clearly, there is emerging evidence on the utility of PEDs for the treatment of giant cerebral aneurysms. Here, we find success in symptom resolution of our patients within a short period of time indicating reduction of aneurysm mass effect on cranial nerve neuropathy and radiographic evidence in two of our patients at follow-ups demonstrating patency of the stents with aneurysm interval size reduction. While the efficacy of PED placement and symptom resolution reported in current literature and in our patients reported here are promising, more data will be needed on the recurrence rates of giant aneurysms treated with PEDs.


The transient receptor potential vanilloid 1 (TRPV1), a ligand-gated nonselective cation channel, is well known for mediating heat and pain sensation in the periphery. Increasing evidence suggests that TRPV1 is also expressed at various central synapses, where it plays a role in different types of activity-dependent synaptic changes. Although its precise localizations remain a matter of debate, TRPV1 has been shown to modulate both neurotransmitter release at presynaptic terminals and synaptic efficacy in postsynaptic compartments. In addition to being required in these forms of synaptic plasticity, TRPV1 can also modify the inducibility of other types of plasticity. Here, we highlight current evidence of the potential roles for TRPV1 in regulating synaptic function in various brain regions, with an emphasis on principal mechanisms underlying TRPV1-mediated synaptic plasticity and metaplasticity. Finally, we discuss the putative contributions of TRPV1 in diverse brain disorders in order to expedite the development of next-generation therapeutic treatments. TRPV1 is a nonselective ligand-gated cation channel predominantly expressed in peripheral endings of small diameter nociceptive primary afferent neurons, where its activation is associated with nociception and pain sensation including thermal hyperalgesia . This hoin vivo , showing a preference for somatic over dendritic compartments of dentate granule cells  interneurons  and can The factors that determine whether eCBs act on TRPV1 or CB1 receptors to regulate synaptic transmission remain unclear. Interestingly, in the bed nucleus of stria terminalis, L-type calcium channel activation in dendrites leads to production and secretion of 2-arachidonoylglycerol (2-AG) that acts on presynaptic CB1 receptors in short-term depression, whereas AEA secretion following mGluR5 activation acts on postsynaptic TRPV1 in LTD . AdditioSpike-timing-dependent long-term potentiation (tLTP) in the striatum and neocortex, important for acquiring new associative memories, requires both TRPV1 and CB1 receptors , 2018. NTRPV1 activity can alter the inducibility of long-term synaptic plasticity . In the In addition to regulating synaptic function, a role for TRPV1 in development is indicated by the ability of capsaicin to activate these channels in hippocampal Cajal-Retzius cells . These cTRPV1 has been linked to numerous neurological and neuropsychiatric disorders, with channel desensitization and blockade as primary therapeutic objectives . EmerginMoreover, TRPV1 may tonically modulate emotional defensive responses such as anxiety, fear and panic . Stress Interestingly, TRPV1 expression is reduced in a transgenic model of Alzheimer’s Disease AD; , which iAccumulating evidence indicate that, in addition to its well-known role in modulating pain transduction, TRPV1 seems to play an important role in regulating brain synaptic transmission and plasticity. TRPV1 can be expressed both presynaptically and postsynaptically, and depending on the specific synapse, it can either increase or decrease neurotransmission. The impact of glial TRPV1 function on central synapses requires further investigation. Given the ubiquitous expression of TRPV1 throughout the brain, it is not surprising that TRPV1 has been implicated in several neurological and psychiatric disorders such as epilepsy, anxiety, and depression as well as drug-addiction disorders . Future AEC and CQC conceived of the general ideas presented in this review and supervised the work. CA-G and RM contributed equally to all sections and helped with figure and table construction. All authors made significant contributions to the information content and writing of this final manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


The public health impact of the coronavirus disease 2019 (COVID-19) pandemic has motivated a rapid search for potential therapeutics, with some key successes. However, the potential impact of different treatments, and consequently research and procurement priorities, have not been clear.Using a mathematical model of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission, COVID-19 disease and clinical care, we explore the public-health impact of different potential therapeutics, under a range of scenarios varying healthcare capacity, epidemic trajectories; and drug efficacy in the absence of supportive care.The impact of drugs like dexamethasone  is likely to be limited in settings where healthcare capacity is lowest or where uncontrolled epidemics result in hospitals being overwhelmed. As such, it may avert 22% of deaths in high-income countries but only 8% in low-income countries (assuming R = 1.35). Therapeutics for different patient populations  and types of benefit  could have much greater benefits, particularly in resource-poor settings facing large epidemics.Advances in the treatment of COVID-19 to date have been focused on hospitalized-patients and predicated on an assumption of adequate access to supportive care. Therapeutics delivered earlier in the course of infection that reduce the need for healthcare or reduce infectiousness could have significant impact, and research into their efficacy and means of delivery should be a priority. Coronavirus disease 2019 (COVID-19) drug development to date has focused on reducing deaths among hospitalized patients, but greater public-health impact could come from drugs delivered to outpatients early in the course of disease, and that prevent hospitalization and/or onwards transmission. The coronavirus disease 2019 (COVID-19) pandemic has led to > 4.5 million deaths as of 1 September 2021 and placed substantial pressure on healthcare systems, with demand for oxygen, advanced respiratory support (ARS), and beds nearing or eclipsing availability in settings hit hardest. This impact has motivated significant efforts to identify and develop therapeutics aimed at treating the disease—a need that has become even greater with the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants able to evade prior immunity . This haTo date, many clinical trials have been conducted to evaluate potential therapeutics for COVID-19, with initial focus centering on hospitalized patients. Dexamethasone has been shown to reduce mortality in both severely/critically ill  and modeThese therapeutics have diverse epidemiological impacts  and vary in which patient populations they are administered to . Given these diverse properties, understanding the potential impacts of each, and how this is affected by other factors  is vital for guiding procurement and research priorities. Here we use a modeling approach to understand the impact of established and potential COVID-19 therapeutics on disease burden and how this is affected by epidemic context and healthcare resources. Our results highlight how limited healthcare resources can constrain this impact, limiting the benefits of existing therapeutics, and provide insight into the types of therapeutic properties that could be of greatest value.A, and Figure 1B). The model tracks healthcare resource use  to determine what care an individual actually receives  under 2 epidemic scenarios that reflected different extents of control: a scenario with a high reproduction number for a poorly mitigated epidemic (R = 2), and another with a low reproduction number for a partially mitigated epidemic (R = 1.35). We varied healthcare resource availability, exploring scenarios with (i) unlimited healthcare, (ii) where availability of ARS only is limited, (iii) where ARS and oxygen availability are both limited; and (iv) where ARS, oxygen, and hospital/ICU beds are all limited. To evaluate the potential impact of different therapeutics, we consider 6 different types of therapeutic effects, each corresponding to a mode of action of at least one proposed therapeutic see . For couEvaluating the Impact of Dexamethasone Under Different Assumptions of Epidemic Spread and Health System Capacity2, and beds) are limited . Our results highlight the substantial difference in the timing and intensity of healthcare demand resulting from epidemics of different sizes. Higher R epidemics  lead to a smaller fraction of moderately ill patients  is strongly dependent on these same factors: there is a substantial reduction in mortality due to the drug when there are adequate healthcare resources, but a much smaller effect when these resources are unavailable. This is especially the case when a larger epidemic has overwhelmed resources . Therapeutics that reduce severity of disease (Type 2) or reduce the duration of hospitalization (Type 3) do have an indirect effect in alleviating healthcare demand, but this is minimal because demand for healthcare resources outstrips supply by such a wide margin, even under comparatively well-controlled epidemics (low R scenario). In these scenarios, a slightly faster throughput of patients therefore does not substantially reduce the number of individuals unable to access healthcare due to a lack of availability.We divide the spectrum of potential effects of the therapeutics currently under investigation into six types  and explbottom row). Type 4 therapeutics  have both a direct effect  and an indirect effect  avert a significant fraction of COVID-19 mortality. For our low R scenario, there is an even greater effect from Type 5 therapeutics (which reduce infectiousness). Through reducing community transmission, they lead to reductions in the overall number of people infected with SARS-CoV-2 during the epidemic and alleviate demand for healthcare resources. This would be especially the case if therapeutics are administered before onset of symptoms (Type 5b), although the coverage that could be achieved with such therapeutics would be expected to be lower than for therapeutics administered following symptom onset (Type 5a). It follows that the estimates of impact are influenced by R and healthcare resources . If healthcare needs do not eclipse resources, the direct effect of hospital-delivered therapeutics is greater than otherwise, although the overall impact on mortality from Types 4, 5a, and 5b remains high.Therapeutics that are not administered in hospitals (and so do not suffer the same limitations) and address patients at an earlier stage of disease progression have a potentially greater impact, even after allowing for the lower coverages that may be achieved  could be considerable in well-resourced settings with an epidemic under control  but far smaller in settings where resources are limited and/or there is large epidemic (averting fewer than 10% of deaths). Although our focus here is on dexamethasone, these results would apply similarly to other therapeutics for which clinical benefit is dependent on the presence of supportive care such as oxygen or ARS.Our results highlight that treatments with different types of effect can yield vastly different scales of population-level impact. In particular, the results show that substantial impact could be achieved with therapeutics delivered to persons not in hospital that either reduce the duration of infectiousness (and hence transmission) or disease severity , in keeping with recent work highlighting the need for effective COVID-19 treatment for early infection in the outpatient setting . Indeed,Although most trials to date have focused on evaluating treatments aimed at critically ill, hospitalized patients, there are promising results from some trials. Several individual/combination monoclonal antibody treatments have shown an impact on viral loads and hospitalization ; howeverhttps://www.bmj.com/content/372/bmj.n334). A related limitation is that we assume levels of healthcare-seeking within the population such that all individuals with COVID-19 requiring hospitalization will seek care. Numerous studies have highlighted the disparities in access to healthcare that exist globally  and the costs of doing so. There thus remain numerous factors that will modulate their effectiveness that warrant discussion here. Perhaps most crucially is the need for rapid, widely available COVID-19 testing to identify persons infected early and hence maximize reductions in onward transmission achieved by drugs with Type 5 properties . Testing capacity thus represents a crucial determinant of the effectiveness of these drugs, but this remains inadequate in many parts of the world: for instance, recent results from a post-mortem surveillance study in Lusaka, Zambia, suggest that the majority of COVID-19 deaths (>70%) had occurred without any test having been conducted Mwananyanda et al. , an, anhttpslly  and underscore the crucial need for effective COVID-19 therapeutics targeting outpatients with mild-to-moderate disease, early in the disease course. However, we also highlight important logistical and practical challenges to achieving the significant impact possible with these therapeutics, underscoring the importance of accompanying clinical trials with operational research in order to ensure mechanisms for drug delivery to affected communities can occur in a way that maximizes their potential benefit.Clinical Infectious Diseases online. Consisting of data provided by the authors to benefit the reader, the posted materials are not copyedited and are the sole responsibility of the authors, so questions or comments should be addressed to the corresponding author.Supplementary materials are available at ciab837_suppl_Supplementary_MaterialsClick here for additional data file.


P < 0.05). Further pathological analysis demonstrated that combination therapy effectively ameliorated fibrosis and myocardial morphological changes of DCM rats via activating the upregulation of AMPK and PPAR-γ signaling pathway, and inhibiting NF-κB activity in myocardial tissues of DCM rats. In conclusion, APS microbubbles combined with UTMD effectively protect the myocardial injury of DCM rats via activating AMPK signaling pathway to alleviate inflammation response, fibrosis and oxidative stress in myocardial tissues.The aim of this study was to investigate the cardioprotective effects and probable mechanism of ultrasound-targeted microbubble destruction (UTMD) combined with astragalus polysaccharide (APS) on diabetic cardiomyopathy (DCM) model rats. The DCM rats with diabetes and cardiomyopathy were induced via chronic treatment of doxorubicin and then randomly divided into the (1) DCM model group; (2) APS microbubble group; (3) UTMDgroup; and (4) APS microbubbles combined with UTMD group. After 4-week intervention, the fasting blood glucose levels, body weight, %HbA1c level and glucose tolerance of DCM rats received combination therapy were significantly improved as compared with those of UTMD or saline-treated ones. Moreover, the heart/body weight ratio, and myocardial contractility were all improved after receiving combination therapy groups compared with others. In addition, significantly upregulated activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) as well as significantly downregulated malondialdehyde (MDA) levels were all observed in the ones received combined treatment compared to others. Furthermore, the lipid accumulation and the expression levels of inflammatory factors were all significantly down-regulated in those ones received combination therapy compared with others (all   Microvascular and macrovascular complications, as well as atherosclerosis-related diseases, are accompanied by other mechanisms such as hyperlipidemia and excessive inflammation . In a rat model of type 2 diabetes constructed by diet combined with streptozotocin, the decrease in blood glucose was small after 4 weeks of APS intervention, but after 8 weeks of intervention, the effect of hypoglycemic effect was very significant, while lipid metabolism disorders that were significantly improved could be observed [23–26]. Studies have shown that APS improves glucose and lipid metabolism and improves insulin resistance through the SIRT1-PGC-1α/PPARα-FGF21 signaling pathway [Previous studies have found that APS can significantly reduce blood glucose, free fatty acids and subsequently reduce the myocardial injury in diabetic rats [observed . APS can pathway . Relevan pathway . It has  pathway .Ultrasound targeted microbubble can selectively identify and accumulate in the target tissue, so as to achieve the purpose of targeted imaging and targeted therapy . The tecIt is worth mentioning that the rational construction of diabetic cardiomyopathy models is important to evaluate the therapeutic potential of candidate therapies. Adriamydine (ADR) is an anthraquinone anticancer antibiotic with a wide antitumor spectrum and strong anti-tumor activity, which is one of the most effective drugs for clinical treatment of solid tumors. Because the affinity of ADR to myocardial tissue is significantly higher than that of other tissues, it has severe cardiotoxicity. The acute toxic effects of ADR on the heart are mainly manifested as myocarditis and arrhythmia, while long-term use easily leads to dilated cardiomyopathy and congestive heart failure. Because the changes of myocardial structure and function induced by ADR in rats are most similar to the characteristics of human ADR cardiomyopathy, and the rat model is simple, economical and reproducible; therefore, the ADR-induced DCM rats were used in this study.in vivo experiments. In this study, we wished to investigate the potential preventive and therapeutic effects of APS combined with UTMD on diabetic cardiomyopathy in rats.Combined with the results of many previous studies, we believe that APS holds the potential to be an option for the effective treatment of DCM. However, considering the conventional administration mode of APS makes it difficult to specifically enrich to heart. Therefore, we propose to combine ultrasound microbubble site-directed release technology to achieve effective targeted therapy, but it still needs to be systematically evaluated by rigorous animal P < 0.05), while LVIDs and LVIDd were significantly smaller (P < 0.05). LVEF and LVFS were significantly higher in APS group than in UTMD group . Furthermore, the staining results of H&E and Masson staining suggested that the myocardial tissue injury was severe in the DCM model group 6 weeks later, and increased and disorganized myocardial interstitial collagen fibers and significantly enlarged cardiomyocytes with spaces could be observed, and vacuoles could be observed. Moreover, we measured the heart weight and the specific gravity of body weight in DCM model rats, and the above parameters of DCM model rats were significantly higher than those of healthy ones (P < 0.05), suggesting more severe myocardial hypertrophy. Combined with literature reports, long-term high glucose state can cause significant fibrosis in rat myocardium, which leads to more rigid ventricular wall and enlarged ventricular chamber, resulting in significantly worse cardiac function, including LVEF, LVFS, Sr, SRr values, in rats. In our study, we saw that the combination significantly improved the above symptoms and improved more significantly relative to APS alone.In this study, we prepared SonoVue microbubbles loaded with APS by non-covalent physical binding method and then used ultrasound energy to target and rupture the microbubbles in the damaged myocardial tissue of rats and release the therapeutic molecules to achieve the enrichment of APS in the myocardial tissue in a rat diabetic cardiomyopathy model, so as to investigate its improvement and therapeutic effect on DCM in an animal model. First, we observed and recorded the general diabetic parameters of DCM model rats during the experiment, including fasting blood glucose, glycosylated hemoglobin, and so on, and the above parameters of DCM model rats were significantly higher than those of healthy ones. After 6 weeks of continuous intervention with APS and APS combined with UTMD, these symptoms of DCM model rats were significantly improved as compared with the model control group, and there were no significant differences between the two APS treatment groups. After 6 weeks of continuous interventionr, the LVEF and LVFS indexes of rats in the APS and UTMD combination group were significantly higher than those in the DCM model group , while the content of MDA was significantly higher (P < 0.05). After 6 weeks of continuous treatment intervention with APS combined with UTMD, the activities of SOD and GSH-PX in myocardial tissue increased, while the MDA content decreased significantly, with significant statistical differences relative to the model control group . In addition, the combination of APS and UTMD has a significant therapeutic advantage over APS alone, suggesting that the use of ultrasound energy loaded APS SonoVue microbubbles at the targeted rupture site of myocardial tissue can effectively enrich APS in myocardial tissue, thus playing a role in the treatment of myocardial tissue injury caused by high glucose.SOD is an antioxidant metalloenzyme existing in organisms, which can catalyze the disproportionation of superoxide anion radicals to generate oxygen and hydrogen peroxide ; GSH-Px in vivo experiments further demonstrated the significantly increased expression levels of the p-AMPK, Beclin1, and Parkin in the heart tissues of DCM model rats after 6 weeks of continuous intervention with APS combined with UTMD compared with saline-treated model control group, and the improvement was more significant relative to APS alone. The above data suggested that long-term administration of APS combined with UTMD can ultimately reduce cardiac injury in diabetic rats by significantly activating the AMPK signaling pathway, which in turn improves cardiomyocyte apoptosis.As an energy sensor, AMPK plays a key role in the regulation of cellular energy balance, and is also gradually considered by the industry as a key modulator of cardiac energy metabolism . Phospho5.This study demonstrated that the combination of ultrasound microbubbles loaded with APS and UTMD can effectively treat diabetic myocardial injury and protect the cardiac functions of DCM rats, and the mechanism may be related to the improvement of myocardial antioxidant capacity and slow the formation of myocardial fibrosis by the APS enriched in the heart. Current combination therapy is expected to be a new method for clinical treatment of DCM.


Nanoparticles are abundant in the subsurface, soil, streams, and water bodies, and are often a critical control on elemental speciation, transport and cycling in the natural environment. This review provides an overview of pyrolyzed biomass-derived nanoparticles (PBNPs), their surface properties and reactivity towards aqueous species. We focus specifically on biochar-derived nanoparticles and activated carbon-derived nanoparticles which fall under our classification of PBNPs. Activated carbon-iron (nano)composites are included in some instances where there are significant gaps in literature because of their environmental relevance. Increased use of activated carbon, along with a resurgence in the manufacture and application of biochar for water treatment and soil amendment, has generated significant concerns about the mobility and toxicity of PBNPs derived from the bulk material in environmental applications. Recent examples are discussed to highlight current progress in understanding the influence of PBNPs on contaminant transport, followed by a critical discussion of gaps and future research directions. The surface functionality of pyrolyzed biomass-derived nanoparticles (PBNPs), described here as those derived from bulk biochar and activated carbon, differs from parent material.The literature on PBNPs derived from biochar is growing, unlike that of activated carbon derived PBNPs.There is a need for better understanding of co-transport of contaminants, photochemistry, and toxicity of PBNPs. Pyrolyzed biomass-derived nanoparticles (PBNPs) are those particles limited in all three dimensions to < 100 nm  refers to a variety of synthesized, amorphous, carbonaceous materials that have higher surface area and porosity than their source material. Because of the surface and textural characteristics of AC, it has been utilized in contaminant removal and various other applications discussed below  are distinct from their parent biomass. Unfortunately, only a limited number of studies have investigated CNPs (herein referred to as PBNPs) as distinct entities from their parent sorbent. From an environmental perspective, most PBNP reactivity is extrapolated from investigations on the parent sorbents or studies on synthesized PBNPs for various other technological applications . Fourier transform infrared (FTIR) spectroscopy indicates that following activation, PBNPs typically demonstrate a decrease in oxygen containing functional groups and an increase in C=C vibrations attributed to an abundance of aromatic structures on the surface  on inorganic contaminant removal from aqueous solutions, typically focused on recovery of heavy metals from industrial wastewater . Co(II) removal by PBNPs was nearly 100% in ultrapure water and decreased to ~ 86% in 0.5 mol L−1 NaCl, whereas bulk AC removed ~ 60% and ~ 52%, respectively logy must be considered to understand how PBNPs leached from AC may migrate in the environment.Pyrzynska and Bystrzejewski  synthesi3O4) and sunflower head waste derived Fe3O4-AC nanoparticle composites (PBNPs) for removal of Cr(VI), Cu(II) and Cd(II) from solution. Both systems demonstrated nearly instantaneous adsorption of all metals investigated, but the adsorption capacity of the PBNPs outmatched that of Fe3O4 nanoparticles alone  and pH 6 for both Cu(II) and Cd(II). The difference in maximum adsorption is a result of contaminant speciation, where Cr(VI) is present as an oxyanion and therefore adsorbs more efficiently at low pH when the surface functional groups are protonated  contaminated water by 80% with a 0.05 (wt%) dosage of PBNPs and > 95% at a 0.5 (wt%) dosage.Recently, Jain et al.  comparedted Fig. . Hosseinted Fig.  found thThe influence of PBNPs on the mobility of inorganic contaminants in aqueous environments has received little attention in recent years. It is probable that PBNPs behave like previously studied ENPs with regards to mobility in soils and aquifers and co-transport of inorganic contaminants. There are various factors that can influence the co-transport of PBNPs and inorganic contaminants, such as PBNP surface chemistry, physical properties, matrix properties, contaminant type, and solution properties , colloidal AC, and various other zero valent iron (ZVI) impregnated ACs  and increasing ethane  to protect the ZVI particles from reacting with environmental H2O/H+ (which decreases the lifetime of the particles), and a thin enough coating  to allow for rapid degradation of TCE via electron shuttling from ZVI to the AC  and magnetic activated carbon (MAC) nanoparticles is principally a function of pH , the contamination of water by trace concentrations of pharmaceuticals is an emerging environmental and health concern  and colloids when submerged in water   oxidation. Dong et al. -loaded PBNPs revealed a change in the position and intensity of peaks for carboxyl groups and semiquinone-bearing functional groups, and the appearance of a new As-O band. The effect of PBNPs on the simultaneous reduction of Cr(VI) and oxidation of As(III) was found to be limited to acidic and alkaline conditions, respectively, whereas under neutral conditions Cr(VI) reduction by As(III) was the dominant remediation mechanism. In a more recent study, Wei et al.  extracte−1, which testifies to the critical effect of increased external surface area on Ni(II) sorption. Moreover, three distinct phases were observed in the kinetics of Ni(II) sorption to PBNPs and bulk biochar: a relatively fast (< 30 min) initial Ni(II) diffusion across the water film in the biochar vicinity for both colloids and bulk biochars, an intra-particle diffusion phase which was significantly faster for PBNPs and identified to be the rate-limiting step in Ni(II) adsorption, and equilibrium with no measurable Ni(II) adsorption. The results highlight the effect of pore opening by ball milling , which accelerates the diffusion of Ni(II) into the particles. The underlying mechanisms of Ni(II) adsorption were proposed to be electrostatic attraction between enhanced oxygen-containing functional groups and Ni cations, and cation–π electron interactions due to the exposure of more of the graphitic structure of biochar by ball milling  sorption kinetics experiments showed a chemical adsorption process which was significantly slower for the composite due to the slow diffusion of Cd(II) into alginate pores. Because of their size, such beads can be easily separated from treated water in a batch reactor or used in a fixed-bed operation  both internal and external surface areas along with pore volume and aromaticity increased, enhancing pore filling and π–π interaction removal mechanisms  , FTIR, and zeta potential measurements , and various competing reactive surfaces present in natural systems .2, resulted in nearly complete inhibition of CIC mobility. Moreover, a positive correlation was identified between pH and colloid mobility. At a pH of < 4, there was complete inhibition of CIC mobility, whereas gradually increasing pH gradually increased mobility  generation under UV illumination, whereas their contribution to •OH generation was minimal. The photogeneration of the aforementioned species depended on the pyrolysis temperature of the biochar, which also has a direct influence on the structure of the resulting colloids and their ability to transfer electrons to O2 molecules and generate 1O2  pool, we review the photochemistry of DBC released from bulk biochars in this section. Fu et al.  showed tGiven the abundance of studies presently being conducted with ENPs, it is clear that PBNPs remain understudied. Much of the literature is focused on carbon-based ENPs such as graphene oxides, carbon nanotubes, and fullerenes , and the insect Chironomus riparius in the same field site in Germany as described above by Mackenzie et al. (In addition to further understanding of contaminant interactions and mobility in the environment, a more complete knowledge of the fate of PBNPs in nature is necessary prior to wide-spread utilization. There is a paucity of literature on the risks of introducing PBNPs to the environment either intentionally or through leaching of the parent material. Recently, Vogel et al.  investigl et al.  investige et al. . The stue et al. . These iThe above studies provide examples of the groundwork necessary to define the precautions needed to progress nanoremediation via PBNPs. An area of concern when considering PBNPs in the environment is changes in ecotoxicity as well as physical and chemical properties with varying scale. This complexity can be observed in Table The comprehensive laboratory research being conducted on PBNPs derived from biochar continues to build our understanding of the surface reactivity of PBNPs. These efforts are supporting accurate predictions of the fate of contaminants in the environment in the presence of PBNPs. As applications of bulk biochar have been employed in recent years and are expected to continue, this is a crucial step in understanding the long-term effects of derived PBNPs on contaminant fate in the environment and ecotoxicology of the PBNPs themselves. Unfortunately, PBNPs derived from AC have received considerably less attention and there remain significant gaps in understanding their reactivity in comparison to the parent material. These gaps in understanding present risks, but also considerable research potential to increase our knowledge of the long-term effects of bulk AC applications.


Heme plays a central role in diverse, life-essential processes that range from ubiquitous, housekeeping pathways such as respiration, to highly cell-specific ones such as oxygen transport by hemoglobin. The regulation of heme synthesis and its utilization is highly regulated and cell-specific. In this review, we have attempted to describe how the heme synthesis machinery is regulated by mitochondrial homeostasis as a means of coupling heme synthesis to its utilization and to the metabolic requirements of the cell. We have focused on discussing the regulation of mitochondrial heme synthesis enzymes by housekeeping proteins, transport of heme intermediates, and regulation of heme synthesis by macromolecular complex formation and mitochondrial metabolism. Recently discovered mechanisms are discussed in the context of the model organisms in which they were identified, while more established work is discussed in light of technological advancements. Heme is an amphipathic prosthetic group consisting of a central iron chelated by porphyrin ring and is essential for the function of proteins that regulate a diverse range life-essential redox processes such as oxygen transport, respiration, detoxification, gas sensing, circadian rhythm and control of gene expression . Labile While many disorders of heme synthesis are caused by mutations in genes directly associated with heme biosynthesis, iron-sulfur cluster formation or iron transport, a smaller subset of tissue-specific diseases are caused by mutations in genes more often associated with regulation of mitochondrial homeostasis. This latter subset of diseases is less well understood as little is known about the interaction between the mitochondrial homeostatic machinery and heme/iron metabolism. This review hence emphasizes regulation of heme synthesis in metazoans and focuses on tissue specific regulatory mechanisms that enable cells to couple heme synthesis to cellular utilization. In recent years, it has become evident that these regulatory mechanisms have converged into several main categories: 1) Regulation of substrate and cofactor transport; 2) Regulation of protein-protein interactions between the core components of the heme synthesis machinery and other regulatory proteins, and 3) Metabolic regulation of heme synthesis. The first and last steps of heme synthesis takes place in the mitochondria, enabling extensive regulation of heme synthesis rates by control of transport mechanisms. Mitochondria are also the organelles that integrate molecular synthesis with energy metabolism. How metabolism and synthesis of molecules (such as heme) are integrated and co-regulated is poorly characterized, but is likely to play a major role in cell-specific regulation. To shed light on these interfaces, we have chosen to focus this review on how heme synthesis is regulated by mitochondrial physiology.S. cerevisiae yeast and mammalian cell culture, and these continue to be important models in understanding heme biochemistry and genetics. However, cultured yeast and mammalian cells are uniformly bathed in media and cannot recapitulate the metabolic heterogeneity of cell types in multicellular organisms. Hence, our use of vertebrate organisms is key for understanding the role of heme synthesis in tissue development and physiology. We will draw attention to the experimental models and to the strengths and limitations of each experimental system when interpreting their findings. This is important for understanding the complexity of heme regulation in the context of mitochondrial function, which adapts to the biology of different cell types in their metabolic or developmental niches  or aminolevulinate dehydratase (ALAD). The enzyme hydroxymethylbilane synthase (HMBS) forms a linear tetrapyrrole hydrodroxymethylbilane (HMB) from four molecules of PBG. This linear tetrapyrrole is then converted to the cyclic tetrapyrrole uroporphyrinogen III via the enzyme uroporphyrinogen synthase (UROS). In the final cytoplasmic step of the process, uroporphyrinogen decarboxylase (UROD) catalyzes the decarboxylation of uroporphyrinogen III (UROgenIII) to synthesize coproporphyrinogen III (CPgenIII).Heme synthesis is a ubiquitous process catalyzed by 8 enzymatic steps that take place in the cytosol and the mitochondria  (via a process that requires the transmembrane protein TMEM14C (via the matrix-facing inner membrane enzyme by protoporphyrinogen oxidase (PPOX). Finally, ferrochelatase (FECH) catalyzes the insertion of ferrous iron into the PPIX macrocycle to form heme  e (CPOX) . PPgenIX TMEM14C  and oxidorm heme .The enzymes of the heme synthesis pathway are identical in all cells  , while cALAS is the rate-limiting enzyme of the heme synthesis pathway and is tightly regulated at several levels. Vertebrates possess two ALAS isozymes, ALAS 1 and 2. ALAS1 is ubiquitously expressed in all cell types, and is tightly regulated by heme , while Avia the ubiquitin-proteasome machinery. Under normoxic conditions, the proline on the LXXAP motif of ALAS2 is hydroxylated and interacts with the von Hippel-Lindau (vHL) protein and is ubiquitinated. ALAS2 protein is also stabilized during hypoxia. In contrast, ALAS1 does not contain an LXXLAP motif and is unlikely to be regulated by oxygen tension (ALAS2 contains an LXXLAP motif which is found in proteins that are reguated by oxygen tension. Its stability within the cytosol is regulated by oxygen levels the  tension .Both ALAS1 and ALAS2 proteins contain a heme regulatory motif (HRM) consisting of three consecutive CP motifs (CP 1-3) at their N-termini. These CP motifs are so-called because they contain a dipeptide motif consisting of cysteine and proline residues . This revia Lon and CLPXP, mediated by their interaction on the ALAS1 CP3 motif. This functions as a mechanism for feedback inhibition of heme synthesis. The stability of ALAS2, highly expressed in differentiating erythroid cells under the control of erythroid-specific promoters, is regulated by CLPXP. However, the ALAS2 protein is stable during erythroid differentiation, indicating that it is not degraded under high heme conditions  proteases LON and CLPXP . ALAS1 inditions . One cavThe proteolytic regulation of yeast ALAS differs from that of vertebrates as yeast do not possess a CLPP gene . Hence, Regulation of ALAS stability by housekeeping proteins is an increasingly important theme in understanding disorders of heme metabolism. Recently, we showed that aberrant ALAS stabilization caused by a CLPX mutation caused overproduction of ALA, leading to accumulation of PPIX, resulting in erythropoietic protoporphyria .ALAS enzymes are dependent on the cofactor pyridoxal phosphate (PLP) for their activity. Yeast ALAS/Hem1 is a homodimeric enzyme in which the one of the monomers are covalently bonded to PLP, while the other monomer is PLP free . In contYeast apo-ALAS requires CLPX to accelerate its incorporation of PLP . While tIn yeast, Mtm1  was identified as a potential mitochondrial transporter for PLP. Mtm1 tightly binds to PLP and is required for incorporation of PLP into mitochondrial proteins. In the absence of Mtm1, there was a significant decrease in the activity of Hem1/ALAS. While a PLP transporter should bind to PLP, the high affinity for Mtm1 to PLP may indicate that other proteins are required as carriers to transfer PLP from Mtm1 to its target proteins . VertebrThe CPOX enzyme catalyzes the oxidation of coproporphyrinogen III to protoporphyrinogen IX. It is specific for the coproporphyrinogen III isoform, rather than the coproporphyrinogen I isoform that is not used for heme synthesis. CPOX is situated in the mitochondrial intermembrane space and is loosely attached to the mitochondrial inner membrane . The proCPOX functions as a homodimer with no cofactor . While iIn the penultimate step of heme synthesis, PPOX catalyzes the oxidation of protoporphyrinogen IX to protoporphyrin IX within the mitochondrial matrix. PPOX functions as a homodimer with an FAD molecule noncovalently bound to one of the subunits within the dimer . The PPOWhile PPOX is not a rate-limiting enzyme in the heme synthesis pathway, its expression, like all the other heme synthesis enzymes, is upregulated during erythroid differentiation . To keepIn vertebrate erythroid cells, full PPOX activity requires CLPX, a mitochondrial protein unfoldase, but not CLPP, the proteolytic subunit of the CLPXP protease , suggestPPOX exists within a large protein complex in the mitochondrial inner membrane (the “heme metabolon”) with other heme synthesis enzymes such as ALAS and FECH, as well as TMEM14C, which plays a role in import of protoporphyrinogen IX into the mitochondrial matrix . It is lFECH catalyzes the final step of heme synthesis which is the insertion of iron into protoporphyrin IX. FECH is synthesized in the cytosol as a pre-protein and translocated to the mitochondrial matrix where it is attached to the mitochondrial inner membrane. The enzyme exists as a homodimer. Each of the monomers in metazoan FECH is attached to a [2Fe-2S] cluster .E.coli FECH, which does not contain a [2Fe-2S] cluster, does not (Atpif1) or pharmacological inhibition of respiration causes disruption of FECH activity. A yeast FECH ortholog that does not possess a [2Fe-2S] cluster was not similarly disrupted; indeed expression of yeast FECH was able to genetically rescue the anemia in zebrafish atpif1 mutants, suggesting the absence of a [2Fe-2S] cluster rendered yeast FECH impervious to regulation by pH. This mode of regulation did not occur in non-erythroid cells. Although knockdown of Atpif1 in mammalian cell erythroid cell lines caused a hemoglobinization defect , requiring adequate levels of glycine in the mitochondrial matrix for heme synthesis. The requisite glycine concentrations are achieved by the activity of glycine transporters in mitochondria. In vertebrates, SLC25A38, a mitochondrial protein which is highly expressed in erythroid cells carries out this function. The function of SLC25A38 as a mitochondrial glycine transporter is highly conserved across species, as is its requirement for initiating heme synthesis  and nuclear ER contact sites  cluster synthesis, which depends on iron availability, is an important regulator of heme synthesis. Fe-S assembly is largely understood to occur in mitochondria, although some aspects of the pathway occur independently in the cytosol and nucleus . A recenIt has been established that heme synthesis must be coupled with metabolic requirements to prevent toxic accumulation of heme and its intermediates. In the mitochondria, ALAS is in a multiprotein complex with succinyl-CoA synthetase (SUCLA2) which plays an essential role in the tricarboxylic acid (TCA) cycle, the main source of energy production in nucleated cells . The phyAnother important aspect of metabolic regulation is the role of iron sensing by the aconitase enzymes. Cytosolic aconitase in iron regulatory protein-1 (IRP-1) plays a central role in the iron restriction response as it is dependent on Fe-S binding to regulate the translation and stability of mRNAs that often play a key role in iron homeostasis  . While iWe envision that the field of heme regulation and mitochondrial homeostasis will continue to grow as technical advances enable us to address the gaps in our knowledge. Advances in imaging, cell biology, genetic engineering, and mitochondrial physiology have enabled us to experimentally address questions that would have been unimaginable just 20 years ago. Because initial studies of heme metabolism and regulation in erythroid cells gave rise to techniques that allowed us to interrogate heme metabolism in different tissue types, we now have a far greater understanding of how metabolic pathways integrate with and respond to the extracellular environment, metabolic requirements, and developmental stimuli. Because heme synthesis is so tightly regulated and tied to specific cellular requirements, we predict that studies of heme regulation will provide a paradigm with which to study how nutrient metabolism in general is regulated in individual cell types.