Despite the advances made in treatment, the prognosis of pancreatic ductal adenocarcinoma (PDAC) remains dismal, even in the locoregional and locally advanced stages, with high relapse rates after surgery. PDAC exhibits a chemoresistant and immunosuppressive phenotype, and the tumor microenvironment (TME) surrounding cancer cells actively participates in creating a stromal barrier to chemotherapy and an immunosuppressive environment. Recently, there has been an increasing use of interventional radiology techniques for the treatment of PDAC, although they do not represent a standard of care and are not included in clinical guidelines. Local approaches such as radiation therapy, hyperthermia, microwave or radiofrequency ablation, irreversible electroporation and high-intensity focused ultrasound exert their action on the tumor tissue, altering the composition and structure of TME and potentially enhancing the action of chemotherapy. Moreover, their action can increase antigen release and presentation with T-cell activation and reduction tumor-induced immune suppression. This review summarizes the current evidence on locoregional therapies in PDAC and their effect on remodeling TME to make it more susceptible to the action of antitumor agents. According to the Global Cancer Observatory, in 2020, pancreatic cancer ranked as the 12th most common cancer for incidence and the 7th in terms of annual number of deaths worldwide . At diagThe treatment of resectable pancreatic ductal adenocarcinoma (PDAC) involves surgery followed by adjuvant chemotherapy. Preferred regimens include Gemcitabine-Capecitabine and mFOLFIRINOX for patients with good performance status ,6. For pDespite the advances made in treatment, the prognosis of PDAC remains poor, with a median overall survival (OS) of approximately 12 months for metastatic disease at diagnosis ,12. PDACThis review aims to summarize the current evidence on locoregional therapies in PDAC and their effect on remodeling the tumor environment to make it more susceptible to the action of antitumor agents.The biological behavior of PDAC is strongly dependent on its interaction with the adjacent tissues. TME refers to all the normal cells, molecules and blood vessels that surround cancer cells. TME may be considered as a dynamic network of cells and stroma constituents; thus, its composition and functions are extremely various and it shows both an intratumor and intertumor heterogeneity ,15 Figu.The cross talk between cancer cells and TME is responsible for tumor growth, metastatic potential and therapeutic resistance ,17,18,19PSCs are star-like-shaped cells that normally exist in a quiescent state but can be activated by various stimuli such as reactive oxygen species (ROS), cytokines, hypoxia and growth factors. When activated, PSCs can release components of extracellular matrix (ECM), metalloproteinases and maintain their activation through a loop sustained by the secretion of autocrine cytokines ,24.The Sonic Hedgehog (Shh) signaling pathway is often hyperactivated in many solid tumors, including PDAC, and appears to promote the activation of PSCs and desmoplasia ,26. In aFurthermore, TGF-β, a pleiotropic cytokine that performs various functions, both tumor-promoting and antitumoral, is also involved in the deposition of ECM components, including fibronectin and collagens. TGF-β promotes the activation and proliferation of PSCs, which, in turn, release additional TGF-β through a positive feedback mechanism ,31. The Dense desmoplasia is a hallmark of the PDAC microenvironment and, together with the increased fluid pressure partly due to proteoglycan and hyaluronan, alters the organ architecture and represents an important obstacle to the delivery of therapeutic agents ,36,37,38PDAC exhibits an immunosuppressive phenotype, and the TME actively participates in creating an immunosuppressive environment by triggering mechanisms that promote immune evasion and restrict the activation of an effective antitumor immune response. CAFs may inhibit cytotoxic T lymphocyte (CTL) function with the release of immunosuppressive cytokines such as IL-10 and TGFB ,50. CAFsGiven the clinical need to improve treatment efficacy in PDAC, the development of new therapeutic strategies should take into consideration the important role of TME in supporting tumor growth and promoting treatment resistance. In this regard, locoregional treatments could reshape the TME, sensitizing tumor cells to systemic treatments by enhancing the delivery of cytotoxic agents or altering the composition of the immune infiltrate.Microwave ablation (MWA), radiofrequency ablation (RFA), radiation therapy (RT), irreversible electroporation (IRE), high-intensity focused ultrasound (HIFU), and intra-arterial infusion chemotherapy are becoming increasingly popular due to their possibility to specifically target the tumor while limiting adverse events .Nonmetastatic locally advanced pancreatic cancer (LAPC) includes 30% of all newly diagnosed PDAC . StandarLocoregional ablative therapies are minimally invasive techniques that use a generator and a needle-like electrode to transmit energy directly to the target location, with the aim of producing tissue necrosis. These interventions are often performed percutaneously with the insertion of an electrode under imaging guidance; however, they can also be performed during laparoscopic/open surgery or endoscopy. The variety of minimally invasive ablative treatments may be classified according to their use of thermal energy, such as radiofrequency (RF), microwave (MO), and cryoablation (CA), or non-thermal energy, such as irreversible electroporation (IRE) . High-InIn RFA, one or more electrodes create alternating currents at high frequencies, which cause very high local temperatures, resulting in thermal coagulation, protein denaturation and, consequently, thermo-coagulative necrosis of the target tissue. An ablated spherical area, generally 2 to 5 cm in diameter, is generated in about 10 to 30 min . With RFSo far, there have been no randomized controlled trials (RCT) regarding RFA effectiveness. However, there is one ongoing RCT (PELICAN RCT) that aims to evaluate if the combination of chemotherapy and RFA prolongs OS compared to chemotherapy alone in patients with LAPC with absence of progression following two months of systemic treatment . In a noStudies on PDAC treated with RFA are mostly focused on treatment via laparotomy or endoscopy, with only a small proportion of treatments performed percutaneously. When percutaneous RFA is feasible, it may avoid laparotomy, thus reducing the risk of infection, bleeding and other surgical complications . In addiRFA can cause stroma denaturation and tissue permeability modifications in order to implement drug delivery. Ware et al. showed that RF affects molecular transport in a 3D model of PDAC with higher diffusion of DAPI fluorescence in spheroids in comparison to no RF. This could influence the response to medications that are passively diffusing in the TME, since the drug molecules would be able to extravasate in large quantities from the vasculature and disseminate deeper and more uniformly throughout the tissue .RFA has been shown to induce a modification in the composition of the inflammatory infiltrate both in the treated tumor areas and in nontarget lesions distant from the locally treated zone, known as the “abscopal effect”. The “abscopal effect” refers to the response in a nontarget lesion distant from the treated site, which occurs due to immune activation and increased immune-responsiveness .Faraoni et al.  used murSimilar to RFA, microwave ablation (MWA) causes target tissue necrosis with a thermo-coagulative process. The majority of the heat produced by MWA is caused by the excitation of polar water molecules, while ionic polarization has a significantly lower impact. MWA produces a greater zone of active heating in a shorter time in comparison to RFA, allowing a more uniform necrosis in the target lesion. The two primary frequency bands utilized are 915 and 2450 MHz, with the latter being the more frequently employed . The theHigh-Intensity Focused Ultrasound (HIFU) technology is a noninvasive technique that uses high-energy ultrasound waves to ablate a limited target volume with US or MRI guide. Focused ultrasound devices are made of a generator that produces ultrasound energy and a transducer that focuses the waves into a beam aimed at a well-defined target region. HIFU has a dual effect on tissues, inducing both thermal and mechanical damage. The thermal effect generated by the absorption of sound waves is different whether the dose of deposited energy is low or high. At low energies (<55 °C), the hyperthermia induced does not generate cell death but increases cell membrane permeability. At high temperatures (>55 °C), cell death is induced by coagulation necrosis . The mecp = 0.002), without any severe complication related to HIFU reported [Numerous large-volume studies have shown that HIFU has a considerable positive impact on patients’ QoL, with improved tumor responsiveness and low rate of adverse events. A recent meta-analysis conducted by Fergadi et al. evaluated 939 patients with PDAC. They assessed that HIFU combined with neoadjuvant chemotherapy is a safe strategy that increases OS and causes less discomfort when compared to chemotherapy alone . AnotherBesides thermal ablation, another application of HIFU that is recently gaining attention is its use as a means to provide targeted drug delivery. This is possible since ultrasound administered at high intensity promotes the creation of transient openings in the cellular membrane, increasing cellular permeability. This process is known as sonoporation . There aRegarding temperature-dependent drug delivery, in vitro and in vivo animal models showed that doxorubicin was released more quickly and concentratedly after HIFU treatment in conjunction with injection of temperature-sensitive liposomes. Another work by Liang et al. showed that temperature-sensitive cerasomes released drug molecules in their target area when the temperature has increased by 5 °C ,100. TheCryoablation (CA) is a thermoablative technology that is based on multiple cycles of freezing and thawing that results in the development of intra- and extracellular ice crystals, osmotic pressure fluctuations, disruption of cells membrane, and eventually cellular death . One of Irreversible electroporation (IRE) is an innovative ablative method employed in the clinical treatment of LAPC that provides intratumorally high-voltage electric pulses, causing the death of tumor cells by destroying the cell membrane integrity, creating nanopores. Compared to conventional ablative modalities, cell death in IRE is based on electrical energy rather than thermal energy and has different advantages: it is not influenced by the “heat sink effect”, avoiding incomplete ablation due to the energy reduction caused by blood flow; it preserves the extracellular matrix of vasculature and shows better safety profiles next to vital structures, especially for vital nerves, vessels, and cavity structures . The preThe procedure can be performed percutaneously under guidance , laparoscopically, or through an open approach following a midline laparotomy  Figure . The per−1; delivered current of 20–50 A), and the cell dies due to loss of homeostasis [Following the treatment, a contrast-enhanced CT scan should be done to confirm the correct ablation zone and to check for any early complications . The meceostasis . The puleostasis . For theeostasis . The inteostasis .It has been demonstrated that IRE not only destroys the tumor itself directly, but also has been shown to boost antitumor immunity and temporarily lessen the stroma-induced immunosuppression . PDAC isRadiation therapy (RT) has been utilized in managing patients with PDAC both in the resectable and in the unresectable PDAC. Theoretically, preoperative radiation therapy has advantages over postoperative therapy, including better tissue oxygenation (which could increase RT effectiveness), sterilization of the operating field (which could reduce iatrogenic tumor seeding), and improved patient tolerance and compliance with treatment setting of resectable disease and unresectable disease . The rolDifferent studies have investigated the role of RT in the immunomodulation in the human PDAC TME following therapy. Mills et al. evaluated the role of stereotactic body radiotherapy (SBRT) as a treatment modality for PDAC to prime cytotoxic T cells by inducing immunogenic tumor cell death in preclinical models . They reAdvanced PDAC has a very poor prognosis due to its chemoresistant nature. Chemoresistance of the tumor depends on the presence of a very dense and poorly vascularized fibrotic tumor stroma that involves tumor environment, the poor vascularization of PDAC and the high expression of the membrane-bound P-170 glycoprotein, part of an ATP-dependent drug efflux enzyme system .Small case series have examined locoregional chemotherapy as an option for PDAC, demonstrating dose-dependent tumor sensitivity. In fact, when compared to systemic chemotherapy, pancreatic artery infusion (PAI) chemotherapy, using different chemotherapeutic agents such as gemcitabine and 5-fluorouracil, gives higher local concentrations of chemotherapeutic drugs while preserving healthy tissues and having a lower rate of side effects. Wang et al. evaluated the efficacy and safety of PAI with nab-paclitaxel in patients with advanced PDAC and demonstrated that PAI is safe, well tolerated, and effective for the relief of clinical symptoms . Qiu et Apart from RT, locoregional treatments are not included in guidelines for the treatment of localized and advanced PDAC. Indeed, NCCN guidelines consider RT only in the case of PDAC amenable to receive preoperative treatment together with induction chemotherapy or alone (stereotactic body RT) before surgery. Moreover, in the case of LAPC, RT may be an option as a single treatment or together with chemotherapy . HoweverThere is increasing evidence that locoregional treatments may remodel tumor TME and contribute to different mechanisms, as demonstrated through high-quality samples ,136,137.Locoregional treatments can modulate the composition of TME in multiple ways: on one hand, they promote structural alterations that facilitate the delivery of a higher amount of drug and, consequently, potentially enhance therapeutic efficacy. In this regard, several studies are evaluating the role of postlocoregional treatment chemotherapy for patients with nonmetastatic PDAC. In a phase II study, all patients undergoing IRE for the treatment of LAPC will receive either FOLFIRINOX or gemcitabine as peri-ablation treatment (NCT03484299). Another phase II study is determining the feasibility, tolerability, and treatment effect of EUS-RFA plus standard-of-care neoadjuvant chemotherapy with FOLFIRINOX or gemcitabine/nab-paclitaxel in LAPC (NCT04990609). A phase II/III trial has been completed, and patients were randomized to receive either IRE and synchronous chemotherapy with gemcitabine or IRE and subsequent gemcitabine starting on day 7 following ablative procedure in LAPC (NCT03673137). Differently, a phase I study is testing the tolerability of chemotherapy and EUS-RFA using the RF Electrode in patients receiving palliative second- or third-line therapy for unresectable nonmetastatic PDAC (NCT05723107). In addition, a phase II study has been completed and evaluated the safety and feasibility of the NanoKnife Low-Energy Direct Current (LEDC) System when used to treat unresectable PDAC (NCT01369420). On the other hand, locoregional therapies often modify the composition of immune response effectors, not only in the treated area, but sometimes also at a distance, as described in the abscopal effect promoted by ablative therapies. This leads to a polarization towards an antitumoral immune response with several observed modifications, including an increase in tumor-associated neutrophils (TANs) and the activation of B and T cells. Furthermore, some studies have documented an increase in PD-L1 expression following local treatments. These findings provide the rationale for the use of immune checkpoint inhibitors (ICI) in combination with locoregional therapies. In this direction, a phase II study is enrolling patients who will receive IRE for LAPC and will be treated with nivolumab postoperatively (NCT03080974). However, it should be noted that the duration and the actual antitumoral effectiveness of immune microenvironment modifications have not yet been established, and it remains to be seen whether they can be exploited therapeutically.PDAC is a chemo- and immune-resistant disease with poor prognosis. Locoregional treatments, even if not considered standard of care, may have a role in interfering with TME with subsequent improvement of chemotherapy outcomes and increased immune sensitivity. Early phase and phase III studies are warranted in order to understand the impact of ablative therapies alone or in combination with chemotherapy/immunotherapy on disease response and survival outcomes.


The field of biosensor development is fueled by innovations in new functional transduction materials and technologies. Material innovations promise to extend current sensor hardware limitations, reduce analysis costs, and ensure broad application of sensor methods. Optical sensors are particularly attractive because they enable sensitive and noninvasive analyte detection in near real-time. Optical transducers convert physical, chemical, or biological events into detectable changes in fluorescence, refractive index, or spectroscopic shifts. Thus, in addition to sophisticated biochemical selector designs, smart transducers can improve signal transmission and amplification, thereby greatly facilitating the practical applicability of biosensors, which, to date, is often hampered by complications such as difficult replication of reproducible selector-analyte interactions within a uniform and consistent sensing area. In this context, stimuli-responsive and optically active Janus emulsions, which are dispersions of kinetically stabilized biphasic fluid droplets, have emerged as a novel triggerable material platform that provides as a versatile and cost-effective alternative for the generation of reproducible, highly sensitive, and modular optical sensing layers. The intrinsic and unprecedented chemical-morphological-optical coupling inside Janus droplets has facilitated optical signal transduction and amplification in various chemo- and biosensor paradigms, which include examples for the rapid and cost-effective detection of major foodborne pathogens. These initial demonstrations resulted in detection limits that rival the capabilities of current commercial platforms. This trend article aims to present a conceptual summary of these initial efforts and to provide a concise and comprehensive overview of the pivotal kinetic and thermodynamic principles that govern the ability of Janus droplets to sensitively and selectively respond to and interact with bacteria. Salmonella enterica, Escherichia coli, or Listeria monocytogenes. [The detection of pathogen-contaminated food is a global public health challenge.  Foodborntogenes.  To avoidtogenes.  In practtogenes.  The methtogenes.  During ttogenes. .The key to reducing the risk of food poisoning and safeguarding the food supply lies in a reliable early-stage detection of foodborne pathogens. New sensing paradigms are urgently needed that are cost-effective, labor efficient, highly specific, and detect the target analyte within a single working day at a food production facility. New biosensor technologies promise to overcome the limitations of current sensor platforms. –13 ElegaHowever, the simple fact that referring to your local newspaper from today leaves a high probability of referencing another foodborne pathogen-caused food recall or even disease outbreak reveals that the efficiency and applicability of these techniques are still in need of improvement. Some methods require long bacterial pre-enrichment and incubation steps. Others have significantly improved time to results but are laboratory-based, require costly equipment, or are complicated to perform. In many cases, biochemical identification assays or read-out techniques are simply prohibitively expensive for a rapid on-site testing of food products and are rather designed for medical diagnostics. The biggest hurdles to overcome, particularly in the context of food monitoring, are the overall cost and practicability of the platform to detect a signal against a complex background noise in order to allow for easy on-site screening of samples. .Liquid–liquid transduction schemes, such as those based on responsive Janus emulsions, are appealing because they are simple and cost-effectively to prepare in any environment from inexpensive commercial reagents and the dynamic liquid interfaces facilitate reactions of synthetic bio-selectors and pathogens within their native aqueous environment. The latter, in principle, allows for an emulation of signal transduction and transmission strategies found in nature, where the highest substrate specificities are often achieved not by interactions between a single selector with a specific analyte but in the form of biochemical logic gates in which multiple independent triggering events actuate a specific reaction cascade. An emulation of such signal selection and amplification strategies requires artificial adaptive material systems that can dynamically respond and adapt to multiple molecular recognition–induced chemical events autonomously. Emulsions, dispersions of fluid droplets stabilized by surfactants, inherently represent a thermodynamically out-of-equilibrium material platform.  EmulsionWhile one-component droplets are ubiquitous and have found widespread applications in many commercial products, including paint, food, cosmetics, and as central components of many medical, pharmaceutical, and performance products, the introduction of a third orthogonal liquid phase opens the path towards a variety of new multicomponent systems that display multiple separate responsive modalities.  More speThis trend article summarizes the initial concepts for implementing responsive Janus emulsions as novel transducers and signal amplifiers in liquid biosensing platforms. The article intends to provide as a resource to both newcomer and experienced researchers in the field and to further stimulate cross-disciplinary research activities in the design of new and improved Janus emulsion sensing platforms. Therefore, as part of a conceptual summary, first the underlying chemical design principles for the generation of these types of stimuli-responsive liquid colloids, the associated implications of their dynamic and reconfigurable droplet geometries in the context of emulating biological recognition events and potential signal transduction pathways to visualize such interactions are discussed. These are followed by an overview of the different Janus emulsion–based pathogen sensing strategies reported to date. Finally, potential opportunities and challenges towards improving the sensitivity and specificity while maintaining the simplicity and cost-effectiveness of Janus emulsion–based sensing paradigms are outlined in the ‘Per conceptual design, Janus emulsions constitute a ‘smart’ material platform, in which the term ‘smart’ can stand as an acronym for the most compelling characteristics of this material class: self-organized, metastable, artificial, responsive, and triggerable. The droplets are comprised of two immiscible fluids that self-organize into distinct gravitationally aligned compartments creating droplet shapes that are determined exclusively by the force balance of interfacial tensions acting at the individual interfaces. As such, depending on the surfactant composition within the continuous phase, Janus emulsions can be generated in a variety of internal droplet geometries, and small changes in the equilibrium of interfacial tensions evoked by changes in the surfactant type, concentration, or effectiveness allow the droplet geometries to be controllably altered before or after emulsification. A broad compositional flexibility in the selection of the constituent fluids and surfactants as well as a selective partitioning of active components into the individual phases of the droplets enable the generation of a large variety of functional Janus droplets with intricate, switchable, and chemically, physically, electrically, magnetically, or photochemically sensitive structures. These fundamentally new forms of thermodynamically out-of-equilibrium liquid colloids are often simple to prepare from inexpensive commercial reagents in a variety of compositions, geometries, sizes, and size dispersities using different methods that range from large-scale, less precise techniques yielding polydisperse emulsion droplets to more precise but small-volume approaches generating uniformly sized and shaped emulsions droplets. From a fundamental perspective, many reported techniques are based on three underlying principles Fig. : FirstlyThe geometry of Janus emulsion droplets is mutually influenced by the type of dispersed fluids, the volume ratio, and their density. The internal Janus droplet morphology is determined by the force-balance of interfacial tensions acting between the constituent phases as expressed by the Neumann triangle.  The physTypically, variations in surfactant effectiveness and thus variations of droplet interfacial tensions result in qualitative changes of an emulsion, such as droplet flocculation or coalescence.  LeveragiN-heterocyclic alkaloids. Caffeine binding decreased the surfactant’s hydrophilic-lipophilic balance and consequently resulted in an increase in the respective interfacial tension at the oil–water interface of the Janus emulsion. This method’s utility was illustrated by simply monitoring changes in droplet morphologies as a novel tool for quantifying caffeine levels in sample solutions. [The design of amphiphilic surface-active components that allow sensitization of the balance of interfacial tensions of Janus emulsions via supramolecular recognition events is particularly attractive because it offers a multitude of opportunities for the design of Janus emulsion sensing platforms. Supramolecular receptors can be specifically synthesized and compartmentalized into the organic phases of the emulsion droplets. Recognition of water-soluble analytes then changes the surfactant effectiveness, for instance via changing the surfactants’ hydrophilic-lipophilic balance, inducing changes in the respective oil–water interfacial tension.  Followinlutions.  Next to lutions.  Janus emCompared to supramolecular interactions, analyte-induced covalent bond cleavages result in pronounced changes in surfactant efficiency and thus more significant morphology changes can be evoked. The concept was first demonstrated using a pH-sensitive sodium 2,2-bis(hexyloxy)propyl sulfate surfactant.  Acid-indcis-diols. Traditionally, the utility of molecular boronic acid sensors is limited due to the poor water solubility of synthetic boronic acid receptors. [The advantages of both reversible supramolecular concepts and pronounced droplet responses observed for covalent droplet surface modifications can be leveraged and combined in the development of dynamic covalent interfacial functionalization paradigms. The modularity of the dynamic covalent surfactant manipulation approach was tested using reversible reactions between surface-immobilized boronic acid surfactants and carbohydrates present within the continuous aqueous phase.  Boronic ceptors.  In this ceptors. , 41.In an alternative reversible covalent functionalization scheme, Zentner et al. harnessed the dynamic covalent nature of imine bonds.  SpontaneNext to stimuli-responsive selector surfactants that are specifically designed to interact with a particular analyte, the effectiveness of commercial emulsifiers themselves also depends significantly on the continuous phase chemical environment. Consequently, droplet morphological changes can be observed and monitored in response to minor variations in electrolyte concentrations or pH within the continuous phase. –57.The outlined initial reports on covalent and noncovalent, reversible and irreversible droplet post-functionalization paradigms demonstrate the versatility of actuating dynamic Janus emulsion responses and provide as a basis for a continued merger of complementary synthetic organic chemistry, supramolecular, and catalytic concepts at the dynamic liquid interfaces of Janus emulsions for the targeted design of other versatile responsive Janus emulsion building blocks that exhibit programmable responses to a wide range of chemical stimuli. In the context of developing new, sensitive, and effective chemosensors based on Janus emulsions, a reliable transduction of the unique chemical-morphological coupling inside Janus emulsions into a readable and ideally quantifiable physical signal output is key. In general, chemo-and biosensors typically comprise two main components:  a recognThe refractive index contrast between the constituent liquid phases of a Janus emulsion produces reflectivity and optical confinement, which allows modulation of the optical characteristics and to manipulate the pathway of light passing through these microscale elements Fig. . GravityJanus droplets are tunable liquid compound microlenses.  DependinDepending on the incident angle of illumination and the droplet morphology, incoming light rays can also be guided along the internal interface through total internal reflection increasing the light intensity inside droplets’ higher refractive index phase.  The lattAlongside variations in the Janus emulsion transmission and reflection properties, Janus droplets have also been demonstrated as powerful stimuli-responsive fluorescent probes. The tunable refractive index contrast between the constituent phases enables the attenuation or enhancement of embedded fluorescent dye intensity that selectively partition into one or both droplet phases.  When a fAlternative fluorescent droplet morphology read-out platforms build upon a compartmentalization of two complementary dyes or pigments into the opposing phases of Janus emulsions. These paradigms ratiometrically detect multiple emissions modulated by an inner filter effect that depends on the internal droplet morphology. , 64 In cResearchers have further pioneered alternative purely refractive index–based signal transduction paradigms that are not based on colorimetric or fluorescent detection of droplet morphology. , 66 MorpThe mechanical and interfacial properties of Janus emulsions exhibit similarity to living cells in that they present dynamic and reactive surfaces, multiple liquid compartments, and can chemically interact with their environment. Consequently, Janus emulsions offer an extraordinary untapped potential for real-time monitoring of interactions with biological entities and the development of new and improved biosensing platforms. In nature, binding and recognition phenomena on cell surfaces are often regulated by a series of cell-surface receptors, which provide their fundamental capability to transduce and convey chemical information autonomously and with high fidelity. These constitute essential processes by which the body maintains control over complex biological functions. , 68 A laThe implications of Janus emulsion–based sensor paradigms are profound as they offer a disruptive new biosensing strategy for rapidly and inexpensively identifying small amounts of pathogenic organisms. Sensory devices that utilize the Janus emulsion–based detection schemes can be readily miniaturized, and the emulsions are easily and cheaply prepared in any environment. In addition, the fundamental components of any biosensor, a recognition, transduction, and response unit are combined within one material system. A targeted combination of the unique chemical, morphological, and optical properties of Janus emulsions provides a multitude of potential signaling pathways for the precise detection and identification of pathogenic organisms and signal amplification in sensing devices.Thus far, researchers have focused on two different signal transduction pathways underpinned by an immobilization of biochemically active surfactants at selective droplet interfaces. In these sensing paradigms Table , moleculIn Janus emulsion morphological assays, the detection strategy relies on reversible reactions between biological targets with droplet interface-immobilized selectors, which triggers changes in the balance of interfacial tensions and thus actuate dynamic reconfigurations in droplet morphology. Such changes in droplet morphology can be readily detected by an alteration of the optical properties of Janus emulsions exploiting the unique refractive, reflective, or light-emissive properties. For instance, leveraging an orthogonal carbohydrate binding of sugar-binding lectins at pathogen cell-surface appentages can be used to alter the droplet interfacial tensions thereby inducing large and predictable changes in the Janus emulsion morphology.  For thisIn turn, Janus droplet agglutination assays build upon a chemically induced tilting of Janus droplets out of their gravitational alignment that can be evoked by multivalent binding interactions with an analyte.  In theseResearch in the field of biosensor development is very active, and there are many reports on the application of rapid sensing techniques for the detection of various bacteria and viruses, focusing on both medical diagnostics and the monitoring of pathogens in food, water, and the environment.  There arConsideration of this need for simplicity highlights that modular sensory layers based on Janus emulsions, although still in their infancy, hold promise to address an unmet need for the development of rapid screening platforms for monitoring food safety. Modular Janus emulsion transduction platforms can be easily and inexpensively prepared from low-cost starting materials in almost any environment. In addition, the unique morphological-optical coupling inside Janus droplets allows facile optical transduction of chemical information in situ, alleviating the need for complicated read-out instrumentation, which lays the foundation for their implementation in simple, low-cost, and high-speed on-site monitoring devices.However, despite their promising potential, there are major challenges that Janus droplet modular sensor platforms need to overcome before discussing their full potential and suitability for practical applications. First and foremost, the stability of droplets and their sensitivity towards detecting pathogens in complex food matrices need to be explored. The unique dynamic behavior of droplets is underpinned by their kinetic stabilization, which, however, conditions their susceptibility to mechanical rupture as well as Ostwald ripening, flocculation or coalescence. Thus, while Janus drops can be produced cheaply and easily, production scalability, distribution and long-term storage may be compromised. With respect to detection efficiency, a continued merger of dynamic Janus droplet interface sensitization with known recognition motifs from supramolecular chemistry, microbiology, or catalysis promises to improve the specificity and sensitivity towards specific pathogens. Hitherto reported paradigms achieved moderate detection thresholds that, while not suitable for the requirements in medical diagnostics, already meet benchmarked target ranges and general sensitivity requirement for the detection of a number of bacterial strains from food samples.  However,Beyond necessary improvements in sensitivity, specificity, and practicability of sensing platforms to track singular events, a particular and unprecedented inherent feature of Janus droplet transducers lies in a more general strategy for tracking multiple independent (bio-)chemical interactions simultaneously, rather than tracking singular events. Instead of designing systems that fulfill a single targeted responsive function, this multifunctional system allows deciphering the structural and energetic basis to track multiple autonomous processes in parallel.  UnderpinConsequently, perhaps the biggest strength and true power of the modular Janus droplet–based transduction layers lies in the dynamic, multicompartmentalized nature of the liquid material itself. Unlike many other transduction techniques, this liquid sensing platform enables signal transduction that goes beyond a simple translation of a chemical detection event into a physical readout. Janus emulsion droplets intrinsically represent a thermodynamically out-of-equilibrium material platform that continuously exchanges molecules with its environment. –85 ProgrThis vision of droplets exhibiting a decentralized chemical intelligence emulates design principles that are common in nature. Often, the key to the high specificity and sensitivity of regulated responses in nature lies in their ability to design interconnected adaptable molecular and supramolecular networks that recognize, propagate, and transduce chemical and biochemical information with high fidelity. Current Janus droplet sensor platforms have obviously not reached this level of complexity. Introducing multiple responsive components into a single system, however, will yield transducers that release informed responses balancing positive and negative feedback loops. In the context of sensing, the challenge then lies in achieving programmed control over this chemical autonomy of the systems and controlling the superpositions of singularities to create an informed sensor data output signal.Currently, we can conveniently generate large quantities of small Janus droplets in highly uniform internal morphologies, control their assembly, reversibly actuate a tilting or chemotactic motility of droplet ensembles, trigger their coalescence, and under certain conditions, manipulate droplet geometry and the reversible uptake and release of chemical contents while monitoring all these processes in real-time. Advances in the compositional flexibility and complexity of the emulsion droplets may pave the path towards the generation of more chemo-intelligent micro-colloids that display multiple responsive units, can communicate with each other, or that display active, adaptive, self-regulatory, and autonomous capabilities, e.g., in the context of achieving spatial and temporal control over chemical reaction cascades. This is analogous to nature’s liquid colloidal systems, where the highest substrate specificities are often not achieved through single recognition events but via a sophisticated positional assembly and spatial separation of biologically or catalytically active reaction centers. Multiple triggering events then transduce into an actuation of a specific reaction cascade, e.g., leading to an immunological response. Similarly, sophisticated artificial Janus droplet–based intelligent multicomponent systems could regulate and modulate chemical reactivity and provide the highest degrees of sensitivity and specificity to liquid-based sensing platforms.Due to their dynamic liquid nature and intrinsic structural responsivity to marginal variations in the force balance of interfacial tensions, Janus emulsions possess an acute sense of their chemical environment. Building on the foundation of both morphological and agglutination assays, advances in the sophistication by which Janus emulsions can be functionalized, stabilized, and organized will certainly be central to evolving droplet-based biosensor technologies. The ability to prepare stimuli-responsive Janus droplets easily and cheaply in any environment, combined with read-out techniques that do not require sophisticated and costly laboratory settings, facilitate in situ monitoring of chemical reactions at the interface and thus provide particular benefits for the development of rapid, on-site detection platforms with increased throughput, distribution, and controllability of assays. For practical considerations, which include environmental sampling, such platforms could involve disposable swab-based test vials with the necessary components distributed in a solution complemented by a locally installed imaging platform. As a result, their miniaturization and distribution could be accomplished through established shipment pathways. Despite this promising potential, the application of Janus emulsion droplets in large-scale single-use swab-based screening devices, that function similarly fast and sophisticated as, e.g., drug screening platforms at airports or antigen test strips, will require a keen understanding of the underlying physico-chemical, morphological, optical, thermodynamic, and dynamic properties of the multicompartment liquid colloids in different environments.The modularity by which the individual interfaces and phase boundaries can be functionalized will further stimulate the rapid development of alternative transduction mechanisms. The unique chemical-morphological-optical coupling inside Janus droplets offers rich opportunities to develop optical read-out concepts. The unique refractive optical properties of the reactive Janus droplets are highlighted by the gravitational alignment of the individual droplet phases and the adjustable refractive index contrast of the dispersed phase liquids. As a result, Janus droplets can manipulate the transmitted light pathway and exhibit intriguing angular anisotropic refraction, reflection, and emission features. Variations in the collected or emitted light intensities of Janus droplet layers can be easily monitored visually or quantitatively using simple fiber-optic setups, e.g., using the light meter of a smartphone camera. Stimuli-responsive colloidal materials that can undergo a trigger-induced switch between a translucent and opaque state, or to reversibly modulate their reflective, refractive, or emissive properties promise to improve and expand the capabilities of current technologies. As such, modular sensing layers based on Janus droplets hold promise to expand the scope and decrease the signal-to-noise ratio in several established refractive index–based sensing technologies, including total internal reflection fluorescence microscopes, dual polarization interferometers, plasmonic resonators, resonant microcavities, or colorimetric iridescent structural color sensing arrays.Today, most Janus emulsion–based sensor paradigms are underpinned by sensitization of droplet interfaces with stimuli-responsive surfactants that are sensitive towards the detection of particular analytes. The design of multi-responsive droplet sensors provides the potential to detect multiple analytes simultaneously and thus to sense complex environments. Modular optically active Janus droplet sensor layers offer facile implementation into sensor arrays, and an intrinsic advantage of optical read-out techniques is that they can be easily multiplexed. Building on the responsive properties that translate external stimuli into a binary on–off state, future efforts will further be directed towards demonstrating the ability of Janus droplets to self-regulate and adapt to multiple triggers in their chemical environment. Biphasic droplets in which more than one stimuli triggers microscale morphological transitions and, in turn, macroscale optical outputs signals could then be used to expand from simple YES or NOT read-outs to building AND/OR logic gate sensor circuits.This is an exciting perspective because Janus droplets can display multiple independent responsive modalities. Next to morphological transitions, droplets can interact with their immediate chemical environment also by reversibly attaching to surfaces, multivalently binding to each other, or exchanging mass non-reciprocally, e.g., mediated by osmotic pressure differences. , 85, 86 Targeting two or more of these separate responsive modalities within a single droplet system will yield adaptive droplet ensembles. The concept of adaptivity requires responsive materials capable to independently and autonomously regulate their responses to different input signals, such as molecular recognition–induced chemical events.  In such Clearly, these approaches will require multidisciplinary collaborative efforts from physicists, chemists, biologists, and engineers, and the intention of this article is to provide a resource and motivate future research developments in advancing concepts and improving biochemical detection paradigms, signal transduction, amplification, and readout technologies. The vision is a facile generation of artificial chemo-intelligent soft colloids that can ultimately rival the complexity and regulatory capabilities of natural systems, which will enable new sensory methods that may surpass the performance of other biochemical sensor technologies in their selectivity, sensitivity, and stability, while maintaining the simplicity and cost-effectiveness of Janus droplet–based modular sensory layers.


Here, we make recommendations for promoting agency based on existing and emerging strategies in neural engineering. The focus is on achieving fast, accurate, and reliable performance while ensuring volitional control over when a decoder is engaged, what exactly is decoded, and how messages are expressed. Additionally, alongside neuroscientific progress within controlled experimental settings, we argue that a parallel line of research must consider how to translate experimental successes into real-world environments. While such research will ultimately require input from prospective users, here we identify and describe design choices inspired by human-factors work conducted in existing fields of assistive technology, which address practical issues likely to emerge in future real-world speech BCI applications.Brain-computer interfaces (BCI) that directly decode speech from brain activity aim to restore communication in people with paralysis who cannot speak. Despite recent advances, neural inference of speech remains imperfect, limiting the ability for speech BCIs to enable experiences such as fluent conversation that promote  Howeverhe world .What might the properties of such an agency-enabling device be? Relative to traditional BCIs that indirectly infer speech through visual cursor control or letter-by-letter using evoked response paradigms , a BCI that directly decodes speech from cortical activity would be efficient, and grant users more immediate access to the rich expressive capabilities of language. Indeed, evidence suggests that people with speech paralysis often prefer strategies that directly decode their speech attempts  and mostUnfortunately, achieving this ideal is nontrivial because neural inference of speech is currently imperfect. Our scientific understanding of both healthy and impaired language production remains incomplete, and current neural interfaces impose limits on the spatiotemporal resolution and signal-to-noise ratio of data, restricting our ability to observe linguistic processes in the brain that would enable robust real-time decoding . As a reTo address these challenges, we consider the neurobiological, linguistic, engineering, and human factors upon which the agency-enabling capacities of a speech BCI depend, and we provide recommendations to guide their development moving forward. We restrict our focus to clinical BCI applications aimed at restoring speech-based communication, and primarily consider intracranial recording modalities due to their demonstrated ability to facilitate real-time speech decoding from brain activity.when users intend to speak. Within those temporal windows, BCIs must know what signals to decode, translating only the dimensions of neural activity associated with communicative information. Finally, BCIs must know how users wish to convey this information and allow for the flexible expression of speech output. Below, we describe existing and emerging strategies that move toward these goals.In order to precisely and reliably broadcast information, speech BCIs must first know A speech BCI must detect the general temporal windows during which users intend to speak. To achieve this, recent BCI systems include a separate speech-detection module that functions prior to decoding speech content in order to identify the temporal onset and offset boundaries of intended speech . Rather Aside from the detection of speech-related windows, decoders must selectively read dimensions of activity corresponding to information that the user wishes to externalize. A critical consideration here is the specific level of the language-production hierarchy associated with the neural signals being decoded. It is well established that spoken language results from a series of hierarchically-organized neural processing steps . An ideaovert speech. By contrast, in order to convey messages, BCI systems may require users with paralysis to engage with speech-decoders in two different ways. First, users may engage in attempted speech, involving a deliberate attempt to articulate. To the extent that residual control of the vocal tract muscles is retained, this may result in vocalization or silent (“mimed”) articulation. Second, users may engage without articulating, typically referred to in the literature as imagined speech. Importantly, despite the absence of articulation, imagined speech is by definition a volitional act with communicative intent. In contrast, we refer to all private processes – ones that lack both articulation and communicative intent – as internal speech. While terminology in reference to these behaviors has been inconsistent across the speech-decoding literature, we stress the need for standardized nomenclature to facilitate collective empirical inquiry into their neural basis.In order to elaborate on these considerations, we first propose a standard terminology in reference to various speech-related behaviors. Healthy speakers produce what we refer to as only remain active during attempted or imagined speech (when speaking is intended) and not during internal speech. The former requirement thus demands sensitivity to communicative dimensions of brain activity, while the latter requirement demands specificity to only those dimensions.While overt speech, by definition, recruits representations across the language-production hierarchy , the extent to which different representations are encoded during attempted, imagined, or internal speech is less clear. For the purpose of conferring agency, speech decoders must target representations that meet two distinct requirements. On one hand, to effectively restore speech to people with paralysis, including to those who are fully locked-in, decoders must target representations that remain sufficiently active even during attempted or imagined speech (when articulation is severely limited or absent). On the other hand, to safeguard mental privacy, decoders must target representations that Let us first address the former requirement. Recently, researchers decoded meaningful sentences from articulatory representations during attempted speech in individuals with severe speech paralysis . This deamodal nature of semantic brain signals allows for decoders that are highly domain-general – perhaps trained to decode during communicative acts but capable of reading speech during altogether non-communicative contexts . Research must focus on whether and how semantic activity differentiates contexts in which intention to communicate is present versus absent.Next, let us consider the requirement that decoders respect mental privacy. While the neural representation of internal speech remains poorly understood, we argue that such private thoughts are unlikely to be encoded within low-level regions associated with motor or sensory processing. As already discussed, articulatory signals are weakly encoded in the absence of a deliberate speech-motor goal . Given tFinally, the communication modality through which speech BCIs ultimately convey output has significant implications for agency and ownership of decoded messages. While text-based communication is an important modality for interfacing with digital technology, synthesis of speech-sounds directly from cortical activity could offer more naturalistic and expressive forms of communication that include linguistic dimensions, such as intonational prosody and syllabic stress patterns, in addition to merely the identity of speech tokens. Traditionally, an approach that incorporates these other dimensions has been challenging in people with paralysis because – in the absence of overtly produced output – the precise temporal alignment between neural activity and intended speech remains unknown. However, modern machine-learning methods that utilize temporal convolutions, data augmentation, and connectionist temporal classification , alleviaWhile the factors discussed so far are critical for providing volitional control, achieving a high-performance speech neuroprosthesis will ultimately require improvements in the neural inference of speech. Such improvements could be realized by better neural interface design, more advanced computational methods, and progress in our neuroscientific understanding of speech production. Intriguingly, improvements may also be realized by introducing knowledge outside of users’ brain activity into the inference process, via the incorporation of language models.Linguistic sequences have statistical structure, such that the probability of possible future outputs are modulated by what came before. Language models (LMs), which have internalized this statistical structure by training on independent large language corpora, are being incorporated into real-time BCI pipelines to aid neural decoding. Currently, the operation of LMs within speech BCIs is analogous to an “autocorrect” function, seeking to improve neural inference either directly at the neural-decoding stage , retrospIn essence, these approaches introduce knowledge outside of users’ brain activity into the inference process, potentially morphing a person’s intended message to conform with the statistical trends found within language corpora. Because of this, concerns have been raised that the incorporation of LMs into decoding pipelines may improve efficiency at the expense of user control . While wWhile we have considered the use of LMs as an “autocorrect” function within BCI pipelines, in principle, they may also be used to predictively generate output, analogous to an “autocomplete” function. Indeed, given that speed is a priority for prospective BCI users, some suggest that until speech can be decoded at fluent conversational rates, “developers should explore rate enhancement features… such as word and phrase prediction” . If LMs As speech BCIs continue to advance in research settings, it is important to keep the primary clinical goal of this technology in focus: to improve autonomy and quality of life for patients who cannot speak. Therefore, in parallel with the continued scientific pursuit of fast, precise, and reliable speech BCIs, research must consider how to translate existing experimental successes into real-world settings in a manner that ultimately realizes those patient benefits.To effectively achieve this transition, we argue that BCI developers should implement human-centered design (HCD) frameworks, soliciting input from those with acute needs and engaging with them in an iterative process of co-design . To our Despite recent advances in speech BCI performance within research settings , decodinGiven that decoded speech is more error-prone than spoken language, there will likely be a need for error-correction capabilities, which is a common feature in traditional AAC devices . Many poFinally, customization over the communication parameters is an important consideration for promoting agency. In traditional AAC devices, users can customize various features of the communication interface, including keyboard layouts, the presence of autocomplete options, the vocabulary of the system, and the voice of the generated speech . Speech In summary, clinically relevant speech BCIs must afford volitional control over when and what is communicated through the device, and how exactly this is expressed. Language-modeling techniques are currently necessary to reach usable performance levels with existing approaches, but the rate of advancement of speech BCIs in recent years illustrates the need to consider how reliance on language models can affect agency. Moving forward, speech BCI research must look beyond the science and toward the ultimate needs of prospective users situated in everyday environments. We advocate for HCD approaches to achieve this. However, in this article we have considered how insights from other domains of assistive technology could address practical issues that speech BCI users are likely to face in real-world contexts.While we have largely focused on software implementations, advances in hardware will also continue to improve the agency-promoting qualities of speech BCIs. Advances in neural interface design will yield better signal resolution (for increased performance), data transmission , and portability . In addiThe original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author.NS: Conceptualization, Formal analysis, Investigation, Writing – original draft. DM: Conceptualization, Formal analysis, Investigation, Writing – review & editing. WC: Supervision, Writing – review & editing. EC: Supervision, Writing – review & editing.


Dear Editor,We read the article “More than 302 million people reached and over 2,200,000 trained in cardiopulmonary resuscitation worldwide: The 2021 ILCOR World Restart a Heart initiative” Published in your journal. The authors emphasized the importance of immediate bystander CPR in saving lives after an out-of-hospital cardiac arrest and encourage year-round CPR training and awareness in all countries.Sudden cardiac arrest (SCA) is a life-threatening condition characterized by the abrupt cessation of cardiac activity, resulting in unresponsiveness, absence of normal breathing, and lack of circulation.Public access defibrillation (PAD) means availability of automated external defibrillators (AEDs) in public or private settings where large groups of people gather or where individuals at high risk for heart attacks reside.However, increasing AED accessibility in India faces challenges such as high costs, maintenance requirements, and lack of public awareness regarding the crucial role that AEDs play in cases of sudden cardiac arrest (SCA). To address these challenges, the government should prioritize AED programs in villages and gradually expand to urban areas. Telephone cardiopulmonary resuscitation (TCPR) programs tailored to laypersons can also be introduced, particularly in developing nations like India, to empower individuals to provide life-saving assistance during SCA.In conclusion, improving CPR training and increasing AED availability in public areas can effectively tackle sudden cardiac arrest cases in India. Collaboration between government agencies, private organizations, and the public is crucial for success. Further research is needed to evaluate the effectiveness of AED programs in India. By collectively addressing these challenges, we can enhance survival rates for SCA and create a healthier, more resilient society.The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.