An integrated wearable microneedle array for the continuous monitoring of multiple biomarkers in interstitial fluid

Harnessing innovation in microneedle technology for Women's healthcare

Women's health management plays a crucial role in modern healthcare, encompassing the prevention, detection, and treatment of female diseases. However, existing technologies often face challenges, such as the invasiveness and discomfort associated with serological testing and injection-based therapies. Microneedles, as an emerging technology in biomedical engineering, demonstrate significant advantages. These micron-sized transdermal devices are applicable in a range of applications, from drug delivery to interstitial fluid sampling, and their painless, minimally invasive nature significantly enhances medication compliance. In recent years, microneedles have been widely utilized in women's health management, showing promising results in early disease prevention and subsequent treatment. Although there are reviews about microneedles applied in disease treatment management, few of them focus on the application of microneedles in the prevention and early detection of women's disease. Herein, we present a comprehensive overview of the current application status of microneedles in women's health management, with a special emphasis on their design and mechanism for disease prevention, and treatment in women. Finally, we discuss the advantages and limitations of microneedles in women's health management, and propose suggestions for future research direction.

A wearable self-aid microneedle chip based on actively transdermal delivery of epinephrine

Epinephrine is important for first aid and usually applied via injection, which is painful and problematic in operation, thereby making it difficult to self-delivery. In this study, a method to actively transdermal delivery of epinephrine is proposed based on incorporating microneedles with iontophoresis, and then a wearable device is fabricated for rapid and controllable self-delivery of epinephrine. The device consists of a hydrogel microneedle array, a conductive drug delivery hydrogel, iontophoresis electrodes, and an encapsulated cartridge with a spring and self-locking micro-mechanism. The microneedles create subcutaneous microchannels, allowing the epinephrine contained in the hydrogel to enter the body under the control of iontophoretic currents. The dosage and rate can be adjusted at different levels by pressing the button so that it can be used by different groups of people for rapid self-aid and recovery from fatigue. The device can be worn in advance if required. In-vitro tests showed that the transdermal delivery rate of the device was between 0.02642 and 0.1059 mg/h cm². As a proof-of-concept application, in-vivo experiments showed that the device could reverse life-threatening shock reactions in a piglet model of hemorrhagic shock through the delivery of epinephrine.

Wide-linearity flexible OFET biosensors for wearable biomarkers detection

Flexible organic field-effect transistor (OFET) sensors, which leverage conjugated π-bonds in organic semiconductor layers to facilitate rapid charge transfer and enhance sensing sensitivity, offer significant advantages for detecting low concentrations of biomarkers in wearable biomedical electronics, such as glucose monitoring for diabetes. However, conventional OFET sensors suffer from a narrow linear range due to limitations in threshold voltage and saturation current. Therefore, a common problem in the field of the OFET-based biomarker sensing is that the narrow linear range of these sensors fails to meet detection requirements. This study addresses this challenge by expanding the linear detection range of OFET glucose sensors to 16.78 μM-1 M through the synergistic integration of four p-type and n-type OFET sensor array. Additionally, to ensure consistency in the fabrication of the sensor array, a fully printed processing technology using a bank structure was developed. Finally, a flexible epidermal continuous blood glucose monitoring system based on the wide-linearity OFET glucose sensor array was constructed to verify its practical feasibility.

Revolutionizing biosensing with wearable microneedle patches: innovations and applications

Wearable microneedle (MN) patches have emerged as a transformative platform for biosensing, offering a minimally invasive and user-friendly approach to real-time health monitoring and disease diagnosis. Primarily designed to access interstitial fluid (ISF) through shallow skin penetration, MNs enable precise and continuous sampling of biomarkers such as glucose, lactate, and electrolytes. Additionally, recent innovations have integrated MN arrays with microfluidic and porous structures to support sweat-based analysis, where MNs act as structural or functional components in hybrid wearable systems. This review explores the design, fabrication, and functional integration of MNs into wearable devices, highlighting advances in multi-analyte detection, wireless data transmission, and self-powered sensing. Challenges related to material biocompatibility, sensor stability, scalability, and user variability are addressed, alongside emerging opportunities in microfluidics, artificial intelligence, and soft materials. Overall, MN-based biosensing platforms are poised to redefine personalized healthcare by enabling dynamic, decentralized, and accessible health monitoring.

Wearable Photonic Device for Multiple Biomarker Sampling and Detection without Blood Draws

Needle-based blood draws or phlebotomy practice in clinics for centuries, often causing pain, discomfort, and inconvenience. Here, a wearable photonic device is presented by integrating a microlens array (MLA) and an optic microneedle array (OMNA) functionalized with immunobinding for safe and needle-free biomarker sampling and detection. The MLA-integrated OMNA amplifies and transmits LED light at 595 nm into skin through the OMNA, bypassing the light-absorbing melanin in the epidermal layer, and evenly distributing it in the capillary-enriched dermis independent of the skin colors. The 595 nm light is absorbed by hemoglobin (Hb) and oxygen-Hb within the capillaries, triggering thermal dilation of capillaries without damaging them or causing petechiae. The light illumination remarkably increases in the concentrations of various blood biomarkers in the skin through biomarker extravasation. These biomarkers bound specifically to the capture antibodies on OMNA with each microneedle covalently immobilized with one specific antibody. The OMNA is extensively modified to amplify the immunobinding signals and achieve sensitivity superior to that of enzyme-linked immunosorbent assay (ELISA) kits. As proof of concept, the functionality of the prototype for minimally invasive sampling and precise multiplexed blood biomarker detection in two mouse models is validated to quantify acute inflammation and specific antibody production.

From population-based to personalized laboratory medicine: continuous monitoring of individual laboratory data with wearable biosensors

Monitoring individuals' laboratory data is essential for assessing their health status, evaluating the effectiveness of treatments, predicting disease prognosis and detecting subclinical conditions. Currently, monitoring is performed intermittently, measuring serum, plasma, whole blood, urine and occasionally other body fluids at predefined time intervals. The ideal monitoring approach entails continuous measurement of concentration and activity of biomolecules in all body fluids, including solid tissues. This can be achieved through the use of biosensors strategically placed at various locations on the human body where measurements are required for monitoring. High-tech wearable biosensors provide an ideal, noninvasive, and esthetically pleasing solution for monitoring individuals' laboratory data. However, despite significant advances in wearable biosensor technology, the measurement capacities and the number of different analytes that are continuously monitored in patients are not yet at the desired level. In this review, we conducted a literature search and examined: (i) an overview of the background of monitoring for personalized laboratory medicine, (ii) the body fluids and analytes used for monitoring individuals, (iii) the different types of biosensors and methods used for measuring the concentration and activity of biomolecules, and (iv) the statistical algorithms used for personalized data analysis and interpretation in monitoring and evaluation.

Bimetallic Metal-Organic Framework Microneedle Array for Wound Healing through Targeted Reactive Oxygen Species Generation and Electron Transfer Disruption

The development of reactive oxygen species (ROS)-based antibacterial strategies that overcome ROS's ultrashort diffusion distance and disrupt bacterial electron transfer represents a promising yet underexplored avenue for nonantibiotic therapies. In this study, we introduce an iron-copper bimetallic metal-organic framework (MOF) with peroxidase (POD)-like enzymatic activity engineered to integrate dual functionalities: bactericidal recognition and electron transfer disruption to synergistically enhance antibacterial efficacy. Mechanistic investigations reveal that boronic-acid-cis-diol interactions enable the MOF to selectively bind to bacterial membranes, where it generates localized ROS, effectively killing bacteria. Concurrently, the alignment of MOF energy levels with the bacterial redox potential facilitates efficient electron transfer from the bacterial membrane to the MOFs, disrupting membrane integrity and inhibiting critical processes such as electron transport and ATP synthesis. When incorporated into biodegradable microneedle patches, the MOF effectively penetrates biofilms and wound exudates, delivering potent antibacterial effects directly to infection sites while simultaneously promoting tissue repair. This strategic combination of bactericidal targeting, electron transfer disruption, and microneedle-mediated delivery highlights the potential of this approach to advance nonantibiotic antibacterial therapies.

A Touch Enabled Hemodynamic and Metabolic Monitor

Accurate health analysis demands real-time tracking of multiple biomarkers and vital signs under dynamic physiological conditions. Current multimodal hybrid platforms provide biochemical and biophysical data but are limited by active sweat collection for biochemical sensing and bulky designs for biophysical sensing. Here a touch-enabled platform is presented that simultaneously monitors vitals and metabolic markers. With a simple tri-finger touch, the platform measures mean arterial pressure and heart rate using photoplethysmography, and glucose, uric acid, and cortisol at rest by leveraging the natural perspiration at the fingertip. Extended studies involving diverse activities reveal strong dynamic interplay among the metabolic and vital profiles, with mean arterial pressure showing the highest sensitivity to cortisol fluctuations. The platform delivers comprehensive health information linking diet, lifestyle, metabolism, and serves as an early metabolic or hormonal stress indicator. Valuable insights gained through the platform position it as a promising tool for personalized health and wellness management.

Use of a Silicon Microneedle Chip-Based Device for the Extraction and Subsequent Analysis of Dermal Interstitial Fluid in Heart Failure Patients

Background/Objectives: Dermal interstitial fluid (dISF) is probably the most interesting biofluid for biomarker analysis as an alternative to blood, enabling higher patient comfort and closer or even continuous biomarker monitoring. The prerequisite for dISF-based analysis tools is having convenient access to dISF, as well as a better knowledge of the presence, concentration, and dynamics of biomarkers in dISF. Hollow microneedles represent one of the most promising platforms for access to pure dISF, enabling the mining of biomarker information. Methods and Results: Here, a microneedle-based method for dISF sampling is presented, where a combination of hollow microneedles and sub-pressure is used to optimize both penetration depth in skin and dermal interstitial fluid sampling volumes, and the design of an open, prospective, exploratory, and interventional study to examine the detectability of inflammatory and cardiocirculatory biomarkers in the dISF of heart failure patients, the relationship between dISF-derived and blood-derived biomarker levels, and their kinetics during a cardiopulmonary exercise test (CPET) is introduced. Conclusions: The dISF sampling method and study presented here will foster research on biomarkers in dISF in general and in heart failure patients in particular. The study is part of the European project DIGIPREDICT-Digital Edge AI-deployed DIGItal Twins for PREDICTing disease progression and the need for early intervention in infectious and cardiovascular diseases beyond COVID-19.

Sustained Release of αO-Conotoxin GeXIVA[1,2] via Hydrogel Microneedle Patch for Chronic Neuropathic Pain Management

Chronic neuropathic pain severely impairs quality of life, with current therapies often causing adverse effects. Our research group identified αO-conotoxin GeXIVA[1,2] as a potent analgesic candidate derived from marine cone snails. However, its clinical application is limited by rapid clearance and complex administration. This study developed a sustained-release hydrogel microneedle patch encapsulating GeXIVA[1,2] to address these challenges. Optimized 4:3 (w/w) polyvinyl alcohol (PVA)-sucrose hydrogel formulation achieved 98.6% structural integrity and controlled swelling (ratio = 1.9 at 48 h). The microneedles demonstrated uniform conical morphology (height: 889 ± 49 µm, base: 381 ± 26 µm) enabling epidermal penetration. In spared nerve injury (SNI) models, a single microneedle patch application increased mechanical paw withdrawal thresholds from 0.056 g to 0.7269 g, maintaining efficacy for 3 days. Chronic constriction injury (CCI) models showed comparable pain relief. Notably, microneedle patch treatment improved locomotor function in SNI mice (total movement: 1518 cm vs. 1126 cm untreated). This hydrogel microneedle patch platform extends GeXIVA[1,2]'s analgesic duration from hours to days through sustained release, while resolving administration challenges through transdermal delivery, expanding the potential applications of GeXIVA[1,2], and demonstrating a promising strategy for the chronic neuropathic pain management.

2D Materials-Based Field-Effect Transistor Biosensors for Healthcare

The need for accurate point-of-care (POC) tools, driven by increasing demands for precise medical diagnostics and monitoring, has accelerated the evolution of biosensor technology. Integrable 2D materials-based field-effect transistor (2D FET) biosensors offer label-free, rapid, and ultrasensitive detection, aligning perfectly with current biosensor trends. Given these advancements, this review focuses on the progress, challenges, and future prospects in the field of 2D FET biosensors. The distinctive physical properties of 2D materials and recent achievements in scalable synthesis are highlighted that significantly improve the manufacturing process and performance of FET biosensors. Additionally, the advancements of 2D FET biosensors are investigated in fatal disease diagnosis and screening, chronic disease management, and environmental hazards monitoring, as well as their integration in flexible electronics. Their promising capabilities shown in laboratory trials accelerate the development of prototype products, while the challenges are acknowledged, related to sensitivity, stability, and scalability that continue to impede the widespread adoption and commercialization of 2D FET biosensors. Finally, current strategies are discussed to overcome these challenges and envision future implications of 2D FET biosensors, such as their potential as smart and sustainable POC biosensors, thereby advancing human healthcare.

Metasurface-enhanced biomedical spectroscopy

Enhancing the sensitivity of biomedical spectroscopy is crucial for advancing medical research and diagnostics. Metasurfaces have emerged as powerful platforms for enhancing the sensitivity of various biomedical spectral detection technologies. This capability arises from their unparalleled ability to improve interactions between light and matter through the localization and enhancement of light fields. In this article, we review representative approaches and recent advances in metasurface-enhanced biomedical spectroscopy. We provide a comprehensive discussion of various biomedical spectral detection technologies enhanced by metasurfaces, including infrared spectroscopy, Raman spectroscopy, fluorescence spectroscopy, and other spectral modalities. We demonstrate the advantages of metasurfaces in improving detection sensitivity, reducing detection limits, and achieving rapid biomolecule detection while discussing the challenges associated with the design, preparation, and stability of metasurfaces in biomedical detection procedures. Finally, we explore future development trends of metasurfaces for enhancing biological detection sensitivity and emphasize their wide-ranging applications.

Printable molecule-selective core-shell nanoparticles for wearable and implantable sensing

Wearable and implantable biosensors are pioneering new frontiers in precision medicine by enabling continuous biomolecule analysis for fundamental investigation and personalized health monitoring. However, their widespread adoption remains impeded by challenges such as the limited number of detectable targets, operational instability and production scalability. Here, to address these issues, we introduce printable core-shell nanoparticles with built-in dual functionality: a molecularly imprinted polymer shell for customizable target recognition, and a nickel hexacyanoferrate core for stable electrochemical transduction. Using inkjet printing with an optimized nanoparticle ink formulation, we demonstrate the mass production of robust and flexible biosensors capable of continuously monitoring a broad spectrum of biomarkers, including amino acids, vitamins, metabolites and drugs. We demonstrate their effectiveness in wearable metabolic monitoring of vitamin C, tryptophan and creatinine in individuals with long COVID. Additionally, we validate their utility in therapeutic drug monitoring for cancer patients and in a mouse model through providing real-time analysis of immunosuppressants such as busulfan, cyclophosphamide and mycophenolic acid.

Rational Design of a New Class of Versatile Enzyme-Based Biosensors

The majority of enzyme-based sensors rely on electrochemical approaches for continuous monitoring. For example, commercially available glucometers are electrochemical-based sensors. However, these sensors are not suitable for contactless monitoring as electron signals require direct conduction from the enzyme reaction site to the signal analyzing unit. Fluorescent dyes, on the other hand, emit photons that can penetrate certain barriers, making them ideal candidates for contactless monitoring. In this study, we investigated the design and functionality of a new class of biosensors based on the conjugation of enzymes with pH-sensitive fluorophores, creating a novel single-molecule biosensor capable of versatile, contactless detection of different disease- and treatment-related biomarkers. We conjugated various enzymes (glucose oxidase, phenylalanine ammonia-lyase, and β-lactamase) with pH-sensitive fluorophores (FITC and pH-sensitive Cy7 derivatives) and tuned linkers' properties to modulate the distance between the enzyme and fluorophore, as well as the hydrophilicity of the linker. The experimental data demonstrate that fluorophore-conjugated enzymes exhibit substrate-dependent fluorescence responses under physiologically relevant buffered conditions, enabling the quantitative analysis of substrate concentrations through fluorescent signal detection. This innovative sensor design not only provides critical insights into enzyme-based fluorescent detection mechanisms but also represents a promising candidate for the development of next-generation contactless biosensing platforms.

Wearable Arduino-Based Electronic Interactive Tattoo: A New Type of High-Tech Humanized Emotional Expression for Electronic Skin

Skin is the largest organ of the human body and holds the functions of sensing, protecting, and regulating. Since ancient times, people have decorated their skin by painting themselves, cutting, and using accessories to express their personality and aesthetic consciousness as a kind of artistic expression, one that shows the development and change of aesthetic consciousness. However, there are concerns regarding the inconvenience, high time cost, and negative body perception with traditional tattoos. In addition, the trend of skin decoration has gradually withdrawn due to a lack of intelligent interaction. In response to these problems, we proposed a wearable electronic skin tattoo that offers a novel means of communication and emotional expression for individuals with communication impairments, WABEIT. The tattoo uses skin-friendly PDMS as the base material, combines multi-mode sensing components such as silver wire circuit, a programmable Surface-Mounted Device (SMD), a thin-film-pressure sensor, and a heart rate sensor, and combines the embedded development board Arduino Nano for intelligent interaction, forming a wearable electronic interactive tattoo capable of sensing the environment, human-computer interaction, and the changeable performance of intelligent perception. The sensor is also equipped with a mobile power supply to support portability. The advantages of WABEIT are as follows: first, it avoids the pain, allergy, and long production process of traditional tattoos. Second, the patterns can adapt to different needs and generate feedback for users, which can effectively express personal emotions. Thirdly, the facility of removal reduces social discrimination and occupational constraints, which is especially suitable for East Asia. Experimental results indicate that the device exhibits a high sensitivity in signal response, a wide variety of pattern changes, and reliable interactive capabilities. The study demonstrates that the proposed design philosophy and implementation strategy can be generalized to the interactive design of other wearable devices, thereby providing novel insights and methodologies for human-computer interaction, electronic devices, and sensor applications.

Sensing the Future of Thrombosis Management: Integrating Vessel-on-a-Chip Models, Advanced Biosensors, and AI-Driven Digital Twins

Thrombotic events, such as strokes and deep vein thrombosis, remain a significant global health burden, with traditional diagnostic methods often failing to capture the complex, patient-specific nuances of thrombosis risk. This Perspective explores the revolutionary potential of microengineered vessel-on-chip platforms in thrombosis research and personalized medicine. We discuss the evolution from basic microfluidic channels to advanced 3D-printed, patient-specific models that accurately replicate complex vascular geometries, incorporating all elements of Virchow's triad. Integrating these platforms with cutting-edge sensing technologies, including wearable ultrasonic devices and electrochemical biosensors, enables real-time monitoring of thrombosis-related parameters. Crucially, we highlight the transformative role of artificial intelligence and digital twin technology in leveraging vast patient-specific data collected from these models. This integration allows for the development of predictive algorithms and personalized digital twins, offering unprecedented thrombosis risk assessment, treatment optimization, and drug screening capabilities. The clinical relevance and validation of these models are examined, showcasing their potential to predict thrombotic events and guide personalized treatment strategies. While challenges in scalability, standardization, and regulatory approval persist, the convergence of vessel-on-chip platforms, advanced sensing, and AI-driven digital twins promises to revolutionize thrombosis management. This approach paves the way for a new era of precision cardiovascular care, offering noninvasive, predictive, and personalized strategies for thrombosis prevention and treatment, ultimately improving patient outcomes and reducing the global burden of cardiovascular diseases.

Wearable flexible ultrasound microneedle patch for cancer immunotherapy

Clinical approaches for cancer therapy face several interrelated challenges involving inefficient drug delivery, potential adverse side effects, and inconvenience. Here, we present an integrated wearable flexible ultrasound microneedle patch (wf-UMP) that serves as a portable platform for convenient, efficient, and minimally invasive cancer therapy. The wf-UMP adopts an all-in-one bioelectronic concept, which integrates a stretchable lead-free ultrasound transducer array for acoustic emission, a bioadhesive hydrogel elastomer for robust adhesion and acoustic coupling, and a dissolvable microneedle patch loaded with biocompatible piezoelectric nanoparticles for painless drug delivery and reactive oxygen species generation. With soft mechanical properties and enhanced electromechanical performance, wf-UMP can be robustly worn on curved and dynamic tissue surfaces for easy and effective manipulation. In preclinical studies involving mice, wf-UMP demonstrated notable anticancer effects by inducing tumor cell apoptosis, amplifying oxidative stress, and modulating immune cell proliferation. Furthermore, the synergistic immunotherapy induced by wf-UMP and Anti-PD1 further improved anticancer immunity by activating immunogenic cell death and regulating macrophages polarization, inhibiting distant tumor growth and tumor recurrence.

Smart Wearable Sensor Fuels Noninvasive Body Fluid Analysis

The advancements in wearable sensor technology have revolutionized noninvasive body fluid monitoring, offering new possibilities for continuous and real-time health assessment. By analyzing body fluids such as sweat, saliva, tears, and interstitial fluid, these technologies provide painless diagnostic alternatives for detecting biomarkers such as glucose, electrolytes, and metabolites. These sensors play a crucial role in early disease detection, chronic condition management, and personalized healthcare. Recent innovations in flexible electronics, microfluidic systems, and biosensing materials have significantly improved the accuracy, reliability, and integration of sensors into everyday textiles. Moreover, the convergence of artificial intelligence and big data analytics has enhanced the precision and personalization of health monitoring systems, transforming wearable sensors into powerful tools for health holographic inspection. Despite significant progress, challenges remain, including improving sensor stability in dynamic environments, achieving real-time data transmission, and covering a broader range of biomarkers. Future research directions focus on enhancing material sustainability through green synthesis, optimizing sampling techniques, and leveraging machine learning to further improve sensor performance. This Review highlights the transformative potential of wearable sensors in medical applications, aiming to bridge gaps in healthcare accessibility and elevate the standards of patient care through noninvasive continuous monitoring technologies.

Machine learning-assisted implantable plant electrophysiology microneedle sensor for plant stress monitoring

Plant electrical signals serve as a medium for long-distance signal transmission and are intricately linked to plant stress responses. High-fidelity acquisition and analysis of plant electrophysiological signals contribute to early stress identification, thereby enhancing agricultural production efficiency. While traditional plant electrophysiology monitoring methods like gel electrodes can capture electrical signals on plant surfaces, which face limitations due to the plant cuticle barrier, impacting signal accuracy. Moreover, the vast and intricate nature of plant electrical signal data, coupled with the absence of specialized large-scale models, impedes signal interpretation and plant physiological correlation. In light of these challenges, we engineered an implantable microneedle array using micromachining technology for monitoring and decoding plant electrical signals in a minimally invasive manner. This innovative sensor can securely adhere to plant tissue over extended periods, enabling the precise recording of electrical signals triggered by transient (mechanical injury) and long-term stresses (drought and salt stress). Based on the collected plant electrophysiological data, we utilized a machine learning model to analyze these signals for the early detection of plant stress with an accuracy of 99.29%. This sensor has great potential and is expected to revolutionize precision agricultural production and provide valuable help in managing plant stress more effectively.

Microneedle technology for enhanced topical treatment of skin infections

Skin infections caused by microbes such as bacteria, fungi, and viruses often lead to aberrant skin functions and appearance, eventually evolving into a significant risk to human health. Among different drug administration paradigms for skin infections, microneedles (MNs) have demonstrated superiority mainly because of their merits in enhancing drug delivery efficiency and reducing microbial resistance. Also, integrating biosensing functionality to MNs offers point-of-care wearable medical devices for analyzing specific pathogens, disease status, and drug pharmacokinetics, thus providing personalized therapy for skin infections. Herein, we do a timely update on the development of MN technology in skin infection management, with a special focus on how to devise MNs for personalized antimicrobial therapy. Notably, the advantages of state-of-the-art MNs for treating skin infections are pointed out, which include hijacking sequential drug transport barriers to enhance drug delivery efficiency and delivering various therapeutics (e.g., antibiotics, antimicrobial peptides, photosensitizers, metals, sonosensitizers, nanoenzyme, living bacteria, poly ionic liquid, and nanomoter). In addition, the nanoenzyme-based multimodal antimicrobial therapy is highlighted in addressing intractable infectious wounds. Furthermore, the MN-based biosensors used to identify pathogen types, track disease status, and quantify antibiotic concentrations are summarized. The limitations of antimicrobial MNs toward clinical translation are offered regarding large-scale production, quality control, and policy guidance. Finally, the future development of biosensing MNs with easy-to-use and intelligent properties and MN-based wearable drug delivery for home-based therapy are prospected. We hope this review will provide valuable guidance for future development in MN-mediated topical treatment of skin infections.

High-density microneedle array-based wearable electrochemical biosensor for detection of insulin in interstitial fluid

The development of point-of-care wearable devices capable of measuring insulin concentration has the potential to significantly improve diabetes management and life quality of diabetic patients. However, the lack of a suitable point-of-care device for personal use makes regular insulin level measurements challenging, in stark contrast to glucose monitoring. Herein, we report an electrochemical transdermal biosensor that utilizes a high-density polymeric microneedle array (MNA) to detect insulin in interstitial fluid (ISF). The biosensor consists of gold-coated polymeric MNA modified with an insulin-selective aptamer, which was used for extraction and electrochemical quantification of the insulin in ISF. In vitro testing of biosensor, performed in artificial ISF (aISF), showed high selectivity for insulin with a linear response between 0.01 nM and 4 nM (sensitivity of ∼65 Ω nM-1), a range that covers both the physiological and the pathological concentration range. Furthermore, ex vivo extraction and quantification of insulin from mouse skin showed no impact on the biosensor's linear response. As a proof of concept, an MNA-based biosensing platform was utilized for the extraction and quantification of insulin on live mouse skin. In vivo application showed the ability of MNs to reach ISF, extract insulin from ISF, and perform electrochemical measurements sufficient for determining insulin levels in blood and ISF. We believe that our MNA-based biosensing platform based on extraction and quantification of the biomarkers will help move insulin assays from traditional laboratory approaches to personalized point-of-care settings.

Nanozyme-based wearable biosensors for application in healthcare

Recent years have witnessed tremendous advances in wearable sensors, which play an essential role in personalized healthcare for their ability for real-time sensing and detection of human health information. Nanozymes, capable of mimicking the functions of natural enzymes and addressing their limitations, possess unique advantages such as structural stability, low cost, and ease of mass production, making them particularly beneficial for constructing recognition units in wearable biosensors. In this review, we aim to delineate the latest advancements in nanozymes for the development of wearable biosensors, focusing on key developments in nanozyme immobilization strategies, detection technologies, and biomedical applications. The review also highlights the current challenges and future perspectives. Ultimately, it aims to provide insights for future research endeavors in this rapidly evolving area.

Implantable photoelectrochemical-therapeutic methotrexate monitoring system with dual-atomic docking strategy

The need for precise modulation of blood concentrations of pharmaceutical molecule, especially for high-risk drugs like Methotrexate (MTX), is underscored by the significant impact of individual variations on treatment efficacy. Achieving selective recognition of pharmaceutical molecules within the complex biological environment is a substantial challenge. To tackle this, we propose a synergistic atomic-molecular docking strategy that utilizes a hybrid-dual single-atom Fe1-Zn1 on a TiO2 photoelectrode to selectively bind to the carboxyl and aminopyrimidine groups of MTX respectively. By integrating this Fe1-Zn1-TiO2 photoelectrode with a microcomputer system, an implantable photoelectrochemical-therapeutic drug monitoring (PEC-TDM) system is developed for real-time, continuous in vivo MTX monitoring. This system facilitates personalized therapeutic decision-making and intelligent drug delivery for individualized cancer therapy, potentially revolutionizing oncological care and enhancing patient outcomes.

A Comprehensive Review of Advanced Lactate Biosensor Materials, Methods, and Applications in Modern Healthcare

Lactate is a key metabolite in cellular respiration, and elevated levels usually indicate tissue hypoxia or metabolic dysregulation. The real-time detection of lactate levels is particularly important in situations such as exercise, shock, severe trauma, and tissue injury. Conventional lactate assays are insufficient to address today's complex and variable testing environments, and thus, there is an urgent need for highly sensitive biosensors. This review article provides an overview of the concept and composition of electrochemical lactate biosensors, as well as their recent advances. Comparisons of popular studies on enzymatic and non-enzymatic lactate sensors, the surface-related materials used for modifications to electrochemical lactate biosensors, and the detection methods commonly used for sensors are discussed separately. In addition, advances in implantable and non-implantable miniaturized lactate sensors are discussed, emphasizing their application for continuous real-time monitoring. Despite their potential, challenges such as non-specific binding, biomaterial interference, and biorecognition element stability issues remain during practical applications. Future research should aim to improve sensor design, biocompatibility, and integration with advanced signal processing techniques. With continued innovation, lactate sensors are expected to revolutionize personalized medicine, helping clinicians to increase treatment efficiency and improve the experience of their use.

Serial Lactate in Clinical Medicine - A Narrative Review

BackgroundBlood lactate is commonly used in clinical medicine as a diagnostic, therapeutic and prognostic guide. Lactate's growing importance in many disciplines of clinical medicine and academic enquiry is underscored by the tenfold increase in publications over the past 10 years. Lactate monitoring is presently shifting from single to serial measurements, offering a means of assessing response to therapy and to guide treatment decisions. With the promise of wearable lactate sensors and their potential integration in electronic patient records and early warning scores, the utility of serial lactate measurement deserves closer scrutiny.MethodsArticles included in this review were identified by searching MEDLINE, PubMed and EMBASE using the term "lactate" alone and in combination with "serial", "point of care", "clearance", "prognosis" and "clinical". Authors were assigned vetting of publications according to their specialty (anesthesiology, intensive care, trauma, emergency medicine, obstetrics, pediatrics and general hospital medicine). The manuscript was assembled in multidisciplinary groups guided by underlying pathology rather than hospital area.FindingsLactate's clinical utility as a dynamic parameter is increasingly recognized. Several publications in the last year highlight the value of serial measurements in guiding therapy. Outside acute clinical areas like the emergency room, operating room or intensive care, obtaining lactate levels is often fraught with difficulty and delays.InterpretationMeasuring serial lactate and lactate clearance offers regular feedback on response to therapy and patient status. Particularly on the ward, wearable devices integrated in early warning scores via the hospital IT system are likely to identify deteriorating patients earlier than having to rely on observations by an often-overstretched nursing workforce.

Self-calibrating multiplexed microneedle electrode array for continuous mapping of subcutaneous multi-analytes in diabetes

Monitoring multiplexed biochemical markers is beneficial for the comprehensive evaluation of diabetes-associated complications. Techniques for multiplexed analyses in interstitial fluids have often been restricted by the difficulties of electrode materials in accurately detecting chemicals in complex subcutaneous spaces. In particular, the signal stability of enzyme-based sensing electrodes often inevitably decreases due to enzyme degradation or interference in vivo. In this study, we developed a self-calibrating multiplexed microneedle (MN) electrode array (SC-MMNEA) capable of continuous, real-time monitoring of multiple types of bioanalytes (glucose, cholesterol, uric acid, lactate, reactive oxygen species [ROSs], Na+, K+, Ca2+, and pH) in the subcutaneous space. Each type of analyte was detected by a discrete MN electrode assembled in an integrated array with single-MN resolution. Moreover, this device utilized an MN-delivery-mediated self-calibration technique to address the inherent problem of decreased accuracy of implantable electrodes caused by long-term tissue variation and enzyme degradation, and this technique might increase the reliability of the MN sensors. Our results indicated that SC-MMNEA could provide real-time monitoring of multiplexed analyte concentrations in a rat model with good accuracy, especially after self-calibration. SC-MMNEA has the advantages of in situ and minimally invasive monitoring of physiological states and the potential to promote wearable devices for long-term monitoring of chemical species in vivo.

Microneedles at the Forefront of Next Generation Theranostics

Theranostics, combining therapeutic and diagnostic functions, marks a revolutionary advancement in modern medicine, with microneedle technology at its forefront. This review explores the substantial developments and multifaceted applications of microneedles, which have evolved from basic transdermal drug delivery devices to sophisticated diagnostic and therapeutic platforms. Microneedles enhance access to biomarkers via interstitial fluid, enabling real-time monitoring of physiological conditions, such as glucose and hormone levels, thus facilitating continuous health tracking. The evolution of microneedle design from solid to dissolvable forms broadens their utility from mere drug delivery to complex sensing and therapeutic applications, including insulin delivery for diabetes management, vaccination, and gene therapy. This paper delves into the integration of microneedles with wearable technologies, highlighting their role in closed-loop systems that combine real-time monitoring with dynamic, precise therapeutic delivery. By addressing gaps in the literature regarding their integrated diagnostic and treatment capabilities, this review underscores the pivotal role of microneedles in personalizing medicine. It concludes with a visionary perspective on the future trajectory of microneedle technology, emphasizing its potential to revolutionize therapeutic strategies through enhanced efficacy, safety, and patient compliance.

Programmable DNA Nanoswitch-Regulated Plasmonic CRISPR/Cas12a-Gold Nanostars Reporter Platform for Nucleic Acid and Non-Nucleic Acid Biomarker Analysis Assisted by a Spatial Confinement Effect

CRISPR/Cas 12a system based nucleic acid and non-nucleic acid targets detection faces two challenges including (1) multiple crRNAs are needed for multiple biomarkers detection and (2) insufficient sensitivity resulted from photobleaching of fluorescent dyes and the low kinetic cleavage rate for a traditional single-strand (ssDNA) reporter. To address these limitations, we developed a programmable DNA nanoswitch (NS)-regulated plasmonic CRISPR/Cas12a-gold nanostars (Au NSTs) reporter platform for detection of nucleic acid and non-nucleic acid biomarkers with the assistance of the spatial confinement effect. Through simply programming the target recognition sequence in NS, only one crRNA is required to detect both nucleic acid and non-nucleic acid biomarkers. The detection limit decreased by ∼196-fold for miRNA-375 and 122-fold for prostate-specific antigen (PSA), respectively. Moreover, versatile evaluation of miRNA-375 and PSA in clinical urine samples can also be achieved, according to which prostate cancer and healthy groups can be well identified.

Integrated Microneedles and Hydrogel Biosensor Platform: Toward a Diagnostic Device for Collection and Dual-Mode Sensing of Monkeypox Virus A29 Protein

The outbreak of the monkeypox epidemic underscores the importance of developing a rapid and sensitive virus detection technique. Microneedles (MNs) offer minimally invasive sampling capabilities, providing a solution for the development of integrated extraction and diagnostic portable devices. Here, we report an integrated MNs and hydrogel biosensor (IMHB) platform, composed of an electronic device, an MN patch, and a hydrogel patch. The IMHB allowed for specific extraction of monkeypox virus (MPXV) directly from lesional skin and virus detection in both electrochemical and colorimetric modes. A bifunctional signal probe 3,3',5,5'-tetramethylbenzidine (TMB) was loaded in a hydrogel patch, providing measurable signals for dual-mode sensing. Additionally, a control area was designed in this platform to collect blank samples from normal skin, enabling ratio analysis and quality control functions. This dual-mode ratiometric sensing strategy exhibited a wide range of 10-1000 ng/mL for MPXV A29 protein, with detection limits of 0.1632 and 0.3017 ng/mL for electrochemical and colorimetric assay, respectively. The developed IMHB platform provides a novel way for rapid on-site determination of MPXV, demonstrating the potential for quick intervention in the early stages of infectious diseases.

Plug-In Design of the Microneedle Electrode Array for Multi-Parameter Biochemical Sensing in Gouty Arthritis

Gouty arthritis is one of the most common forms of inflammatory arthritis and has brought a significant burden on patients and society. Current strategies for managing gout primarily focus on long-term urate-lowering therapy. With the rapid advancement of point-of-care testing (POCT) technology, continuous monitoring of gout-related biomarkers like uric acid (UA) or inflammatory cytokines can provide rapid and personalized diagnosis for gout management. In this study, a plug-in design of a microneedle electrode array (PIMNA) was developed and integrated into a multi-parameter sensing portable system in combination with embedded circuits and a mobile application. The system enabled real-time, in situ, and dynamic monitoring of biomarkers, including UA, reactive oxygen species (ROS), and pH at gouty joints. The multi-parameter monitoring system demonstrated a wide linear response range, excellent selectivity, stability, reproducibility, and reliable signal transmission performance. In vivo experiments demonstrated the real-time monitoring capability of PIMNA for UA, ROS, and pH, showing the potential to facilitate urate-lowering management and inflammation assessment. Prospectively, the system enables quantitative analysis of the complexity and diversity of gout, presenting promising applications in clinical practice. This work provides a unique strategy with potential for broader applications in gout management and arthritic disease treatment.

Reusable gallium-based electrochemical sensor for efficient glucose detection

Among wearable sensing devices, electrochemical sensors are overwhelming in biochemical detection due to their simple design but high sensitivity. Most electrochemical sensors are disposable, which significantly impairs the service life. Here we present a reusable gallium (Ga)-based multilayer electrochemical glucose biosensor to extend noninvasive monitoring of glucose in the interstitial fluid. This multilayer sensor includes Ga as a conductive interconnector, poly(3,4-ethylenedioxythiophene) as an electrode layer to prevent oxidation and metal leakage, a nano-Pt layer to enhance the electrochemical properties, and a nano-Prussian blue layer for reducing the hydrogen peroxide reduction potential. The biosensor can be renewed without causing damage to its overall structure by automatically eliminating the modified nanocomposites via the electrolysis-induced bubbles. The biosensor showed high sensitivity (24.6 μA mM-1 cm-2), wide linear range (0.01-26 mM), excellent stability (i.e., pH, long-term use) and superior selectivity, that is comparable to those of the current electrochemical tools for glucose detection. More importantly, incorporated with the reverse iontophoresis, the Ga-based hybrid sensor was applied as a skin patch on rat for the in vivo noninvasive and continuous monitoring of interstitial fluid glucose. The results showed a good correlation with that measured by blood glucometer. As a whole, this Ga-based electrochemical biosensor should endow new functions like biochemical analysis in biofluids for Ga-based bioelectronic sensing devices, in which almost are physical sensors. We believe that the reusability of electrochemically controllable processes may further inspire the development of more integrated and long-term stable Ga-based biosensing devices.

Wearable Biodevices Based on Two-Dimensional Materials: From Flexible Sensors to Smart Integrated Systems

The proliferation of wearable biodevices has boosted the development of soft, innovative, and multifunctional materials for human health monitoring. The integration of wearable sensors with intelligent systems is an overwhelming tendency, providing powerful tools for remote health monitoring and personal health management. Among many candidates, two-dimensional (2D) materials stand out due to several exotic mechanical, electrical, optical, and chemical properties that can be efficiently integrated into atomic-thin films. While previous reviews on 2D materials for biodevices primarily focus on conventional configurations and materials like graphene, the rapid development of new 2D materials with exotic properties has opened up novel applications, particularly in smart interaction and integrated functionalities. This review aims to consolidate recent progress, highlight the unique advantages of 2D materials, and guide future research by discussing existing challenges and opportunities in applying 2D materials for smart wearable biodevices. We begin with an in-depth analysis of the advantages, sensing mechanisms, and potential applications of 2D materials in wearable biodevice fabrication. Following this, we systematically discuss state-of-the-art biodevices based on 2D materials for monitoring various physiological signals within the human body. Special attention is given to showcasing the integration of multi-functionality in 2D smart devices, mainly including self-power supply, integrated diagnosis/treatment, and human-machine interaction. Finally, the review concludes with a concise summary of existing challenges and prospective solutions concerning the utilization of 2D materials for advanced biodevices.

Microneedle-Based Electrochemical Array Patch for Ultra-Antifouling and Ultra-Anti-Interference Monitoring of Subcutaneous Oxygen

Oxygen saturation is a crucial indicator in the management of various diseases and in preoperative diagnosis, and the detection of oxygen content is valuable in guiding clinical treatment. However, as the classical and dominant oxygen detection strategies, current photoelectric oximeters and electrochemical-based blood gas analyzers often suffer from significant interindividual variation and poor compliance, respectively. In recent years, wearable microneedles (MNs) for analyzing biomarkers in interstitial fluid (ISF) have received great attention and recognition mainly for the reason that the content of the substances distributed in ISF has a better correlation with that in blood circulation compared with other body fluids such as sweat and saliva. Herein, an MN-based electrochemical array system was developed for continuous subcutaneous oxygen sensing, in which gold-modified commercial acupuncture MNs were used as the sensing units, and a tailored mini-workstation, a nonwoven fabric, and a water and air isolation membrane were integrated to fabricate a wearable array patch. Notably, a multifunctional swelling resin with good biocompatibility was adopted to decorate the MN surface as a protective layer and as an electrolyte gel. The swelling resin featured the ability to reduce epidermis secretions during the sensor array penetrating the skin and to decrease the interference of other biomolecules in ISF for oxygen assay during measurement. This proposed array patch can perform the subcutaneous oxygen analysis in the physiological range of 6-150 mmHg with high sensitivity (0.3817 μA/mmHg) and low theoretical limit of detection (5.06 mmHg). It also showed decent stability and selectivity in the presence of several kinds of exogenous and endogenous substances. Finally, the patch accomplished continual monitoring of the subcutaneous oxygen content during long-term physical exercise, showing great potential in providing warning about the hypoxia status of the human body. It could be foreseen that this high-performance patch will play an active role in respiratory disease evaluation, surgical monitoring, and public health care.

Toward precision medicine: End-to-end design and construction of integrated microneedle-based theranostic systems

With the growing demand for precision medicine and advancements in microneedle technology, microneedle-based drug delivery systems have evolved into integrated theranostic platforms. However, the development of these systems is currently limited by the absence of clear conclusions and standardized construction strategies. The end-to-end concept offers an innovative approach to theranostic systems by creating a seamless process that integrates target sampling, sensing, analysis, and on-demand drug delivery. This approach optimizes each step based on data from the others, effectively eliminating the traditional separation between drug delivery and disease monitoring. Furthermore, by incorporating artificial intelligence and machine learning, these systems can enhance reliability and efficiency in disease management, paving the way for more personalized and effective healthcare solutions. Based on the concept of end-to-end and recent advancements in theranostic systems, nanomaterials, electronic components, micro-composites, and data science, we propose a modular strategy for constructing integrated microneedle-based theranostic systems by detailing the methods and functions of each critical component, including monitoring, decision-making, and on-demand drug delivery units, though the total number of units might vary depending on the specific application. Notably, decision-making units are emerging trends for fully automatic and seamless systems and featured for integrated microneedle-based theranostic systems, which serve as a bridge of real-time monitoring, on-demand drug delivery, advanced electronic engineering, and data science for personalized disease management and remote medical application. Additionally, we discuss the challenges and prospects of integrated microneedle-based theranostic systems for precision medicine and clinical application.

mPatch: A Wearable Hydrogel Microneedle Patch for In Vivo Optical Sensing of Calcium

This study presents an in vivo optical hydrogel microneedle platform that measures levels of analytes in interstitial fluid. The platform builds on a previously published technique for molding hydrogel microneedles by developing a composite hydrogel (i.e., PEGDA and polyacrylamide) that is sufficiently stiff to penetrate skin in the hydrated state and whose fluorescence changes dynamically-via a conjugated aptamer-depending on level of analyte. In a demonstration relevant to hypercalcemia, the hydrogel microneedle distinguished varying concentrations of calcium (within a range of 0 to 2 mM, which spans physiologically meaningful variations for hypoparathyroidism) within 10 minutes. In rats, a compact CMOS sensor measuring fluorescence from microneedles distinguished low hypercalcemic (1.7 mM) from high hypercalcemic (2.3 mM) ionized calcium levels as determined from reference blood measurements. Overall, this work demonstrates in vivo feasibility of a concept-which we call mPatch-for an optical hydrogel microneedle to measure small changes in levels of analytes in interstitial fluid, which does not rely on extraction of interstitial fluid out of the dermis.

Recent progress in the 3D printing of microneedle patches for biomedical applications

3D-printed microneedles (MNs) have emerged as a transformative technology in drug delivery, diagnostics, and cosmetics, providing a minimally invasive alternative to traditional methods. This review highlights the advancements in 3D printing technologies, including fused deposition modeling (FDM), digital light processing (DLP), and stereolithography (SLA), which enable the precise fabrication of MNs with customizable geometries and functionalities. The unique ability of MNs to penetrate the stratum corneum facilitates enhanced delivery of therapeutic agents, biosensing capabilities, and improved patient compliance. Recent innovations in MNs design, such as biomimetic structures and optimized geometries, have significantly improved their mechanical properties and drug delivery efficiency. Furthermore, integrating sensing elements within MNs enables real-time monitoring of biomarkers, paving the way for personalized medicine. Despite the promising applications, challenges remain, including regulatory considerations, material biocompatibility, and manufacturing scalability. This review discusses the current state of 3D-printed MNs, their diverse applications, and future directions. By addressing existing limitations and exploring novel materials and hybrid fabrication techniques, 3D-printed MNs have the potential to revolutionize healthcare delivery and improve patient outcomes.

Microneedles: multifunctional devices for drug delivery, body fluid extraction, and bio-sensing

Microneedles represent a miniaturized mechanical structure with versatile applications, including transdermal drug delivery, vaccination, body-fluid extraction, and bio-sensing. Over the past two decades, microneedle-based devices have garnered considerable attention in the biomedicine field, exhibiting the potential for mitigating patient discomfort, enhancing treatment adherence, avoiding first-pass effects, and facilitating precise therapeutic interventions. As an application-oriented technology, the innovation of microneedles is generally carried out in response to a specific demand. Currently, three most common applications of microneedles are drug delivery, fluid extraction, and bio-sensing. This review focuses on the progress in the materials, fabrication techniques, and design of microneedles in recent years. On this basis, the progress and innovation of microneedles in the current research stage are introduced in terms of their three main applications.

Influence of next-generation artificial intelligence on headache research, diagnosis and treatment: the junior editorial board members' vision - part 2

Part 2 explores the transformative potential of artificial intelligence (AI) in addressing the complexities of headache disorders through innovative approaches, including digital twin models, wearable healthcare technologies and biosensors, and AI-driven drug discovery. Digital twins, as dynamic digital representations of patients, offer opportunities for personalized headache management by integrating diverse datasets such as neuroimaging, multiomics, and wearable sensor data to advance headache research, optimize treatment, and enable virtual trials. In addition, AI-driven wearable devices equipped with next-generation biosensors combined with multi-agent chatbots could enable real-time physiological and biochemical monitoring, diagnosing, facilitating early headache attack forecasting and prevention, disease tracking, and personalized interventions. Furthermore, AI-driven advances in drug discovery leverage machine learning and generative AI to accelerate the identification of novel therapeutic targets and optimize treatment strategies for migraine and other headache disorders. Despite these advances, challenges such as data standardization, model explainability, and ethical considerations remain pivotal. Collaborative efforts between clinicians, biomedical and biotechnological engineers, AI scientists, legal representatives and bioethics experts are essential to overcoming these barriers and unlocking AI's full potential in transforming headache research and healthcare. This is a call to action in proposing novel frameworks for integrating AI-based technologies into headache care.

Engineering the Functional Expansion of Microneedles

Microneedles (MNs), composed of an array of micro-sized needles and a supporting base, have transcended their initial use to replace hypodermic needles in drug delivery and fluid collection, advancing toward multifunctional platforms. In this review, four major areas are summarized in interdisciplinary engineering approaches combined with MNs technology. First, electronics engineering, the most extensively researched field, enables applications in biomonitoring, electrical stimulation, and closed-loop theranostics through the generation, transmission, and transformation of electrical signals. Second, in electromagnetic engineering, the responsiveness of electromagnetic induction offers prospects for remote and programmable therapeutic applications. Third, photonic engineering endows MNs with novel functionalities, such as waveguiding and photonic manipulation to enhance optical therapeutic capabilities and facilitate the visualization of disease progression and treatment processes. Lastly, it reviewed the role of mechanical engineering in conferring shape adaptability and programmable motion features necessary for various MNs applications. This review focuses on the functionalities that emerge from the intersection of MNs with complementary engineering technologies, aiming to inspire further research and innovation in microneedle technology for biomedical applications.

Wearable Electrochemical Biosensors for Advanced Healthcare Monitoring

Recent advancements in wearable electrochemical biosensors have opened new avenues for on-body and continuous detection of biomarkers, enabling personalized, real-time, and preventive healthcare. While glucose monitoring has set a precedent for wearable biosensors, the field is rapidly expanding to include a wider range of analytes crucial for disease diagnosis, treatment, and management. In this review, recent key innovations are examined in the design and manufacturing underpinning these biosensing platforms including biorecognition elements, signal transduction methods, electrode and substrate materials, and fabrication techniques. The applications of these biosensors are then highlighted in detecting a variety of biochemical markers, such as small molecules, hormones, drugs, and macromolecules, in biofluids including interstitial fluid, sweat, wound exudate, saliva, and tears. Additionally, the review also covers recent advances in wearable electrochemical biosensing platforms, such as multi-sensory integration, closed-loop control, and power supply. Furthermore, the challenges associated with critical issues are discussed, such as biocompatibility, biofouling, and sensor degradation, and the opportunities in materials science, nanotechnology, and artificial intelligence to overcome these limitations.

Self-Extracting Dextran-Based Hydrogel Microneedle Arrays with an Interpenetrating Bioelectroenzymatic Sensor for Transdermal Monitoring with Matrix Protection

Continuous glucose monitors have revolutionized diabetes management, yet such devices are limited by their cost, invasiveness, and stability. Microneedle (MN) arrays could offer improved comfort compared to invasive implanted or mm-sized needle devices, but such arrays are hampered by complex fabrication processes, limited mechanical and sensor stability, and/or cytotoxicity concerns. This work demonstrates the first crosslinked hydrogel microneedle-bioelectroenzymatic sensor arrays capable of biomarker extraction and robust transdermal continuous monitoring in artificial interstitial fluid for 10 days. The fabrication process via micromolding of dextran-methacrylate (Dex-MA) and dry-state visible light crosslinking is simple and permits the robust fixation of diverse prefabricated electrodes in a single array. Dry-state crosslinking minimized material shrinkage to enable the formation of resistant Dex-MA microneedles with shape control and reproducibility. The polymer substitution level (9-62%) and mass content (10-30 wt%) affect the mechanical, swelling, and bioelectrocatalytic properties of the integrated sensors. Crosslinked Dex-MA hydrogel matrices provide beneficial cytotoxicity protection and flux-limiting membrane properties to the integrated second generation dehydrogenase-based nanostructured buckypaper biosensor and Ag/AgCl reference electrodes. Polysaccharide-based microneedle technology with encapsulated porous bioelectrodes promise to be a valuable alternative to more invasive devices for safer and longer-term biomarker monitoring.

Active-matrix extended-gate field-effect transistor array for simultaneous detection of multiple metabolites

With the deepening understanding of diseases, increasing attention has been paid to personalized healthcare and precise diagnosis, which usually depend on the simultaneous monitoring of multiple metabolites, therefore requiring biological sensing systems to possess high sensitivity, specificity, throughput, and instant monitoring capabilities. In this work, we demonstrated the active-matrix extended-gate field-effect transistor (AMEGFET) array that can perform instant analysis of various metabolites in small amounts of body fluids collected during routine physiological activities. The extended gate electrodes of the AMEGFETs comprise ordered mesoporous carbon fibers loaded with both oxidoreductase enzymes for specific metabolites and platinum nanoparticles. By selecting customized electrode combinations, the AMEGFET array can monitor the concentrations of metabolites closely associated with chronic diseases and lifestyles, such as glucose, uric acid, cholesterol, ethanol, and lactate. The switch function of AMEGFET not only simplifies the readout circuitry for large-scale arrays but also avoids the mutual interferences among sensing units. The high flexibility and scalability make the AMEGFET array widely applicable in establishing high-throughput sensing platforms for biomarkers, providing highly efficient technical support for proactive health and intelligent healthcare.

Physiological monitoring for occupational heat stress management: recent advancements and remaining challenges

Occupational heat stress poses a major threat to worker health and safety that is projected to worsen with global warming. To manage these adverse effects, most industries rely on administrative controls (stay times and work-to-rest allocations) that are designed to limit the rise in body core temperature in the "average" individual. However, due to the extensive inter- and intra-individual variation in thermoregulatory function, these administrative controls will result in some individuals having their work rate and productivity unnecessarily restricted (false positives), while others may be subject to rises in heat strain that compromise health (false negatives). Physiological monitoring has long been touted as a more effective approach for individualized protection from excessive heat stress. This has led to extensive interest in the use of wearable technology for heat stress management from both the scientific community and manufacturers of wearable devices, which has accelerated in the past decade. In this review, we evaluate the merits of the recent and emerging approaches to manage occupational heat strain with wearable physiological monitors. Against this background, we then describe the issues that we perceive to be unresolved regarding the use of wearable heat strain monitors and the research efforts needed to address those issues. Particular emphasis is directed to the efficacy of existing physiological indicators of heat strain, how to define upper limits for those indicators and the efforts required to rigorously validate emerging wearable heat strain monitoring devices.

Wearable Systems of Reconfigurable Microneedle Electrode Array for Subcutaneous Multiplexed Recording of Myoelectric and Electrochemical Signals

The real-time monitoring of in vivo electrophysiological and biochemical signals provides critical insights into the activities of tissues and organs. As the activity and metabolic state of different sites in the muscle vary, multichannel detection is necessary to capture the functional state of the whole muscle, yet the access to the bio-information in subcutaneous space remained challenging. This work reports the development of a reconfigurable microneedle electrode array integrated system designed to achieve painless and minimally invasive monitoring of subcutaneous electromyogram (EMG), oxygen species, and pH through an array of thumbtack-shaped microneedle (TSMN) electrode. By assembling discrete TSMNs into an array, the system enables multi-parameter detection with single microneedle resolution. The PEDOT: PSS layer is electrochemically deposited on the TSMNs, enhancing their signal-sensing capabilities and electrochemical properties. Additionally, the design of the pogo pin interface ensures reliable signal transmission and stable device performance, while allowing flexible replacement of the TSMNs, which enhances system maintainability and longevity. Validation experiments conducted on in vivo animal models demonstrate the system's capability in real-time monitoring of muscle fatigue and indicators related to sciatic nerve injury. These results advance the development of wearable technologies for monitoring subcutaneous physiological and biochemical information for diagnosing neuromuscular disorders.

Microneedle Electrode Patch Modified with Graphene Oxide and Carbon Nanotubes for Continuous Uric Acid Monitoring and Diet Management in Hyperuricemia

Hyperuricemia is a common disorder induced by purine metabolic abnormality, which will further cause chronic kidney disease, cardiovascular disease, and gout. Its main pathological characteristic is the high uric acid (UA) level in the blood, so that the detection of UA is highly important for hyperuricemia diagnosis and therapy. Herein, we report a biocompatible and minimally invasive microneedle electrode patch (MEP) for continuous UA monitoring and diet management in hyperuricemia. The composite of graphene oxide and carboxylated multiwalled carbon nanotubes was modified on the microneedle electrode surface to enhance its sensitivity, selectivity, and stability, thus realizing the continuous detection of UA in the interstitial fluid to accurately predict the UA level in the blood. This further allowed us to study the hypouricemic effect of anthocyanins on the hyperuricemia model mouse. It was found that anthocyanins extracted from blueberry can effectively inhibit the activity of xanthine oxidase to reduce the production of UA. The UA level of hyperuricemia model mice fed with anthocyanins is ∼1.7 fold lower than that of the control group. We believe that this MEP offers enormous promise for continuous UA monitoring and diet management in hyperuricemia.

Active-reset protein sensors enable continuous in vivo monitoring of inflammation

Continuous measurement of proteins in vivo is important for real-time disease management and prevention. Implantable sensors for monitoring small molecules such as glucose have been available for more than a decade. However, analysis of proteins remains an unmet need because the lower physiological levels require that sensors have high affinities, which are linked to long complexation half-lives (t1/2 ~20 hours) and slow equilibration when concentrations decrease. We report active-reset sensors by use of high-frequency oscillations to accelerate dissociation, which enables regeneration of the unbound form of the sensor within 1 minute. When implemented within implanted devices, these sensors allow for real-time, in vivo monitoring of proteins within interstitial fluid. Active-reset protein sensors track biomarker levels on a physiological timescale for inflammation monitoring in living animals.

Synergistic Strategies of Biomolecular Transport Technologies in Transdermal Healthcare Systems

Transdermal healthcare systems have gained significant attention for their painless and convenient drug administration, as well as their ability to detect biomarkers promptly. However, the skin barrier limits the candidates of biomolecules that can be transported, and reliance on simple diffusion poses a bottleneck for personalized diagnosis and treatment. Consequently, recent advancements in transdermal transport technologies have evolved toward active methods based on external energy sources. Multiple combinations of these technologies have also shown promise for increasing therapeutic effectiveness and diagnostic accuracy as delivery efficiency is maximized. Furthermore, wearable healthcare platforms are being developed in diverse aspects for patient convenience, safety, and on-demand treatment. Herein, a comprehensive overview of active transdermal delivery technologies is provided, highlighting the combination-based diagnostics, therapeutics, and theragnostics, along with the latest trends in platform advancements. This offers insights into the potential applications of next-generation wearable transdermal medical devices for personalized autonomous healthcare.

Advances in the combination of stem cell exosomes with medical devices-the new direction for combination products

Exosomes (exos), nanoscale extracellular vesicles, play a critical role in tissue development and function. Stem cell-derived exos, containing various tissue repair components, show promise as natural therapeutic agents in disease treatment and regenerative medicine. However, challenges persist in their application, particularly in targeted delivery and controlled release, which are crucial for enhancing their biological efficacy. The integration of medical devices may provide a superior platform for improving drug bioavailability. Consequently, the combination products of stem cell-derived exos and medical devices present novel opportunities for expanding the therapeutic potential of exosomes. This review offers a comprehensive overview of the current research frontier in stem cell-derived exos combined with medical devices and discusses the prospective challenges and future prospects in this field.

Beyond Glucose Monitoring: Multianalyte Sensor Use in Diabetes

The incidence, prevalence, mortality, and health expenditure associated with diabetes continue to grow, despite efforts. The use of multianalyte sensors, which detect glucose as well as key analytes such as ketones, lactate, insulin, uric acid, and electrolytes, may provide additional information to guide earlier identification and management of diabetes and its complications. We undertook a narrative review using a systematic approach in May 2023, with a bridge search undertaken in April 2024. Four biomedical databases were searched: MEDLINE (Ovid), Embase, Emcare, and Cochrane Library. Searches for gray literature were conducted on ClinicalTrials.gov, Google Scholar, and websites of relevant organizations. Included studies incorporated articles on multianalyte sensors in diabetes and single-analyte sensors proposing integration into multianalyte diabetes management, with no limits placed on publication date and study design. Data were screened and extracted using CovidenceTM software. Overall, 11 articles were included, of which 7 involved multianalyte sensors (involving glucose and other analytes) and 4 single-analyte sensors (measuring non-glucose substances for proposed future integration into multianalyte systems). Analytes examined were ketones (n = 3), lactate (n = 4), uric acid (n = 3), insulin (n = 1), and potassium (n = 1). Results demonstrated that in vitro and in vivo measurements of multi- and single-analyte sensors accurately and reliably corresponded with human capillary and serum samples. While the literature on this topic is sparse, our review demonstrated that measurement of glucose and other analytes can be feasibly undertaken using multi- and single-analyte sensors. More studies in humans are needed to establish clinical utility in diabetes self-management and assist with technological improvements.

Applied body-fluid analysis by wearable devices

Wearable sensors are a recent paradigm in healthcare, enabling continuous, decentralized, and non- or minimally invasive monitoring of health and disease. Continuous measurements yield information-rich time series of physiological data that are holistic and clinically meaningful. Although most wearable sensors were initially restricted to biophysical measurements, the next generation of wearable devices is now emerging that enable biochemical monitoring of both small and large molecules in a variety of body fluids, such as sweat, breath, saliva, tears and interstitial fluid. Rapidly evolving data analysis and decision-making technologies through artificial intelligence has accelerated the application of wearables around the world. Although recent pilot trials have demonstrated the clinical applicability of these wearable devices, their widespread adoption will require large-scale validation across various conditions, ethical consideration and sociocultural acceptance. Successful translation of wearable devices from laboratory prototypes into clinical tools will further require a comprehensive transitional environment involving all stakeholders. The wearable device platforms must gain acceptance among different user groups, add clinical value for various medical indications, be eligible for reimbursements and contribute to public health initiatives. In this Perspective, we review state-of-the-art wearable devices for body-fluid analysis and their translation into clinical applications, and provide insight into their clinical purpose.