Yonggang Huang

Stable mounting is a central requirement for skin-interfaced wearable biomedical devices, because accurate and long-term measurements with clinical utility typically demand intimate contact with the skin, whereas practical use also requires gentle removal to minimize skin irritation and damage. Existing mounting strategies often struggle to satisfy these competing requirements simultaneously, especially under prolonged wear or in the presence of sweat and moisture. Suction-based mounting has recently emerged as a promising alternative because it can provide strong, reversible, and adhesive-free attachment, yet its underlying mechanics remain insufficiently understood. Here, we establish analytical models for the deformation and force of suction cups in a fully explicit form, covering both the cone suction cup and an optimized ring suction cup design. Unlike previous approaches that rely on indirect quantities such as the pressure difference and contact radius, which are not available before experiments and therefore cannot serve as controllable design variables, the present framework yields direct relations between suction performance and geometry parameters, material properties, and loading conditions, including the maximum push down displacement and the subsequent pull up displacement. The resulting formulas agree closely with accurate numerical solutions and lead to compact scaling laws that clearly identify how geometry and material parameters govern suction performance. These results provide a quantitative and physically transparent foundation for the design of suction-based mounting strategies in wearable devices.

ABSTRACT Accurate measurement of biofluid flow rate is critical for clinical diagnostics and physiological monitoring, such as in cerebrospinal fluid shunt assessment and vascular blood flow evaluation. Thermal flow sensors, particularly hot‐film and calorimetric types, are widely used in biomedical settings due to their broad dynamic range and long‐term stability. However, their performance declines at high flow rates. To overcome this drawback, we propose a transient heating method that applies a short‐duration thermal pulse and tracks the peak temperature response. This method, validated by experiments using artificial blood and vessels, significantly improves sensitivity to the flow rate change at high flow rates and reduces energy consumption. There exists an optimal heating time to maximize sensitivity to the flow rate. A contour plot of flow rate sensitivity vs. the heating time and flow rate is obtained to guide the selection of optimal heating time for different flow conditions.

Pressure ulcers remain a persistent challenge in healthcare, particularly for individuals with limited mobility or compromised sensation. Early detection is critical to prevent ischemic damage leading to necrosis, infections, and prolonged hospital stays. Conventional sensing technologies that integrate into the mattress, while effective in gathering data on pressure distributions, are restricted to stationary environments, and they can miss significant periods when patients leave their beds or shift positions. Furthermore, these systems do not offer consistent information on the specific spatial distribution of pressure across the body, because the sensors integrate with the mattress and not the body. Recent research establishes capabilities in soft, skin-interfaced wireless alternatives, but in designs that require specialized processes and materials that might not scale effectively for practical production and use. Here, we present a wireless, skin-integrated pressure monitoring system that mounts on the skin, in anatomically matched forms and with soft mechanical interfaces, for continuous data collection. This platform, built on manufacturable components and designs, features an array of soft, elastomer-encapsulated pressure sensors that minimize discomfort, with wireless communications and an independent power management system to enable operation across diverse healthcare settings, including homes, outpatient facilities, and operating rooms, all without physical tethers. Additionally, an external alarm satellite device delivers vibratory and visual alerts if predefined pressure thresholds are exceeded, guiding caregivers or patients to take timely action. Experimental and finite element analysis support the design principles, and deployments on patients in hospital settings illustrate modes for practical use.

Recently reported winged microelectronic systems offer passive flight mechanisms as a dispersal strategy for purposes in environmental monitoring, population surveillance, pathogen tracking, and other applications. Initial studies indicate potential for technologies of this type, but advances in structural and responsive materials and in aerodynamically optimized geometries are necessary to improve the functionality and expand the modes of operation. Here, we introduce environmentally degradable materials as the basis of 3D fliers that allow remote, colorimetric assessments of multiple environmental parameters-pH, heavy metal concentrations, and ultraviolet exposure, along with humidity levels and temperature. Experimental and theoretical investigations of the aerodynamics of these systems reveal design considerations that include not only the geometries of the structures but also their mass distributions across a range of bioinspired designs. Preliminary field studies that rely on drones for deployment and for remote colorimetric analysis by machine learning interpretation of digital images illustrate scenarios for practical use.

The electron multiplication efficiency of microchannel plates (MCPs) is fundamentally determined by their secondary electron emission characteristics. This study investigates the gain performance of MCPs modified with atomic layer deposited (ALD) aluminum oxide (Al₂O₃) films—known for their high secondary electron yield. Systematic experiments were conducted with varying ALD cycle numbers (20, 50, 100, and 150) to deposit Al₂O₃ films on the inner microchannel surfaces. Results reveal a non-monotonic relationship between the gain and the deposition cycle, with the extreme gain observed at 50 cycles. Beyond this optimal point, further increases in cycle number (e.g., 100–150 cycles) led to a noticeable gain degradation. These findings establish a clear correlation between the ALD deposition cycle and the MCP electron gain, providing valuable insights for the surface refinement of electron multiplication devices. The proposed ALD modification strategy offers a promising approach for developing high-performance MCP.

Neuronal control of skeletal muscle function is ubiquitous across species for locomotion and doing work. In particular, emergent behaviors of neurons in biohybrid neuromuscular systems can advance bioinspired locomotion research. Although recent studies have demonstrated that chemical or optogenetic stimulation of neurons can control muscular actuation through the neuromuscular junction (NMJ), the correlation between neuronal activities and resulting modulation in the muscle responses is less understood, hindering the engineering of high-level functional biohybrid systems. Here, we developed NMJ-based biohybrid crawling robots with optogenetic mouse motor neurons, skeletal muscles, 3D-printed hydrogel scaffolds, and integrated onboard wireless micro-light-emitting diode (μLED)-based optoelectronics. We investigated the coupling of the light stimulation and neuromuscular actuation through power spectral density (PSD) analysis. We verified the modulation of the mechanical functionality of the robot depending on the frequency of the optical stimulation to the neural tissue. We demonstrated continued muscle contraction up to 20 minutes after a 1-minute-long pulsed 2-hertz optical stimulation of the neural tissue. Furthermore, the robots were shown to maintain their mechanical functionality for more than 2 weeks. This study provides insights into reliable neuronal control with optoelectronics, supporting advancements in neuronal modulation, biohybrid intelligence, and automation.

Assessing the mechanical properties of soft tissues holds broad clinical relevance. Advances in flexible electronics offer possibilities for wearable monitoring of tissue stiffness. However, existing technologies often rely on tethered setups or require frequent calibration, restricting their use in ambulatory environments. This study introduces a mechano-acoustic wave sensing technology for automated, wireless elastography. The patch-form sensor maintains conformal contact with the skin, regardless of body motion or deformation. It provides continuous, depth-sensitive estimation of subcutaneous tissue stiffness through real-time surface wave dispersion analysis. Theoretical and experimental investigations on phantom materials and tissues spanning a wide range of Young's modulus (in kilopascals to megapascals) demonstrate the capability of the device to rapidly and robustly evaluate the stiffness at depths up to several centimeters. The device shows compatibility with various tissue models, with results consistent with in-parallel ultrasound elastography measurements. Deployment of the device during exercises confirms its viability for ambulatory monitoring, enabling continuous assessment of variation in tissue stiffness.

Analytical solutions of diffusion theory for light propagation in turbid media are essential for optical diagnostics and therapeutic applications, including cerebral oximetry, hemodynamic monitoring, and photostimulation. While existing solutions work reasonably well for collimated light sources-lasers and optical fibers-analytical solutions for LEDs remain missing, despite the growing use of LEDs in wearable and implantable bioelectronics. We present a method to solve the diffusion theory and derive analytical solutions for two biomedically relevant configurations: 1) surface-mounted LEDs on semi-infinite media (e.g., wearable devices) and 2) embedded LEDs in infinite media (e.g., implantable devices). Beyond a distance of 4 times the scattering length of the medium to the LED source, our analytical solutions are reasonably accurate, within 6% error for 1) and 3% for 2). This represents significant improvements over existing analytical solutions, characterized by 26% and 15% error, respectively. Using our analytical solutions, we derive tissue optical properties ([Formula: see text] and [Formula: see text]) from diffuse reflectance results with <7% error, and we determine the irradiance threshold for photostimulation, aligned with experimental optogenetic activation data. Our analytical solutions are readily adaptable to various biomedical applications, offering a rigorous theoretical foundation for next-generation LED-based bioelectronics, to enable more accurate optical diagnostics and therapies in clinical applications.

Abstract Emerging classes of wearable microfluidic sensors of eccrine sweat enable non‐invasive and real‐time monitoring of health status in applications that range from sports to worker safety, environmental exposures, and medical care. Opportunities for improving the performance of these systems include those in colorimetric detection of biochemical species with high accuracy across a wide dynamic range, in efficient collection of sweat and local measurements of sweat loss across a broad spectrum of sweat rates, and in an expanded set of biomarker targets. This paper introduces concepts in 3D microfluidic structures, surface chemistry, interface design, and colorimetric chemical reagents that address these opportunities. Demonstrations involve accurate quantification of sweat rate and total loss over a wide range, as well as precise colorimetric sensing of chloride, xanthine, and creatinine, as biomarkers associated with electrolyte balance, purine metabolism, and kidney function, respectively. Benchtop evaluations confirm high sensitivity and reproducibility, while on‐body trials illustrate reliable biomarker tracking in response to dietary intake and physiological activity. These ideas and chemistries expand the possibilities in sweat‐based diagnostic strategies, in strategies that have the potential to align with established, high‐volume manufacturing practices for commercial production.

Quantum hydrodynamic theory (QHT) provides a computationally efficient alternative to time-dependent density functional theory for simulating plasmonic nanostructures, but its predictive power depends critically on the choice of ground-state electron density and energy functional. We present OF-PGSLN, a scalable and accurate QHT framework that integrates orbital-free (OF) density functional theory with a Laplacian-level kinetic energy functional (PGSLN). We calibrate the model using density functional theory and time-dependent density functional theory for sodium jellium nanospheres, determining optimal parameters to reproduce both ground-state density and localized surface plasmon resonances. Our results show that OF-PGSLN accurately captures the size-dependent localized surface plasmon energies and oscillator strengths with less computational cost. We further apply the method to sodium nanodimers and find that the commonly used linear superposition of single-sphere density becomes inaccurate at sub-nanometer gaps. In contrast, OF-PGSLN captures critical interaction-induced changes in electron density and optical response. This approach overcomes key limitations of existing QHT models by enabling accurate and stable simulations for arbitrary nanostructures beyond simple geometries. Overall, OF-PGSLN provides a scalable, accurate, and generalizable framework for quantum plasmonic simulations, offering a powerful tool for modeling complex nanostructures.

The increasing demand for continuous, comprehensive physiological information captured by skin-interfaced wireless sensors is hindered by their relatively high-power consumption and the associated patient discomfort that can follow from the use of high capacity batteries. This paper presents an adaptive electronics platform and a tri-modal energy harvesting approach to reduce the need for battery power. Specifically, the schemes focus on sensors that involve light in their operation, through use of (i) photometric methods, where ambient light contributes directly to the measurement process, (ii) multijunction photovoltaic cells, where ambient light powers operation and/or charges an integrated battery, and (iii) photoluminescent packaging, where ambient light activates light-emitting species to enhance the first two schemes. Additional features of interest are in (i) in-sensor computational approaches that decrease the bandwidth and thus the energy consumption in wireless data communication and (ii) radio frequency power transfer for battery charging. These ideas have utility across broad other classes of wearable devices as well as small, portable electronic gadgetry.

Accurate identification of sleep stages and disorders is crucial for maintaining health, preventing chronic conditions, and improving diagnosis and treatment. Direct respiratory measurements, as key biomarkers, are missing in traditional wrist- or finger-worn wearables, which thus limit their precision in detection of sleep stages and sleep disorders. By contrast, this work introduces a simple, multimodal, skin-integrated, energy-efficient mechanoacoustic sensor capable of synchronized cardiac and respiratory measurements. The mechanical design enhances sensitivity and durability, enabling continuous, wireless monitoring of essential vital signs (respiration rate, heart rate and corresponding variability, temperature) and various physical activities. Systematic physiology-based analytics involving explainable machine learning allows both precise sleep characterization and transparent tracking of each factor's contribution, demonstrating the dominance of respiration, as validated through a diverse range of human subjects, both healthy and with sleep disorders. This methodology enables cost-effective, clinical-quality sleep tracking with minimal user effort, suitable for home and clinical use.

Wireless bioresorbable electrical stimulators have broad potential as therapeutic implants. Such devices operate for a clinically relevant duration and then harmlessly dissolve, eliminating the need for surgical removal. A representative application is in treating peripheral nerve injuries through targeted stimulation at either proximal or distal sites, with operation for up to one week. This report introduces enhanced devices with additional capabilities: (1) simultaneous stimulation of both proximal and distal sites, and (2) robust operation for as long as several months, all achieved with materials that naturally resorb by hydrolysis in surrounding biofluids. Systematic investigations of the materials and design aspects highlight the key features that enable dual stimulation and with enhanced stability. Animal model studies illustrate beneficial effects in promoting peripheral nerve regeneration, as quantified by increased total muscle and muscle fiber cross-sectional area and compound muscle action potentials. These findings expand the clinical applications of bioresorbable stimulators, particularly for long-term nerve regeneration and continuous neuromodulation-based monitoring. Wireless bioresorbable stimulators are promising therapeutic implants that naturally dissolve after use. Here, the authors developed a device that operates for months and enables simultaneous multi-site stimulation, preventing early muscle atrophy and accelerating reinnervation in nerve injury models.

Abstract Titanium nitride film was deposited on a glass substrate by reactive magnetron sputtering. The composition and structure of the film were studied by SEM, XRD and XPS. The results show that the atomic ratio of titanium to nitrogen in the film is TiN1.05, and the crystal orientation of the film is mainly TiN (111). The optical properties of titanium nitride films in the wavelength range from 380nm to 2500nm were studied in detail using a spectral ellipsometer. Four commonly used dispersion models including Gaussian and Lorentz are compared to resolve the fitting effect of the ellipsometry spectrum of titanium nitride films. The fitting results were validated by reflection and transmission spectra. The results show that the Lorentz model combined with the Drude model is the best fit for the elliptic spectrum of titanium nitride films over the entire range of bands tested.

The sense of touch conveys critical environmental information, facilitating object recognition, manipulation, and social interaction, and can be engineered through haptic actuators that stimulate cutaneous receptors. An unfulfilled challenge lies in haptic interface technologies that can engage all the various mechanoreceptors in a programmable, spatiotemporal fashion across large areas of the body. Here, we introduce a small-scale actuator technology that can impart omnidirectional, superimposable, dynamic forces to the surface of skin, as the basis for stimulating individual classes of mechanoreceptors or selected combinations of them. High-bit haptic information transfer and realistic virtual tactile sensations are possible, as illustrated through human subject perception studies in extended reality applications that include advanced hand navigation, realistic texture reproduction, and sensory substitution for music perception.

The dynamic change in fractional vegetation cover （FVC） in arid areas is an important basis for the development and evolution of desertification as well as critical component land desertification control. Using Hebukeser （also known as Hefeng）, a typical arid zone county, as the study area, we analyzed the changes in the ecological landscape pattern of vegetation with different coverages； investigated the dynamic changes of landscapes with different FVC from the perspectives of change frequency statistics, geocoding method, and migration of the center； and elaborated on the dynamic shift of various types of landscapes and the rule of migration of the center. The finding showed that： Over the course of the 20-year period, the county's average FVC increased from 18.00%-20.39%. Notable differences were observed in the county's spatial distribution, with low FVC predominating and very high and high FVC primarily distributed in the northern and central villages. The area with four changes in vegetation cover accounted for 71.98% of the total area, primarily representing the distribution area of the very high FVC, and the area with no change accounted for just 0.08%. The proportion of stable and fluctuating area was the same, 39.60% and 42.54%, respectively； the conversion between different types of FVC was frequent, with "very low → low," "low → very low," and "low → medium" conversion types. The center of medium, high, and very high FVC was distributed in the north, indicating that the vegetation in the north was growing well and that ecological projects like restoring pasture to grassland had yielded excellent results. The distribution of landscape patches with very low and low FVC was more compact and stable, while the diversity of the overall landscape pattern remained stable and unchanged, with the Evenness Index increasing from 0.17-0.19. The degree of fragmentation between various types of FVC was low, and the distribution was more centralized. During the past 20 years, the FVC in Hefeng had fluctuated upward with large amplitude. The desert area in the county's south was the highest priority for future vegetation protection as well as desertification prevention and control. Future vegetation protection and desertification control efforts should prioritize the southern desert area.

Anti-vignetting glass (AVG) is a key material for the second-generation and third-generation low-light-level night vision devices. Its ability to eliminate stray light determines the signal-to-noise ratio and imaging clarity of optical components. In this paper, the influence of different physical and chemical treatment processes on the stray light elimination performance of anti-vignetting glass was studied. The optimum process parameters were determined as temperature 690°C, atmosphere pressure 0.3 MPa, and time 10000 min. The transmittance of the prepared AVG absorption layer was only 0.16%, which had excellent stray light elimination performance.

Hemodialysis for chronic kidney disease (CKD) relies on vascular access (VA) devices, such as arteriovenous fistulas (AVF), grafts (AVG), or catheters, to maintain blood flow. Nonetheless, unpredictable progressive vascular stenosis due to neointimal formation or complete occlusion from acute thrombosis remains the primary cause of mature VA failure. Despite emergent surgical intervention efforts, the lack of a reliable early detection tool significantly reduces patient outcomes and survival rates. This study introduces a soft, wearable device that continuously monitors blood flow for early detection of VA failure. Using thermal anemometry, integrated sensors noninvasively measure flow changes in large vessels. Bench testing with AVF and AVG models shows agreement with finite element analysis (FEA) simulations, while human and preclinical swine trials demonstrate the device's sensitivity. Wireless adaptation could enable at-home monitoring, improving detection of VA-related complications and survival in CKD patients.

Amino acids are essential for protein synthesis and metabolic processes in support of homeostatic balance and healthy body functions. This study quantitatively investigates eccrine sweat as a significant channel for loss of amino acids during exercise, to improve an understanding of amino acid turnover and to provide feedback to users on the need for supplement intake. The measurement platform consists of a soft, skin-interfaced microfluidic system for real-time analysis of amino acid content in eccrine sweat. This system relies on integrated fluorometric assays and smartphone-based imaging techniques for quantitative analysis, as a simple, cost-effective approach that does not require electrochemical sensors, electronics or batteries. Human subject studies reveal substantial amino acid losses in sweat from working muscle regions during prolonged physical activities, thereby motivating the need for dietary supplementation. The findings suggest potential applications in healthcare, particularly in athletic and clinical settings, where maintaining amino acid balance is critical for ensuring proper homeostasis.

At present, the craze of postgraduate entrance examination is sweeping the whole country. With the enrollment expansion of colleges and universities, the number of postgraduate students is increasing year by year. The training of postgraduate students is becoming one of the important ways for colleges and universities to ensure the output of high-quality talents. High or low innovative ability of graduate students of scientific research is to measure each college graduate reference of teaching and talent training effect. There is a huge development space of this article is based on the graduate student innovation ability of the background of the realistic possibility. From the perspective of

Opioid overdose accounts for nearly 75,000 deaths per year in the United States, now a leading cause of mortality among young people aged 18 to 45 years. At overdose levels, opioid-induced respiratory depression becomes fatal without the administration of naloxone within minutes. Currently, overdose survival relies on bystander intervention, requiring a nearby person to find the overdosed individual and have immediate access to naloxone to administer. To circumvent the bystander requirement, we developed the Naloximeter: a class of life-saving implantable devices that autonomously detect and treat overdose while simultaneously contacting first responders. We present three Naloximeter platforms, for fundamental research and clinical translation, all equipped with optical sensors, drug delivery mechanisms, and a supporting ecosystem of technology to counteract opioid-induced respiratory depression. In small and large animal studies, the Naloximeter rescues from otherwise fatal opioid overdose within minutes. This work introduces life-changing, clinically translatable technologies that can broadly benefit a susceptible population recovering from opioid use disorder.