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Neurological injuries significantly impair quality of life by disrupting neural transmission. Traditional implantable stimulators often rely on internal batteries, which limit device longevity and necessitate repeated surgical interventions. This study presents the experimental validation of a battery-free, RFID-powered neural platform for peripheral nerve signal acquisition and stimulation, targeting TRL-6 validation. The prototype incorporates an adjustable analog front-end with gains up to 93 dB and a biphasic current-controlled stimulator. Validation was performed through benchtop testing, biological tissue assessments using porcine tissue, and functional in vivo trials in adult Wistar rats (n = 3) over a three-month period. Benchtop evaluation confirmed gain accuracy with errors below 2.2 dB and precise stimulation timing. The system maintained a stable 3.3 V wireless power link through 20 mm of biological tissue using RFID. In vivo experiments indicated a 100% functional success rate (51/51 trials) in eliciting gross motor responses via wireless stimulation. Thermal safety was confirmed, with a maximum operating temperature of 28 °C, remaining well below physiological limits. The results demonstrate the functional feasibility of a battery-free, RFID-powered neural interface for wireless signal acquisition and stimulation, supporting system-level validation of this architecture.

This study presents a sustainable, battery-free UV (ultraviolet) dose sensor designed for intelligent food packaging applications. The device integrates laser-induced graphene (LIG) electrodes, a ZnO-CNT (carbon nanotube) UV-active composite, and a bio-derived ionochromic cell composed of blueberry anthocyanins and a NaCl electrolyte. This work advances the platform by introducing a quantitative and predictive dose-color mapping framework for cumulative UV detection under zero-bias operation. A controlled charge-injection protocol was employed to emulate UV-generated photocurrent, enabling systematic investigation of charge-transfer-driven ionochromic kinetics across five current levels (0.2-3 mA). HSB (hue-saturation-brightness)-based colorimetric analysis was performed to quantify the time-dependent chromatic evolution, and a numerical fitting model was developed to map charge accumulation to color shifts. Using this calibration, the color response at microampere-level photocurrents-corresponding to real zero-bias UV operation-can be predicted. The resulting model enables estimation of the cumulative time required for the ionochromic cell to transition from red to purple under realistic UV intensities. By combining self-powered sensing with predictive colorimetric modeling, this work significantly enhances the functionality of battery-free UV indicators, enabling quantitative dose measurement without external electronics for safer food-supply-chain monitoring.

The design of a wearable bioelectronic device for electrotherapeutic wound healing and real-time monitoring is critical for smart healthcare. However, developing multifunctional materials remains challenging due to energy supply or sensing interface issues. Herein, a simple strategy for integrating wound dressings of battery-free electrotherapy and wound sensors via Dopamine (DA)-modified MXene-silver nanowire (Ag NWs)-bacterial cellulose (BC) (PMAB) cross-linked interpenetrating networks has been presented. Specifically, DA and BC significantly enhanced the antioxidant and mechanical properties of MXene, while Ag NWs improved the electrical and antimicrobial activities of PMAB. The solid-state supercapacitor fabricated upon PMAB displayed excellent energy storage properties (2.5 F cm-2), replacing conventional power for delivering electrical stimulation (ES) to accelerate wound healing. NIH 3T3 fibrolast showed rapid migration and higher proliferation rate (over 70%) under ES (1 V). Meanwhile, wound dressing of cross-linking interpenetrating structure of MXene and BC performs superior mechanosensing properties, with internal resistance change only 1.5 times of initial resistance over 60 days, which enables monitoring physical signal stabilization for wound assessment and management. This work would provide novel ideas of smartsensors for designing battery-free wearable wound dressings.

Here, we present an intelligent wound patch system (iWPS) that integrates an organic electrochemical transistor (OECT) sensor, a DNase-responsive DNA hydrogel preloaded with cefazolin sodium (CS), and a flexible supercapacitor (FSC) for wireless, battery-free wound management. The OECT sensor detects Staphylococcus aureus with a detection limit of 1 × 104 CFU/mL and high selectivity against common interferents. Upon exposure to bacterial DNase, the DNA hydrogel degrades, triggering responsive release of CS. The FSC achieves an areal capacitance of 606.88 mF/cm2, can be wirelessly charged via an NFC antenna within 50 s, and subsequently provides on-demand electrical stimulation for over 1.5 h per charge. In a rat wound infection model, the iWPS combining responsive drug release and electrical stimulation achieved a healing rate of 93.52% at day 12 post-treatment, significantly outperforming the untreated control (65.94%) and either modality alone. Collectively, the iWPS establishes a battery-free platform that uniquely integrates real-time bacterial sensing, responsive antibiotic release, and on-demand electrical stimulation for advanced wound care.

Technologies for sensing and translating throat signals into speech have advanced the communication for people with vocal impairments. However, the practical deployment of these technologies is currently hindered by tethered system, bulky components and the lack of emotional recognition capability. Here, we demonstrate a wireless, battery-free artificial throat patch system (ATPS) coupling with deep learning method to enable simultaneous recognition of speech and emotion. The sensing module of the ATPS integrates a carbon nanotube-based thin-film strain sensor and a miniaturized flexible printed circuit board (FPCB). Real-time sensing and transmission of throat signals is facilitated by a smartphone-linked system incorporating an FPCB with an embedded near-field communication antenna and low-power electronic components. Furthermore, the information-rich sensor readouts are further extracted and successfully demonstrated to be sufficient to emotional recognition of speech by implementing a hybrid deep learning architecture. This proposed system expands the arsenal of tools available for mute patients in speech recognition and communication and further realizes personalized clinical implementations.

The development of efficient and durable energy harvesting systems is essential for next-generation smart infrastructure. Conventional polymer-based triboelectric nanogenerators (TENGs) suffer from low dielectric constants and limited polarization, restricting output and lifespan. Here, we present a ZnSnO3-doped Ecoflex and layered double hydroxide (LDH)-reinforced polyurethane (PU) nanofiber-based TENG, forming a synergistic triboelectric interface. ZnSnO3 enhances dielectric response and surface charge generation, while LDH-PU nanofibers improve charge retention and polarization stability. The optimized EZ1/PL5-TENG delivers 186 V peak voltage, 5.6 µA peak current, and 8.84 µC/m2 surface charge density, maintaining stable performance over 20,000 cycles. The device efficiently converts biomechanical motion into electrical energy, as demonstrated in both wearable flexion sensing and a motion-triggered, battery-free street lighting system that directly powers LEDs. This scalable, flexible TENG platform offers high output, long-term durability, and practical applicability, highlighting its potential for sustainable smart city illumination, sensing networks, and self-powered electronics.

Wearable colorimetric biosensors enable noninvasive, real-time monitoring with intuitive readouts, yet most platforms rely on photographing the sensing area, making measurements highly susceptible to ambient light, background reflections, and user-dependent factors from camera angle, distance, and motion. Here, we present a fully integrated wireless, battery-free multi-modal optoelectronic-colorimetric microfluidic system that directly quantifies colorimetric signals in situ, eliminating the need for photography. The device combines a microfluidic patch containing colorimetric sensors for uric acid, alcohol, and pH with a detachable near-field communication (NFC) optoelectronic module comprising custom light-emitting diode (LED)-photodiode pairs for localized illumination and reflectance detection, enabling reading by both the NFC primary antenna and a smartphone. On-body studies in healthy participants and gout patients show robust interference-resistance performance across diverse ambient light levels and human skin tones, and reliable multiplex sweat analysis to track metabolic fluctuations following purine-rich and alcohol-rich diets and to evaluate allopurinol therapy.

Here, we develop a next-generation wireless, battery-free oxygen generating O2-Macrodevice and wearable power transfer platform that can enable long-term immune protection and subcutaneous function of therapeutic cells. We demonstrate this device supports xenogeneic islet transplantation in C57BL/6J mice evidenced by 90-day diabetes reversal and glucose responsiveness in vivo. We also show partial glycemic control via high-density (>8,000 islets/cm2) human stem-cell derived islets (SC-islets) without immune-suppression in subcutaneous sites for 90 days. Additionally, we confirmed the device supports allogenic islet cell survival and 90-day diabetic reversal in rats. Finally, we demonstrate 1-month islet survival in a nonhuman primate without the need for immune suppression in the subcutaneous space. Collectively, these results indicate the device supports cell survival and function across multiple transplant models in three species without the need for any immunosuppression or external user intervention. These results represent an important set of advances towards immunosuppression free, minimally invasive islet transplantation.

Continuous monitoring of pressure and temperature at skin interfaces is essential for preventing tissue damage and circulation-related complications in immobile patients. However, most existing healthcare pressure sensors remain bulky, wired, and battery-powered, which limit their suitability for long term use. Here, we report a battery-free, wireless multimodal sensing platform in which single-layer graphene functions as a high-performance pressure-sensing active layer, achieving high sensitivity (1.75 × 10-3 kPa-1, gauge factor = 8.6) and excellent stability (over 1000 operational cycles). The platform enables real-time, reversible detection of pressure and temperature at the skin-device interfaces without external power source. By leveraging deep-learning algorithms, particularly deep neural networks (DNNs), the acquired signals are classified into distinct sitting postures, thereby enabling intelligent and continuous monitoring of patient status. Furthermore, integrated augmented- and virtual-reality (AR/VR) interfaces visualize pressure distributions in real time, enabling immersive and remote healthcare oversight. Collectively, this work introduces a graphene-based smart sensing platform that seamlessly integrates wireless operation, AI-driven analytics, and AR/VR visualization for advanced patient monitoring as a sort of personalized and interactive smart healthcare.

The development of wireless implantable devices opens opportunities for continuous monitoring of arteriovenous grafts (AVGs) in dialysis patients, who face high risks of graft failure and morbidity due to stenosis. Current methods for graft monitoring rely heavily on intermittent hospital-based tests and skilled personnel. Here, we report a battery-free implantable AVG with a wireless pressure sensor embedded for real-time stenosis detection. The graft incorporates a soft, flexible circuit, enabling external resonant frequency transmission. The capacitive pressure sensor demonstrates high sensitivity and the ability to detect both arterial and venous stenosis. Stretchable conductive inks enhance the resilience of the inductor under mechanical stress, while laser micromachining manufactures flexible, serpentine patterns in the graft's elastomeric layer. Additionally, the thin sensor profile maintains graft flexibility and can integrate with the expanded polytetrafluoroethylene, bringing it closer to commercial AVG functionality. Using a phantom flow model, the bioelectronic system successfully detects both arterial and venous stenoses wirelessly via inductive coupling. Overall, this class of sensor technologies and wireless electronics presented in this work provides an effective solution for real-time dialysis access monitoring, with the potential to significantly reduce AVG failure rates and improve patient outcomes through early intervention.

Body water is essential for homeostasis and tissue function, including waste removal, blood pressure regulation, thermoregulation, and cell signaling. However, existing dehydration analysis technologies face limitations in real-time detection and automatic feedback. Moreover, existing fluid-intake monitoring technologies focus primarily on intake volume, neglecting physiologically relevant factors such as beverage pH, temperature, and type. We propose a smartphone-interfaced, soft platform that can support unobtrusive hydration monitoring in daily life and during physical activity by tracking resonance-frequency shifts induced by hydrogel hydration and swelling. The hydrogel sensor integrated with a 6 mm-diameter antenna conformally adheres to sweat-rich skin or intraoral soft tissue, enabling non-invasive assessment of sweat biomarkers and beverage-intake metrics. This multimodal interface exhibits pH-dependent resonance-frequency shifts across physiologically relevant pH levels, along with volume-dependent shifts. A linear decrease in frequency was observed with increasing fluid intake (R2 = 0.981), and beverage temperature elicited a statistically significant response (p = 0.009). Distinct frequency-domain responses across beverage types indicate the feasibility of dietary-pattern profiling and preventive diagnostics. The platform supports real-time detection of hydration imbalance and provides a basis for future expansion toward broader metabolic and physiological monitoring.

The increasing elderly population has made falls due to frailty a critical issue, with physical and cognitive factors interacting to elevate the risks of fractures and solitary deaths. Falls are challenging to predict due to the involvement of multiple factors, necessitating the development of continuous gait monitoring and fall detection technologies. Although various fall detection methods have been proposed, many rely on batteries requiring maintenance with circuit complexity, higher costs, or both. This study aims to develop an unintentional-falling detection system by utilizing triboelectric nanogenerator (TENG) technology to create a battery-free insole device. The device was tested to analyze the feature of the voltage signals produced by unintentional falls. The results suggest that the signals generated by the device are sufficiently distinguishable from the frequency-amplitude and the ratio of maximum and minimum voltage values during one gait cycle, indicating the feasibility of constructing a battery-free system capable of detecting unintentional-falling.

As the most fundamental and widely-used technique in molecular diagnostics, polymerase chain reaction (PCR) plays a crucial role across various applications including epidemic surveillance and medical diagnosis. For the numerous epidemics such as COVID-19, the massive and frequent detection has challenged the PCR equipment in system miniaturization and hardware cost efficiency as well as rapid and precise detection. In conventional methods, fluorescence-PCR requires huge costly optical instruments, and the DNA-Probe-PCR can only detect a corresponding sample. In addition, both the fluorescence-PCR and DNA-Probe-PCR suffer from complex pre-label or modification procedure, further increasing the fabrication cost. In this work, we demonstrate the first probe-free electrical-digital-PCR (EdPCR) chip based on impedance detection: 1) A sensor-on-circuit structure is proposed to replace the bulky costly optical instrument with a single CMOS chip, enabling the PCR equipment to be portable and disposable. 2) A harmonic-voting method is proposed to reduce the testing pixel error rate (PER). The system is implemented in 55nm CMOS process, and in-vitro PCR experiment is conducted in various samples. The on-chip sensing array of the proposed PCR chip achieves a pixel density of 1111 pixels/mm2, which is the highest in the state of the arts. Additionally, the proposed harmonic-voting method reduces the measured PER of impedance judgment by 35%, achieving an average PER of 12.2%.

Continuous monitoring of physiological parameters associated with dynamic biomechanics, such as intracranial pressure (ICP) and vital signs, is important for clinical diagnosis of brain diseases and timely medical intervention. Current skin-interfaced and implant technologies face challenges in terms of bulky tethers and/or percutaneous wires with high infection risks. Here, we report the wireless, battery-free, and lightweight devices for both wearable and fully implantable applications. The devices incorporate an ultrathin piezoelectric resonator with suspended lithium niobate thin film (LNTF, 3 μm thick), enabling the wireless tracking of mechanophysiological signals by detecting variations in resonance frequency. We experimentally and computationally establish the operational principles of the resonator sensor and assess the device performance as wearables for dynamically monitoring artery pulse and apnea events during respiration. Implantable wireless pressure sensors adapted from this scheme allow for untethered, minimally invasive ICP sensing with a low detection limit of 0.15 mmHg over a wide range up to 240 mmHg. In vivo experiments performed on rat models validate the device capabilities of accurately capturing clinically relevant ICP variations and elevated levels of ICP under pathophysiological conditions of hydrocephalus, with excellent biocompatibility after long-term implantation periods. These findings create the clinical significance of such battery-less and wireless devices for precise characterization of dynamic biomechanics of living tissues.

Conventional drug delivery and diagnostic models are increasingly inadequate for the evolving demands of precision medicine and real-time treatment. Integrated theranostic systems offer a promising solution; however, challenges such as wired control, non-degradable materials, and poor wet-tissue integration hinder their clinical adoption. Here, we present an integrated theranostic adhesive patch (ITAP) that combines wireless operation, full biodegradability, and robust bioadhesion on wet-tissue surfaces for seamless diagnostic and therapeutic functionality. The ITAP adheres stably to moist tissues through a biocompatible hydrogel layer, continuously monitors physiological motion via resonant mechanical sensing, and enables precise on-demand drug release through the magnetically activated electrochemical corrosion of magnesium (Mg) valves. By introducing thickness-graded Mg valves and distance-dependent magnetic actuation, the system enables programmable, sequential, and selective drug release with tolerance to physiological motion and anatomical variability. Experimental results demonstrate strong wet-tissue adhesion, sensitive mechanical signal detection, and controllable drug release under magnetic stimulation. In vivo studies in an asthmatic rat model validated the integrated functionality, achieving wireless respiratory rhythm monitoring and triggered bronchodilator delivery with significant therapeutic efficacy. In vitro degradation tests and in vivo biocompatibility evaluations confirmed the transient and safe nature of all device components, avoiding the need for device retrieval. This bioresorbable theranostic platform establishes a practical framework for wireless, tissue-conformal diagnosis and therapy, offering new opportunities for minimally invasive and personalized interventions on dynamic wet tissue surfaces.

Injectable bioelectronics offer a minimally invasive approach to peripheral nerve stimulation but remain limited by onboard energy storage and fragile leads. Here, we present SEED, a leadless, battery-free bioelectronic interface engineered for percutaneous delivery through a standard 14-gauge needle. SEED (Stimulating Electrode for Electroceutical Delivery) operates in the magnetoquasistatic regime using low-frequency (65 kilohertz) resonant inductive coupling, externalizing waveform generation and control, enabling programmable neuromodulation without onboard active electronics. A spiral-helix electrode geometry promotes longitudinal nerve engagement while limiting off-target field spread. Benchtop and ex vivo characterization demonstrates precise, programmable control of stimulation frequency, pulse width, and amplitude under physiologically relevant conditions. In vivo validation in a rat sciatic nerve model confirms frequency-locked motor responses and graded neural recruitment following percutaneous deployment. SEED exhibits strong radiopacity and acoustic contrast, supporting compatibility with ultrasound and computed tomography for image-guided neuromodulation. This platform provides a scalable pathway toward minimally invasive bioelectronic therapies.