Hulin Zhang

Plantar temperature and pressure reflect the plantar health status of diabetic patients and serve as critical indicators for evaluating disease progression. However, existing plantar monitoring devices are still limited by single-modal signal acquisition, bulky device configurations, and a strong reliance on external power supplies. Herein, we report a thermogalvanic hydrogel-based smart insole integrating self-powered sensing units for self-decoupled plantar monitoring. The insole integrates 16 self-decoupled thermogalvanic hydrogel sensing units, which convert plantar temperature difference and pressure stimuli into decouplable electrical signals via the thermogalvanic effect and the active iontronic piezoresistive effect, respectively. The incorporation of the backend acquisition circuit into the smart monitoring insole enables remote plantar temperature-difference and pressure mapping. Cloud-based machine learning further empowers the insole to assess plantar status in diabetic patients and distinguish disease-associated gait patterns. This work provides a versatile strategy for developing multimodal intelligent wearable platforms for personalized foot health monitoring and disease management.

Wound management critically requires the synergistic integration of real-time monitoring and precise intervention. Current electrical stimulation dressings suffer from external power dependence, poor air permeability, restricted customizability, and decoupled monitoring and treatment. Herein, this study presents a self-powered, breathable porous thermogalvanic hydrogel dressing, which employs a poly(vinyl alcohol)/poly(ethylene glycol) diacrylate double-network matrix loaded with the [Fe(CN)6]3–/4– redox couple and is endowed with personalized wound-matching capability by DLP-based 3D printing. By coupling the thermogalvanic and active piezoresistive effects, the dressing achieves real-time monitoring of wound temperature and deformation, along with additional functionality for wound exudate detection and pH visualization. Furthermore, the dressing provides biomimetic electrical stimulation without exogenous drugs or external power, enabling closed-loop monitoring and treatment. Integrated with a deep learning algorithm, the dressing delivers 96.5% wound severity classification accuracy and accelerates wound healing in mice, reaching 98.09% closure on day 14. This work offers a new paradigm for precise personalized wound management with potential for clinical translation.

Hand motor dysfunction involves limited finger flexion and impaired release control, making finger flexion angles and active relaxation ability key metrics for rehabilitation assessment. However, existing flexible electronics quantify deformation amplitude, while deformation rate remains difficult to read out directly. Here, we report a mechanically trained poly(vinyl alcohol)-NaCl hydrogel with the relaxation piezoionic effect for self-powered, self-decoupled monitoring of stress magnitude and acceleration. The hydrogel produces a positive piezoionic voltage above 20 mV during compression and a reverse relaxation piezoionic voltage above 18 mV during unloading. Experiments and multiphysics simulations show that the reverse piezoionic voltage correlates with deformation recovery rate, enabling electrical readout of unloading speed. The hydrogel is further integrated into a multichannel platform for real-time finger rehabilitation visualization. This work provides an autonomous strategy for hand rehabilitation monitoring and a design principle for bioelectronic platforms in motion analysis, human–machine interaction, and personalized healthcare.

Flexible NO ₂ gas sensors were fabricated using DIW-printed CNT/Ag composite electrodes and In ₂ O ₃ nanoparticles. The sensor exhibits room-temperature operation, stable flexible sensing behavior, and reliable NO ₂ detection under bending deformation.

Driven by the surging demand for the Internet of Things and flexible electronics, thermoelectric hydrogels have overcome the rigidity and brittleness inherent to conventional inorganic thermoelectric materials. Leveraging unique advantages such as high flexibility, tissue-like mechanical properties, and tunable ionic conductivity, they exhibit broad application prospects. However, the unique composite architecture of these materials also poses significant challenges for their rational design and performance optimization. This review summarizes recent advances in thermoelectric hydrogels, beginning with an in-depth analysis of the fundamental working mechanisms, including the Seebeck effect, thermogalvanic effect, and thermodiffusion effect, all governed by electronic or ionic carriers. Key performance parameters are presented, with special focus on the dimensionless figure of merit, while the essential tradeoffs among the Seebeck coefficient, electrical conductivity, and thermal conductivity are thoroughly discussed. Furthermore, the paper highlights controllable fabrication strategies for thermoelectric hydrogels, including polymer network design and incorporation of functional fillers, and provides performance optimization approaches based on electronic, ionic, and hybrid thermoelectric gels. Representative applications in energy harvesting, human–machine interaction, and biomedical monitoring are reviewed to illustrate real-world implementation prospects.

The ionic thermoelectric (i-TE) technology offers a compelling pathway for harvesting low-grade heat, distinguished by its exceptionally high thermopower and inherent material versatility. However, development in this field is constrained by the complex interplay among electrochemical, thermodynamic, and transport phenomena, which poses significant challenges to the fundamental understanding, accurate performance evaluation, and systematic screening of new materials. This review provides a systematic overview and outlook of the i-TE landscape, bridging fundamental principles with future applications. We begin by deconstructing the core components—electrolytes and electrodes—to elucidate the material design strategies that govern the performance. The discussion then progresses to a multi-scale evaluation of key metrics, from intrinsic i-TE properties to device-level energy conversion and storage capabilities. A central focus is placed on dissecting the persistent chemical and physical challenges, including ion selectivity, transport dynamics, and interfacial engineering. This review further surveys the emerging applications of i-TE, ranging from wearable power generation and active cooling to multimodal sensing and integrated multifunctional systems. Furthermore, we highlight the paradigm-shifting potential of synergistic systems, where coupling thermoelectric effects with electrochemical, photocatalytic, or hydrovoltaic processes unlocks unprecedented functionalities and performance enhancements. Ultimately, this review synthesizes current understanding to propose a strategic roadmap for this field. It outlines the key scientific and engineering perspectives on standardization, scalable manufacturing, and reliability that are essential to translate laboratory innovations into viable commercial technologies.