As the primary skin-contact interface in wearable electrocardiograph (ECG) devices, epidermal electrodes play a pivotal role in determining both signal quality and biocompatibility. With continuous advancements in materials science and structural engineering, next-generation flexible and stretchable bioelectrodes have emerged, enabling long-term ECG monitoring and offering superior signal-to-noise ratios compared to conventional clinical electrodes. Their performance in ensuring reliable signal acquisition and user comfort is primarily governed by key interfacial mechanical and electrical properties, including mechanical compliance (i.e., flexibility and stretchability), interfacial adhesion (i.e., conformability and adhesion strength), and electrical characteristics (i.e., contact impedance). In recent years, significant progress has been made in enhancing the signal acquisition capabilities of flexible and stretchable bioelectrodes by optimizing these critical interfacial attributes. This review highlights the latest advances in conformable epidermal electrodes, encompassing traditional wet electrodes, flexible dry electrodes, novel dry electrodes based on organic electrochemical transistors, and integrated wearable systems. We systematically examine strategies for improving skin-electrode interface performance in ECG monitoring. Finally, we discuss ongoing challenges and future directions to advance epidermal electrode technologies for next-generation wearable healthcare applications.

Diabetic foot ulcers (DFUs) are a serious complication of diabetes and often result in amputation. Traditional wound care methods have limitations in addressing the complex pathophysiology of DFUs. Hydrogel dressings, a type of biomaterial, have emerged as promising candidates for treating DFUs due to their biocompatibility, ability to retain moisture, and potential to incorporate therapeutic agents. Hydrogels create a moist environment, promote cell migration, and reduce inflammation, thereby supporting wound healing. Incorporating bioactive molecules, such as growth factors and anti-inflammatory agents, can further enhance the effectiveness of hydrogels. Additionally, stem cells can be loaded into hydrogels to improve tissue regeneration and help modulate the wound microenvironment. Recent advancements in hydrogel technology have also led to the development of smart hydrogels that can respond to changes in wound conditions, such as glucose levels and pH. These intelligent dressings offer personalized care by delivering targeted treatments based on real-time wound data. This review explores the mechanisms behind DFU development, the role of hydrogels in wound healing, and recent progress in hydrogel technologies for personalized DFU care.