• Organic Electrochemical Transistors (OECTs) have emerged as a powerful platform for flexible and wearable biosensing due to their intrinsic ion–electron coupling, high transconductance, low operating voltage, and excellent compatibility with aqueous and biological environments. Unlike conventional field-effect devices, OECTs operate through volumetric electrochemical doping mechanisms, enabling high sensitivity and signal amplification in real-time biofluid monitoring.

  • The development of functional polymers with embedded nanoparticles has advanced the fields of microfluidics, biosensors, and flexible electronics, resulting in devices and systems with new principles of operation, improved performance, and increased portability. The field of wearable devices has adopted many of these advances and tailored them to meet the specific needs of wearables, including reliable electronic-tissue interfaces, increased comfort, reduced weight, integration with flexible substrates or textiles, and compact design. 

  • Cardiovascular diseases remain a leading cause of morbidity and mortality worldwide, creating a critical need for advanced technologies capable of monitoring and modulating cardiac function. Recent advances in soft materials, bioelectronics, and system integration have enabled the development of implantable electronic/optoelectronic devices that mechanically conform to the dynamic surface of the heart, providing unprecedented opportunities for cardiac sensing, mapping, and therapy. This tutorial will provide an overview of the field, spanning the progression from functional materials and device architectures to fully integrated implantable systems.