Adhesive hydrogels for bioelectronics

Benefiting from the unique advantages of superior biocompatibility, strong stability, good biodegradability, and adjustable mechanical properties, hydrogels have attracted extensive research interests in bioelectronics. However, due to the existence of an interface between hydrogels and human tissues, the transmission of electrical signals from the human tissues to the hydrogel electronic devices will be hindered. The adhesive hydrogels with adhesive properties can tightly combine with the human tissue, which can enhance the contact between the electronic devices and human tissues and reduce the contact resistance, thereby improving the performance of hydrogel electronic devices. In this review, we will discuss in detail the adhesion mechanism of adhesive hydrogels and elaborate on the design principles of adhesive hydrogels. After that, we will introduce some methods of performance evaluation for adhesive hydrogels. Finally, we will provide a perspective on the development of adhesive hydrogel bioelectronics.