Nanomaterial-based biohybrid hydrogel in bioelectronics

Despite the broadly applicable potential in the bioelectronics, organic/inorganic material-based bioelectronics have some limitations such as hard stiffness and low biocompatibility. To overcome these limitations, hydrogels capable of bridging the interface and connecting biological materials and electronics have been investigated for development of hydrogel bioelectronics. Although hydrogel bioelectronics have shown unique properties including flexibility and biocompatibility, there are still limitations in developing novel hydrogel bioelectronics using only hydrogels such as their low electrical conductivity and structural stability. As an alternative solution to address these issues, studies on the development of biohybrid hydrogels that incorporating nanomaterials into the hydrogels have been conducted for bioelectronic applications. Nanomaterials complement the shortcomings of hydrogels for bioelectronic applications, and provide new functionality in biohybrid hydrogel bioelectronics. In this review, we provide the recent studies on biohybrid hydrogels and their bioelectronic applications. Firstly, representative nanomaterials and hydrogels constituting biohybrid hydrogels are provided, and next, applications of biohybrid hydrogels in bioelectronics categorized in flexible/wearable bioelectronic devices, tissue engineering, and biorobotics are discussed with recent studies. In conclusion, we strongly believe that this review provides the latest knowledge and strategies on hydrogel bioelectronics through the combination of nanomaterials and hydrogels, and direction of future hydrogel bioelectronics.