Abstract

Alongside the advances in inorganic nano-assemblies that have fueled a technological revolution in microelectronics, biofabrication technologies are emerging to enable the assembly of biological molecules into structures for biotechnology. Integrating biological systems with electronics enables the construction of devices with properties that combine the features of both but faces unique challenges for device fabrication, including engineering robust interfaces that bridge the material differences (e.g., stiffness, conductivity). This interface can be engineered across multiple hierarchical levels—ranging from physical adsorption at the molecular scale to nano- and micron-scale entrapment using biosynthesized extracellular matrices (ECM) or ECM-inspired synthetic hydrogels to create living electronic materials. Due to their inherent properties, hydrogels remain one of the most widely used platforms to assemble three-dimensional living structures on abiotic surfaces. Their crosslinked nano-scale matrices function as scaffolds to support cell retention and molecular exchange. Their high-water content provides a suitable environment for cell growth while their solid-like form allows easy handling and protects electronics from direct exposure to water. Complementing the use of hydrogels as scaffolds for biofabrication, spatial patterning techniques have been developed that use light, electrical, or mechanical stimuli to control both material and cellular deposition.