attributes of both biotic and abiotic materials for unprecedented opportunities in life and energy sciences. [10] Recent developments in micro-and nano-technology have yielded biointerfaces on multiple length scales, ranging from the nanoscale subcellular level to the macroscale level of epidermal electronics. Freestanding nanostructures and nanoscale devices allow cellular and subcellular biointerfaces, while macroscale devices enable the formation of biointerfaces with tissues and organs. Furthermore, a range of nano-and micro-fabrication methods for 3D structures has been developed, including 3D printing, [12][13][14][15][16][17][18] colloidal selfassembly, [19,20] controlled folding, [21][22][23] and templated growth. [24][25][26] Early progress in bioelectronics enabled integrating electronic elements with cellular scaffolds for monitoring and control of tissue functions and activities in a 2D configuration. However, biological tissues inherently adopt a complex 3D architecture, in which cells inhabit a complex microenvironment comprising extracellular matrix (ECM) and neighboring cells. 3D materials with defined geometries, compatible mechanical properties, and integrated electronic components represent an ideal scaffold for monitoring and regulating cell behaviors in the 3D microenvironment. Indeed, 3D biointerfaces are now advancing our understanding of molecular mechanisms involved in cancer. [1,27,28] They are also creating new opportunities in the fields of tissue engineering and biomedicine, where 3D constructs grown in vitro or ex vivo can then be transplanted into the human body for organ repair. [29] In this review, we summarize recent progress in nano-and microscale optical and electrical biointerfaces, where nanostructured materials and microfabricated systems are used to interface with biological systems. Based on the fundamental science inherent to the device/material biointerface, we first discuss the connection between energy science and bioelectronics. Then, we give an overview of bioelectronics tools for biointerfaces. Further, we focus on representative biointerfaces, including neural, cardiac, and microbial biointerfaces. Finally, we discuss future opportunities for nano-and microscale bioelectronics.
The Connection between Biointerfaces and Energy SciencesBiological systems communicate with and respond to the external world via different cues, such as electrical, chemical, Different research fields in energy sciences, such as photovoltaics for solar energy conversion, supercapacitors for energy storage, electrocatalysis for clean energy conversion technologies, and materials-bacterial hybrid for CO 2 fixation have been under intense investigations over the past decade. In recent years, new platforms for biointerface designs have emerged from the energy conversion and storage principles. This paper reviews recent advances in nano-and microscale materials/devices for optical and electrical biointerfaces. First, a connection is drawn between biointerfaces and energy science, and how these t...