Biomaterial surface modification for underwater adhesion

Biomaterial surfaces tend to adhere only under dry conditions, preventing them from being used in underwater environments such as body fluids. Therefore, biomaterial surfaces with underwater adhesion ability have received increasing attention. In nature, some organisms can adapt to different environments by evolving appendages with underwater adhesion capability and unique functions. Most of these outstanding functions are derived from special micro/nanostructures and/or chemical compositions of these organisms. Thus, modification of biomaterials surfaces with similar microstructures and chemical groups would help promote underwater adhesion. In this review, we discuss (1) the mechanisms of underwater adhesion; (2) surface modification strategies for underwater adhesion, including mussel-inspired, interlocking, bio-structured surface, and specific adhesion strategies; and (3) the challenges and potential of developing surface-modified, multiscale biomaterials with underwater adhesion. © 2020 The Authors