Multifunctional biopolymer coatings inspired by loach skin

Abstract

Anti-biofouling surfaces are very important owing to their significant roles in microfluidic devices, biosensors and biomedical devices. However, traditional anti-biofouling surfaces could contaminate the environment. Thus, the development of environment-friendly coatings is an essential undertaking in efforts to resolve the problems associated with conventional anti-biofouling surfaces. Herein, a novel strategy inspired by the slippery surface of loach skin is proposed for the rational design of anti-biofouling surfaces. In this strategy, hydrophilic biopolymers, including chitosan, carboxymethyl cellulose, mPEG-amine (MW, 10,000 Da) and alginate, are grafted on a porous polycaprolactone (PCL) membrane. The porous PCL surface is a biomimetic surface inspired by the skin surface of a loach that secretes mucus. Previously developed antifouling surfaces were often toxic or the coating substances were easily released to the outside, and their drag reduction effects were not examined. The developed coating surface is not toxic and the coating material is not depleted to the outside. The resultant covalent biopolymer-coated surfaces (BCSs) exhibit excellent hydrophilic property and drag reduction effect in water. Especially, the additional coating of mPEG-amine on the alginate-coated surface exhibits the best drag reduction performance. In addition, the BCSs show superior anti-biofouling performance by resisting the adhesion of bacteria (Escherichia coli and Maribacter dokdonensis) and NIH3T3 fibroblasts. The proposed covalent biopolymer coatings could be potentially utilised as eco-friendly surfaces for drag reduction and anti-biofouling.