Chiral structures of polymers influence their resistance to protein adsorption and bacterial adhesion as investigated by quartz crystal microbalance with dissipation

Chiral stereochemical strategy for antimicrobial adhesion is a newly-developed method with growing interest. However, the effect of chiral structures on the anti-biofouling property is still unclear. Herein, we employed quartz crystal microbalance with dissipation (QCM-D) to study the ability of two polyurethanes modified by distinct isomers of chiral borneol compounds to inhibit proteins adsorption and bacteria adhesion. Two types of polyurethanes containing endo-L-borneol-based side chains (PLBA) or exo-iso-borneol-based side chains (PIBA) were synthesized through a thiol-ene ‘click’ reaction and polyaddition polymerization. The structure, chirality and surface wettability of the polyurethanes (PLBA-PU/PIBA-PU) were investigated, confirming the intact molecular chirality of borneol and the improved surface hydrophobicity of the polyurethanes after introducing borneol-based side chains. We monitored the protein adsorption and bacteria adhesion on these polyurethane surfaces by QCM-D. The PLBA-PU and PIBA-PU surfaces exhibit enhanced protein resistance and antimicrobial adhesion properties. Moreover, significant difference in anti-biofouling performance was found by QCM-D between PLBA-PU and PIBA-PU, where L-configuration of borneol on the polyurethane surfaces provides enhanced anti-biofouling function compared to exo-iso-borneol.