Protein adsorption resistance of anti-biofouling block copolymers containing amphiphilic side chains

Abstract

Surface active block copolymers (SABCs) with amphiphilic side chains containing ethoxylated fluoroalkyl groups have previously demonstrated advantageous properties with regard to marine fouling resistance and release. While it was previously postulated that the ability of the block copolymer surface to undergo an environment-dependent transformation in surface structure aided this behaviour, protein adsorption characteristics of the surface were never explored. This study aims to expand our knowledge of protein interaction with the amphiphilic surface active block copolymer in an aqueous environment through experiments with bovine serum albumin (BSA), a widely utilized test protein. Fluorescence microscopy analysis using BSA labelled with fluorescein isothiocyanate (BSA–FITC) was performed on a SABC test surface to establish the polymer's protein adsorption resistance. Additionally, atomic force microscopy (AFM) based chemical force microscopy (CFM) was utilized to examine the force of adhesion of an AFM tip functionalized with strands of BSA protein with the SABC. No measurable force of adhesion was detected for 58% of the measurements of adhesion force taken for a BSA coated AFM tip interacting with the surface of the amphiphilic SABC in a PBS buffer. Furthermore, no measurements of force of adhesion were made in excess of 0.15 nN. This was in contrast to the non-zero mean adhesion force seen for several control surfaces in PBS buffer.