A Systematic Spr Study of Human Plasma Protein Adsorption Behavior on the Controlled Surface Packing of Self-assembled Poly (Ethylene Oxide) Triblock Copolymer Surfaces

A well-controlled biocompatible nonfouling surface is significant for biomedical requirements, especially for the improvement of biocompatibility. We demonstrate the low or nonbiofouling surfaces by coating hydrophobic–hydrophilic triblock copolymers of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) on the CH3-terminated self-assembled monolayer (SAM). Two types of copolymers are used to modify the surface, one with different PEO/PPO ratios (∼20/80, 40/60, and 80/20, w/w) but the same PPO molecular weight (∼2 k), the other with different copolymer MWs (∼9, 11, and 15 k) but the same PEO/PPO ratio (80/20, w/w). In situ surface plasmon resonance (SPR) sensor is used to evaluate polymer adsorption on the SAMs and subsequent protein adsorption on the copolymer-treated surface. The effects of PEO-PPO-PEO molecular weight, PPO-to-PEO ratio, and ionic strength on protein adsorption from single protein solutions of fibrinogen, BSA, and complex mixed proteins are systematically investigated. A Pluronic™ F108 treated surface is highly resistant to nonspecific protein adsorption under the optimized conditions (MW of 15 k and PEO/PPO ratio of 80/20). This work demonstrates that the PEO-PPO-PEO polymer is able to achieve ultra low fouling surface via surface modification by controlling surface packing density of polymers (molecular weight, hydrophobic/hydrophilic ratio, and hydrophilic group coverage). © 2009 Wiley Periodicals, Inc. J Biomed Mater Res 201