Antifouling Biointerfaces Based On Photodefinable Reactive Coatings

Poly(ethylene glycol) (PEG) or PEG-like molecules have long been reported as promising substances to suppress non-specific protein adsorption, or to resist cell adhesion. However, sufficient knowledge, synthesis skill, and cost are required to induce terminal groups on PEG. In this present study, we investigate the usefulness of exploiting a photodefinable polymer for the immobilization of a variety of PEG-like molecules that do not require functional groups. The photodefinable polymer, poly(4-benzoyl-p-xylylene-co-p-xylylene), can be prepared by chemical vapor deposition (CVD) polymerization on a wide range of different substrates/materials. The photoactivated carbonyl groups of the polymer has the potential to enable light-induced cross-linking of molecules and can rapidly react via insertion into CH- or NH-bonds upon photo-illumination at 340 nm. Molecules ranging from poly(ethylene glycol) (average Mn 400), poly(ethylene glycol) methyl ether methacrylate, dextran, to ethanolamine, are used as model anti-fouling materials in the study. Their antifouling properties towards fribrinogen and streptavidin adsorptions were studied using a combination of fluorescence microscopy and quartz crystal microbalancing (QCM). In addition, controlled anti-fouling presentation was also demonstrated on a non-conventional substrate, such as a stent, by using this coating technology. The photoimmobilization procedure based on the photodefinable CVD coating described in this study indeed introduce a simple and cost effective pathway for non-fouling modification. This technique may find applications in microfluidics, cell culture study, diagnostic devices, and implant devices.