Paper BI-MoP17
Nonfouling Microstructures on Hydroxylated Substrates via Chemical Vapor Deposition and Surface Initiated Atom Transfer Radical Polymerization
Monday, November 15, 2004, 5:00 pm, Room Exhibit Hall B
The ability to covalently modify hydroxylated substrates such as glass and metal oxides with a non-fouling polymer coating is an important goal, in view of their wide application as biomaterials and in biotechnology. Most current approaches rely upon physisorption of PEG-containing polymers or grafting of the polymers from solution to the surface (â?ografting toâ? approach). We report here a â?ografting fromâ? strategy in which an oligo(ethylene glycol) functionalized monomer is polymerized in situ from the surface of glass to provide high-density polymer brushes that overcomes the intrinsic limitation of low surface density of PEG chains realized by â?ografting toâ? strategies. A silane initiator presenting a terminal bromoisobutyrate moiety was used to form a SAM on hydroxylated substrates via chemical vapor deposition (CVD). This SAM was used as substrate for surface initiated atom transfer radical polymerization (SI-ATRP) of oligo(ethylene glycol) methyl methacrylate (OEGMA). The SI-ATRP was carried out in an oxygen free environment with CuBr/bipyridine as catalysts in a water /methanol mixture. Poly(OEGMA) brushes with a tunable thickness between 2 and 10 nm can be synthesized in situ, and these brushes are exceptionally resistant to protein adsorption, even from 100% fetal bovine serum. We also report a new masking strategy to pattern the surface with the initiator silane SAM, which enabled facile patterning of the surface with the poly(OEGMA) brushes. When NIH 3T3 fibroblasts were seeded onto those surfaces, cells were confined within the regions demarcated by the polymer and were maintained within the pattern for over a week.