title: Radio frequency glow discharge-induced acidification of fluoropolymers.
abstract: Fluoropolymer surfaces are unique in view of the fact that they are quite inert, have low surface energies, and possess high thermal stabilities. Attempts to modify fluoropolymer surfaces have met with difficulties in that it is difficult to control the modification to maintain bulk characteristics of the polymer. In a previously described method, the replacement of a small fraction of surface fluorine by acid groups through radio frequency glow discharge created a surface with unexpected reactivity allowing for attachment of proteins in their active states. The present study demonstrates that 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride (EDC) reacts with the acid groups on fluoropolymer surfaces in a novel reaction not previously described. This reaction yields an excellent leaving group in which a primary amine on proteins can substitute to form a covalent bond between a protein and these surfaces. In an earlier study, we demonstrated that collagen IV could be deposited on a modified PTFE surface using EDC as a linker. Once collagen IV is attached to the surface, it assembles to form a functional stratum resembling collagen IV in native basement membrane. In this study, we show data suggesting that the fluorine to carbon ratio determines the acidity of the fluoropolymer surfaces and how well collagen IV attaches to and assembles on four different fluoropolymer surfaces.
authors: Cell and Synthetic Interface Engineering Laboratory, Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa 52242, USA.
authors: Benjamin M
authors: BM
authors: Krawczyk
authors: Jonas
authors: J
authors: Baltrusaitis
authors: Colin M
authors: CM
authors: Yoder
authors: Terrence G
authors: TG
authors: Vargo
authors: Ned B
authors: NB
authors: Bowden
authors: Khalid N
authors: KN
authors: Kader
mesh_terms: D000143:Acids / Q000737:chemistry*; D002244:Carbon / Q000032:analysis; D024141:Collagen Type IV / Q000378:metabolism; D005461:Fluorine / Q000032:analysis; D005466:Fluorocarbons / Q000737:chemistry*; D006801:Humans; D056951:Photoelectron Spectroscopy; D058105:Polymerization; D011108:Polymers / Q000737:chemistry*; D011138:Polytetrafluoroethylene / Q000737:chemistry; D011145:Polyvinyls / Q000737:chemistry; D011846:Radio Waves; D013499:Surface Properties; D013816:Thermodynamics
chemical_list: D000143:Acids; D024141:Collagen Type IV; D005466:Fluorocarbons; D011108:Polymers; D011145:Polyvinyls; C035125:poly-N-vinylcarbazole; D005461:Fluorine; D002244:Carbon; D011138:Polytetrafluoroethylene