Surface grafting on poly(ethylene terephthalate) track-etched microporous membrane by activation with trifluorotriazine: Application to the biofunctionalization with GRGDS peptide

Abstract

A two-step wet chemistry protocol has been developed for the surface derivatization of poly(ethylene terephthalate) (PET) track-etched membrane used as cell culturing support, that is, (a) activation by trifluorotriazine (1 M in acetonitrile (ACN), 30 degrees C, 3 h); (b) coupling to amine-terminated molecules, namely 3,5-bis(trifluoromethyl)benzylamine ((F)Tag), (L)-4,5-[H-3]-lysine, and Gly-Arg-Gly-Asp-Ser (GRGDS) pentapeptide (10(-3) M in PB-ACN, 1:1 (v/v), 20 degrees C, 17 h). The grafting rates determined by X-ray photoelectron spectroscopy, from the F/C and N/C atomic ratios, are in the range of 100-140 pmol/cm(2) (apparent surface), whereas the liquid scintillation counting assays give higher values (180-d230 pmol/cm(2)) corresponding to the open surface reactivity. PET-g-(F)Tag is reasonably stable under two usual sterilization conditions of biomaterials, that is, steam heating at 121 degrees C and gamma-irradiation at 25 kGy. On the other hand, PET-g-GRGDS is found to be stable only under ionization radiation (84% of remaining peptide molecules), but damaged in a large extent by the autoclave treatment (23% of remaining peptide molecules). The surfaces of the sterilized PET and PET-g-GRGDS samples have been characterized by water contact angle measurement and by atomic force microscopy analysis in air and under water. Comparatively to the corresponding nonsterilized surfaces, gamma-irradiated surfaces are slightly more hydrophilic and also slightly more rough and jagged. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 195-208, 2010