REACTIVITY ASSAY OF SURFACE CARBOXYL CHAIN-ENDS OF POLY(ETHYLENE-TEREPHTHALATE) (PET) FILM AND TRACK-ETCHED MICROPOROUS MEMBRANES USING FLUORINE LABELED AND OR H-3 LABELED DERIVATIZATION REAGENTS - TANDEM ANALYSIS BY X-RAY PHOTOELECTRON-SPECTROSCOPY (XPS) AND LIQUID SCINTILLATION-COUNTING (LSC)/

Poly(ethylene terephthalate) (PET) films and track-etched microporous membranes of two different porosities were pretreated by hydrolysis an d/or oxidation in order to enhance the amount of carboxyl chain-ends d isplayed on their surface. The reactivity of these carboxyl functions was determined by derivatization assays in which the reactions were ca rried out under conditions likely to be encountered in the coupling of water-soluble biochemical signals on the surface of biomaterials. Ori ginal reagents, fluorine-labelled and/or H-3-labelled aminoacid compou nds, were used. The derivatized PET samples were examined by X-ray pho toelectron spectroscopy (XPS) to characterize their apparent surfaces, and by liquid scintillation counting (LSC) to quantify the amount of tags fixed on their open surfaces. Using this dual assay technique, we analyzed the surface of microporous membranes which are currently use d as substrates for cell culture systems.