Characterization of plasma proteins adsorbed onto biomaterials by MALDI-TOFMS

The analysis of plasma proteins adsorbed onto a polyurethane (PU) biomateri al was performed using matrix-assisted laser desorption/ionization time-of- fight mass spectrometry (MALDI-TOFMS). This article marks the first study o n MALDI-TOFMS analysis of multiple proteins adsorbed from plasma, in vitro, onto the surface of a biomaterial to easily enable their characterization. Plasma standards from three different hosts were placed in contact with no n-porous PU, a model biomaterial. Following the use of washing protocols de veloped in our laboratory, the biomaterial was analyzed, directly, with MAL DI-TOFMS. Proteins with molecular weights (M-r) ranging from ca. 6.5 to 150 kDa were observed in the mass spectra and characterized upon comparison wi th proteins of known M-r. The proteins observed were tentatively identified as those known to adsorb onto PU, both in vitro and in vivo. In an attempt to model in vivo sorption, the PU biomaterial was exposed to freshly colle cted canine plasma, in vitro, for different lengths of lime. Corresponding MALDI-TOFMS spectra displayed increasing protein signal for a number of dif ferent proteins with increasing times of exposure to plasma. This method pr ovided qualitative and semi-quantitative analysis of the proteins adsorbed onto the biomaterial surface. (C) 2000 Elsevier Science Ltd. All rights res erved.