Matrix-assisted laser desorption ionization mass spectrometry detection ofproteins adsorbed in vivo onto contact lenses

Identification of the biomolecules that form the first adsorbed monolayer, which thus effect "interface conversion", in competitive adsorption from mu lticomponent biological solutions can be challenging because of limitations in mass resolution and sensitivity of established techniques. In this stud y matrix-assisted laser desorption ionization (MALDI) time of flight mass s pectrometry is developed and applied as a novel surface analytical method t o enable analysis of adsorbed multicomponent biomolecule layers directly on the biomaterial surfaces. We show that proteins adsorbed in vivo (on human eyes) an contact lenses can be detected rapidly and conveniently by the di agnostic highly resolved mass signals recorded by MALDI mass spectrometry T his new approach allows detection of minor (and major) proteinaceous consti tuents of biofouled layers at levels substantially below monolayer coverage . Identification is done by comparison with molecular masses of known prote ins. Specifically, it is shown that in addition to lysozyme, other low mole cular weight proteins adsorb from human tear fluid onto contact lenses; the se proteins had not been detected in earlier studies using other techniques . (C) 2000 John Wiley & Sons, Inc.