Quantitative determination of the peptide retention of polymeric substrates using matrix-assisted laser desorption/ionization mass spectrometry

Polymer surface-peptide binding interactions have been shown previously to lead to reductions in peptide matrix assisted laser desorption/ionization ( MALDI) ion signals. In previous studies, increases in surface-peptide bindi ng were characterized by the increases in both the initially adsorbed and r etained quantities of I-125-radiolabeled peptides. The present studies esta blish a specific correlation between the peptide retention properties of th e polymer surface and the reduction in the peptide MALDI ion signal. This c orrelation is demonstrated by obtaining MALDI mass spectra of angiotensin I applied to various polymer surfaces having a range of peptide adsorption a nd retention properties. In addition, the use of a MALDI based method of st andard additions is shown to allow the quantitation of the polymer surface- peptide retention affinity for angiotensin I and porcine insulin. The MALDI standard additions method for measurement of surface-peptide retention aff inities offers a number of significant advantages over conventional radiola beled peptide binding methods and promises to be a valuable tool for the de termination of this important biomaterial characteristic. (J Am Soc Mass Sp ectrom 2000, 11, 62-68) (C) 2000 American Society for Mass Spectrometry.