In situ chemical modification of peptide microarrays: characterization by desorption/ionization on silicon nanowires.

Peptide microarrays are useful devices for the high throughput study of biomolecular or peptide-cell interactions. Whereas the synthesis of unmodified peptide libraries is an easy task and can be performed at reasonable cost, the synthesis of libraries of modified peptides remains expensive and time consuming. This bottleneck led us to examine the possibility to produce modified peptide microspots by in situ chemical modification of unmodified peptide microspots. The great advantage would be the preparation of a series of complex microarrays (daughter microarrays) starting from an easy-to-make and cost-effective unmodified peptide microarray (parent microarray). One step toward this goal has been presented in the accompanying chapter dealing with the in situ methylation methodology for studying the specificity of antibodies directed toward methylated epitopes. Here we describe the development of a novel desorption/ionization on silicon nanowires mass spectrometry (DIOSiNWs-MS) technique for characterizing the in situ chemical modification of peptides.