Peptide Microarrays on Coated Silicon Slides for Highly Sensitive Antibody Detection

The method described in this chapter shows that the sensitivity of a peptide-based microimmunoassay is greatly improved by using a new, specifically developed substrate made of silicon coated by an optimized layer of silicon oxide. A set of six peptides corresponding to the sequences of human and rat acetylcholine receptor subunits was immobilized on glass and silicon slides coated by a copolymer of N ,N -dimethylacrylamide, N -acryloyloxysuccinimide, and 3-(trimethoxysilyl) propyl methacrylate, copoly(DMA–NAS–MAPS). The spotted probes were incubated with rabbit anti-sera and with purified antibodies raised against the corresponding peptides. The coated silicon slides, in comparison against the glass substrates, showed a five- to tenfold enhancement of the fluorescence signals, leading to the specific detection of the full set of antibodies down to a concentration of 0.5–1 ng/mL in serum. The sensitivity provided by the test allows its use for the diagnosis of antibodies in clinical samples.