A Sol-gel Integrated Dual-readout Microarray Platform for Quantification and Identification of Prostate-specific Antigen

Abstract

Here, we report a sol-gel integrated affinity microarray for on-chip matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) that enables capture and identification of prostate?specific antigen (PSA) in samples. An anti-PSA antibody (H117) was mixed with a sol?gel, and the mixture was spotted onto a porous silicon (pSi) surface without additional surface modifications. The antibody easily penetrates the sol-gel macropore fluidic network structure, making possible high affinities. To assess the capture affinity of the platform, we performed a direct assay using fluorescein isothiocyanate-labeled PSA. Pure PSA was subjected to on-chip MALDI-TOF-MS analysis, yielding three clear mass peptide peaks (m/z = 1272, 1407, and 1872). The sol-gel microarray platform enables dual readout of PSA both fluorometric and MALDI-TOF MS analysis in biological samples. Here we report a useful method for a means for discovery of biomarkers in complex body fluids.

Biosensors Using an Antibody as a Recognition Element

“…Biorecognition by an antibody has been applied to detect a prostate-specific antigen (PSA) based on a sol-gel integrated affinity microarray for on-chip matrix-assisted laser desorption/ionization time-offlight mass spectrometry (MALDI-TOF-MS). 13 Megger et al described the application of tandem mass tags (TMT) for the labeling of whole intact cells. 14 The enrichment of TMT protein by an anti-TMT antibody was applied to increase the relative amount of labeled protein at the levels of whole cells.…”