Improved porous silicon microarray based prostate specific antigen immunoassay by optimized surface density of the capture antibody

• We develop porous silicon based microarray for PSA detection in human serum.
• We optimize density of capturing antibody for improving sandwich immunoassay of PSA.
• Porous silicon has high capacity of capturing of antibody.
• The microarray offers 800 fg mL−1 (0.6 amol) of PSA in human serum.
• It also has broad detection dynamic ranges (800 fg mL−1 to 80 ng mL−1).

Enriching the surface density of immobilized capture antibodies enhances the detection signal of antibody sandwich microarrays. In this study, we improved the detection sensitivity of our previously developed P-Si (porous silicon) antibody microarray by optimizing concentrations of the capturing antibody. We investigated immunoassays using a P-Si microarray at three different capture antibody (PSA – prostate specific antigen) concentrations, analyzing the influence of the antibody density on the assay detection sensitivity. The LOD (limit of detection) for PSA was 2.5 ng mL−1, 80 pg mL−1, and 800 fg mL−1 when arraying the PSA antibody, H117 at the concentration 15 μg mL−1, 35 μg mL−1, and 154 μg mL−1, respectively. We further investigated PSA spiked into human female serum in the range of 800 fg mL−1 to 500 ng mL−1. The microarray showed a LOD of 800 fg mL−1 and a dynamic range of 800 fg mL−1 to 80 ng mL−1 in serum spiked samples.

Figure optionsDownload as PowerPoint slide