Improved porous silicon microarray based prostate specific antigen immunoassay by optimized surface density of the capture antibody
Lee SW., Kim S., Malm J., Jeong OC., Lilja H., Laurell T.
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 2.5ngmL-1, 80pgmL-1, and 800fgmL-1 when arraying the PSA antibody, H117 at the concentration 15μgmL-1, 35μgmL-1, and 154μgmL-1, respectively. We further investigated PSA spiked into human female serum in the range of 800fgmL-1 to 500ngmL-1. The microarray showed a LOD of 800fgmL-1 and a dynamic range of 800fgmL-1 to 80ngmL-1 in serum spiked samples. © 2013 Elsevier B.V.