SENSING OF PROSTATE SPESIFIC ANTIGEN BY DIFFERENTIAL PULSE ANODIC STRIPPING VOLTAMMETRY OF GOLD NANOPARTICLE - SILVER ENHANCED LABELS

Abstract

A sensitive prostate specific antigen (PSA) detection method based on peptide cleavage and silver enhancement of gold nanoparticle (AuNP) has been developed. PSA is serine protease produced by both normal prostate glandular cells and prostate cancer cells. PSA widely used as a biomarker for prostate cancer (PCa). The activity of PSA was detected by following mechanism: first, some immobilized peptide on the bottom of wellplate was undergo cleaving process via biotin-avidin interaction, leaving short peptide (without thiol group) that could not form a link with gold nanoparticle. Meanwhile, the remaining peptide which not undergo such process could self-assemble with AuNPs, followed by autocatalytic reduction with silver enhancement solutions to silver metal (Ag). The Ag content on AuNPs was determined by differential pulse anodic stripping voltammetry, after axidation of Ag metal to Ag+ ions, using screen printed carbon electrode. The measurement conditions and immunoassay components had been optimized in this study. The detection of PSA was successfully carried out by this method with limit detection value of 152.204 ng/mL, but further development is necessary to improve the limit detection value.

Keywords

• anodic stripping voltammetry
• gold nanoparticle
• peptide
• prostate specific antigen