Aptamer and rolling circle amplification-involved sandwich assay for platelet-derived growth factor-BB with absorbance analysis

摘要

This paper described an aptamer-based absorbance assay combining rolling circle amplification (RCA) for platelet-derived growth factor-BB (PDGF-BB). PDGF-BB was specifically captured by an antibody on a microplate, and then bound with an anti-PDGF-BB aptamer connected with a primer sequence, forming a sandwich complex. The primer sequence was extended by RCA reaction to generate a long single-stranded DNA with repeated copies. The amplified DNA product was hybridized with many biotinylated short DNA probes, and then labeled with streptavidin-horseradish peroxidase conjugate (SA-HRP). The HRP catalyzed the conversion of a substrate to a colored product, which was measured by simple absorbance analysis to achieve the detection of PDGF-BB. By involving RCA and HRP catalysis amplification, sensitive detection of PDGF-BB with a good selectivity was obtained; the detection limit reached 3.1 pM.