RESUMEN
We reported an aptamer-based sandwich-type biosensor to detect the platelet derived growth factor-BB (PDGF-BB) by chemiluminescence (CL). Employing magnetic beads as a peculiar immobilizing carriers, a sandwich-type biosensor for detection of PDGF-BB had developed. Firstly, Anti-PDGF-BB was immobilized on the surface of magnetic beads to serve as capture antibody. Then we added PDGF-BB and PDGF-BB-binding aptamer to make sandwich-type complex eventually. CL signal was generated by reaction of 3,4,5-trimethoxyl-phenylglyoxal (TMPG) and guanine nucleobases (G) of PDGF-BB aptamer strands. Moreover, this strategy further improved the sensitivity of detection via biotin-streptavidin reaction that one streptavidin molecule combined with four G-rich sequences which included aptamer. The experimental results showed that the CL intensity was linear to the concentration of PDGF-BB in the range from 1 × 10-8 to 2 × 10-7 M. With magnified protocol, the CL intensity had a good linear relation on the concentration of PDGF-BB in the range from 4 × 10-10 to 2 × 10-8 M. The limit of detection was 0.15 nM at a signal-to-noise ratio of 3. The proposed method was simple, label-free and had high sensitivity which to be expected to provide new way for clinical detection of PDGF-BB.