Sensitive Fluorescence Aptasensor Based on Hybridization Chain Reaction with Upconversion Nanoparticles by Triplex DNA Formation for Bisphenol A Detection
Yu Wang, Xudong Zhao, Bingyang Huo, Shuyue Ren, Jialei Bai, Yuan Peng, Shuang Li, Dianpeng Han, Jiang Wang, Tie Han, Zhixian Gao
Abstract
Application of nanotechnology to detection can effectively increase the biocompatibility of detection sensors. However, since the traditional signal output element has a high background value, the detection sensitivity is often limited. Here, we designed a fluorescence aptasensor based on hybridization chain reaction (HCR) and triplex structure (TS). The aptamer was competitively bound by bisphenol A (BPA) and complementary DNA (cDNA). Unbound cDNA was obtained by magnetic separation. HCR could be triggered by cDNA to form long double-stranded DNA (dsDNA) products. The upconversion nanoparticle (UCNP)-modified ssDNA can form a TS with the HCR product. Thereby, the distance between the UCNPs and Dabcyl on the hairpin was brought closer, and fluorescence was quenched to generate a signal change. HCR and the low background value of UCNPs could improve the sensitivity of detection. The aptasensor has a detection limit as low as 0.057 ng/mL and has been successfully applied to actual sample detection. Its high sensitivity, strong specificity, and excellent biocompatibility make it promising for other target detection and clinical diagnosis.