A sensitive and recyclable fluorescence aptasensor for detection and extraction of platelet-derived growth factor BB

A fluorescence aptasensor has been designed for sensitive and recyclable detection and extraction of platelet-derived growth factor BB (PDGF-BB) based on nanogel, Thioflavin T (ThT), hairpin DNA containing PDGF-BB aptamer (0.56-2.98 μM), G-quadruplex and its partially complementary strand, and the complementary DNA of the aptamer. Upon addition of PDGF-BB, the aptamer binds to its target, resulting in opening of the hairpin DNA, and formation of the G-quadruplex structure. After addition of ThT, a strong fluorescence signal is obtained. In the absence of PDGF-BB, the fluorescence intensity is weak. The aptasensor showed a high selectivity toward PDGF-BB. In the presence of the complementary DNA of the aptamer (cDNA), the aptamer hybridized with cDNA, which led to the fast dissociation of PDGF-BB from the aptamer to achieve accurate extraction of PDGF-BB. In addition, the hairpin DNA-modified nanogels can be recycled multiple times. The nanogels are successfully applied to complex matrixes for detection and extraction of PDGF-BB in human serum without interference from the sample matrix and they have excellent cytocompatibility.