Ultrasensitive electrochemical detection of VEGF based on split aptamers-controlled two-dimensional DNA assembly

In this study, an ultrasensitive electrochemical method is developed for the detection of VEGF based on split aptamers-mediated recognition and subsequently generated two-dimensional DNA products. The sandwich structure formed by split aptamers and VEGF is the basic unit for primary hand-in-hand nanowire assembly and downstream hybridization chain reaction (HCR) as the branched assembly. These events adjust the adsorption capability of DNA probes at the MnO2 nanosheets, which can be well reflected by the electrochemical responses. By analyzing the declined current peak, this VEGF biosensor shows a wide linear range and a limit of detection down to 2 pg/mL. High selectivity and practical utility are demonstrated by experimental results. This method also possesses good extensibility for the design of split aptamers and HCR fuel strands, which exhibits wide application prospects.