Perylene Derivative and K2S2O8 as Highly Efficient Electrochemical System for Constructing Sensitive Amperometric Aptasensor

Abstract

To design highly efficient electrochemistry system was important for construct simple and sensitive biosensors, which was crucical in clinical diagnosis and therapy. In this work, a novel electrochemistry probe N,N’-di(1-hydroxyethyl dimethylaminoethyl) perylene diimide (HDPDI) with positive charges was reported to show two-electron redox behavior in neutral phosphate buffer solution between 0 and -1.0 V. And K2S2O8 in solution could significantly increased the reduction current of HDPDI at -0.29 V, which was interpreted with cyclic catalysis mechanism of K2S2O8. Moreover, HDPDI as electrochemical probe and K2S2O8 as signal enhancer was used to design aptasensors for protein detection. Thrombin was used as target model protein. Thiolate ssDNA with thrombin-binding sequence was immobilized on gold electrode to selectively capture thrombin and adsorb HDPDI. The thrombin-unbound ssDNA with random coil structure could adsorb HDPDI through electrostatic attraction interaction. However, the thrombin-bound ssDNA became G-quadruplex structure and hardly adsorbed HDPDI. Thus, with increasing the concentration of thrombin, the current signal stepwisely decreased and was taken as detection signal. Compared with other aptasensors based on electrochemistry molecules without signal enhancer, the proposed aptasensors exhibited wider linear response for thrombin between 1 pg mL-1 and 100 ng mL-1 with lower detection limit 0.13 pg mL-1. In addition, the proposed aptasensor showed good feasibility in human serum samples.

Keywords: Perylene derivative, K2S2O8, Electrochemical system, Cyclic catalysis, aptasensor