Impedimetric ultrasensitive detection of trypsin based on hybrid aptamer-2DMIP using a glassy carbon electrode modified by nickel oxide nanoparticle

Abstract

In this study, the attempt has been made in the direction to design a new artificial receptor biosensor by use of a hybrid method of molecularly imprinted polymer (MIP) and aptamers (Apt) to ultra-trace Trypsin (Trp) enzyme recognition. Firstly, the effective surface of the electrode was increased by NiO nanoparticles electrochemical deposition. Then a prepared complex containing Apt-Trp was incubated on the NiO surface. A specific surface of Trp bind to one aptamer tail-end. The other tail of the aptamer was attached to NiONP from the NH2 side and in this treatment, the protein target was immobilized as the template. The electropolymerization process was performed using dopamine to completely form a polymeric matrix around the target protein. Finally, the Trp molecule was eliminated with suitable eluent, and the prepared Apt-2DMIP biosensor was used for analytical experiments. This real-time detective sensor had unparalleled selectivity and sensitivity in the presence of off-target species to the Trp. A good diagnostic linear range from 1to 90 pg.mL−1 was obtained with a detection limit of 0.75 pg.mL−1. The imprinting factor was calculated without and in the presence of aptamer, and the results showed that aptamer significantly increased the throughput of the biosensor. Finally, in real samples including blood human serum and urine samples, the efficiency of the biosensor was evaluated, and satisfactory results were obtained.