A novel aptamer biosensor using ZnO-3DNGH for sensitive and selective detection of Listeria monocytogenes

Abstract

A novel electrochemical luminescence (ECL) sensor was fabricated by self-assembly of an amino-modified aptamer onto a zinc oxide-three-dimensional nitrogen-doped graphene composite (ZnO-3DNGH)-modified electrode surface for the measurement of Listeria monocytogenes (LM) levels. As introduced the nitrogen element into the graphene framework, the prepared 3DNGH porous nanomaterial provides better conductivity and a larger surface area for Ru(bpy)32+. Meanwhile, ZnO served as the catalyst, which can effectively enhance the electrochemical performance. In optimal condition, the sensor exhibited a linear relationship between the luminescence signal (△IECL) and the logarithm of LM concentration (CLM) over the range 15 CFU·mL−1 to 1.5 × 107 CFU·mL−1 with a correlation coefficient of 0.9904 and a limit of detection (S/N = 3) of 5 CFU·mL−1. The sensor was successfully demonstrated to be capable of measuring the level of LM in both pork and milk samples, with rates of recovery of 91.4%-104.2% as calculated by a standard addition method. The results of the study demonstrate that the novel sensor offers a new method of sensitive and selective measurement of LM in complex samples, with considerable potential for applications in the fields of food inspection, molecular diagnosis, and biotechnology.