Ultrasensitive detection of Listeria monocytogenes using solid‐state electrochemiluminescence biosensing based on the quenching effect of ferrocene on ruthenium pyridine

Abstract

A solid‐state electrochemiluminescence (ECL) biosensing switch system based on the specific recognition of an aptamer and the destruction of pyridine ruthenium by ferrocene was successfully developed for the detection of Listeria monocytogenes detections. The switching system consisted of two principal parts, the ECL luminescent substrate and the ECL intensity switch. The ECL luminescent substrate was fabricated by attaching an aptamer of Listeria monocytogenes modified with DNA labeled with bipyridine ruthenium complementary to one end of the aptamer, and ferrocene‐labeled DNA complementary to the other end of the aptamer, to an electrode, and so act as an intensity switch. The identification reaction consisted of the specific binding of the aptamer with Listeria monocytogenes causing the labeled ferrocene to be removed from the luminescent substrate, the structural change resulting in a significant increase in the intensity of ECL due to the decreased quenching effect of ferrocene toward the ECL luminescent substrate. Accordingly, the change in ECL intensity indirectly reflected the concentration of Listeria monocytogenes in the sample. The results demonstrated that the system produced a good linear relationship over the concentration range of 1.4 × 101–1.4 × 106 CFU/ml. The present study established that this was a feasible approach for the detection of Listeria monocytogenes in milk and pork samples.