As a gram-positive foodborne pathogen, Listeria monocytogenes (LM) can cause many serious diseases to the human health coupled with high mortality rates, thus constructing effective method to detect LM is of great significance. Herein, a novel sandwich-type electrochemical immunosensor was proposed for LM by introducing 3,4,9,10-perylene tetracarboxylic acid/graphene ribbons (PTCA/GNR) nanohybrids as sensing platform and ferrocene/gold nanoparticles (Fc/Au NPs) as signal amplifier. The high conductivity and large surface area of GNR can increase the immobilizing amount of primary antibody (PAb) and enhance the electron transport rate, while Au NPs can carry secondary antibodies (SAb) and Fc derivative (Fc-SH) to form SAb-Au NPs-Fc signal amplifier. Through using Fc molecules as signal probe, its peak current can appear and increase varied from the LM concentrations, hence a highly sensitive sandwich-type immunosensor was constructed: the linear range is wide from 10 to 2×10 4 CFU mL -1 and the limit of detection is low to 6 CFU mL -1 . Furthermore, the specificity of the immunosensor was also studied and a satisfactory result was obtained.
As one of the most hazardous and deadliest pathogens, Listeria monocytogenes (LM) posed various serious diseases to the human being, thus designing effective strategy for its detection is of great significance. In this work, by preparing Ti 3 C 2 T x MXenes nanoribbon (Ti 3 C 2 T x R) as carrier and selecting thionine (Th) acted simultaneously as signal probe and functional monomer, a LM pathogen-imprinted polymers (PIP) integrated probe electrochemical sensor was design to monitor LM for the first time, that was carried out through the electropolymerization of Th on the Ti 3 C 2 T x R/GCE surface in the existence of LM. Upon eluting the templates from the LM imprinted cavities, the fabricated PIP/Ti 3 C 2 T x R/GCE sensor can rebound LM cells effectively. By recording the peak current of Th as the response signal, it can be weakened when LM cell was re-bound to the LM imprinted cavity on PIP/Ti 3 C 2 T x R/GCE, and the absolute values of peak current change increase with the increasement of LM concentrations. After optimizing three key parameters, a considerable low analytical limit (2 CFU mL -1 ) and wide linearity (10-10 8 CFU mL -1 ) for LM were achieved. In addition, the experiments demonstrated that the PIP/Ti 3 C 2 T x R sensor offers satisfactory selectivity, reproducibility and stability.
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