A Novel and Disposable Enzyme-Labeled Amperometric Immunosensor Based on MWCNT Fibers forListeria monocytogenesDetection

Abstract

A sensitive and specific immunosensor was developed by immobilizing HRP-labeled antibody againstListeria monocytogenesonto the surface of the novel multiwalled carbon nanotube fibers. Firstly, the influence of immunoelectrode modification methods (chemical and physical method) on detection sensitivity and stability was studied. Next, immunosensor was developed, optimized, and applied for the detection ofL. monocytogenes. The morphology was characterized by scanning electron microscopy (SEM), and electrochemical behaviors were by cyclic voltammetry. SEM image, relative response (%), and current data showed chemical modification for immunoelectrode was helpful to capture more target bacteria and obtain more stable current response, resulting in improving the detection sensitivity. The linear relationship betweenL. monocytogenesconcentration andΔIpcwas from 102to 105 cfu/mL (R2=0.993), and LOD was1.07×102 cfu/mL.L. monocytogenesin mixed bacteria (1.51 × 103 cfu/mL) of milk sample (S/N > 14) were detected by developed immunosensor, showing good specificity. Good storage stability and reproducibility (RSD < 6.5%) also showed the potential application of immunosensor for the rapid detection ofL. monocytogenes.