New immobilization method of anti-PepD monoclonal antibodies for the detection of Listeria monocytogenes p60 protein – Part B: Rapid and specific sandwich ELISA using antibodies immobilized on a chitosan/CNC film support

This paper presents the application of a new support based on chitosan and reinforced with cellulose nanocrystals (m-CCG) for the detection of Listeria monocytogenes p60 protein in sandwich ELISA. This support consists of biopolymer membrane optimized for the covalent immobilization of the specific monoclonal antibodies against the unique short peptide of eleven amino acids (PepD, QQQTAPKAPTE) of L. monocytogenes p60 protein (anti-PepD mAb). Using the optimized immobilization method of anti-PepD mAb on m-CCG (m-CCG + anti-PepD mAb), the detection of L. monocytogenes culture was improved by 17% in Tryptic soy broth and by 24% in Listeria enrichment broth containing 0.5% of dextrose (modified LEB) on m-CCG compared to standard ELISA support. Moreover, the evaluation of the selectivity of detection of L. monocytogenes by anti-PepD mAb immobilized on m-CCG allowed the absence of any cross-reaction between the support and the nine other bacteria commonly found in food environment.