Detection of Listeria monocytogenes based on teicoplanin functionalized magnetic beads combined with fluorescence assay

• Published in: Microchemical journal Vol. 171; p. 106842
• Main Authors: Deng, Mei, Chen, Guanhua, Feng, Xiaoyan, Wang, Zhengzheng, Xu, Qian, Xu, Hengyi
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2021
• Subjects: Listeria monocytogenes; Magnetic beads; Quantum dot microspheres; Teicoplanin; Listeria monocytogenes; Magnetic beads; Teicoplanin; Quantum dot microspheres
• ISSN: 0026-265X; 1095-9149
• DOI: 10.1016/j.microc.2021.106842

[Display omitted] •The MBs-PEG-BSA-Teic and QBs-PEG-Ab based strategy was successfully established.•The strategy used to detect L. monocytogenes with good sensitivity and specificity.•The dual mediation system can increase the load of Teic and improve sensitivity. Listeria monocytogenes (L. monocytogenes) is a zoonosis pathogen that can cause listeriosis with a high morbidity and mortality. Accordingly, a strategy with high sensitivity and exploitability for detecting L. monocytogenes must be developed. Herein, we introduced a double mediation system based on polyethylene glycol (PEG) and bovine serum albumin (BSA) to prepare teicoplanin (Teic)-functionalized magnetic beads (MBs). This system was then combined with monoclonal antibody-modified quantum dot microspheres (QBs), to develop a rapid and sensitive strategy for detecting L. monocytogenes. Teic, as an antibiotic, mainly bind to Gram-positive bacteria via forming the five-point hydrogen bond between the heptapeptide on its main chain and the terminal D-alanyl-D-alanine (D-Ala-D-Ala) on the cell wall of Gram-positive bacteria. In addition, the antibody guaranteed the specificity for L. monocytogenes detection. The capture efficiency (CE) of MBs-PEG-BSA-Teic for L. monocytogenes at the concentrations ranging from 2.6 × 101 CFU/mL to 2.6 × 104 CFU/mL exceeded 92% in phosphate-buffered saline (PBS) and 89% in the spiked ground beef samples. The limit of detection of the strategy for L. monocytogenes was 2.6 × 101 CFU/mL in both PBS and spiked ground beef samples. Therefore, the proposed strategy is capable of detecting L. monocytogenes with a high specificity and an excellent sensitivity.