Potentiometric Detection of Listeria monocytogenes via a Short Antimicrobial Peptide Pair-Based Sandwich Assay

Abstract

Peptide-based sandwich assays are promising tools in molecular detection, but may be restricted by the availability of "pairs" of affinity peptides. Herein, a new potentiometric sandwich assay for bacteria based on peptide pairs derived from an antimicrobial peptide (AMP) ligand is demonstrated. As a model, the original AMP with a welldefined structure for Listeria monocytogenes (LM) can be split into two fragments to serve as the peptide pairs for the sandwich assay. The recognition and binding of the short peptide pairs to the target can be verified by circular dichroism, flow cytometry, fluorometry, and optical microscopy. The potentiometric magnetic bead-based sandwich assay is designed by using horseradish peroxidase as a label. The enzyme can catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine with H 2 O 2 to induce a potential change on a polymeric membrane ionselective electrode. Under optimal conditions, the concentration of LM can be determined potentiometrically in a linear range of 1.0 × 10 2 to 1.0 × 10 6 CFU mL −1 with a detection limit of 10 CFU mL −1 (3σ). The proposed sensing strategy expands the applications of peptides in the field of bioassays.

Recent advances in potentiometric biosensors

“…In contrast to antibodies and aptamers, peptides are intrinsically more stable in harsh environments. Qin and his coworkers designed a potentiometric sandwich assay for bacteria involving peptide pairs derived from an antimicrobial peptide ligand [137] (as shown in Fig. 8B).…”

Magnetic‐Field‐Driven Extraction of Bioreceptors into Polymeric Membranes for Label‐Free Potentiometric Biosensing

“…Peptide‐based potentiometric biosensors show promise for sensing but are still rare [7] . Previously, we reported a short antimicrobial peptide (AMP) pair‐based potentiometric sandwich assay, in which enzyme labels and/or additional indicators were used to report the receptor–bioanalyte interaction [7a] . Clearly, a general approach for direct potentiometric sensing of bioanalytes without probe labeling and indicator addition is desired.…”

Electrochemical Peptide-Based Sensors for Foodborne Pathogens Detection

“…As can be observed in Figure 6 B,C, the split peptides were designed according to the long peptide in order to maintain the excellent recognition ability. The calculated folded structures of the original peptide and the synthesized split peptide pairs are presented in Figure 6 D (herein, chains of b, d, and f were used as the capture fragments, and chains of a, c, and e were used as the detection fragments) [ 55 ].…”

“…( D ) Calculated folded structures of the original peptide and synthesized split peptide pairs. Copyright (2021) American Chemical Society [ 55 ].…”