Detection of pathogenic Gram-negative bacteria using an antimicrobial peptides-modified bipolar electrode-electrochemiluminescence platform

Abstract

Real-time, label-free detection of Gram-negative bacteria with high selectivity and sensitivity is demonstrated using a bipolar electrode-electrochemiluminescence (BPE-ECL) platform. This platform utilizes anode luminescence and cathode modification of antimicrobial peptides (AMPs) to effectively capture bacteria. Magainin I, basic AMP from Xenopus skin, boasting an a-helix structure, exhibits a preferential affinity for the surface of Gram-negative pathogens. The covalent attachment of the peptide's C-terminal carboxylic acid to the free amines of a previously thiolated linker ensures its secure immobilization onto the surface of interdigitated gold-plated cathode of BPE. The AMP-modified BPE sensor, when exposed to varying concentrations of Gram-negative bacteria, produces reproducible ECL intensities, allowing for the detection of peptide-bacteria interactions within the range of 1 to 10⁴ CFU mL^-1. Furthermore, this AMP-modified BPE sensor demonstrates a selective capacity to detect E. coli O157:H7 amidst other Gram-negative strains, even at a concentration of 1 CFU mL^-1. This study underscores the high selectivity of Magainin I in bacterial detection, and the AMP-modified BPE-ECL system holds significant promise for rapid detection of Gram-negative bacteria in various applications. The AMP-modified BPE sensor to various concentrations of Gram-negative bacteria generated reproducible ECL intensity that detected peptide-bacteria interactions in the range of 1 to 10⁴ CFU mL^-1. The AMP-modified BPE sensor also selectively detected E. coli O157:H7 from other Gram-negative strains at a concentration of 1 CFU mL^-1. In this paper, AMP demonstrated high selectivity in bacterial detection. The AMP-modified BPE-ECL system prepared has a great potential for application in the field of rapid detection of Gram-negative bacteria.