Development of a fluorescence assay for highly sensitive detection of <i>Pseudomonas aeruginosa</i> based on an aptamer-carbon dots/graphene oxide system

Abstract

An aptamer-based fluorescence assay for culture-independent detection of <i>Pseudomonas aeruginosa</i> was developed. This assay was enabled by highly specific aptamers conjugated with photoluminescent carbon dots (CDs) as the fluorescent probe and graphene oxide (GO) as the quencher. Specially, high-throughput sequencing was achieved during systematic evolution of ligands <i>via</i> exponential enrichment (SELEX) for accurate recognition of aptamers. This assay displayed high specificity towards <i>P. aeruginosa</i> and was resistant to interference by other ubiquitous bacteria including <i>Escherichia coli</i>, <i>Bacillus subtilis</i>, <i>Staphylococcus aureus</i>, <i>Enterococcus faecalis</i>, and <i>Clostridium perfringens</i>. After the conditions were optimized, this assay achieved a wide detection range for <i>P. aeruginosa</i> varying from 10¹ CFU mL^-1 to 10⁷ CFU mL^-1. Notably, it approached an excellent detection limit as low as 9 CFU mL^-1. Therefore, this fluorescence assay was considered successfully developed for highly sensitive detection of <i>P. aeruginosa</i>. This assay also detected the contamination of <i>P. aeruginosa</i> in tap water and commercial bottled water, thereby suggesting its potential application in real water samples.