An on-site bacterial detection strategy based on broad-spectrum antibacterial epsilon-polylysine functionalized magnetic nanoparticles combined with a portable fluorometer

摘要

A sensitive on-site bacterial detection strategy is presented that integrates thebroad-spectrum capturing feature of epsilon-polylysine-functionalized magnetic nanoparticles with an in-house built portable fluorometer. Based on the electrostatic interaction, the functionalized magnetic nanoparticles (epsilon-PL-MNPs) were prepared for Gram-positive and Gram-negative bacterial separation and subsequent viable release. epsilon-PL-MNPs show a broad reactivity towards bacteria with the high capture efficiency from real-world sample media. They also enable controlled viable bacterial release with pH adjustment. Detection of bacteria is based on a combination of broad-spectrum capture with colorimetric and fluorimetric immunoassays. A portable fluorometer is built to enhance the applicability for sensitive on-site detection. A limit of detection of 98CFUmL(-1) is achieved that is comparable to that of a known spectrofluorometric method for E. coli DH5 alpha.