Fabrication Of Signal Molecules AHLs Imprinted Fluorescence Probe And Its Application

Quorum sensing signal molecules are metabolites of bacteria,and the higher the concentration of bacteria in the environment,the more signal molecules are secreted.When the concentration reaches the threshold,the signal molecules can regulate the expression of specific genes controlling bacterial virulence,putrefaction and biofilm.Therefore,the detection of signal molecules in food environment can evaluate the bacterial contamination of food,which is of great significance to ensure food safety and reduce the occurrence of foodborne diseases.In this paper,EU（DBM）3phen-doped carboxylated polystyrene fluorescence nanospheres（FPM）were prepared by swelling method,with the average diameter of about136.8 nm.A molecularly imprinted fluorescence probe（FPM@MIPs）was constructed using FPM as the core,cbz-N-acyl homoserine lactone as template,methacrylic acid as functional monomer and glycol dimethacrylate as the crosslinker.The results show that the adsorption capacity of FPM@MIPs probe to the template is 50.1 mg/g,and the adsorption equilibrium can be achieved in 8 min at the experimental concentration of 20 mg/L.The binding sites of template molecule are distributed on the surface and inside of the probe,mainly through chemical way to binding the targets.After incubation of FPM@MIPs probe with the target for 7 min,the fluorescence signal is stable,and the fluorescence quenching effect of C4-HSL,C6-HSL and C8-HSL is good.The developed FPM@MIPs-based detection method has wide linear range of 0μg/L-80μg/L for C₄-HSL,C₆-HSL and C₈-HSL,respectively,with the limit of detection of1.18μg/L-6.52μg/L.The recovery of AHLs added to milk samples is 85.1%-93.1%,and the relative standard deviation is 4.99%-8.39%.The results of inter-and intra-day experiments show that the method is stable.The fluorescence of FPM@MIPs probe is stable within 8 weeks.The FPM@MIPs can inhibit the biofilm formation of Pseudomonas aeruginosa,and the amount of FPM@MIPs probe and the culture time of bacteria had a great effect on the inhibition of biofilm formation,while the temperature had a little effect.The fluorescence probe based on polystyrene microspheres doping with EU（DBM）3phen provides a new method for early detection of bacterial contamination in food and a new material for inhibition of bacterial biofilm formation.