One-step synthesis of mannose-modified polyethyleneimine copolymer particles as fluorescent probes for the detection of Escherichia coli

Abstract Development of effective pathogen detection systems is critical for human health. In this study, Escherichia coli ( E. coli ) O157:H7 as a model microorganism, mannose-modified polyethyleneimine copolymer particles (Man-PEI CPs) were one-step synthesized through nucleophilic addition between primary amine and aldehyde group, and the fluorescent Man-PEI CPs have been successfully applied for selective and sensitive detection of Escherichia coli . The Man-PEI CPs with highly solubility had an average particle diameter of 54.4 nm. The fluorescence quantum yields of Man-PEI CPs was 0.42. The fluorescent Man-PEIs could provide good targeting ability toward E. coli pili due to the selectively binding to the FimH lectin unit of mannose. In order to get good binding efficiency to E. coli , the ratio of polyethyleneimine to mannose during their synthesis was optimized. The fluorescence emission by Man-PEI CPs/ E. coli conjugate is closely related to the content of E. coli . Man-PEI CPs showed selective response towards E. coli and our assay exhibited potential practical applications for E. coli determination in water, beer and human urine. The simple, inexpensive and efficient preparation of Man-PEI CPs showed potential advantages in the detection of bacteria.