Rapid detection of pathogenic bacteria based on a universal dual-recognition FRET sensing system constructed with aptamer-quantum dots and lectin-gold nanoparticles

The threat to public health from bacterial infections has led to an urgent need to develop simpler,faster and more reliable bacterial detection methods.In this work,we developed a universal dual-recognition based sandwich fluorescence resonance energy transfer(FRET)sensor by using specific aptamer-modified quantum dots(Aptamer-QDs)as energy donor and lectin concanavalin A(Con A)modified gold nanoparticles(Con A-AuNPs)as energy acceptor to achieve rapid and sensitive detection of Escherichia coli(E.coli)within 0.5 h.In the presence of the target E.coli,the energy donor of Aptamer-QDs and acceptor of Con A-AuNPs were close to each other,causing changes of FRET signals.Based on the constructed FRET sensor,a linear detection range of from 10^(2)cfu/mL to 2×10^(8)cfu/mL with the detection limit of 45 cfu/mL for E.coli was achieved.Furthermore,the FRET sensor was applied to detect E.coli in the milk and orange juice with the detection limit of 300 cfu/mL and 200 cfu/mL,respectively and recovery rate from 83.1%to 112.5%.The strategy holds great promise in pathogenic bacteria detection due to its rapid and sensitivity.