Microfluidic-SERS platform with in-situ nanoparticle synthesis for rapid E. coli detection in food

A microfluidic-surface enhanced Raman spectroscopy (SERS) platform for rapid detection of Escherichia coli in food products is proposed. By implementing a Y-junction serpentine microfluidic channel, we achieved in-situ synthesis of silver nanoparticles (AgNPs), for enhancing SERS signal intensity. The synthesis of AgNPs was guided by specific aptamers bound to the bacterial cell, which facilitated formation of nanoparticles. This aptamer guided in-situ synthesis ensured specificity and accuracy in detecting E. coli with a limit of detection of 1.1 CFU/mL and a linear detection range from 10² to 10⁸ CFU/mL, showing superior sensitivity compared to other reported methods. The technique also showed recovery value ranging from 83 to 125 % for lettuce sample. The platform combines the advantages of microfluidics and SERS, enabling rapid, sensitive, and label-free detection of pathogens in food. This method addresses limitations of conventional culture-based techniques and other molecular diagnostics, offering a promising tool for microbial food safety analysis.