Detection And Inactivation Of Foodborne Pathogens Based On A Plasmonic Chip

Infections or contaminations caused by foodborne pathogens have always been one of the major threats to human health.Pathogenic bacteria with even a low concentration can lead to serious infectious diseases,which can seriously threaten human life and health.Therefore,rapid and sensitive detection of food-borne microorganisms is of great significance for food safety.At present,diverse biosensors have been reported for sensitive detection of bacteria,however,most of the detection platforms have suffered from several issues,such as contamination of the sensing element,limited single detection signal and repeated pollution caused by the proliferation of bacteria after detection.Therefore,it is extremely urgent to develop a multi-functional food-borne pathogen sensing platform that integrates highly sensitive detection and sterilization functions together.In this study,a multifunctional biochip was designed and prepared to achieve the capture,dual-mode detection and in-situ inactivation of foodborne pathogens.First,a plasmonic gold film with tortuous nano-slits and gaps on a glass slide was prepared with a simple,green solution synthesis method.Secondly,a self-assemble layer of 4-mercaptophenylboronic acid(4-MPBA)was modified on the gold surface to obtain the plasmonic chip.The main features of this plasmonic chip include:1)the nanotopography and the surface modification of 4-MPBA can realize the synergistic capture of pathogenic bacteria;2)the abundant gaps makes the plasmonic chip have strong electromagnetic field,that can enhance the Raman and fluorescence signals to for dual-mode sensitive detection of pathogenic bacteria;3)upon irradiating of near-infrared(NIR)laser,the plasmonic chip can produce photothermal effect,which can achieve the in-situ sterilization and avoid secondary pollution caused by bacterial proliferation after detection.In this paper,the common food-borne pathogenic bacteria Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)were used as model bacteria to explore the application of this multifunctional plasmonic chip for bacteria detection and killing.As a result,the plasmonic chip not only can achieve the synergistic capture of bacteria,but also can enable the bacteria detection with a good sensitivity(detection limit of fluorescence method is 103 CFU mL-1,which can be as low as 102 CFU mL-1 in Raman detection.).In addition,the chip exhibits an excellent antibacterial efficiency,which is 98.76%toward E.coli and 97.73%toward S.aureus respectively.Therefore,this multifunctional plasmonic chip can successfully realize the bacterial capture,dual-mode detection and inactivation,and has a great potential for food safety.