Detection of E. coli O157:H7 via GO-modified fiber optic SPR sensor with Au nanoparticle signal amplification

Escherichia coli O157:H7 (E. coli O157:H7) is a public health hazard for enteric pathogens. Thus, it is essential to detect E. coli with high sensitivity. In this study, a dual signal enhancement fiber-optic surface plasmon resonance (SPR) sensor is proposed to enhance the sensitivity. The sensor surface was modified by graphene oxide (GO) as the signal enhancement layer and the Au nanoparticles (AuNPs) were used for secondary signal amplification. It can significantly improve the sensitivity by four orders of magnitude compared with the traditional fiber-optic SPR sensor. The limit of detection (LOD) for E. coli O157: H7 was 142 CFU/mL and the detection range was 10³ - 10⁷ CFU/mL. The developed sensor has high sensitivity and specificity. Therefore, the sensor may be a potential tool for detecting other biological pathogens.