Surface Plasmon Resonance Immunosensor for the Detection of Campylobacter jejuni

Campylobacteriosis is an internationally important foodborne disease caused by Campylobacter jejuni. The bacterium is prevalent in chicken meat and it is estimated that as much as 90% of chicken meat on the market may be contaminated with the bacterium. The current gold standard for the detection of C. jejuni is the culturing method, which takes at least 48 h to confirm the presence of the bacterium. Hence, the aim of this work was to investigate the development of a Surface Plasmon Resonance (SPR) sensor platform for C. jejuni detection. Bacterial strains were cultivated in-house and used in the development of the sensor. SPR sensor chips were first functionalized with polyclonal antibodies raised against C. jejuni using covalent attachment. The gold chips were then applied for the direct detection of C. jejuni. The assay conditions were then optimized and the sensor used for C. jejuni detection, achieving a detection limit of 8 x 10(6) CFUmL(-1). The sensitivity of the assay was further enhanced to 4 x 10(4) CFUmL(-1) through the deployment of a sandwich assay format using the same polyclonal antibody. The LOD obtained in the sandwich assay was higher than that achieved using commercial enzyme-linked immunosorbent assay (ELISA) (10(6)-10(7) CFUmL(-1)). This indicate that the SPR-based sandwich sensor method has an excellent potential to replace ELISA tests for C. jejuni detection. Specificity studies performed with Gram-positive and Gram-negative bacteria, demonstrated the high specific of the sensor for C. jejuni.