Self assembled monolayer based surface plasmon resonance biosensors for pathogen detection

Surface plasmon resonance (SPR) is a rapid and label-free detection technique for the detection of pathogenic microorganisms. A preliminary study to investigate the capability of an alkanethiol mixed self assembled monolayer (SAM) based SPR biosensor to detect pathogens was demonstrated. A protocol for the detection of pathogens suspended in phosphate buffered saline with Tween 20 (PBST) (pH 7.4) was developed. Antisera against Escherichia coli O157:H7 suspended in sodium acetate (NaOAc) (pH 5.5) was immobilized on an activated sensor chip. Escherichia coli O157:H7 broth was diluted in PBST and passed over the immobilized antibodies to run a direct assay. For sandwich assays anti-Escherichia coli O157:H7 sera suspended in PBST was passed over the bound bacteria. Sandwich assay produced an enhanced signal compared to direct assay. Results indicate that a SAM based SPR biosensor has the potential for rapid detection of pathogens by monitoring the biomolecular interactions on the sensor surface.