Mono and dithiol surfaces on surface plasmon resonance biosensors for detection of Staphylococcus aureus

The capability of alkane monothiol and dithiol dendritic tether based self-assembled monolayers (SAM) in conjunction with surface plasmon resonance (SPR) for the detection of Staphylococcus aureus was investigated. An antibody based detection protocol for S. aureus, suspended in phosphate buffered saline with Tween 20 (PBST) was developed. Direct and sandwich assays were carried out on the immobilized antibodies against S. aureus. The effect of primary and secondary antibody concentrations on detection was investigated using a Box-Behnken surface response model. Specificity of anti-S. aureus to detect S. aureus in a mixture with Escherichia coli O157:H7 was also researched. Both the surfaces could detect S. aureus to the level of 105 CFU/ml in a sandwich assay, with good specificity against E. coli O157:H7. Results indicate that mono and dithiol self-assembled monolayers can be employed for rapid detection of S. aureus.