Preliminary studies on the rapid detection of staphylococcus aureus using a microfluidic device and nanopatterned hydrogels

We studied the use of nanopatterned hydrogels as a possible foundation for medical devices for the detection of Staphylococcus aureus. Nanopatterned hydrogels, approximately 200 nm in diameter, were created by locally crosslinking dry amine-terminated poly(ethylene glycol) [PEG] (6000 Da) thin films using a focused electron beam. These gels then had a dry height of 50 nm and a swell ratio of about five. They were patterned into arrays with approximately 500 nm inter-gel spacing and functionalized with Immunoglobulin G [IgG], a biomolecule that binds protein A. We then placed these arrayed gels into a simple microfluidic device and exposed them to various bacterial samples. We show, using an assay that binds IgG to protein A expressing Staphylococcus aureus [S.aureus], that nanopatterned hydrogels can be used as probes for detection. We further show the specificity of our assay by using a protein A knock-out variant of S. aureus, Staphylococcus Epidermidis and Escherichia coli as negative controls.