Laser-Fabricated Plasmonic Nanostructures for Surface-Enhanced Raman Spectroscopy of Bacteria Quorum Sensing Molecules.

We used a laser-directed fabrication to create silver nanostructures on glass cover slips via photo-reduction. The resulting silver films exhibited plasmonic properties which show promise in application towards surface enhanced Raman spectroscopy (SERS). The enhancement factor calculated for the deposits was approximately ~106 using the standard thiophenol, which is comparable to other SERS-active plasmonic nanostructures fabricated through more complex techniques, such as electron beam lithography. The silver nanostructures were then employed in the enhancement of Raman signals from N-butyryl-L-homoserine lactone, a signaling molecule relevant to bacteria quorum sensing. In particular, the work presented here shows that the laser-deposited plasmonic nanostructures are promising candidates for monitoring concentrations of signaling molecules within biofilms containing quorum sensing bacteria.