In situ polydopamine-assisted deposition of silver nanoparticles on a two dimensional support as an inexpensive and highly efficient SERS substrate

Fabrication of cheap and disposable substrates with high surface enhanced Raman scattering (SERS) effects is essential for practical SERS application. In this study, versatile substrates (silica plate, polyethylene film and filter paper) were simply modified with polydopamine followed by in situ silver nanoparticle deposition to fabricate a two-dimensional SERS substrate. This kind of SERS substrate has good reproducibility (relative standard deviation (RSD) <8% (spot-to-spot) and <12% (batch-to-batch)) and stability (>89% after 2 months). Using 4-mercaptopyridine (4-Mpy) as the probe molecule, the enhancement factor could reach 107. This facile and general approach can be easily scaled up to fabricate cheap, easily portable, flexible and disposable SERS substrates, which can be applied for on-site SERS detection.