SERS-from-scratch: An electric field-guided nanoparticle assembly method for cleanroom-free and low-cost preparation of surface-enhanced Raman scattering substrates

Ultrasensitive detection of analytes is important in forensic science, environmental monitoring and medical diagnostics. Surface-enhanced Raman scattering (SERS) is an analytical detection method with single-molecule sensitivity, but nanofabrication of SERS substrates poses a barrier to its application. Here, we report on a facile and rapid approach to prepare ultrasensitive SERS substrates in situ by using electrokinetics to assemble Ag nanoparticles on a scored conducive surface. We demonstrate the unique characteristic of our method to produce highly SERS-active surfaces from a wide range of materials, including commercially available glass slides pre-coated with indium fin oxide (ITO). We show that the SERS from scratch substrates can detect trace quantities of explosives, drugs and pesticides, with sensitivities superior to some commercially available products.