Brushing, a simple way to fabricate SERS active paper substrates

A simple and facile method has been demonstrated to fabricate low-cost surface enhanced Raman scattering (SERS) active microfluidic paper chips using a painting brush. This strategy solves the problem of mass production of highly reproducible SERS substrates without complicated or bulky micro- or nanofabrication instruments. Rhodamine 6G (R6G) was chosen as a probe molecule to evaluate the performance of the SERS active chip. To further demonstrate the possibility of this method's potential application in environmental monitoring, trace malachite green (MG) was successfully analyzed on this chip. The performance of our chips was desirable. The paper substrates with silver nanoparticles deposited by brush were found to be cost-efficient and highly sensitive (LOD for R6G and MG are 1 nM and 10 nM, respectively), and have good reproducibility (∼15% relative standard deviation).