SERS Barcode Libraries: A Microfluidic Approach

Microfluidic technologies have emerged as advanced tools for surface‐enhanced Raman spectroscopy (SERS). They have proved to be particularly appealing for in situ and real‐time detection of analytes at extremely low concentrations and down to the 10 × 10 −15   m level. However, the ability to prepare reconfigurable and reusable devices endowing multiple detection capabilities is an unresolved challenge. Herein, a microfluidic‐based method that allows an extraordinary spatial control over the localization of multiple active SERS substrates in a single microfluidic channel is presented. It is shown that this technology provides for exquisite control over analyte transport to specific detection points, while avoiding cross‐contamination; a feature that enables the simultaneous detection of multiple analytes within the same microfluidic channel. Additionally, it is demonstrated that the SERS substrates can be rationally designed in a straightforward manner and that they allow for the detection of single molecules (at concentrations as low as 10 −14   m ). Finally, it is shown that rapid etching and reconstruction of SERS substrates provides for reconfigurable and reusable operation.