Versatile SERS-fluidic platforms for optical analysis of liquids

Optical detection techniques have been extensively implemented for liquid biosensing and, among all, surface enhanced Raman spectroscopy (SERS) constitutes the one of the most promising analytical method as alternative to current traditional bioassays. With the attempt to develop point-of-impact diagnostic devices, in the present study, advanced and standard manufacturing processes were successfully combined with nanoparticles (NPs) engineering for the development of multifunctional lab-on-chips (LoCs) that integrate SERS sensors for liquid optical probing. As a matter of fact, LoCs allow to handle easily micro- to nanoliters volumes of samples as well as to perform multifunctional analyses on the same restricted volumes while avoiding cross-contaminations. Furthermore, due to the exploitation of 3D printing process, the LoCs design can be rapidly prototyped to highly integrate networks of channels and detection chambers of varied size and shape smartly arranged with respect to the Raman set-up in order to optimize signal delivery and collection. Within the detection chambers, SERS functionality is achieved by the selective interaction of the target analytes with gold NPs with embedded optical fibers positioned at different excitation and collection angles. The resulting SERS-fluidic devices, characterized by different detection configurations, represent highly versatile SERS-fluidic platforms providing high repeatability, high sensitivity and speed of analysis, possibly revolutionizing liquid biopsy by making it costless, on-chip, handy, and easy to use.