Abstract: In one aspect, the disclosure relates to methods of label-free surface-enhanced Raman spectroscopy (SERS) comprising plasmonically enhanced electronic Raman scattering (ERS) signals from metal nanostructures as an internal calibration standard to improve multivariate analysis of living biological systems, and the uses of the methods therein. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.

Abstract: The present disclosure relates to a surface-enhanced Raman spectroscopy complex probe capable of effectively detecting a catecholamine compound even at extremely low concentrations. The complex probe includes a nanolaminate including a nanogap and metal nanoparticles. In this case, the nanolaminate and the metal nanoparticles are modified to a compound that may be bound to each functional group included in catecholamine, and thus, catecholamine included in an analyte is doubly recognized by the complex probe. In addition, since a hotspot emitting a strong SERS signal is formed by a nanogap included in a nanolaminate, it is possible to effectively detect a catecholamine compound even at extremely low concentrations.