Application of SERS Spectroscopy for the Study of Biological Molecules

Surface-Enhanced Raman Spectroscopy (SERS) is a specialized spectroscopic technique based on the enhancement of the Raman scattering signals of molecules adsorbed or in close proximity to certain rough or nanostructured metal surfaces. It’s an extremely sensitive and powerful analytical tool for the investigation of biological molecules, revolutionizing the field of bioanalytical chemistry. The enhancement of Raman signal is due to various effects, the most important is thought to be the interaction between the electromagnetic wave associated with the laser used and the rough metal substrate (i.e., silver/copper/gold surfaces) on which the molecule is placed. When substrates are used, their characteristics are crucial for the reliability and sensitivity of experiments, as well as the ease of reproducibility of measurements. In the present work, we report on preliminary measurements to investigate the characteristics of two commercial SERS substrates, which have different nanostructures and patterns, properly designed to operate at an excitation wavelength of 785 nm. Aspirin C was used as a representative molecule to evaluate their application for SERS study of biological molecules, thanks to its characteristic fingerprint. Aspirin C is commercially available in the form of effervescent tablets, with acetylsalicylic acid and ascorbic acid as active principles with mainly analgesic and anti-inflammatory properties. The results are discussed also considering future applications for the detection of analytes of environmental interest.