Application of SERS Spectroscopy for the study of biological molecules

Surface-enhanced Raman spectroscopy (SERS) is a variant of Raman scattering and a very active field of research, used for the chemical analysis of compounds and the detection of chemical and biological molecules of environmental interest. This technique consists of an intensification of several orders about the magnitude of the Raman signal of a molecule obtained by using metal nanostructures (for instance, metal nanoparticles) or nanopatterned substrates. This intensification 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 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 SERS capability, 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.