Laser-synthesized Au nanoparticle arrays for therapeutic drug monitoring.
Pistaffa M., Zanchi C., Trusso S., Lucotti A., Tommasini M., de Grazia U., Ciusani E., Casazza M., Ossi P.M.
In the field of therapeutic drug monitoring, spectroscopic methods based on light scattering and plasmonics, such as Surface Enhanced Raman Spectroscopy (SERS), constitute a promising and complementary approach to standard techniques to quantitatively detect drugs in biological fluids ($e.g.$, blood, plasma). SERS has the advantage over standard methods to provide molecular-level information with reduced sample preparation, much shorter times and reduced costs. Here, we report on the performance of nanostructured Au substrates, synthesized by Pulsed Laser Ablation (PLA) in inert gas at high pressure, as efficient and, under certain circumstances, reusable SERS sensors to detect drug molecules. In particular, controlling growth parameters in the PLA process allows for fine-tuning the aggregation of the gold nanoparticles synthesized in the laser-generated plasma and deposited on rigid supports, to get substrates for SERS application with highly differentiated surface nanostructures and optical properties, characterized by excellent spatial reproducibility, with a good signal-to-noise ratio. As a case study of interest for clinical application we show the possibility to obtain a calibration curve from a reusable sensor for the anti-epilepsy drug carbamazepine. The detection of the drug from biological fluids (plasma or serum), is considered as the starting point to correlate the intensity of selected SERS features from the drug to its concentration in the blood of treated patients.