Plasmon-enhanced Raman spectroscopy for early detection of Alzheimer's disease

Recent advancements in the fabrication of plasmonic nanoparticles have paved the way toward a controlled design of tailor-made substrates with fine-tuning of their plasmonic and surface properties. According to the above scheme the unique combination of sensitivity and selectivity of surface-enhanced Raman spectroscopy (SERS) coupled with the use of novel signal-enhancing plasmonic substrates can afford a valuable choice for the effective chemical and structural analysis of species of biomedical interest [1]-[3]. Although substantial attempts have been made, the SERS detection of such species is still demanding and far from becoming a clinical tool. However, the development of reliable plasmonic supports specifically designed for sensitive, reproducible and rapid detection of biomolecules at low costs can offer the perspective of a reliable routine SERS analysis. In this work a nanotechnological basis is complemented with main key enabling technologies (KETs) such as photonics and advanced materials to build up a strategy for label-free detection of proteins and biomarkers on a sub-micromolar concentration. Silver nanowires are gathered on a teflon membrane under pressure producing 1-2 mm-large SERS spots with a uniform silver coverage. Once tested on model proteins, these supports exhibit high sensitivity as well as signal reproducibility throughout the whole silver surface. Then, the effective detection of Alzheimer's biomarkers is demonstrated. Strategies for optimizing the SERS response and reducing possible signal variability are presented. Overall, these supports offer potential for development of cost-effective and flexible SERS assays of different targets of interest in the analytical and biomedical fields.