Plasmonic nanostructures based on novel metamolecular units for biological samples investigation

Development of novel plasmonic nanopatterns is of great interest for various applications, including chemical and biological analysis. Systems based on gold nanoelements have been designed and tested in several research works for the study and detection of various kinds of biological analytes, giving appreciable results. Plasmonic properties associated to the nanostructure can be tuned by changing the size and the shape of the nanoparticles or the periodicity or, more in general, the geometry of the nanopattern. These features are key to many applications aiming at signal enhancement and low threshold sensing. In this work we present a study of periodic arrangements of novel plasmonic metamolecular unit cells made of triangular nanoelements. Nanostructures analyzed were fabricated using electron beam lithography technique (EBL) that allows to create patterns with high accuracy and repeatability. Morphological analysis was realized . by Scanning Electron Microscopy (SEM) and their plasmonic properties were studied and compared using experimental set-up for Surface Plasmon Resonance (SPR) and Surface Enhanced Raman Spectroscopy (SERS) measurements. We tested the sensing performance of our nanostructures by analyzing the SARS-CoV-2 (COVID-19) Spike Antibody (3525) getting its molecular fingerprint. Our results suggest that these plasmonic patterns are promising to develop highly sensitive nanosensors for the detection of biological analytes.