Scientific research activity is focused on two main lines: micro- and nano- patterned diatom silica shells have been modified by nanometric layers of gold and tested as substrates in Surface Enhanced Raman Spectroscopy (SERS) experiments. Gain factors ranging from 103 and 105 have been demonstrated, not still competitive compared to those achievable by artificial plasmonic substrates. However, systematic tests with different diatom species and different metallic layer depositions (varying thicknesses and materials) will be performed. The advantage in use of bio-materials as substrates for SERS lies in the possibility to exploit a sort of natural "factory" of nanostructures which are able to self-replicate with high accuracy, thus allowing to get rid of expensive, high-technology nanofabrication facilities.
Multicomponent nanoparticles are actually considered the most promising devices for environmental monitoring and biomedical diagnostic. Moreover, the complexity of such nanosystems offers a unique testing platform for electromagnetic models at the nanoscale, which can be verified by simple and inexpensive experiments. Synthesis of gold nanoparticles in presence of organic and biological molecules produces, in one-pot and in mild chemical conditions, hybrid nano-complexes that can be tailored for specific biomedical application, such as subcellular imaging and photo-activated hyperthermia therapy. By changing shape, dimension and biological component, i.e. DNA, siRNA, protein, enzyme or aptamer, target analytes of environmental interest, such as heavy toxic metals, can be detected at very low concentration levels by naked-eye assay.
Contact: Luca De Stefano