The control of light with artificial structures is one of the key issues in modern photonics. Since the initial discovery of Surface-Enhanced Raman Scattering (SERS), an increased amount of work has been done on the research of substrates for highly efficient Raman scattering enhancement due to their extraordinary potential for trace analysis and biological tags. Recently, the plasmonic optical responses of metal nanoparticles, based on Localized Surface Plasmon Resonances (LSPR) in the visible and near IR region, has been intensively researched. It has been demonstrated that the plasmon resonance is closely related to the size and shape of metal nanoparticles and to the dielectric properties of the surrounding medium. In SERS spectroscopy it is of crucial importance to develop systems of interacting metal nanostructures capable of producing high field enhancement with highly reproducible characteristics on controllable metal-dielectric substrates. The possibility of engineering complex metal nanoparticle arrays with distinctive plasmonic resonances extending across the entire visible spectrum can have a significant impact on the design and fabrication of novel nanodevices based on broadband plasmonic enhancement. Electron beam lithography (EBL) is an ideal method for the fabrication of engineered SERS substrates by controlling both the shape and the position of each particle at the nanoscale. In the present work we studied artificial electromagnetic (EM) nanomaterials to develop innovative plasmonic nanobiosensors based on SERS and working in the visible frequency band. Au photonic crystals (PCs) and photonic quasi crystals (PQCs) are proposed for the engineering of reproducible SERS substrates. Using a molecular monolayer of pMA (p-mercaptoaniline) as a Raman reporter, we show that high values of SERS enhancement factors can be achieved in photonic structures. To demonstrate the feasibility of the fabricated nanostructures as efficient SERS substrates for biological applications, we devised a method to deposit single cells (human prostatic) on the photonic surfaces. Preliminary results on SERS sampling of single prostatic human cells indicated that the present engineered metamaterials may be used as an ultrasensitive Raman probe to monitor subtle molecular changes in the cell and open up interesting new opportunities in biosensing.
Surface-Enhanced Raman Spectroscopy on Engineered Plasmonic Photonic Nanostructures for "label free" Biosensing
M Pannico;P Musto;M Rippa;P Mormile;L Petti
2013
Abstract
The control of light with artificial structures is one of the key issues in modern photonics. Since the initial discovery of Surface-Enhanced Raman Scattering (SERS), an increased amount of work has been done on the research of substrates for highly efficient Raman scattering enhancement due to their extraordinary potential for trace analysis and biological tags. Recently, the plasmonic optical responses of metal nanoparticles, based on Localized Surface Plasmon Resonances (LSPR) in the visible and near IR region, has been intensively researched. It has been demonstrated that the plasmon resonance is closely related to the size and shape of metal nanoparticles and to the dielectric properties of the surrounding medium. In SERS spectroscopy it is of crucial importance to develop systems of interacting metal nanostructures capable of producing high field enhancement with highly reproducible characteristics on controllable metal-dielectric substrates. The possibility of engineering complex metal nanoparticle arrays with distinctive plasmonic resonances extending across the entire visible spectrum can have a significant impact on the design and fabrication of novel nanodevices based on broadband plasmonic enhancement. Electron beam lithography (EBL) is an ideal method for the fabrication of engineered SERS substrates by controlling both the shape and the position of each particle at the nanoscale. In the present work we studied artificial electromagnetic (EM) nanomaterials to develop innovative plasmonic nanobiosensors based on SERS and working in the visible frequency band. Au photonic crystals (PCs) and photonic quasi crystals (PQCs) are proposed for the engineering of reproducible SERS substrates. Using a molecular monolayer of pMA (p-mercaptoaniline) as a Raman reporter, we show that high values of SERS enhancement factors can be achieved in photonic structures. To demonstrate the feasibility of the fabricated nanostructures as efficient SERS substrates for biological applications, we devised a method to deposit single cells (human prostatic) on the photonic surfaces. Preliminary results on SERS sampling of single prostatic human cells indicated that the present engineered metamaterials may be used as an ultrasensitive Raman probe to monitor subtle molecular changes in the cell and open up interesting new opportunities in biosensing.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
