Photonic-plasmonic nanostructures and biosensors
Photonic-plasmonic biosensors are micro- and nano-structured devices that allows the selective detection of biological species with a very high sensitivity through enhanced light-matter interaction. Research and development in this field made these devices able to compete with those based on electrochemical response, that are still the most widespread ones. In particular, the constant progress in nanofabrication techniques and material nanostructures allows to realize a new generation of extremely sensitive optical biosensors that are able to detect a biological target at a few- or even single-molecule level. This gives the possibility of a selective and early detection of the molecular events associated, for instance, with blood or lymphatic system cancer. In these devices, the physical processes that are used to detect the analyte include localized and extended surface Plasmon resonances (SPR), fluorescence, surface Raman scattering, and light diffraction.
Our research activity is devoted to the theoretical and experimental study of the optical response and of the sensitivity of optical biosensors for the analysis of proteins and peptides of oncologic interest. This activity will be mainly focused on two different systems: i) dielectric multilayers supporting Bloch surface waves (BSW); ii) metallic nanostructures supporting surface plasmons polaritons (SP), propagating or localized. In both cases, the proposed structures are based on the e.m. field confinement and amplification that allows the detection at high sensitivity in the far-field of biomolecular species chemically bound or adsorbed on the active area of biosensor. The structures are designed and their optical response is simulated through specifically developed numerical codes. Devices are first characterized through advanced optical spectroscopy techniques, and then tested via a comparative analysis of the optical properties of the blank system with those of the device after functionalization and analyte exposure.
The most recent result has been the design and fabrication of a nano-antenna structure where the e.m. field is locally enhanced by exploiting surface plasmon polariton adiabatic compression, which is able to enhance Raman scattering signals, simultaneously with an Atomic Force microscopy detection. These solutions open new routes towards the development of new devices to localize and detect a very low number of molecules.
In a different approach, by using coordination chemistry on glass surfaces and the chemistry of metallic nanoparticles layered on glass surfaces we are realizing new materials exerting antimicrobial action only in the presence of microbes, with a non- toxic, re-usable action. They can inhibit the formation of biofilms and may be prepared on purpose, to be specialized against a particular type of microorganism, being also activated by an external, non invasive stimulus (e.g. light).
G. Dacarro, M. Galli, G. Guizzetti, M. Liscidini, M. Patrini
Fondazione Cariplo 2007-2010 "Glass surfaces with antimicrobial properties based on the tuned and controlled release of metal cations: a far reaching study on the use of surface coordination chemistry and of surface layers of metal nanoparticles to prepare smart materials of biomedical interest"
Regione Lombardia 2007-2009, research-educational project "From materials science to molecular biomedicine"
MIUR Cofin 2006-2009 "Advanced photonic devices for biomedical applications"
Nanoscale chemical mapping using three-dimensional adiabatic compression of surface plasmon polaritons,
F. De Angelis, G. Das, P. Candeloro, M. Patrini, M. Galli, A. Bek, M. Lazzarino, I. Maksymov, C. Liberale, L. C. Andreani, and E. Di Fabrizio,
Strong modification of light emission from a dye monolayer via Bloch surface waves,
M. Liscidini, M. Galli, M. Shi, G. Dacarro, M. Patrini, D. Bajoni, and J. E. Sipe,
Demonstration of diffraction enhancement via Bloch surface waves in a-SiN:H multilayers,
M. Liscidini, M. Galli, M. Patrini, R. W. Loo, M. C. Goh, C. Ricciardi, F. Giorgis, and J. E. Sipe,