A. Rossi - Academia.edu (original) (raw)

Papers by A. Rossi

physica status solidi (a), 2000

Biosensors and Bioelectronics, 2011

A porous silicon biosensor based on P450 enzyme for arachidonic acid detection was developed. A n... more A porous silicon biosensor based on P450 enzyme for arachidonic acid detection was developed. A new transduction method is presented with a simultaneous measurement of refractive index and fluorescence intensity changes when the analyte is binding to an enzyme on the porous silicon surface. A fluorophore bound to a cysteine residue in an allosteric position of the haem domain (BMP) of cytochrome P450 BM3 enhances its fluorescence intensity upon interaction with its substrate arachidonic acid, involved in diseases such as Alzheimer's, liver cancer and cellular inflammation processes. BMP has been anchored on porous silicon surface and the new transduction method has been successfully exploited to develop a biosensor for arachidonic acid, reaching a detection limit of 10 M arachidonic acid in a dynamic range of 10-200 M. Moreover, the change of the refractive index has been also monitored at the same time, displaying a higher detection limit of 30 M. Preliminary test were also conducted in plasma proving the high specificity and selectivity of the sensor even in presence of interferents in the range of 50-100 M.

Biosensors and Bioelectronics, 2007

There is a growing need for virus sensors with improved sensitivity and dynamic range, for applic... more There is a growing need for virus sensors with improved sensitivity and dynamic range, for applications including disease diagnosis, pharmaceutical research, agriculture and homeland security. We report here a new method for improving the sensitivity for detection of the bacteriophage virus MS2 using thin films of nanoporous silicon. Porous silicon is an easily fabricated material that has extremely high surface area to volume ratio, making it an ideal platform for surface based sensors. We have developed and evaluated two different methods for covalent bioconjugation of antibodies inside of porous silicon films, and we show that the pore penetration and binding efficiency depend on the wettability of the porous surface. The resulting films were used to selectively capture dye-labeled MS2 viruses from solution, and a viral concentration as low as 2 × 10 7 plaque-forming units per mL (pfu/mL) was detectable by measuring the fluorescence from the exposed porous silicon film. The system exhibits sensitivity and dynamic range similar to the Luminex liquid array-based assay while outperforming protein micro-array methods.

Diamond and Related Materials, 2005

Polycrystalline 3C–SiC thin films grown by LPCVD on different substrates were characterized by vi... more Polycrystalline 3C–SiC thin films grown by LPCVD on different substrates were characterized by vibrational and electronic spectroscopies and electron diffraction measurements aimed at studying the samples microstructure. Raman spectra evidence the coexistence of crystallites, whose size distribution depends on the deposition conditions, and of a disordered matrix. On the other side, IR reflectivity measurements show spectra which are strongly influenced

Applied Physics Letters, 2008

We report stable photoluminescence from 6H silicon carbide nanocrystals dispersed in three differ... more We report stable photoluminescence from 6H silicon carbide nanocrystals dispersed in three different solvents: water, hydrofluoric acid, and toluene. Transmission electron micrograph surveys reveal a size distribution that contains a significant fraction of monocrystal particles with diameters below 3 nm-small enough for quantum confinement to play a role in increasing the effective bandgap energy. The ultraviolet photoluminescence band observed at 3.5 eV in the colloidal solutions is consistent with quantum confinement estimates based on the effective mass model.

physica status solidi (a), 2000

Biosensors and Bioelectronics, 2011

A porous silicon biosensor based on P450 enzyme for arachidonic acid detection was developed. A n... more A porous silicon biosensor based on P450 enzyme for arachidonic acid detection was developed. A new transduction method is presented with a simultaneous measurement of refractive index and fluorescence intensity changes when the analyte is binding to an enzyme on the porous silicon surface. A fluorophore bound to a cysteine residue in an allosteric position of the haem domain (BMP) of cytochrome P450 BM3 enhances its fluorescence intensity upon interaction with its substrate arachidonic acid, involved in diseases such as Alzheimer's, liver cancer and cellular inflammation processes. BMP has been anchored on porous silicon surface and the new transduction method has been successfully exploited to develop a biosensor for arachidonic acid, reaching a detection limit of 10 M arachidonic acid in a dynamic range of 10-200 M. Moreover, the change of the refractive index has been also monitored at the same time, displaying a higher detection limit of 30 M. Preliminary test were also conducted in plasma proving the high specificity and selectivity of the sensor even in presence of interferents in the range of 50-100 M.

Biosensors and Bioelectronics, 2007

There is a growing need for virus sensors with improved sensitivity and dynamic range, for applic... more There is a growing need for virus sensors with improved sensitivity and dynamic range, for applications including disease diagnosis, pharmaceutical research, agriculture and homeland security. We report here a new method for improving the sensitivity for detection of the bacteriophage virus MS2 using thin films of nanoporous silicon. Porous silicon is an easily fabricated material that has extremely high surface area to volume ratio, making it an ideal platform for surface based sensors. We have developed and evaluated two different methods for covalent bioconjugation of antibodies inside of porous silicon films, and we show that the pore penetration and binding efficiency depend on the wettability of the porous surface. The resulting films were used to selectively capture dye-labeled MS2 viruses from solution, and a viral concentration as low as 2 × 10 7 plaque-forming units per mL (pfu/mL) was detectable by measuring the fluorescence from the exposed porous silicon film. The system exhibits sensitivity and dynamic range similar to the Luminex liquid array-based assay while outperforming protein micro-array methods.

Diamond and Related Materials, 2005

Polycrystalline 3C–SiC thin films grown by LPCVD on different substrates were characterized by vi... more Polycrystalline 3C–SiC thin films grown by LPCVD on different substrates were characterized by vibrational and electronic spectroscopies and electron diffraction measurements aimed at studying the samples microstructure. Raman spectra evidence the coexistence of crystallites, whose size distribution depends on the deposition conditions, and of a disordered matrix. On the other side, IR reflectivity measurements show spectra which are strongly influenced

Applied Physics Letters, 2008

We report stable photoluminescence from 6H silicon carbide nanocrystals dispersed in three differ... more We report stable photoluminescence from 6H silicon carbide nanocrystals dispersed in three different solvents: water, hydrofluoric acid, and toluene. Transmission electron micrograph surveys reveal a size distribution that contains a significant fraction of monocrystal particles with diameters below 3 nm-small enough for quantum confinement to play a role in increasing the effective bandgap energy. The ultraviolet photoluminescence band observed at 3.5 eV in the colloidal solutions is consistent with quantum confinement estimates based on the effective mass model.