Porous silicon (PSi) is a nanostructured material increasingly exploited for both refractometric and (bio)sensing applications, though currently suffering of restricted real applications due to insufficient sensitivity and, in turn, poor limit of detection. In this talk, development, characterization, and application (to both refractometry and biosensing) of a novel ultrasensitive technique for the non-amplified label-free discrimination of either bulk or surface refractive index changes (namely, Interferogram Average over Wavelength – IAW – reflectance spectroscopy) using nanostructured PSi interferometer is discussed. As to refractometric applications, a minimum bulk refraction index variation of 10-7 RIU was experimentally measured using NaCl aqueous solutions, with a theoretical limit of detection of 10-8 RIU. As to biosensing applications, a minimum concentration of TNFα, a protein biomarker of inflammation and sepsis, at concentration of 3 nM was experimentally monitored, with high selectivity and limit of detection of 200 pM. Both these results represent a 10000-fold improvement with respect to the commonly used fast Fourier Transform reflectance spectroscopy for PSi interferometers used in non-amplified label-free mode. The IAW reflectance spectroscopy envisages bringing PSi optical (bio)sensors at the forefront of ultrasensitive label-free biosensing techniques with ultimate limit of detection in the order of pM level. This enables porous silicon targeting real application for point-of-care clinical analysis where low analyte concentrations are required to be detected in small volume of biological samples.

10000-Fold Improvement in (Bio)Sensing Using Nanostructured Porous Silicon Interferometers by Interferogram Average Over Wavelength Spectroscopy

G. Barillaro
2017-01-01

Abstract

Porous silicon (PSi) is a nanostructured material increasingly exploited for both refractometric and (bio)sensing applications, though currently suffering of restricted real applications due to insufficient sensitivity and, in turn, poor limit of detection. In this talk, development, characterization, and application (to both refractometry and biosensing) of a novel ultrasensitive technique for the non-amplified label-free discrimination of either bulk or surface refractive index changes (namely, Interferogram Average over Wavelength – IAW – reflectance spectroscopy) using nanostructured PSi interferometer is discussed. As to refractometric applications, a minimum bulk refraction index variation of 10-7 RIU was experimentally measured using NaCl aqueous solutions, with a theoretical limit of detection of 10-8 RIU. As to biosensing applications, a minimum concentration of TNFα, a protein biomarker of inflammation and sepsis, at concentration of 3 nM was experimentally monitored, with high selectivity and limit of detection of 200 pM. Both these results represent a 10000-fold improvement with respect to the commonly used fast Fourier Transform reflectance spectroscopy for PSi interferometers used in non-amplified label-free mode. The IAW reflectance spectroscopy envisages bringing PSi optical (bio)sensors at the forefront of ultrasensitive label-free biosensing techniques with ultimate limit of detection in the order of pM level. This enables porous silicon targeting real application for point-of-care clinical analysis where low analyte concentrations are required to be detected in small volume of biological samples.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/902942
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