We have studied the adsorption of xanthine, a nucleobase present in human tissue and fluids that is involved in important metabolic processes, on citrate-reduced gold colloidal nanoparticles by means of surface-enhanced Raman scattering (SERS), absorption, and X-ray photoelectron spectroscopy (XPS) measurements, along with density functional theory (DFT) calculations. The citrate anions stabilize the colloidal suspensions by strongly binding the gold nanoparticles. However, these anions do not impair the adsorption of xanthine on positively-charged active sites present on the metal surface. We have obtained the Fourier transform (FT)-SERS spectra of adsorbed xanthine by laser excitation in the near infrared spectral region, where interference due to fluorescence emission does not usually occur. In fact, the addition of chloride ions to the Au/xanthine colloid induces the aggregation of the gold nanoparticles, whose plasmonic band is shifted to the near infrared region where there is the exciting laser line of the FT–Raman instrument. Hence, this analytical approach is potentially suitable for spectroscopic determination of xanthine directly in body fluids, avoiding fluorescence phenomena induced by visible laser irradiation.

SERS, XPS and DFT study of xanthine adsorbed on citrate-stabilized gold nanoparticles / Caporali, S.; Muniz-Miranda, F.; Pedone, A.; Muniz-Miranda, M.. - In: SENSORS. - ISSN 1424-8220. - 19:12(2019), pp. 2700-2710. [10.3390/s19122700]

SERS, XPS and DFT study of xanthine adsorbed on citrate-stabilized gold nanoparticles

Muniz-Miranda F.;Pedone A.;
2019

Abstract

We have studied the adsorption of xanthine, a nucleobase present in human tissue and fluids that is involved in important metabolic processes, on citrate-reduced gold colloidal nanoparticles by means of surface-enhanced Raman scattering (SERS), absorption, and X-ray photoelectron spectroscopy (XPS) measurements, along with density functional theory (DFT) calculations. The citrate anions stabilize the colloidal suspensions by strongly binding the gold nanoparticles. However, these anions do not impair the adsorption of xanthine on positively-charged active sites present on the metal surface. We have obtained the Fourier transform (FT)-SERS spectra of adsorbed xanthine by laser excitation in the near infrared spectral region, where interference due to fluorescence emission does not usually occur. In fact, the addition of chloride ions to the Au/xanthine colloid induces the aggregation of the gold nanoparticles, whose plasmonic band is shifted to the near infrared region where there is the exciting laser line of the FT–Raman instrument. Hence, this analytical approach is potentially suitable for spectroscopic determination of xanthine directly in body fluids, avoiding fluorescence phenomena induced by visible laser irradiation.
2019
19
12
2700
2710
SERS, XPS and DFT study of xanthine adsorbed on citrate-stabilized gold nanoparticles / Caporali, S.; Muniz-Miranda, F.; Pedone, A.; Muniz-Miranda, M.. - In: SENSORS. - ISSN 1424-8220. - 19:12(2019), pp. 2700-2710. [10.3390/s19122700]
Caporali, S.; Muniz-Miranda, F.; Pedone, A.; Muniz-Miranda, M.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11380/1188488
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