Binding of p-mercaptobenzoic acid and adenine to gold coated electroless etched silicon nanowires studied by surface-enhanced Raman scattering

Mohaček Grošev, Vlasta; Gebavi, Hrvoje; Bonifacio, Alois; Sergo, Valter; Daković, Marko; Bajuk-Bogdanović, Danica (2018) Binding of p-mercaptobenzoic acid and adenine to gold coated electroless etched silicon nanowires studied by surface-enhanced Raman scattering. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 200 . pp. 102-109. ISSN 1386-1425

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Abstract

Modern diagnostic tools ever aim to reduce the amount of analyte and the time needed for obtaining the result. Surface-enhanced Raman spectroscopy is a method that could satisfy both of these requirements, provided that for each analyte an adequate substrate is found. Here we demonstrate the ability of gold-sputtered silicon nanowires (SiNW) to bind p-mercaptobenzoic acid in 10-3, 10-4 and 10-5 M and adenine in 30 and 100 μM concentrations. Based on the normal mode analysis, presented here for the first time, the binding of p-mercaptobenzoic acid is deduced. The intensity enhancement of the 1106 cm-1 band is explained by involvement of the C-S stretching deformation, and the appearance of the broad 300 cm-1 band attributed to S-Au stretching mode. Adenine SERS spectra demonstrate the existence of the 7H tautomer since the strongest band observed is at 736 cm-1. The adenine binding is likely to occur in several ways, because the number of observed bands in the 1200 – 1600 cm-1 interval exceeds the number of observed bands in the normal Raman spectrum of the free molecule.

Item Type:	Article
Uncontrolled Keywords:	silicon nanowires; normal mode analysis: substrate binding: biosensors, SERS; mercaptobenzoic acid; hot spots mapping
Subjects:	NATURAL SCIENCES > Physics > Atomic and Molecular Physics NATURAL SCIENCES > Chemistry > Physical Chemistry
Divisions:	Division of Materials Physics
Projects:	Project title Project leader Project code Project type COST action BM1401 Raman for clinics Juergen Popp UNSPECIFIED UNSPECIFIED Hibridne silicijske nanostrukture za senzoriku Mile Ivanda IP-2014-09-7046 UNSPECIFIED
Depositing User:	Vlasta Mohaček Grošev
Date Deposited:	09 May 2018 15:53
URI:	http://fulir.irb.hr/id/eprint/4029
DOI:	10.1016/j.saa.2018.04.016

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