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Colorimetric-based detection of TNT explosives using functionalized silica nanoparticles

Idros, N and Ho, MY and Pivnenko, M and Qasim, MM and Xu, H and Gu, Z and Chu, D (2015) Colorimetric-based detection of TNT explosives using functionalized silica nanoparticles. Sensors (Switzerland), 15. pp. 12891-12905. ISSN 1424-8220

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© 2015 by the authors; licensee MDPI, Basel, Switzerland. This proof-of-concept study proposes a novel sensing mechanism for selective and label-free detection of 2,4,6-trinitrotoluene (TNT). It is realized by surface chemistry functionalization of silica nanoparticles (NPs) with 3-aminopropyl-triethoxysilane (APTES). The primary amine anchored to the surface of the silica nanoparticles (SiO<inf>2</inf>-NH<inf>2</inf>) acts as a capturing probe for TNT target binding to form Meisenheimer amine–TNT complexes. A colorimetric change of the self-assembled (SAM) NP samples from the initial green of a SiO<inf>2</inf>-NH<inf>2</inf> nanoparticle film towards red was observed after successful attachment of TNT, which was confirmed as a result of the increased separation between the nanoparticles. The shift in the peak wavelength of the reflected light normal to the film surface (λ<inf>peak</inf>) and the associated change of the peak width were measured, and a merit function taking into account their combined effect was proposed for the detection of TNT concentrations from 10<sup>−12</sup> to 10<sup>−4</sup> molar. The selectivity of our sensing approach is confirmed by using TNT-bound nanoparticles incubated in AptamerX, with 2,4-dinitrotoluene (DNT) and toluene used as control and baseline, respectively. Our results show the repeatable systematic color change with the TNT concentration and the possibility to develop a robust, easy-to-use, and low-cost TNT detection method for performing a sensitive, reliable, and semi-quantitative detection in a wide detection range.

Item Type: Article
Uncontrolled Keywords: aptamer colorimetric explosives functionalized nanoparticles label-free self-assembly film
Divisions: Div B > Photonics
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 19:45
Last Modified: 25 Feb 2021 06:39
DOI: 10.3390/s150612891