Apart from national security and military purposes, it is also of great importance to detect picric acid (PA) in aqueous solution for pollution control. Herein, we report a gold nanoparticle (AuNP)-based sensor for detection of PA in aqueous condition, based on metal-enhanced fluorescence (MEF) of poly(allylamine)hydrochloride (PAH). Notable enhancement in fluorescence intensity is observed when PAH is incubated with Au@SiO nanoparticles, where silica shell controls the distance between gold core and PAH. Almost ∼280 fold enhancement is recorded when PAH is incubated with ∼45 nm diameter Au nanoparticles. A significant reduction in excited state lifetime followed the enhancement in fluorescence intensity, identifying the mechanism to be primarily obtained from the intrinsic radiative decay rate enhancement of PAH. The MEF sensor shows excellent selectivity for detection of PA in water, among similar electron deficient compounds via fluorescence quenching. The detection limit of the sensor is calculated to be 79 nM, in the linear range. Detection of PA is demonstrated in simulated water samples, where matrix effects are taken into account to assess the efficacy of the sensor.
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http://dx.doi.org/10.1016/j.aca.2020.07.001 | DOI Listing |
Anal Bioanal Chem
January 2025
School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou, 510006, China.
Although fluorescence analysis methods are widely used in pesticide residue detection, improving their sensitivity and selectivity remains a challenge. This paper presents a novel ratio fluorescence sensor based on the molecular imprinting polymers (MIPs) and metal-enhanced fluorescence for visual detection of dicamba (DIC). Calcium fluoride (CaF) quantum dots (QDs) were immobilized on the surface of Ag@MIPs, resulting in a blue fluorescence response signal (Ag@MIPs-CaF).
View Article and Find Full Text PDFSensors (Basel)
December 2024
Department of Chemistry and Biochemistry, Institute of Fluorescence, University of Maryland, Baltimore County, 701 E Pratt St, Baltimore, MD 21202, USA.
We report on the detection and quantification of aqueous DNA by a fluorophore-induced plasmonic current (FIPC) sensing method. FIPC is a mechanism described by our group in the literature where a fluorophore in close proximity to a plasmonically active metal nanoparticle film (MNF) is able to couple with it, when in an excited state. This coupling produces enhanced fluorescent intensity from the fluorophore-MNF complex, and if conditions are met, a current is generated in the film that is intrinsically linked to the properties of the fluorophore in the complex.
View Article and Find Full Text PDFACS Sens
December 2024
UNAM-National Nanotechnology Research Center, Bilkent University, 06800 Ankara, Turkey.
Research has shown that the expression level of microRNA-155 (miRNA-155) is positively correlated with clinical stage and depth of invasion in patients with cervical cancer and cervical intraepithelial neoplasia and tends to be highly expressed. Therefore, it is very important to develop sensitive miRNA-155 analysis methods for the early diagnosis, treatment, and prognostic evaluation of cervical cancer. In this study, a near-infrared light-driven fluorescent biosensor based on the metal-enhanced fluorescence effect of polydopamine-coated upconversion nanoparticle (UP/Au) and two toehold-mediated strand displacement (TMSD) steps was constructed for the detection of miRNA-155.
View Article and Find Full Text PDFAnal Chim Acta
November 2023
School of Water, Energy and Environment, Cranfield University, Cranfield, MK43 0AL, UK.
The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which was first reported in early January 2020, continues to devastate the worlds public health system. Herein, we report on the development of a novel metal-enhanced fluorescence (MEF) and electrochemical biosensor for SARS-CoV-2 spike (S) protein. To develop the MEF biosensor, SiO-coated Si-doped ZnSeS quantum dots (QDs) were newly synthesized and conjugated to an aptamer-molecular beacon (Apta-MB) probe.
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