An enzyme immobilized glutathione (GSH)-capped CdTe quantum dot (QD)-based fluorescence assay has been developed for monitoring organophosphate pesticides. In principle, GSH-capped CdTe QDs exhibit higher sensitivity towards HO produced from the active enzymatic reaction of acetylcholinesterase (AChE) and choline oxidase (CHOx), which results in the fluorescence (FL) "turn-off" of the GSH-capped CdTe QDs. A "turn-on" FL of the CdTe QDs at 520 nm was recovered in the presence of organophosphate (OP). The FL changes of the GSH-capped CdTe QD/AChE/CHOx biosensor reasonably correspond to the amount of OP pesticides. The detection limit of the CdTe/AChE/CHOx biosensor towards paraoxon, dichlorvos, malathion and triazophos was 1.62 × 10 M, 75.3 × 10 M, 0.23 × 10 M and 10.6 × 10 M, respectively. The GSH-capped CdTe QDs/AChE/CHOx biosensor was applied as a FL nanoprobe for assaying the enzymatic activity of AChE. The inhibited AChE was reactivated up to 94% using pyridine oximate (2-PyOx), and functionalized pyridinium oximates (4-CPyOx and 4-CPyOx) of varying chain lengths. It was found that the reactivation potency of the tested oximes varied with the chain length of the oximes. This biosensing system offers the promising benefit for the determination of the OP pesticides in food, water and environmental samples.
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http://dx.doi.org/10.1039/d0ra03055d | DOI Listing |
Talanta
January 2025
The Associated Laboratory for Green Chemistry (LAQV) of the Network of Chemistry and Technology (REQUIMTE) - the Portuguese Research Centre for Sustainable Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, 4050-313, Porto, Portugal. Electronic address:
Background: Analyte-triggered semiconductor quantum dots (QDs) modulation in the presence of non-consistently responsive fluorescent species represents a challenging analytical issue in concrete multi-way data handling. QDs with heterogeneous sizes and/or uneven distribution of functional moieties on their surfaces exhibit significant fluctuations in the fluorescent response components, known as chemical rank, across different excitation/emission modes. This phenomenon may lead to a substantial deviation from the proportionality prescribed by Beer-Lambert law.
View Article and Find Full Text PDFHeliyon
December 2022
Cancer Gene Therapy Research Center, Zanjan University of Medical Sciences, Zanjan, Iran.
This study aimed to directly detect the V617F point mutation of the Janus kinase 2 () gene in the target DNA using a FRET-based biosensor. The water-soluble GSH-CdTe-QDs were synthesized by a one-step process, then GSH-QD conjugated to the termini amino-modified oligonucleotides target via carboxylic groups on the QD surface. The prepared QDs-DNA biosensor was applied in the quantitative and rapid detection of V617F mutation with a detection limit of 3 × 10 mol L based on the FRET mechanism.
View Article and Find Full Text PDFJ Appl Microbiol
July 2021
BioNanotechnology and Microbiology Laboratory, Center of Bioinformatics and Integrative Biology (CBIB), Biological Sciences Faculty, Universidad Andres Bello, Santiago, Chile.
Aim: Fluorescent semiconductor nanoparticles or quantum dots (QDs) have excellent properties as photosensitizers in photodynamic therapy. This is mainly a consequence of their nanometric size and the generation of light-activated redox species. In previous works, we have reported the low-cost biomimetic synthesis of glutathione (GSH) capped QDs (CdTe-GSH QDs) with high biocompatibility.
View Article and Find Full Text PDFRSC Adv
June 2020
School of Studies in Chemistry, Pt. Ravishankar Shukla University Raipur Chhattisgarh 492010 India.
An enzyme immobilized glutathione (GSH)-capped CdTe quantum dot (QD)-based fluorescence assay has been developed for monitoring organophosphate pesticides. In principle, GSH-capped CdTe QDs exhibit higher sensitivity towards HO produced from the active enzymatic reaction of acetylcholinesterase (AChE) and choline oxidase (CHOx), which results in the fluorescence (FL) "turn-off" of the GSH-capped CdTe QDs. A "turn-on" FL of the CdTe QDs at 520 nm was recovered in the presence of organophosphate (OP).
View Article and Find Full Text PDFHeliyon
March 2018
CAS Key Lab of Bio-Medical Diagnostics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, 215163, PR China.
In this work, we have developed one-pot aqueous synthesis of glutathione (GSH) binding CdTe quantum dots (QDs) for cell imaging. UV-Vis absorption spectrum, Fourier transform infrared spectrum, photoluminescence spectrum, and high-resolution transmission electron microscopy are applied to characterize the physical and chemical properties of the nanocomposites. The bioimaging efficiency of the GSH-capped CdTe QDs is further evaluated on Hela cells.
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