scholarly journals Molecularly Imprinted Silica-Coated CdTe Quantum Dots for Fluorometric Determination of Trace Chloramphenicol

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 5965
Author(s):  
Xiaoxiao Chen ◽  
Yang Liu ◽  
Pu Li ◽  
Yichen Xing ◽  
Chaobiao Huang
Keyword(s):  
Quantum Dots ◽  
Fluorescence Quenching ◽  
Limit Of Detection ◽  
Recognition System ◽  
Electron Transfer Reaction ◽  
Trace Detection ◽  
Molecularly Imprinted ◽  
Specific Recognition ◽  
Quenching Efficiency ◽  
Photo Induced Electron Transfer

A dual recognition system with a fluorescence quenching of quantum dots (QDs) and specific recognition of molecularly imprinted polymer (MIP) for the detection of chloramphenicol (CAP) was constructed. MIP@SiO2@QDs was prepared by reverse microemulsion method with 3-aminopropyltriethoxysilane (APTS), tetraethyl orthosilicate (TEOS) and QDs being used as the functional monomer, cross-linker and signal sources, respectively. MIP can specifically recognize CAP, and the fluorescence of QDs can be quenched by CAP due to the photo-induced electron transfer reaction between CAP and QDs. Thus, a method for the trace detection of CAP based on MIP@SiO2@QDs fluorescence quenching was established. The fluorescence quenching efficiency of MIP@SiO2@QDs displayed a desirable linear response to the concentration of CAP in the range of 1.00~4.00 × 102 μmol × L−1, and the limit of detection was 0.35 μmol × L−1 (3σ, n = 9). Importantly, MIP@SiO2@QDs presented good detection selectivity owing to specific recognition for CAP, and was successfully applied to quantify CAP in lake water with the recovery ranging 102.0~104.0%, suggesting this method has the promising potential for the on-site detection of CAP in environmental waters.

scholarly journals Black phosphorus-Au nanocomposite-based fluorescence immunochromatographic sensor for high-sensitive detection of zearalenone in cereals

Nanophotonics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 2397-2406
Author(s):  
Shijie Li ◽  
Fuyuan Zhang ◽  
Junping Wang ◽  
Wenjun Wen ◽  
Shuo Wang
Keyword(s):  
Quantum Dots ◽  
Food Safety ◽  
Fluorescence Quenching ◽  
Density Functional ◽  
Limit Of Detection ◽  
Black Phosphorus ◽  
Sensitive Detection ◽  
The Density Functional Theory ◽  
Quenching Efficiency ◽  
Novel Method

AbstractRapid and high-sensitive detection of mycotoxins is believed to be of vital importance in assuring food safety. In this study, we developed a novel fluorescence immunochromatographic sensor (ICS) for the mycotoxin of zearalenone (ZEN) in cereals. This was done by using a black phosphorus-Au nanocomposite (BP-Au) as the 2D quenching platform. Herein, gold nanoparticles (AuNPs) were directly reduced on the surface of BP nanosheets (BPNSs) to form BP-Au nanocomposites, showing higher fluorescence (quantum dots, λEm = 525 nm) quenching efficiency compared to the BPNSs and AuNPs. The fluorescence quenching efficiency of the prepared BP-Au nanocomposite reached 73.8%, which was 1.73-fold and 1.44-fold higher than AuNPs and BPNSs, respectively. The density functional theory was also successfully used to explore the formation mechanism of the BP-Au nanocomposite. By introducing the quantum dots/BP-Au signal/quencher pair, a high-sensitive fluorescence quenching ICS (B-FICS) was developed for the detection and discrimination of ZEN with the limit of detection of 0.1 μg/l in pure working buffer. This was 2.5-fold more sensitive than AuNPs-based FICS (A-FICS). The B-FICS was successfully applied in real cereals detection with the sample limit of detection of 2 μg/kg. The successful construction of B-FICS offers a novel method for a rapid and high-sensitive detection of ZEN in cereals. It also provides a new practical application of 2D BPNSs in food safety sensing.

scholarly journals Carbon Quantum Dots Encapsulated Molecularly Imprinted Fluorescence Quenching Particles for Sensitive Detection of Zearalenone in Corn Sample

Toxins ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 438 ◽  
Author(s):  
Manyu Shao ◽  
Ming Yao ◽  
Sarah De Saeger ◽  
Liping Yan ◽  
Suquan Song
Keyword(s):  
Quantum Dots ◽  
Fluorescence Quenching ◽  
Sol Gel ◽  
Carbon Quantum Dots ◽  
Detection Range ◽  
Molecularly Imprinted ◽  
Relative Standard ◽  
Sol Gel Process ◽  
One Step ◽  
Optimized Conditions

An eco-friendly and efficient one-step approach for the synthesis of carbon quantum dots (CDs) that encapsulated molecularly imprinted fluorescence quenching particles (MIFQP) and their application for the determination of zearalenone (ZEA) in a cereal sample are described in this study. CDs with high luminescence were first synthesized, and then encapsulated in the silica-based matrix through a non-hydrolytic sol-gel process. The resulting ZEA-imprinted particles exhibited not only an excellent specific molecular recognition of ZEA, but also good photostability and obvious template binding-induced fluorescence quenching. Under the optimized conditions, the fluorescence intensity of MIFQP was inversely proportional to the concentration of ZEA. By validation, the detection range of these fluorescence quenching materials for ZEA was between 0.02 and 1.0 mg L−1, and the detection limit was 0.02 mg L−1 (S/N = 3). Finally, the MIFQP sensor was successfully applied for ZEA determination in corn with recoveries from 78% to 105% and the relative standard deviation (RSD %) was lower than 20%, which suggests its potential in actual applications.

scholarly journals Fluorescent Nanosensor based on Molecularly Imprinted Polymers Coated on Graphene Quantum Dots for Fast Detection of Antibiotics

2018 ◽  
Author(s):  
Tongchang Zhou ◽  
Arnab Halder ◽  
Yi Sun
Keyword(s):  
Quantum Dots ◽  
Fluorescence Intensity ◽  
Molecularly Imprinted Polymers ◽  
Limit Of Detection ◽  
Sol Gel ◽  
Graphene Quantum Dots ◽  
Carboxyl Groups ◽  
One Pot ◽  
Molecularly Imprinted ◽  
Imprinted Polymers

In this work, we firstly explored a mild, clean, and highly efficient approach for the synthesis of graphene quantum dots (GQDs). GQDs with carboxyl groups or amino groups, were prepared from one-pot environmentally friendly method assisted by hydrogen peroxide, respectively. It was proved that carboxyl groups played an important role in the fluorescence quenching. Based on these findings, we developed a novel fluorescent nanosensor by combining molecularly imprinted polymers (MIPs) with carboxyl functionalized GQDs for the determination of tetracycline (TC) in aqueous samples. The nanocomposite was prepared using a sol-gel process. GQDs-MIPs showed strong fluorescent emission at 410 nm when excited at 360 nm, which was subsequently quenched in the presence of TC. Under optimum conditions, the fluorescence intensity of GQDs-MIPs decreased in response to the increase of TC concentration with good linearity rage of 1.0-104 µg L-1. The limit of detection was determined to be 1 µg L-1. The fluorescence intensity of GQDs-MIPs was more strongly quenched by TC compared to the corresponding non-imprinted polymers, GQDs-NIPs. With the high sensitivity, the material was also successfully worked for the detection of TC in real spiked milk samples.

scholarly journals CdTe0.5S0.5/ZnS Quantum Dots Embedded in a Molecularly Imprinted Polymer for the Selective Optosensing of Dopamine

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 693 ◽  
Author(s):  
Kiana Khadem-Abbassi ◽  
Hervé Rinnert ◽  
Lavinia Balan ◽  
Zahra Doumandji ◽  
Olivier Joubert ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Ethylene Glycol ◽  
Molecularly Imprinted Polymer ◽  
Limit Of Detection ◽  
Low Cost ◽  
Core Shell ◽  
Selective Detection ◽  
Imprinted Polymer ◽  
Molecularly Imprinted ◽  
Cross Linker

This work describes the preparation of molecularly imprinted polymer (MIP)-modified core/shell CdTe0.5S0.5/ZnS quantum dots (QDs). The QDs@MIP particles were used for the selective and sensitive detection of dopamine (DA). Acrylamide, which is able to form hydrogen bonds with DA, and ethylene glycol dimethylacrylate (EGDMA) as cross-linker were used for the preparation of the MIP. Highly cross-linked polymer particles with sizes up to 1 µm containing the dots were obtained after the polymerization. After the removal of the DA template, MIP-modified QDs (QDs@MIP) exhibit a high photoluminescence (PL) with an intensity similar to that of QDs embedded in the nonimprinted polymer (NIP). A linear PL decrease was observed upon addition of DA to QDs@MIP and the PL response was in the linear ranges from 2.63 µM to 26.30 µM with a limit of detection of 6.6 nM. The PL intensity of QDs@MIP was quenched selectively by DA. The QDs@MIP particles developed in this work are easily prepared and of low cost and are therefore of high interest for the sensitive and selective detection of DA in biological samples.

Enhancement of the Fluorescence Quenching Efficiency of DPPH• on Colloidal Nanocrystalline Quantum Dots in Aqueous Micelles

2011 ◽  
Vol 21 (5) ◽  
pp. 1941-1949 ◽  
Author(s):  
Tuanjai Noipa ◽  
Surangkhana Martwiset ◽  
Nutthaya Butwong ◽  
Thawatchai Tuntulani ◽  
Wittaya Ngeontae
Keyword(s):  
Quantum Dots ◽  
Fluorescence Quenching ◽  
Quenching Efficiency ◽  
Aqueous Micelles

Fabrication of a Dopamine Sensor Based on Carboxyl Quantum Dots

2015 ◽  
Vol 15 (10) ◽  
pp. 7871-7875 ◽  
Author(s):  
Fei Zhao ◽  
Jongsung Kim
Keyword(s):  
Quantum Dots ◽  
Energy Transfer ◽  
Fluorescence Quenching ◽  
Fluorescence Intensity ◽  
Limit Of Detection ◽  
Simple Procedure ◽  
Electronic Energy ◽  
Solution Ph ◽  
Electronic Energy Transfer

A quantum dot (QD)-based optical biosensor was developed to detect the activity of dopamine (DA) via the quenching of QD fluorescence intensity. In this study, we examined the fluorescence quenching of DA-conjugated quantum dots (DA@QDs) at various solution pH values. The fluorescence intensity of the QDs is quenched by electronic energy transfer from the QDs to the o-quinone group of dopamine oxide. The degree of fluorescence quenching was dependent on DA concentration. The influence of the external environment pH factor on fluorescence quenching was investigated. The results showed that the degree of fluorescence quenching of DA@QDs was highest in a slightly alkaline solution-pH of approximately 9. Fluorescence enhancement with increased pH appears to be due to electronic energy transfer, which is related to an increased degree of dopamine-o-quinone oxidation. The fluorescence quenching of QDs by DA is of considerable interest due to its potential for the direct detection of the DA in vivo via a simple procedure with a very low limit of detection.

scholarly journals Deposition of CdTe quantum dots on microfluidic paper chips for rapid fluorescence detection of pesticide 2,4-D

The Analyst ◽  
2019 ◽  
Vol 144 (4) ◽  
pp. 1282-1291 ◽  
Author(s):  
Zhong Zhang ◽  
Xin Ma ◽  
Mengfan Jia ◽  
Bowei Li ◽  
Jianhui Rong ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Fluorescence Detection ◽  
Molecularly Imprinted Polymers ◽  
Cdte Quantum Dots ◽  
Sensitive Detection ◽  
Molecularly Imprinted ◽  
Imprinted Polymers ◽  
Specific Recognition

Novel fluorescent microfluidic paper chips were developed by the combination of molecularly imprinted polymers and microfluidic paper chips with CdTe quantum dots for the specific recognition and sensitive detection of the pesticide 2,4-D.

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