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

Biosensors ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 82 ◽  
Author(s):  
Tongchang Zhou ◽  
Arnab Halder ◽  
Yi Sun
Keyword(s):  
Quantum Dots ◽  
Molecularly Imprinted Polymers ◽  
Limit Of Detection ◽  
Fluorescent Sensor ◽  
Sol Gel ◽  
Graphene Quantum Dots ◽  
Carboxyl Groups ◽  
One Pot ◽  
Molecularly Imprinted ◽  
Imprinted Polymers

In this work, we developed a novel fluorescent sensor by combining molecularly imprinted polymers (MIPs) with graphene quantum dots (GQDs) for the determination of tetracycline (TC) in aqueous samples. Firstly, we developed a one-pot green method to synthesize GQDs as the fluorescent probes. GQDs with carboxyl groups or amino groups were fabricated. It was found that carboxyl groups played an important role in the fluorescence quenching. Based on these findings, the GQDs-MIPs microspheres were prepared using a sol-gel process. GQDs-MIPs showed strong fluorescent emission at 410 nm when excited at 360 nm, and the fluorescence was quenched in the presence of TC. Under optimum conditions, the fluorescence intensity of GQDs-MIPs decreased in response to the increase of TC concentration. The linear rage was from 1.0 to 104 µg·L−1, and the limit of detection was determined to be 1 µg·L−1. The GQDs-MIPs also demonstrated high selectivity towards TC. The fluorescent sensor was successfully applied for the detection of TC in real spiked milk samples.

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.

Composite Material Based on Carbon Dots and Molecularly Imprinted Polymers: A Facile Probe for Fluorescent Detection of 4-Nitrophenol

NANO ◽  
2020 ◽  
Vol 15 (08) ◽  
pp. 2050105
Author(s):  
Min Wang ◽  
Manjie Gao ◽  
Linlin Deng ◽  
Xun Kang ◽  
Lijuan Yang ◽  
...  
Keyword(s):  
Composite Material ◽  
Molecularly Imprinted Polymers ◽  
Carbon Dots ◽  
Limit Of Detection ◽  
Sol Gel ◽  
Synthesis Method ◽  
Fluorescent Detection ◽  
Molecularly Imprinted ◽  
Imprinted Polymers ◽  
Selective Determination

A new fluorescence composite material for the sensitive and selective determination of 4-nitrophenol (4-NP) was developed based on molecularly imprinted polymers (MIPs) incorporated with carbon dots (CDs). First, fluorescent CDs with a high quantum yield (QY) of 51.8% were prepared by hydrothermal synthesis method by using anhydrous citric acid as carbon source and AEAPMS as surface modifier. Then, CDs were fabricated with MIPs (CDs@MIPs) by sol–gel method using 4-NP as template, (3-aminopropyl) triethoxysilane (APTES) as functional monomer, tetraethoxysilane (TEOS) as cross-linker and CDs as signal sources, respectively. The CDs@MIPs exhibited strong fluorescence property and high selectivity to 4-NP as it incorporated merits of CDs and MIPs. Under optimized conditions, the relative fluorescence intensity of CDs@MIPs decreased linearly with the concentration of 4-NP from 0.025[Formula: see text][Formula: see text]g[Formula: see text]mL[Formula: see text] to 5[Formula: see text][Formula: see text]g[Formula: see text]mL[Formula: see text]. The limit of detection (LOD) of 4-NP was 5[Formula: see text]ng[Formula: see text]mL[Formula: see text] (35[Formula: see text]nM). Specificity and selectivity experiments showed that CDs@MIPs can selectively detect 4-NP with rare interference of other competitive analogs and metal ions. Finally, CDs@MIPs was successfully used to detect 4-NP in river water samples with the recoveries ranging from 94.0% to 103.4%. The results demonstrated that the prepared CDs@MIPs can be applied to the selective and sensitive detection of trace 4-NP in real samples.

scholarly journals Molecularly Imprinted Polymers for Gossypol via Sol–Gel, Bulk, and Surface Layer Imprinting—A Comparative Study

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 602 ◽  
Author(s):  
Lulu Wang ◽  
Keke Zhi ◽  
Yagang Zhang ◽  
Yanxia Liu ◽  
Letao Zhang ◽  
...  
Keyword(s):  
Surface Layer ◽  
Adsorption Capacity ◽  
Adsorption Kinetics ◽  
Molecularly Imprinted Polymers ◽  
Sol Gel ◽  
Freundlich Isotherm ◽  
Bulk Polymerization ◽  
Order Kinetic ◽  
Molecularly Imprinted ◽  
Imprinted Polymers

Three gossypol molecularly imprinted polymers (MIPs) were prepared by bulk polymerization (MIP1), surface layer imprinting using silica gel as the support (MIP2), and the sol-gel process (MIP3). The as-prepared MIPs were characterized by SEM and nitrogen adsorption−desorption techniques to study the morphology structure. The adsorption experiments exhibited that MIP1 had adsorption capacity as high as 564 mg·g−1. The MIP2 showed faster adsorption kinetics than MIP1 and MIP3. The adsorption equilibrium could be reached for gossypol in 40 min. A selectivity study showed that the adsorption capacity of MIPs for gossypol was about 1.9 times higher than that of the structurally-similar analogs ellagic acid and 6.6 times higher than that of the quercetin. It was found that the pseudo-second-order kinetic model and the Freundlich isotherm model were more applicable for the adsorption kinetics and adsorption isotherm of gossypol binding onto the MIP1 and MIP2, respectively. Results suggested that among those three, the MIP2 was a desirable sorbent for rapid adsorption and MIP1 was suitable for selective recognition of gossypol.

scholarly journals Recent Applications of Molecularly Imprinted Sol-Gel Methodology in Sample Preparation

Molecules ◽  
2019 ◽  
Vol 24 (16) ◽  
pp. 2889 ◽  
Author(s):  
Mohammad Mahdi Moein ◽  
Abbi Abdel-Rehim ◽  
Mohamed Abdel-Rehim
Keyword(s):  
Sample Preparation ◽  
Molecularly Imprinted Polymers ◽  
Mechanical Stability ◽  
Sol Gel ◽  
High Capacity ◽  
Promising Alternative ◽  
Molecularly Imprinted ◽  
Imprinted Polymers ◽  
Molecularly Imprinted Technology ◽  
Stability Issues

Due to their selectivity and chemical stability, molecularly imprinted polymers have attracted great interest in sample preparation. Imprinted polymers have been applied for the extraction and the enrichment of different sorts of trace analytes in biological and environmental samples before their analysis. Additionally, MIPs are utilized in various sample preparation techniques such as SPE, SPME, SBSE and MEPS. Nevertheless, molecularly imprinted polymers suffer from thermal (stable only up to 150 °C) and mechanical stability issues, improper porosity and poor capacity. The sol-gel methodology as a promising alternative to address these limitations allowing the production of sorbents with controlled porosity and higher surface area. Thus the combination of molecularly imprinted technology and sol-gel technology can create influential materials with high selectivity, high capacity and high thermal stability. This work aims to present an overview of molecularly imprinted sol-gel polymerization methods and their applications in analytical and bioanalytical fields.

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