Imprinted Fluorescence Sensor Research Articles

Highly Selectivity Molecularly Imprinted Fluorescence Sensor Based on Carbon Quantum Dots for the Determination of Anthraquinones.

Due to the complexity of traditional Chinese medicines (TCMs), it is very important to develop a method that can recognize anthraquinones, the active ingredients in TCMs, with high selectivity. Here, a molecularly imprinted fluorescence sensor was coated on the surface of carbon quantum dots (CDs). Allobarbital was used as functional monomer for this application using theoretical calculations and was successfully synthesized and characterized. The template molecule chrysophanol was combined with the functional monomer allobarbital using a hydrogen bond array. Then, a series of adsorption experiments were performed to study the specific recognition of anthraquinones by the prepared sensors. The results showed that the prepared sensor had a good linear response to concentrations of chrysophanol in the concentration range 0.5 mg · L-1 to 8.0 mg · L-1, a low detection limit (5.0 μg · L-1), high stability, and a short response time (20 min). Additionally, the obtained fluorescence sensor was successfully applied to selectively recognize anthraquinones in TCMs with recoveries of 90.1% to 101.7%. The prepared sensor displays excellent sensitivity and high selectivity towards anthraquinones, mainly due to the specific hydrogen binding sites for the target molecules. Overall, this fluorescence sensor can selectively recognize anthraquinones in TCMs, and provide a method for quality monitoring and rational utilization of TCMs.

Molecularly Imprinted Fluorescent Sensors Based on Nitrogen-Doped CDs for Highly Selective Detection of Aspirin

In this paper, we prepared a fluorescent sensor based on carbon quantum dots (CDs) and molecularly imprinted technology (MIT) that was successfully synthesized and applied to the detection of aspirin (Asp) residues in biological and pharmaceutical samples. The molecularly imprinted fluorescence sensor had the high sensitivity of quantum dots and the high selectivity of molecularly imprinted polymers (MIPs). Nitrogen-doped carbon quantum dots (N-CDs) with high fluorescence intensity were prepared and then was coated with silicon by the reverse microemulsion method. Finally, 3-aminopropyltriethoxysilane (APTES) was used as the functional monomer and Asp as the template molecule, molecularly imprinted layers were formed around the N-CDs. Under the best experimental conditions, the detection limit of the sensor was 0.198[Formula: see text]mg[Formula: see text]L[Formula: see text]. Between 0.9–9.0[Formula: see text]mg[Formula: see text]L[Formula: see text], this fluorescence sensor had a good linear relationship with the concentration of Asp. To test the practicability of the sensor, we used this fluorescent sensor to detect Asp in human urine and saliva. Satisfied recovery rate between 101.1–105.1% and 102.1–106.0% were obtained, respectively.

A Molecularly Imprinted Fluorescence Sensor Based on the ZnO Quantum Dot Core-Shell Structure for High Selectivity and Photolysis Function of Methylene Blue.

ZnO quantum dots and CuFe2O4 nanoparticles were synthesized by chemical precipitation. The ZCF composite was created by the solvothermal method. A new molecularly imprinted fluorescence sensor (ZCF@MB-MIP) with unique optical properties and specific MB recognition was successfully generated. ZCF@MB-MIPs were characterized by Fourier-transform infrared spectroscopy, transmission electron microscopy, and X-ray diffraction and were applied for the selective detection of methylene blue (MB). The optimal working time of ZCF@MB-MIPs was 15 min, and the optimal working concentration was 37 mg·L–1. The fluorescence intensity was linearly quenched within the 0–100 μmol·L–1 MB range, and the detection limit was 1.27 μmol·L–1. The imprinting factor of the sensor (IF, KMB-MIPs/N-MIPs) was 5.30. At the same time, a real-time monitoring system was established for the photodegradation process of MB, which had the effect of reflecting the degradation degree of MB at any given time. Hence, ZCF@MB-MIPs are a promising candidate for use in MB monitoring, and they also provides a new strategy for constructing a multifunctional fluorescence sensor with a high selectivity and photolysis function.

Carbon dots incorporated metal–organic framework for enhancing fluorescence detection performance

The fluorescence detection of environmental pollution residues is hugely significant; thus, the improvements in sensitivity and selectivity are still a great task. In this work, a novel molecularly imprinted fluorescence sensor (CDs&ZIF-8@MIPs) with a core–shell structure was prepared for the highly sensitive and selective quantification of malachite green (MG). The high sensitivity was contributed from carbon dots (CDs) as the fluorescence materials and ZIF-8 nanoparticles served as the support materials to ameliorate the dispersibility of CDs. The high selectivity is mainly derived from fabricating thin molecular imprinting polymers in ZIF-8 surfaces. Under the optimum conditions, CDs&ZIF-8@MIPs displayed rapid reaction time (2.0 min), lower detection limit (2.93 nM) with the concentration linear range of 20–180 nM and high selectivity to MG among MG analogs. Importantly, the developed monitoring method was successfully applied to MG determination with the satisfactory recoveries in environmental water samples. This present work effectively improved the sensitivity and selectivity of fluorescence sensors for MG detection.

Preparation of molecularly imprinted fluorescence sensor based on carbon quantum dots via precipitation polymerization for fluorescence detection of tetracycline

AbstractA facile and effective method was proposed to prepare the molecularly imprinted fluorescence sensor with carbon quantum dots, which were modified vinyl groups by acrylic acid on the surface. The obtained fluorescence composite material was investigated by transmission electron microscope and Fourier transform infrared spectra. After the experimental conditions were optimized, a linear range of 1.0–60 μmol L−1 was obtained and the detection limit was 0.17 μmol L−1. The novel fluorescence sensor can be successfully used to detect tetracycline in real samples. This study provides a convenient strategy for selective recognition and rapid detection of tetracycline in the complex environment.

Ultrasensitive turn on molecularly imprinted fluorescence sensor for glycoprotein detection based on nanoparticles signal amplification

In this work, we proposed a “turn on” molecularly imprinted fluorescence sensor (MIFS) for ultrasensitive detection of glycoprotein using horseradish peroxidase (HRP) as a model target based on nanoparticles signal amplification. Boronic acid modified magnetic nanoparticles were employed as supporting matrix for HRP imprinting by surface oriented imprinting strategy. Boronic acid modified tetra(4-carboxyphenyl) porphyrin nanoparticles (BA-TCPP NPs) as signal tag were captured by imprinted magnetic nanoparticles in the presence of HRP based on boronate affinity sandwich assay. The dissolution of TCPP NPs into thousands of porphyrin molecules resulted in amplified fluorescence signal detection of HRP. As a result, the MIFS could be applied in the detection of HRP in the linear range of 0.1 μg/L–10 mg/L with LOD of 0.042 μg /L (S/N = 3). Due to the high selectivity of molecular imprinting technique, the high affinity of bononic acid with glycoprotein, and the high sensitivity of nanoparticles signal amplification, the sensitivity of the “turn on” MIFS was two orders of magnitude higher than traditional “turn off” MIFS. The “turn on” MIFS were successfully applied to determine of HRP in urine samples with average recoveries ranging from 98 % to 104 % and RSD below 4.4 %.The results proved that signal amplification combined with boronate affinity sandwich assay was an effective method to construct MIFS with conspicuous sensitivity.

Visual Simultaneous Detection of Hepatitis A and B Viruses Based on a Multifunctional Molecularly Imprinted Fluorescence Sensor.

Simultaneous detection of large viruses has been a great obstacle in the field of molecular imprinting. In this work, for the first time, a multifunctional molecularly imprinted sensor for single or simultaneous determination of hepatitis A virus (HAV) and hepatitis B virus (HBV) is provided. Visual detection was realized due to the color of green and red quantum dots that varied with the concentration of the target substance. The combination of hydrophilic monomers and metal chelation reduced the nonspecific binding and enhanced the specificity of adsorption. As a result, satisfactory selectivity and sensitivity were obtained for the detection of the two viruses, with imprinting factors of 3.70 and 3.35 for HAV and HBV, and limits of detection of 3.4 and 5.3 pmol/L, respectively, that were achieved within 20 min. The excellent recoveries during simultaneous detection and single detection modes indicate the prominent ability of the proposed sensor to detect HAV and HBV in human serum and the potential ability to simultaneously detect multiple viruses in real applications.

A Novel Aggregation‐Induced Emission Luminogen Based Molecularly Imprinted Fluorescence Sensor for Ratiometric Determination of Rhodamine B in Food Samples

AbstractIntroducing aggregation‐induced emission luminogens (AIEgens) to fluorescence sensors will endow them with outstanding luminescence properties in aggregated state or solid state, which is an effective strategy for developing polymer‐based fluorescence sensors. Herein, a novel fluorescence sensor of TPE‐A‐MIPs was developed by introducing an AIEgen as the fluorescence signal part into molecularly imprinted polymers (MIPs). MIPs in this sensor served as a polymeric artificial receptor to Rhodamine B (RhB), which offered high selectivity. TPE‐A‐MIPs also showed excellent sensitivity with ratiometric fluorescence response to RhB. A detection limit of 1.41 μmol/L with the linear range in 0.0‐10.0 μmol/L was obtained. Furthermore, TPE‐A‐MIPs was successfully applied in detecting RhB in real food samples with satisfactory recoveries and relative standard deviations. This work not only demonstrated the feasibility of introducing AIEgens into MIPs to develop fluorescence sensors, but also greatly expanded the potential applications of AIEgens and MIPs in the field of fluorescence detection.

Recent Advances and Perspectives of Molecularly Imprinted Polymer-Based Fluorescent Sensors in Food and Environment Analysis.

Molecular imprinting technology (MIT), also known as molecular template technology, is a new technology involving material chemistry, polymer chemistry, biochemistry, and other multi-disciplinary approaches. This technology is used to realize the unique recognition ability of three-dimensional crosslinked polymers, called the molecularly imprinted polymers (MIPs). MIPs demonstrate a wide range of applicability, good plasticity, stability, and high selectivity, and their internal recognition sites can be selectively combined with template molecules to achieve selective recognition. A molecularly imprinted fluorescence sensor (MIFs) incorporates fluorescent materials (fluorescein or fluorescent nanoparticles) into a molecularly imprinted polymer synthesis system and transforms the binding sites between target molecules and molecularly imprinted materials into readable fluorescence signals. This sensor demonstrates the advantages of high sensitivity and selectivity of fluorescence detection. Molecularly imprinted materials demonstrate considerable research significance and broad application prospects. They are a research hotspot in the field of food and environment safety sensing analysis. In this study, the progress in the construction and application of MIFs was reviewed with emphasis on the preparation principle, detection methods, and molecular recognition mechanism. The applications of MIFs in food and environment safety detection in recent years were summarized, and the research trends and development prospects of MIFs were discussed.

A thin shell and “sunny shape” molecular imprinted fluorescence sensor in selective detection of trace level pesticides in river

Abstract This investigation presented a novel strategy for the preparation of hybrid structure silica/ZnO/molecularly imprinted polymers (SiO2/ZnO/MIPs) to fluorescence recognization and detection of the pyrethroids. Firstly, carboxylated SiO2 nanoparticles (Si-NPs) and amino-functionalized ZnO quantum dots (QDs) were linked together by the function of amination under the assistance of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and 1-hydroxy-5-pyrrolidinedione (NHS). Next, the “sunny shape” molecular imprinted polymers (MIPs) layers were anchored on the surface of SiO2/ZnO QDs by the technique of atom transfer radical polymerization (ATRP) and surface molecular imprinting. The resulting nanoparticles were characterized by TEM, FT-IR, fluorescence spectra and the adsorptive properties were detected by the UV–vis spectrophotometer. Through the results, the strategy shortened the preparation time and presented more rapid and sensitive detection performance than the traditional methods. The fluorescence detection results demonstrated this material owned special recognition property to the templates, which contributed that the fluorescence intensity decreased linearly with the variation of pyrethroids in the concentration range 1.0–80 μmol L−1 under the optimized conditions and the detection limit was 0.13 μmol L−1. Moreover, the successful applications in practical samples indicated that the synthesis method in this investigation provided a novel way to the pyrethroids detection in river.