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Ultra-selective fiber optic SPR platform for the sensing of dopamine in synthetic cerebrospinal fluid incorporating permselective nafion membrane and surface imprinted MWCNTs-PPy matrix
摘要： Surface plasmon resonance (SPR) based dopamine sensor is realized using the state-of-art technique of molecular imprinting over an optical fiber substrate. Polypyrrole (PPy) is depicted as an effective polymer for the imprinting of dopamine through a green synthesis approach. Sensitivity of the probe is enhanced by the augmenting effect of surface imprinting of dopamine in polypyrrole over multiwalled carbon nanotubes (MWCNTs). To ensure the permselectivity of the probe towards dopamine molecules, a cation exchange polymer, nafion, is utilized as a membrane over imprinted sites to reduce the interference from anionic analytes like ascorbic acid and uric acid at physiological pH. The probe is characterized for a wide range of dopamine concentration from 0 to 10-5 M in artificial cerebrospinal fluid. Various probe parameters are varied to maximize the sensitivity of the sensor. The sensor possesses 18.9 pM as the limit of detection (LOD) which is lowest of those reported in the literature. The manifestation of sensing probe over an optical fiber along with the improved LOD makes the approach highly advantageous in terms of stability, repeatability, online remote monitoring, fast response, and miniaturization for its in vivo/in vitro applications in clinical sensing of dopamine.
关键词： surface plasmon,dopamine,Optical fiber,polypyrrole,nafion,molecular imprinting,sensor,multiwalled carbon nanotube
更新于2025-10-22 19:40:53
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Rapid detection of sulfaguanidine in fish by using a photonic crystal molecularly imprinted polymer
摘要： A photonic crystal (PC) sensor was prepared through molecular imprinting by using dispersed SiO2 microspheres as PC, sulfaguanidine (SG) as template, methacrylic acid as monomer, and ethylene glycol dimethacrylate as crosslinker. The preparation conditions were optimized as follows: molar ratio of template, monomer, and crosslinker was 1:10:4; pH was 6.0 in phosphate buffer; and volume fraction of methanol was 15%. The relationship between wavelength shift of reflection peak and SG concentration was found as: △λ=7.8887 lg(C)+79.9664. The response time was only 5 min. The limit of detection was 2.8×10-10 mol L-1. The sensor exhibited higher specificity for SG than its sulfonamide analogs. The sensor maintained original sensing performance after five cycles of usage. The recoveries of SG ranged from 93.8% to 111.2% in lake water and from 88.5% to 115.2% in fish samples. This finding suggested that the sensor can be used in food samples with complicated matrix.
关键词： Sulfaguanidine,Sensor,Photonic crystal,Molecular imprinting
更新于2025-09-23 15:23:52
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Electrochemiluminescence sensor based on upconversion nanoparticles and oligoaniline-crosslinked gold nanoparticles imprinting recognition sites for the determination of dopamine
摘要： For the determination of dopamine (DA) in serum samples, a quenching-type electrochemiluminescence sensor was constructed in this study. Upconversion nanoparticles (UCNPs) enhanced by covalent organic frameworks (COFs)-based hybrid and oligoaniline-crosslinked gold nanoparticles (AuNPs) imprinting recognition sites were introduced in electrochemiluminescence (ECL) system at first time. The porous COFs-based hybrid with large specific surface area was modified on the electrode firstly to hold more UCNPs and imprinting recognition sites. AuNPs, here, was employed in developed sensor for two objectives: 1) AuNPs on COFs-based hybrid enabled the hybrid to tunnel the electrons, which helped to improve the ECL intensity; 2) AuNPs-based thioaniline units (PATP@AuNPs) electropolymerized on the electrode in the presence of template to form oligoaniline-crosslinked AuNPs matrix. Then the exclusion of template from matrix yielded molecularly three-dimensional imprinted contours with conductivity, conducive to specific recognition and further amplify the ECL. The double recognition mode in this work involves the recognition effect of imprinted contours and quenching effect of o-benzoquinone species. The quantum chemical calculation was performed to analyzing the possible recognition and binding mechanisms of molecularly three-dimensional imprinted contours. The results showed imprinted contours could bind the target by complementary spatial cavities and weak interactions. The proposed approach yields a wide detection range (10-14-10-6 M), low limit of detection (LOD=2×10-15 M) and acceptable recoveries (93.25%-112.97%) in rat serum sample, demonstrating that the developed method holds great promise to be applied to DA detection in practical samples.
关键词： Electroconductibility molecular imprinting polymer,Covalent organic frameworks,Oligoaniline-crosslinked gold nanoparticles,Dopamine,Electrochemiluminescence
更新于2025-09-23 15:23:52
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A brief overview of molecularly imprinted polymers supported on titanium dioxide matrices
摘要： Molecularly imprinted polymer (MIP) is a polymer competent of mimicking selective binding of target or template molecule, which is characteristic of enzyme and antibodies. MIP has a wide range of applications in various fields of science and can be used as a sensor, catalyst, drug delivery component, etc. To overcome some demerits of MIP, the process of formation of imprinting cavity was carried out by nanoimprinting materials, which enables the imprinting technique to create more effective recognition sites than those obtained by traditional approaches. Here, in this article, we described a brief account of various discoveries happened in titanium dioxideebased molecularly imprinted polymeric system that shows a wide variety of chemical applications. The intention of this article is to provide comprehensive knowledge and information to all researchers who are interested in exploiting molecular imprinting technology toward the rational design of various chemical sensors operating on different transduction principles, ranging from electrochemical to piezoelectric, being used for the detection of different template molecules as they pose considerable impact on the understanding of the origin of life and all processes that occur in living organisms.
关键词： Applications,Titanium dioxide,Molecular imprinting,Imprinted structures
更新于2025-09-23 15:23:52
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Dual-emission color-controllable nanoparticle based molecular imprinting ratiometric fluorescence sensor for the visual detection of Brilliant Blue
摘要： Single-component dual-emission nanoparticles were synthesized by chelating the organic ligand 8-hydroxyquinoline (HQ) to the surface of CdTe/ZnS quantum dots, namely CdTe/ZnQ2, and were used to construct a novel mesoporous structured molecular imprinting ratiometric fluorescence sensor by facile one-pot sol-gel polymerization for the visual detection of Brilliant Blue. The CdTe/ZnQ2 had bimodal fluorescence belonging to CdTe and ZnQ2 segments, respectively; significantly, the emission wavelength of CdTe was optimized to be 630 nm for the largest overlap with the absorption spectrum of Brilliant Blue. Consequently, fluorescence resonance energy transfer (FRET) efficiency was greatly enhanced, resulting in ideal determination. A favorable linearity toward Brilliant Blue was obtained within 0–1.0 μmol?L-1 along with profuse color evolution from orange to yellowish orange to yellowish green to green, and a high detectability of 8.8 nmol?L-1 was offered. Excellent recognition selectivity for Brilliant Blue over possibly coexistent food colorants was demonstrated, with a high imprinting factor of 7.1. Furthermore, endogenous Brilliant Blue was detected ranging from 0.21–41.03 mg/kg in six typical food samples with relative standard deviations lower than 3.5%, and the results agreed well with that afforded by conventional methods. Using Brilliant Blue as a model, this dual-emission color-controllable nanoparticle based imprinting ratiometric fluorescence sensor provided promising perspectives for the highly selective and sensitive, rapid, visual detection of colored substances in complicated matrices.
关键词： Molecular imprinting,Brilliant Blue,Dual-emission nanoparticles,Ratiometric fluorescence,Visual detection
更新于2025-09-23 15:23:52
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Surface Plasmon Resonance Based Highly Selective Fiber Optic Dopamine Sensor Fabricated Using Molecular Imprinted GNP/SnO <sub/>2</sub> Nanocomposite
摘要： Fabrication and characterization of a highly selective fiber optic surface plasmon resonance-based dopamine sensor using molecular imprinted graphene nanoplatelets/tin oxide (SnO2) nanocomposite have been reported. The synthesis of sensing layer has been carried out using a series of optimizations and morphological studies. The effectiveness of the sensing layer over other possible probe designs has been proved by performing control experiments for a dopamine concentration range covering the suggested level of dopamine for human being. The limit of detection (LOD) of the sensor evaluated is 0.031 μM, which is lower than the LOD values of various dopamine sensors fabricated using different methods. The specificity of the sensor for dopamine has been confirmed by performing experiments using various interferands while the stability and reusability of the sensor probe have been checked by performing experiments repeatedly for a long period of time. Apart from high sensitivity, low LOD, and fast response, the sensor can be used for remote sensing and online monitoring of dopamine.
关键词： surface plasmon resonance,SnO2 nanoparticles,optical fiber sensor,GNP/SnO2 nanocomposite,graphene,Dopamine,molecular imprinting
更新于2025-09-23 15:23:52
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Highly sensitive and selective estimation of aspartame by chitosan nanoparticles–graphene nanocomposite tailored EQCM-MIP sensor
摘要： Here, a molecularly imprinted electrochemical quartz crystal microbalance (MIP-EQCM) sensor for aspartame is developed by grafting the aspartame-imprinted polymeric matrix of chitosan on gold-coated quartz crystal electrode. Chitosan nanoparticles being biocompatible, biodegradable and also having large surface area provide a better platform by forming a well-dispersed composite suspension with graphene. Additionally graphene facilitates direct electron transfer to electrode surface for electrochemical study because of having enhanced electrical conductivity. This EQCM-MIP sensor was characterized by atomic force microscopy, contact angle measurements, cyclic voltammetry and differential pulse voltammetry (DPV). The obtained MIP showed high affinity to aspartame. A reliable method for analysis of aspartame in real and commercial samples was achieved by coupling EQCM-MIP with DPV. Linear relationship with R2 = 0.9749 (EQCM) and R2 = 0.9760 (DPV) on binding of aspartame at various concentrations was observed. Detection limit of 0.45 μg mL?1 (EQCM) and 0.07 μg mL?1 (DPV) of the fabricated sensor shows that high sensitivity and high selectivity among various structural analogues of aspartame were also achieved. The improved detection limit is promising for determination of trace amount of aspartame. This demonstrates good memory capacity of this EQCM sensor. High recovery percentage and applicability of EQCM-MIP sensor in real matrices and commercial samples offers good potential for various applications.
关键词： Electrodeposition,Aspartame,Quartz crystal microbalance,Graphene,Chitosan nanoparticles,Molecular imprinting
更新于2025-09-23 15:21:21
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Semiconductor Photocatalysis - Materials, Mechanisms and Applications || Alternative Approaches in Development of Heterogeneous Titania-Based Photocatalyst
摘要： Three alternative approaches for the development of heterogeneous photocatalysts are comparatively evaluated, namely (i) the use of molecular imprinting concept for the development of heterogeneous catalysts employing rhodamine B as template and sol–gel as synthesis route; (ii) the impregnation of TiCl4 on mixed nano- and micro-metric silicas, followed by calcination; (iii) the use of industrial and academic chemical residues as source of potential photocatalyst species impregnated on supports. All tests were carried on with rhodamine B as target molecule. For comparative reasons, photocatalytic tests were carried out with commercial titania (P25). The solids were characterized by nitrogen porosimetry, small-angle X-ray scattering (SAXS), zeta potential (ZP), diffuse reflectance spectroscopy in the ultraviolet region (DRS-UV), diffuse reflectance infrared Fourier transmission spectroscopy (DRIFTS), and Rutherford backscattering spectrometry (RBS). The supported catalysts resulting from silica nanoparticles and residue of the petrochemical industry achieved higher percentage of the dye degradation under ultraviolet (68.0 and 66.8%, respectively) radiation. The industrial waste reached the highest photocatalytic activity under visible (61%) radiation, while the commercial P25 achieved 82.0and 12.3% for ultraviolet and visible radiation, respectively. The textural and structural characteristics of the supported catalyst prepared with fumed silica and petrochemical waste (SiPe), namely the low-energy bandgap (1.8 eV), large surface area (280 m2 g?1), high pore volume (1.9 cm3 g?1), and high zeta potential value (?36.4 mV), may have been responsible for their high activity.
关键词： supported photocatalyst,molecular imprinting,Rhodamine B,titania,residue,silicas
更新于2025-09-23 15:21:01
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A novel ECL sensor based on a boronate affinity molecular imprinting technique and functionalized SiO2@CQDs/AuNPs/MPBA nanocomposites for sensitive determination of alpha-fetoprotein
摘要： In this work, a boronate-affinity sandwich electrochemiluminescence (ECL) sensor was constructed to detect alpha-fetoprotein (AFP) based on a multiple signal amplification strategy. Gold nanoparticles (AuNPs) were utilized and modified on the surface with chitosan in order to facilitate electron transfer. The composite of the molecularly imprinted polymer (MIP) enhanced the selectivity of alpha-fetoprotein detection. 4-mercaptophenylboronic acid (MPBA) was used as the tracing tag for capture of alpha-fetoprotein. SiO2 nanoparticles carried carbon quantum dots (CQDs) labeled with gold nanoparticles and produced an ECL signal. Under the optimum experimental conditions, the linear range for alpha-fetoprotein was between 0.001 and 1000 ng/mL with a correlation coefficient of 0.9952, and the detection limit was 0.0004 ng/mL (S/N=3). This proposed ECL sensor displayed several advantages, including outstanding selectivity, fine reproducibility, high sensitivity, low detection limit and wide linear range. Furthermore, the newly constructed boronate-affinity sandwich ECL sensor was successfully applied to the determination of alpha-fetoprotein in serum samples, indicating great potential for application in clinical diagnostics.
关键词： Alpha-fetoprotein,Molecular imprinting,Boronate-affinity,Carbon quantum dots,ECL sensor
更新于2025-09-23 15:21:01
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Towards Detection of Glycoproteins Using Molecularly Imprinted Nanoparticles and Boronic Acid-Modified Fluorescent Probe
摘要： Glycoproteins represent a group of important biomarkers for cancer and other life-threatening diseases. Selective detection of specific glycoproteins is an important step for early diagnosis. Traditional glycoprotein assays are mostly based on lectins, antibodies, and enzymes, biochemical reagents that are costly and require special cold chain storage and distribution. To address the shortcomings of the existing glycoprotein assays, we propose a new approach using protein-imprinted nanoparticles to replace the traditional lectins and antibodies. Protein-imprinted binding sites were created on the surface of silica nanoparticles by copolymerization of dopamine and aminophenylboronic acid. The imprinted nanoparticles were systematically characterized by dynamic light scattering, scanning and transmission electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, and elemental analysis. A boronic acid-modified fluorescent probe was used to detect the target glycoprotein captured by the imprinted nanoparticles. Using horseradish peroxidase as a model glycoprotein, we demonstrated that the proposed method can be applied to detect target protein containing multiple glycosylation sites. Because of their outstanding stability and low cost, imprinted nanoparticles and synthetic probes are attractive replacements of traditional biochemical reagents to develop simpler, faster, and more cost-effective analytical methods for glycoproteins.
关键词： glycoprotein,molecular imprinting,boronic acid,fluorescent probe
更新于2025-09-19 17:15:36