scholarly journals Protein Determination with Molecularly Imprinted Polymer Recognition Combined with Birefringence Liquid Crystal Detection

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4692 ◽  
Author(s):  
Maciej Cieplak ◽  
Rafał Węgłowski ◽  
Zofia Iskierko ◽  
Dorota Węgłowska ◽  
Piyush S. Sharma ◽  
...  

Liquid crystal-based sensors offer the advantage of high sensitivity at a low cost. However, they often lack selectivity altogether or require costly and unstable biomaterials to impart this selectivity. To incur this selectivity, we herein integrated a molecularly imprinted polymer (MIP) film recognition unit with a liquid crystal (LC) in an optical cell transducer. We tested the resulting chemosensor for protein determination. We examined two different LCs, each with a different optical birefringence. That way, we revealed the influence of that parameter on the sensitivity of the (human serum albumin)-templated (MIP-HSA) LC chemosensor. The response of this chemosensor with the (MIP-HSA)-recognizing film was linear from 2.2 to 15.2 µM HSA, with a limit of detection of 2.2 µM. These values are sufficient to use the devised chemosensor for HSA determination in biological samples. Importantly, the imprinting factor (IF) of this chemosensor was appreciable, reaching IF = 3.7. This IF value indicated the predominant binding of the HSA through specific rather than nonspecific interactions with the MIP.

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 693 ◽  
Author(s):  
Kiana Khadem-Abbassi ◽  
Hervé Rinnert ◽  
Lavinia Balan ◽  
Zahra Doumandji ◽  
Olivier Joubert ◽  
...  

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.


Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 269
Author(s):  
Biresaw D. Abera ◽  
Inmaculada Ortiz-Gómez ◽  
Bajramshahe Shkodra ◽  
Francisco J. Romero ◽  
Giuseppe Cantarella ◽  
...  

Tetracycline (TC) is a widely known antibiotic used worldwide to ‘’treat animals. Its residues in animal-origin foods cause adverse health effects to consumers. Low-cost and real-time measuring systems of TC in food samples are, therefore, extremely needed. In this work, a three-electrode sensitive and label-free sensor was developed to detect TC residues from milk and meat extract samples, using CO2 laser-induced graphene (LIG) electrodes modified with gold nanoparticles (AuNPs) and a molecularly imprinted polymer (MIP) used as a synthetic biorecognition element. LIG was patterned on a polyimide (PI) substrate, reaching a minimum sheet resistance (Rsh) of 17.27 ± 1.04 Ω/sq. The o-phenylenediamine (oPD) monomer and TC template were electropolymerized on the surface of the LIG working electrode to form the MIP. Surface morphology and electrochemical techniques were used to characterize the formation of LIG and to confirm each modification step. The sensitivity of the sensor was evaluated by differential pulse voltammetry (DPV), leading to a limit of detection (LOD) of 0.32 nM, 0.85 nM, and 0.80 nM in buffer, milk, and meat extract samples, respectively, with a working range of 5 nM to 500 nM and a linear response range between 10 nM to 300 nM. The sensor showed good LOD (0.32 nM), reproducibility, and stability, and it can be used as an alternative system to detect TC from animal-origin food products.


2019 ◽  
Vol 15 (3) ◽  
pp. 251-257
Author(s):  
Bahareh Sadat Yousefsani ◽  
Seyed Ahmad Mohajeri ◽  
Mohammad Moshiri ◽  
Hossein Hosseinzadeh

Background:Molecularly imprinted polymers (MIPs) are synthetic polymers that have a selective site for a given analyte, or a group of structurally related compounds, that make them ideal polymers to be used in separation processes.Objective:An optimized molecularly imprinted polymer was selected and applied for selective extraction and analysis of clozapine in rat brain tissue.Methods:A molecularly imprinted solid-phase extraction (MISPE) method was developed for preconcentration and cleanup of clozapine in rat brain samples before HPLC-UV analysis. The extraction and analytical process was calibrated in the range of 0.025-100 ppm. Clozapine recovery in this MISPE process was calculated between 99.40 and 102.96%. The limit of detection (LOD) and the limit of quantification (LOQ) of the assay were 0.003 and 0.025 ppm, respectively. Intra-day precision values for clozapine concentrations of 0.125 and 0.025 ppm were 5.30 and 3.55%, whereas inter-day precision values of these concentrations were 9.23 and 6.15%, respectively. In this study, the effect of lipid emulsion infusion in reducing the brain concentration of drug was also evaluated.Results:The data indicated that calibrated method was successfully applied for the analysis of clozapine in the real rat brain samples after administration of a toxic dose to animal. Finally, the efficacy of lipid emulsion therapy in reducing the brain tissue concentration of clozapine after toxic administration of drug was determined.Conclusion:The proposed MISPE method could be applied in the extraction and preconcentration before HPLC-UV analysis of clozapine in rat brain tissue.


2021 ◽  
Vol 11 (4) ◽  
pp. 1577
Author(s):  
Marco Mora-Granados ◽  
David González-Gómez ◽  
Jin Su Jeong ◽  
Alejandrina Gallego-Picó

Studies for monitoring the bioavailability of dietary flavonoid compounds generate great interest. Among them, low-molecular-weight phenolic acids, secondary metabolites present in colonic catabolism and urinary excretion, have been proposed as biomarkers of polyphenol intake. Using 4-hydroxyphenylacetic acid as a template, a molecularly imprinted polymer (MIP) was synthesized for selective extraction of these hydroxylated metabolites from human urine samples and posterior analysis in an HPLC-DAD-MS system. Polymers were characterized by Scanning electron microscopy (SEM), Attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), Brunauer-Emmett-Teller (BET) method, and binding experiments. MIP presents specific recognition ability for template and analogues molecules. This capacity of recognition and the pH dependence of the binding strength was also studied. The method was validated over a concentration range of 0.25–40 mg/L, r2 > 0.995. In the optimized conditions, the recovery value was 94% with RSD 1.2%. The Limit of Detection (LOD) and Limit of Quantification (LOQ) were 1.22 and 3.69 mg/L, respectively. In our knowledge, it is the first time that this methodology is applied to analyze urinary catabolites of the polyphenol compound and to provide a specific method and simple analysis alternative. The selective extraction of these metabolites improves the application and results obtained by other less sensitive analysis methods than the validation method. It also facilitates the development of new screening methods.


Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1279 ◽  
Author(s):  
Yeşeren Saylan ◽  
Semra Akgönüllü ◽  
Handan Yavuz ◽  
Serhat Ünal ◽  
Adil Denizli

Sensors have been extensively used owing to multiple advantages, including exceptional sensing performance, user-friendly operation, fast response, high sensitivity and specificity, portability, and real-time analysis. In recent years, efforts in sensor realm have expanded promptly, and it has already presented a broad range of applications in the fields of medical, pharmaceutical and environmental applications, food safety, and homeland security. In particular, molecularly imprinted polymer based sensors have created a fascinating horizon for surface modification techniques by forming specific recognition cavities for template molecules in the polymeric matrix. This method ensures a broad range of versatility to imprint a variety of biomolecules with different size, three dimensional structure, physical and chemical features. In contrast to complex and time-consuming laboratory surface modification methods, molecular imprinting offers a rapid, sensitive, inexpensive, easy-to-use, and highly selective approaches for sensing, and especially for the applications of diagnosis, screening, and theranostics. Due to its physical and chemical robustness, high stability, low-cost, and reusability features, molecularly imprinted polymer based sensors have become very attractive modalities for such applications with a sensitivity of minute structural changes in the structure of biomolecules. This review aims at discussing the principle of molecular imprinting method, the integration of molecularly imprinted polymers with sensing tools, the recent advances and strategies in molecular imprinting methodologies, their applications in medical, and future outlook on this concept.


The Analyst ◽  
2021 ◽  
Vol 146 (20) ◽  
pp. 6323-6332
Author(s):  
Xiang Li ◽  
Yangguang Li ◽  
Pai Yu ◽  
Yanbin Tong ◽  
Bang-Ce Ye

A molecularly imprinted polymer grown on a nitrogen-doped Fe-MOF modified glassy carbon electrode for the detection of clenbuterol hydrochloride and ractopamine in humans.


2021 ◽  
pp. 174751982198995
Author(s):  
Yi Wang ◽  
Jianshe Tang ◽  
Li Xiang

A simple and efficient electrochemical sensor based on a homemade reshaped micropipette tip carbon paste electrode is reported. Molecularly imprinted polymer membranes of graphene oxide and polypyrrole are synthesized and modified on the surface of micropipette tip carbon paste electrode. The merit of the method is evaluated under optimized conditions via differential pulse voltammetrics. The prepared sensor exhibits remarkable sensitivity toward dopamine with a linear range of 6.4 × 10−8–2 × 10−4 M, with a limit of detection as low as 1 × 10−8 M. The proposed method is applied for the determination of dopamine in urine samples by the standard addition route. A range of 1 × 10−7–1 × 10−4 M is obtained from these samples. The relative recoveries are in the range of 95.2%–104%. The proposed method has acceptable performance for the determination of dopamine in real samples with excellent sensitivity and selectivity.


Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 1030 ◽  
Author(s):  
Guangyang Liu ◽  
Xiaodong Huang ◽  
Lingyun Li ◽  
Xiaomin Xu ◽  
Yanguo Zhang ◽  
...  

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.


Biosensors ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 31 ◽  
Author(s):  
Bogdan Feier ◽  
Adrian Blidar ◽  
Alexandra Pusta ◽  
Paula Carciuc ◽  
Cecilia Cristea

In this study, a new electrochemical sensor was developed for the detection of cefalexin (CFX), based on the use of a molecularly imprinted polymer (MIP) obtained by electro‒polymerization in an aqueous medium of indole-3-acetic acid (I3AA) on a glassy carbon electrode (GCE) and on boron-doped diamond electrode (BDDE). The two different electrodes were used in order to assess how their structural differences and the difference in the potential applied during electrogeneration of the MIP translate to the performances of the MIP sensor. The quantification of CFX was performed by using the electrochemical signal of a redox probe before and after the rebinding of the template. The modified electrode was characterized using atomic force microscopy (AFM), scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The influence of different parameters on the fabrication of the sensor was tested, and the optimized method presented high selectivity and sensitivity. The MIP-based electrode presented a linear response for CFX concentration range of 10 to 1000 nM, and a limit of detection of 3.2 nM and 4.9 nM was obtained for the BDDE and the GCE, respectively. The activity of the sensor was successfully tested in the presence of some other cephalosporins and of other pharmaceutical compounds. The developed method was successfully applied to the detection of cefalexin from real environmental and pharmaceutical samples.


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