Remote magnetically stimulated xanthan-biochar-Fe3O4-molecularly imprinted biopolymer hydrogel toward electrochemical enantioselection of l-tryptophan.

Monitoring the levels of L-Tryptophan (L-Trp) in body fluids is crucial due to its significant role in metabolism and protein synthesis, which ultimately affects neurological health. Herein, we have developed a novel magneto-responsive electrochemical enantioselective sensor for the recognition of L-Trp based on oriented biochar derived from Loofah, Fe3O4 nanoparticles, and molecularly imprinted polydopamine (MIPDA) in xanthan hydrogel. The successful synthesis of these materials has been confirmed through physicochemical and electrochemical characterization. Various operational factors such as pH, response time, loading sample volume, and loading of active materials were optimized. As a result, the sensor exhibited an affordable linear range of 1.0-60.0 µM, with a desirable limit of detection of 0.44 µM. Furthermore, the proposed electrochemical sensor demonstrated good reproducibility and desirable selectivity for the determination of L-Trp, making it suitable for analyzing L-Trp levels in human plasma and serum samples. The development presented offers an appealing, easily accessible, and efficient strategy. It utilizes xanthan hydrogel to improve mass transfer and adhesion, biochar-stabilized Fe3O4 to facilitate magnetic orientation and accelerate mass transfer and sensitivity, and polydopamine MIP to enhance selectivity. This approach enables on-site evaluation of L-Trp levels, which holds significant value for healthcare monitoring and early detection of related conditions.

Reusable magnetic molecular imprinted polymers based on magnetic graphene oxide for selective identification and detection of eugenol in environmental water samples.

In this study, a reliable method for determining eugenol content in environmental water samples was established by combining magnetic solid-phase extraction with high-performance liquid chromatography. Magnetic molecular imprinted polymers MGO@MIPs were prepared through surface molecular imprinting technique with eugenol as the template molecule. The material displayed good superparamagnetic properties and magnetic responsiveness in favor of rapid separation. The adsorption properties of MGO@MIPs for eugenol were evaluated through adsorption kinetics and selectivity experiments. MGO@MIPs were found to have favorable reusability and obvious selectivity for eugenol. In addition, adsorption and elution conditions were investigated. Under optimal conditions, a linear relationship was obtained between the concentration of eugenol and its peak area in the range of 0.02-5 mg/L (R2 = 0.9998) and the limit of detection was 4.0 × 10-6 mg/mL. The performance of the established method was assessed with the average recovery of 96.59-102.20% and the relative standard deviation (RSD) below 3.5%. The application of this method provides a new perspective for the separation, enrichment and detection of eugenol in water environment.

Magnetic molecular imprinted covalent organic framework composite for the magnetic solid-phase extraction of bisphenol AF.

A magnetic molecular imprinted covalent organic framework composite (MCOF-MIP) that possessed the 'dual-selectivity' of a covalent organic framework and molecular imprinted polymer (MIP) with rapid response performance was successfully prepared for the removal of bisphenol AF (BPAF) from real water and blood samples. First, the MCOF was separately synthesized using magnetic Fe3O4 as the magnetic core, 1,3,5-triaminobenzene and 2,5-dibromobenzene-1,4-diformaldehyde as precursors and a deep eutectic solvent (DES) as the solvent using a solvothermal synthesis method. The MCOF showed high crystallinity and good adsorption capacities for BPAF (107.4 mg g-1), bisphenol A (113.6 mg g-1), bisphenol S (120.0 mg g-1) and bisphenol F (82.1 mg g-1). To further improve the selectivity for BPAF, an MIP, which uses BPAF as a template, was introduced to form the MCOF-MIP. Due to the dual selectivity of MCOF and MIP, the MCOF-MIP exhibited relatively high selective adsorption capacity to BPAF (243.1 mg g-1) compared to that for the MCOF (107.4 mg g-1), while the adsorption capacities (149.7-109.4 mg g-1) for the other three compounds were not significantly improved. Furthermore, a magnetic solid-phase extraction (MSPE) method was established, and MSPE parameters such as adsorbent dosage, adsorption time, desorption solvent and desorption time were optimized. Combined with high-performance liquid chromatography with diode-array detection (HPLC-DAD) analysis, a rapid and sensitive method was developed to detect BPAF, which showed good linearity (r > 0.9969) ranging from 0.1 to 400 µg mL-1. Low limits of detection (0.04 µg mL-1, S/N = 3) and quantitation (0.1 µg mL-1, S/N = 10) and good precision with low relative SDs (<1.2 % for intra-day and <1.1 % for inter-day) were also obtained. Finally, MSPE coupled with HPLC-DAD was employed for the analysis of BPAF in water and blood samples, and the recoveries of BPAF were satisfactory (91.1-112.6 %).

Fluorescent Probes Based on Ag NPs@N/GQDs and Molecularly Imprinted Polymer for Sensitive Detection of Noradrenaline in Bananas.

Fluorescence intensity and selective recognition ability are crucial factors in determining the analytical techniques for fluorescent probes. In this study, a core-shell fluorescent material, composed of silver nanoparticles@nitrogen-doped graphene quantum dots (Ag NPs@N/GQDs), was synthesised using mango leaves as the raw material through a thermal cracking method, resulting in strong fluorescence luminescence intensity. By employing noradrenaline as a template molecule and using a surface molecular imprinting technique, a molecularly imprinted membrane (MIP) was formed on the surface of the fluorescent material, that was subsequently eluted to obtain a highly specific, fluorescent probe capable of recognising noradrenaline. The probe captured various concentrations of noradrenaline using the MIP, which decreased the fluorescence intensity. Then a method for detecting trace amounts of noradrenaline was established. This method exhibited a linear range from 0.5 -700 pM with a detection limit of 0.154 pM. The proposed method was implemented in banana samples. Satisfactory recoveries were confirmed at four different concentrations. The method presented a relative standard deviation (RSD) of less than 5.0%.

Synthesis of molecularly imprinted polymer by precipitation polymerization for the removal of ametryn.

Ametryn (AME) is a triazine herbicide which is mainly used to kill unwanted herbs in crops. Despite its importance in agriculture, the usage of AME also poses a risk to humans and the ecosystem due to its toxicity. Hence, it is important to develop a method for the effective removal of AME from various water sources which is in the form of molecular imprinting polymer (MIP). In this study, MIP of AME was synthesized via precipitation polymerization using AME as the template molecule with three different functional monomers including methacrylic acid (MAA), acrylamide (AAm) and 2-vinylpyridine (2VP). The three different synthesized polymers namely MIP (MAA), MIP (AAm) and MIP (2VP) were characterized using Fourier Infra-red spectroscopy (FTIR) and Field Emission Electron Microscopy (FESEM). Then, the batch binding study was carried out using all three MIPs in which MIP (MAA) attained the highest rebinding efficiency (93.73%) among the synthesized polymers. The Energy-Dispersive X-ray spectroscopy (EDX) analysis, Brunauer-Emmett-Teller (BET) analysis and thermogravimetric analysis (TGA) were also conducted on the selected MIP (MAA). Adsorption studies including initial concentration, pH and polymer dosage were also conducted on MIP (MAA). In this study, the highest adsorption efficiency was attained at the optimum condition of 6 ppm of AME solution at pH 7 with 0.1 g of MIP (MAA). MIP (MAA) was successfully applied to remove AME from spiked distilled water, tap water and river water samples with removal efficiencies of 95.01%, 90.24% and 88.37%, respectively.

Molecular imprinted polymer-based potentiometric approach for the assay of the co-formulated tetracycline HCl, metronidazole and bismuth subcitrate in capsules and spiked human plasma.

BACKGROUND: An anti-H-pylori co-formulated mixture of tetracycline HCl (TET), metronidazole (MET), and bismuth subcitrate (BSC) is recently available. Only two chromatographic and spectrophotometric methods are reported for determining those drugs simultaneously where the effect of impurities that could be present as well as the biological fluids matrix influence do not be taken into consideration. There is a need to develop an easy-to-use potentiometric technique for analysis of TET, MET, and BSC in their co-formulated capsules, in presence of some official impurities and in spiked human plasma. RESULTS: Three carbon paste electrodes (CPEs) were fabricated for this purpose. Being a solid contact ion-selective electrode, CPE suffers from the creation of a water layer affecting its stability and reproducibility. Besides, it has a common problem in differentiation between two drugs carrying the same charge (positively charged TET and MET). Water layer formation was prevented through inserting polyaniline nanoparticles (≈10.0 nm diameter) between solid contact and ion-sensing membrane in the three proposed sensors. TET and MET interference was overcome by synthesizing a corresponding molecular imprinted polymer (MIP) for each drug. The synthesized MIPs were inserted in equivalent sensing membranes and characterized using several techniques. The suggested MIPs have a noticeable enhanced sensitivity in potentiometric determination. The obtained LODs were 5.88 × 10-8, 5.19 × 10-7, and 1.73 × 10-6 M for TET, MET and BSC proposed CPEs, respectively, with corresponding slopes of 57.37, 56.20, and -57.40 mV decade-1. SIGNIFICANCE: The proposed potentiometric method makes the detection of the three cited drugs simple, fast, and feasible. This approach is the first for determining three drugs potentiometrically in one combined formulation. The obtained results were compared favorably with previously reported potentiometric methods.

All-solid-state chip utilizing molecular imprinted polymer for erythromycin detection in milk samples: Printed circuit board-based potentiometric system.

Detection of erythromycin (ERY) residues in commercial milk samples is crucial for the safety assessment. Herein, a printed circuit board was patterned as a feasible miniaturized potentiometric sensor for ERY determination in dairy samples. The proposed chip design fits to a 3.5-mm female audio plug to facilitate the potential measurements of working electrode versus reference one in this all-solid-state system. The sensor utilizes molecular imprinted polymer (MIP) for the selective recognition of the studied drug in such challenging matrix. The electrode stability is achieved through the addition of poly (3,4-ethylenedioxythiophene) nano-dispersion on its surface. The proposed device detects down to 6.6 × 10-8 M ERY with a slope of 51 mV/decade in the 1 × 10-7-1 × 10-3 M range. The results display high accuracy (99.9% ± 2.6) with satisfactory relative standard deviation for repeatability (1.6%) and reproducibility (5.0%). The effect of common antibiotic classes, namely, amphenicols, beta-lactams, fluoroquinolones, sulfonamides, and tetracyclines, can be neglected as evidenced by their calculated binding capacities towards the proposed MIP. The calculated selectivity coefficients also show a good electrode performance in the presence of naturally present inorganic ions allowing its application to different milk samples.

A Novel Hexokinases Inhibitor Based on Molecularly Imprinted Polymer for Combined Starvation and Enhanced Photothermal Therapy of Malignant Tumors.

The heat tolerance of tumor cells induced by heat shock proteins (HSPs) is the major factor that seriously hinders further application of PTT, as it can lead to tumor inflammation, invasion, and even recurrence. Therefore, new strategies to inhibit HSPs expression are essential to improve the antitumor efficacy of PTT. Here, we prepared a novel nanoparticle inhibitor by synthesizing molecularly imprinted polymers with a high imprinting factor (3.1) on the Prussian Blue surface (PB@MIP) for combined tumor starvation and photothermal therapy. Owing to using hexokinase (HK) epitopes as the template, the imprinted polymers could inhibit the catalytic activity of HK to interfere with glucose metabolism by specifically recognizing its active sites and then achieve starvation therapy by restricting ATP supply. Meanwhile, MIP-mediated starvation downregulated the ATP-dependent expression of HSPs and then sensitized tumors to hyperthermia, ultimately improving the therapeutic effect of PTT. As the inhibitory effect of PB@MIP on HK activity, more than 99% of the mice tumors were eliminated by starvation therapy and enhanced PTT.

Molecularly imprinted polymers (MIPs): emerging biomaterials for cancer theragnostic applications.

Cancer is a disease caused by abnormal cell growth that spreads through other parts of the body and threatens life by destroying healthy tissues. Therefore, numerous techniques have been employed not only to diagnose and monitor the progress of cancer in a precise manner but also to develop appropriate therapeutic agents with enhanced efficacy and safety profiles. In this regard, molecularly imprinted polymers (MIPs), synthetic receptors that recognize targeted molecules with high affinity and selectivity, have been intensively investigated as one of the most attractive biomaterials for theragnostic approaches. This review describes diverse synthesis strategies to provide the rationale behind these synthetic antibodies and provides a selective overview of the recent progress in the in vitro and in vivo targeting of cancer biomarkers for diagnosis and therapeutic applications. Taken together, the topics discussed in this review provide concise guidelines for the development of novel MIP-based systems to diagnose cancer more precisely and promote successful treatment. Molecularly imprinted polymers (MIPs), synthetic receptors that recognize targeted molecules with high affinity and selectivity, have been intensively investigated as one of the most attractive biomaterials for cancer theragnostic approaches. This review describes diverse synthesis strategies to provide the rationale behind these synthetic antibodies and provides a selective overview of the recent progress in the in vitro and in vivo targeting of cancer biomarkers for diagnosis and therapeutic applications. The topics discussed in this review aim to provide concise guidelines for the development of novel MIP-based systems to diagnose cancer more precisely and promote successful treatment.

Specific detection of n-propanol gas via terahertz metasurface sensor modified by molecularly imprinted polymer.

As an organic substance, n-propanol gas has been paid attention to in environmental monitoring and exhalation of lung cancer patient. In this paper a rapid detection method for n-propanol gas is developed based on molecularly imprinted polymers (MIP) and terahertz (THz) metasurface sensors. We first prepared a MIP suitable for detecting the n-propanol gas. And then the n-propanol MIP was modified to the THz metasurface sensor for detecting the n-propanol gas. Since the MIP adsorbed with n-propanol changes the dielectric environment of the sensor, the resonance frequency of the sensor also change. So we based on the n-propanol concentration was analyzed according to the change in resonance frequency. The experimental results showed that the sensor can effectively detect the n-propanol concentration in the range of 50-500 ppm (parts per million). In addition, we also verified the specificity and repeatability of the sensor. This work provides a new idea and method for the sensitive and specific detection of n-propanol gas.

Construction of a Molecularly Imprinted Sensor Modified with Tea Branch Biochar and Its Rapid Detection of Norfloxacin Residues in Animal-Derived Foods.

Norfloxacin (NOR) is a common antibiotic used in humans and animals, and its high levels can cause intolerance or poisoning. Therefore, NOR levels in animal-derived foods must be monitored due to potential side effects and illegal use phenomena. This research centered on the development of an environmentally friendly electrochemical sensor for NOR detection. Potassium carbonate activated tea branch biochar (K-TBC) as an efficient use of waste was coated on the surface of glassy carbon electrode (GCE), and a molecular-imprinted polymer (MIP) layer was subsequently electropolymerized onto the modified electrode. NOR was used as template molecule and o-phenylenediamine (o-PD) and o-aminophenol (o-AP) were used as bifunctional monomers. The electrochemical sensor was built and its electrochemical behavior on NOR was investigated. The sensor demonstrated an excellent linear current response to NOR concentrations in the ranges of 0.1-0.5 nM and 0.5-100 nM under ideal experimental circumstances, with a detection limit of 0.028 nM (S/N = 3). With recoveries ranging from 85.90% to 101.71%, the designed sensor was effectively used to detect NOR in actual samples of milk, honey, and pork. Besides, the fabricated sensor had low price, short detection time, good selectivity and stability, which can provide a theoretical and practical basis for the actual monitoring of NOR residues.

Surface imprinting by using bi-functional monomers on spherical template magnetite for selective detection of levodopa in biological fluids.

The present work introduces an innovative biosensing platform for greatly sensitive determination of levodopa medicine. Initially, spherical magnetic (SM) nanoparticles were prepared by hydrothermal fabrication approach and used as a pattern to make spherical magnetic molecular imprinted polymer (SMMIP). Afterward, levodopa-molecularly imprinted layer was grown on the surface of the spherical magnetic pattern by electropolymerization with dopamine and resorcinol as bi-functional monomers and levodopa as a template molecule, which enhanced the specific recognition of the sensing platform to levodopa. The presence of SM nanoparticles could not only accelerate the mass transfer, the electron transport rate, and improve specific surface area of the electrode but also facilitate the recognition of the polymer, in this way increasing the current response and improving the performance of the biosensor. The superior sensing efficiency of the presented biosensor was confirmed based on the low limit of detection of 10 nmol L-1 which represented two linear ranges from 0.5 to 200 µmol L-1 and 200-1000 µmol L-1 for levodopa. More importantly, the practicability of the biosensor was proved by detecting levodopa in tablet, blood serum and plasma, implying that the sensing platform was suitable for monitoring levodopa in actual biological fluid and medicine.

Innovative molecularly imprinted electrochemical sensor for the nanomolar detection of Tenofovir as an anti-HIV drug.

Tenofovir (TNF) is an antiviral medicine that is utilized to treat the human immunodeficiency virus (HIV). However, its level must be controlled in the human body and environment at the risk of causing kidney and liver problems. Therefore, determining TNF concentration in real samples with more advanced, inexpensive, and accurate sensing systems is essential. In this work, a novel electrochemical nanosensor for TNF determination based on molecularly imprinted polymer (MIP) on the screen-printed electrode modified with functionalized multi-walled carbon nanotubes, graphite carbon nitride, and platinum nanoparticles (MIP-Pt@g-C3N4/F-MWCNT/SPE) was constructed through the electro-polymerization approach. The molecularly imprinted polymers were prepared on the electrode surface with TNF as the template molecule and 2-aminophenol (2-AP) as the functional monomer. Moreover, factors that affect sensor response were optimized. Pt@g-C3N4/F-MWCNT nanocomposite had an excellent synergistic effect on MIP, allowing rapid and specific identification of the test substance. The results demonstrated that the electro-polymerization of 2-AP supplies large amounts of functional groups for the binding of the template molecules, which remarkably enhances the sensitivity and specific surface area of the MIP sensor. This surface enlargement increased the analyte accessibility to imprinted molecular cavities. Under optimum conditions, the oxidation peak current had a linear relationship with TNF concentration ranging from 0.005 to 0.69 µM with a low detection limit of 0.0030 µM (S/N = 3). The results demonstrated that the designed MIP sensor possesses acceptable sensitivity, repeatability, and reproducibility toward TNF determination. Moreover, the developed sensor was applied to biological and water samples to determine TNF, and satisfactory recovery results of 95.6-104.8% were obtained (RSD less than 10.0%). We confirm that combining as-synthesized nanocomposite Pt@g-C3N4/F-MWCNT with MIP improves the limitations of MIP-based nanosensors. The proposed electrode is also compatible with portable potentiostats, allowing on-site measurements and showing tremendous promise as a point-of-care (POC) diagnostic platform.

Picomolar or beyond Limit of Detection Using Molecularly Imprinted Polymer-Based Electrochemical Sensors: A Review.

Over the last decades, molecularly imprinted polymers (MIPs) have emerged as selective synthetic receptors that have a selective binding site for specific analytes/target molecules. MIPs are synthetic analogues to the natural biological antigen-antibody system. Owing to the advantages they exhibit, such as high stability, simple synthetic procedure, and cost-effectiveness, MIPs have been widely used as receptors/sensors for the detection and monitoring of a variety of analytes. Moreover, integrating electrochemical sensors with MIPs offers a promising approach and demonstrates greater potential over traditional MIPs. In this review, we have compiled the methods and techniques for the production of MIP-based electrochemical sensors along with the applications of reported MIP sensors for a variety of analytes. A comprehensive in-depth analysis of recent trends reported on picomolar (pM/10-12 M)) and beyond picomolar concentration LOD (≥pM) achieved using MIPs sensors is reported. Finally, we discuss the challenges faced and put forward future perspectives along with our conclusion.

A Highly Sensitive Molecularly Imprinted Polymer (MIP)-Coated Microwave Glucose Sensor.

A novel, low-cost, sensitive microwave microfluidic glucose detecting biosensor incorporating molecularly imprinted polymer (MIP) is presented. The sensing device is based on a stub resonator to characterize water glucose solutions. The tip of one of the stubs is coated with MIP to increase the selectivity of the sensor and hence the sensitivity compared to the uncoated or to the coated with non-imprinted polymer (NIP) sensor. The sensor was fabricated on a FR4 substrate for low-cost purposes. In the presence of the MIP, the sensor loaded with a glucose solution ranging from 50 mg/dL to 400 mg/dL is observed to experience an absorption frequency shift of 73 MHz when the solutions flow in a microfluidic channel passing sensing area, while the lower limit of detection (LLD) of the sensor is discovered to be 2.4 ng/dL. The experimental results show a high sensitivity of 1.3 MHz/(mg/dL) in terms of absorption frequency.

A sensing platform of molecular imprinted polymer-based polyaniline/carbon paste electrodes for simultaneous potentiometric determination of alfuzosin and solifenacin in binary co-formulation and spiked plasma.

Solid contact ion-selective electrodes (ISEs) have witnessed versatile applications in pharmaceutical and biological analysis however they suffer from some limitations. Besides formation of water layer, the doped ion exchanger in sensing membrane fails to distinguish between two ionic species having relatively similar lipophilicity and carrying same charges. Those shortcomings practically hampered the simultaneous determination of alfuzosin and solifenacin in their combined pharmaceutical combination. Hence, this paper was directed to develop two carbon paste electrodes allowing their simultaneous determination based on molecular imprinted polymers (MIPs). Efforts were firstly directed to stabilize the potential signals through synthesis of polyaniline (PANI) nanoparticles with 26 nm particle size as confirmed by means of UV-spectrophotometry, Zeta-sizer and transmission electron microscope. This was followed by its doping at electrode/ion selective membrane interface leading to diminished potential drift, better Nernstian slopes and lower limit of detections. Secondly, MIPs for each drug were prepared by precipitation polymerization technique and fully characterized by Fourier-transform infrared spectroscopy, field-emission scanning electron microscope, differential scanning calorimetry, surface area analysis and rebinding studies. The prepared MIPs were then incorporated in membrane cocktail and doped over PANI layer. The graved cavities inside MIPs act as synthetic host-tailored receptors that could recognize and bind specifically to each drug. The obtained Nernstian slopes were 57.16 mV/decade for alfuzosin MIP-based sensor and 58.17 mV/decade for solifenacin MIP-based one with respective LOD values of 7.9 × 10-7 M and 8.9 × 10-8 M. Moreover, no interference was ostensibly detected from dosage form excipients, plasma constituents or degradation products/official impurities allowing quantification of alfuzosin and solifenacin in their combined capsule, spiked human plasma and in presence of their degradation products.

Ultra selective and high-capacity dummy template molecular imprinted polymer to control quorum sensing and biofilm formation of Pseudomonas aeruginosa.

Here a highly selective molecular imprinting polymer was developed to attenuate biofilm formation of the multidrug-resistant pathogen Pseudomonas aeruginosa by disrupting the intermolecular signaling system. Firstly, a dummy template molecular imprinting polymer (MIP) was rationally designed through molecular modeling to capture 2-heptyl-3-hydroxy-4-quinolone (Pseudomonas quinolone signal). This multifunctional signaling molecule interferes with the pathogenicity of P. aeruginosa as an auto-inducer. Then, the synthesized MIP and the non-imprinted polymer (NIP) as reference polymer were evaluated for their binding capacity and biofilm inhibition. The results indicated a significant difference in biofilm inhibition (∼56%) between imprinted (∼67%) and non-imprinted (∼11%) polymer, which is an impressive level, especially for the treatment of various surfaces affected by P. aeruginosa. These results open a new window in the special biological application of MIPs as a promising candidate to reduce concerns in clinical or industrial issues by preventing microbial infections.

A Novel Solid-State PVC-Membrane Potentiometric Dopamine-Selective Sensor Based on Molecular Imprinted Polymer.

A novel solid-state polyvinylchloride (PVC) membrane potentiometric dopamine-selective microsensor was constructed based upon dopamine-imprinted polymer used as the ionophore in the membrane structure. The optimum membrane composition was determined as 4% (w/w) MIP, 69% (w/w) bis(2-ethylhexyl) sebacate (DOS), 26% (w/w) PVC, and 1% (w/w) potassiumtetrakis(4-chlorophenyl) borate (KTpClPB). The detection limit of the microsensor was determined to be 3.71×10-7 mol.L-1. The microsensor exhibited a super-Nernstian response for dopamine over the concentration range of 10-6-10-1 mol.L-1, with a short response time (<15 s) and a slope of 60.3±1.3 mV per decade (R2: 0.9998) over seven weeks. The microsensor was effectively performed in a pH range of 4.0-8.0 and a temperature range of 5-30 °C. The microsensor has been successfully demonstrated for the rapid, accurate, selective and reproducible determination of dopamine in pharmaceutical formulations with the recovery of 104.3-104.8%. The obtained results were in good harmony with the UV-Vis results at a confidence level of 95%.

Ultrasensitive and highly selective "turn-on" fluorescent sensor for the detection and measurement of melatonin in juice samples.

Melatonin (MLT), a hormone related to the regulation of brain functions, is directly related to sleep quality and is considered to be a possible adjuvant therapy for patients needing hospitalization for coronavirus disease 2019 pneumonia, and accurate measurement of MLT is crucial. Herein, a new, highly sensitive, and easy operation fluorescent probe was provided based on Zr metal-organic framework encapsulation into the molecularly imprinted polymer (MOF@MIP). By combining unique properties of MIP and fluorescent MOF, selectivity and operation of the applied method were significantly improved. Different characterization methods, such as XRD, FT-IR, and FE-SEM, were used to confirm the synthesis reliability. MOF@MIP was successfully used for the precise identification and ultrasensitive detection for trace amounts of MLT. The detection mechanism for the analytical system is based on the ''turn-on'' fluorescence (FL) signal in 404 nm. The findings proved that it is possible to detect trace amounts of MLT in real samples including grape, cherry, and sour cherry juice. The linear range and the limit of detection (LOD) for trace amounts of MLT were obtained as 1-100 ng/mL and 0.18 ng/mL, respectively.

Multi-template molecularly imprinted polymer hybrid nanoparticles for selective analysis of nonsteroidal anti-inflammatory drugs and analgesics in biological and pharmaceutical samples.

The multi-template molecularly imprinted polymers reinforced with hybrid oxide nanoparticles were developed for the selective separation and determination of the trace level of naproxen (NPX), methocarbamol (MTH), and omeprazole (OMZ) simultaneously from biological and pharmaceutical samples. The polymers were constructed by magnetic core@shell molecularly imprinted polymer nanocomposite (Fe3O4/ZnO/CuO/MWCNT@MIP). An electrochemical sensor has been fabricated for this purpose. Fe3O4/ZnO/CuO/MWCNT nanocomposite was introduced to improve the electron transport capability and increase the sensor surface area, as well as enhance the electronic conductivity. The triple-template MIP-coated layer provides simultaneous selective identification of three analytes by using [Fe (CN)6]3-/4-as the redox probe. Electrochemical behavior of MTH, NPX, and OMZ on the modified electrode (Fe3O4/ZnO/CuO/MWCNT@MIP) by various techniques such as cyclic voltammetry, differential pulse voltammetry, and chronoamperometry was examined. The morphology of the modified and unmodified carbon paste electrodes was performed by scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). The average crystal size for fabricated nanoparticles obtained by calculating the X-ray diffraction technique was 17 nm in the Scherer method. The particle size which was determined by SEM was 48 nm. Some electrochemical parameters such as the diffusion coefficient and electron transfer coefficient were determined. The effect of many variables such as the pH and scan rate was also investigated. Under optimal conditions, the sensor is designed in the linear range 5.0 nM-100 µM and 5.0 nM-100 µM and 1.0 nM-130 µM with a detection limit of 1.5 nM, 1.0 nM, and 0.7 nM for measurement OMZ, NPX, and MTH, respectively. The relative standard deviation (RSD) of the five measurements was 1.21%, 2.23%, and 2.56% for NPX, MTH, and OMZ. Finally, the designed sensor was successfully used for simultaneous detection of target analytes in the real samples; tablets, water samples, and biological samples.