An electrochemical sensor based on carbon nanofiber and molecular imprinting strategy for dasatinib recognition.

Herein, we proposed a new approach to design a MIP-based electrochemical sensor with carbon nanofiber (CNF), which could improve its conductivities as well as electrode sensitivity and successful detection of dasatinib (DAS). CNFs are capable of forming high porosity with significant interconnected porous networks. The poly(2-hydroxyethyl-methacrylate-N-methacryloyl-L-tyrosine) (PHEMA-MATyr) copolymer was synthesized in the presence of both CNF and DAS by photopolymerization. After optimization of the parameters, the modified MIP-based electrochemical sensor demonstrated the ability to determine the DAS in the linear working range of 1.0 × 10-14-1.0 × 10-13 M for the standard solution and commercial serum samples with a LOD of 1.76 × 10-15 and 2.46 × 10-15, respectively. Good linearity for DAS was observed with correlation coefficients (r) of 0.996 and 0.997 for the standard solution and commercial serum samples, respectively. The recoveries of the DAS ranged from 99.45 % to 99.53 % for the tablet dosage form and commercial serum samples, with average relative standard deviations below 1.96 % in both cases. The proposed modified sensor demonstrated significant sensitivity and selectivity for the rapid determination of DAS in commercial serum samples and tablet form.

A comparative study of electropolymerization and photopolymerization for the determination of molnupiravir and their application in an electrochemical sensor via computationally designed molecularly imprinted polymers.

A comparative analysis of molecularly imprinted polymers based on different synthesis techniques was performed for the recognition of molnupiravir (MOL). The polymerizations were performed with 3-thienyl boronic acid (3-TBA) as a functional monomer by electropolymerization (EP) and with guanine methacrylate (GuaM) as a functional monomer by photopolymerization (PP). Morphological and electrochemical characterizations of the developed sensors were investigated to verify the constructed sensors. Moreover, quantum chemical calculations were used to evaluate changes on the electrode surface at the molecular and electronic levels. The dynamic linear range of both designed sensors under optimized experimental conditions was found to be 7.5 × 10-12-2.5 × 10-10 M and 7.5 × 10-13-2.5 × 10-11 M for EP and PP, respectively. The effect of various interfering agents on MOL peak current was assessed for the selectivity of the study. In the presence of 100 times more interfering agents, the RSD and recovery values were determined. The RSD values of GuaM/MOL@MIP/GCE and poly(Py-co-3-PBA)/MOL@MIP/GCE sensors were found to be 1.99% and 1.72%, respectively. Furthermore, the recovery values of the MIP-based sensors were 98.18-102.69% and 98.05-103.72%, respectively. In addition, the relative selectivity coefficient (k') of the proposed sensor was evaluated, and it exhibited good selectivity for MOL with respect to the NIP sensor. The prepared sensor was successfully applied to determine MOL in commercial serum samples and capsule form. In conclusion, the developed sensors provided excellent reproducibility, repeatability, high sensitivity, and selectivity against the MOL molecule.

Comparative MIP sensor technique: photopolymerization or thermal polymerization for the sensitive determination of anticancer drug Regorafenib in different matrixes.

Regorafenib (REG) is a diphenylurea derivative oral multikinase inhibitor. It plays an important role in the treatment of colorectal cancer, metastatic gastrointestinal stromal tumors, and hepatocellular carcinoma. Molecularly imprinted polymer (MIP) based glassy carbon electrodes (GCE) were fabricated using photopolymerization (PP) and thermal polymerization (TP) methods. The characterizations of the proposed sensors were investigated by electrochemical techniques, Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). Several parameters were studied in detail for the optimum conditions of MIP-based sensors, such as dropping volume, photopolymerization and thermal polymerization durations, removal medium and time, and rebinding time. Both sensors' analytical validation and electroanalytical performance comparison were made in different REG concentrations ranging between 0.1 nM and 2.5 nM in standard solution and commercial human serum samples. The limit of detection (LOD) of PP-REG@MIP/GCE and TP-REG@MIP/GCE were 9.13 × 10-12 M and 1.44 × 10-11 M in standard solutions and 2.04 × 10-11 M and 2.02 × 10-11 M in serum samples, respectively. The applicability of the proposed sensors was tested using commercial human serum samples and pharmaceutical form of REG with high recovery values (PP-REG@MIP/GCE and TP REG@MIP/GCE sensors, 99.56-101.59%, respectively). The selectivity of the sensor for REG was investigated in the presence of similar molecules: Sorafenib, Sunitinib, Nilotinib, and Imatinib. The developed techniques and sensors checked the possible biological compounds and ions' effects and storage stability.

A semi-covalent molecularly imprinted electrochemical sensor for rapid and selective detection of tiotropium bromide.

Tiotropium bromide (TIO) is a long-acting bronchodilator used in the treatment of chronic obstructive pulmonary disease (COPD) and asthma. Specifically, it is used to prevent patients from worsening breathing difficulties. In this study, a new TIO-imprinted electrochemical sensor was designed to detect TIO in serum and pharmaceutical samples. Methacryloyl-L-histidine-cobalt(II) [MAH-Co(II)] has been used as a metal-chelating monomer for synthesizing selective molecularly imprinted polymer (MIP). MIP film has been developed on glassy carbon electrodes using MAH-Co(II) as the functional monomer, 2-hydroxyethyl methacrylate (HEMA) as the basic monomer, and ethylene glycol dimethacrylate (EGDMA) as the cross-linker in the photopolymerization method. The surface characterization of the developed MAH-Co(II)@MIP/GCE electrochemical sensor was done using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Also, the electrochemical behavior of the sensor was provided by differential pulse voltammetry (DPV), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) techniques. Under optimized experimental conditions, the linearity range was in the range of 10-100 fM, and the limit of detection (LOD) and limit of quantitation (LOQ) values were calculated as 2.73 fM and 9.75 fM, respectively. The MAH-Co(II)@MIP/GCE sensor was used to precisely determine TIO in capsule and commercial serum samples. The results demonstrated that the MIP could specifically recognize TIO compared to structurally related drugs and could be reliably applied to the direct determination of drugs from real samples.

A sensitive and selective electrochemical sensor based on molecularly imprinted polymer for the assay of teriflunomide.

In this work, pyrrole-histidine has been designed, synthesized and, used as a novel functional monomer to fabricate a molecularly imprinted electrochemical sensor for the selective and sensitive detection of teriflunomide (TER). The molecularly imprinted thin film of electrochemical sensor was constructed by directly electropolymerization of co-polymer of pyrrole-histidine (PyHis) with pyrrole in the presence of a template, TER, on a glassy carbon electrode (GCE). After electropolymerization, the structure and morphology of the fabricated MIP sensor were characterized by Fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) and its electrochemical parameters such as cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS). The poly (pyrrole-co-pyrrole-histidine) [Poly (Py-co-PyHis)]@MIP/GCE sensor have a linear TER concentration in the of 0.1-1.0 pM with a low detection limit of 11.38 fM. The present strategy for electrochemical sensor have been also showed excellent recovery in synthetic serum samples and tablet dosage form with the recoveries 97.56% and 100.35%, respectively. The developed [Poly (Py-co-PyHis)]@MIP/GCE sensor exhibited an excellent electrochemical response for TER due to the synergistic effect of conducting polymer and molecularly imprinting techniques.

Simple preparation of surface molecularly imprinted polymer based on silica particles for trace level assay of bisphenol F.

A new electrochemical sensor based on molecularly imprinted tetraethyl orthosilicate (TEOS)-based porous interface was developed for selective recognition of bisphenol F (BPF) in this study. The sensor was prepared by depositing the solution containing TEOS and L-tryptophan (L-Trp) in the presence of cetyltrimethylammonium bromide (CTAB) as a pore-maker via hydrolysis/condensation reaction on the glassy carbon electrode (GCE). While the surface morphology and structure characterization were carried out using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), electrochemical characterization was performed through electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The resulted MIP(TEOS:L-Trp)@GCE achieved a wide linear range of 1 × 10-15-1 × 10-14 M for BPF detection with an excellent detection limit of 0.291 fM. Furthermore, the recovery of BPF from spiked bottled water and serum samples varied between 98.83 and 101.03%. These results demonstrate that MIP(TEOS:L-Trp)@GCE was found to be a simple, sensitive, and selective smart interface to detect trace pollution even from complicated samples.

Enantioselective recognition of esomeprazole with a molecularly imprinted sol-gel-based electrochemical sensor.

A simple, selective, and accurate electrochemical chiral sensor based on molecularly imprinted polymer (MIP) has been developed for sensitive and selective detection of esomeprazole (ESOM). For this purpose, the porous MIP sensor was prepared using tetraethyl orthosilicate (TEOS) and cetyltrimethylammonium bromide (CTAB) in the presence of ß-cyclodextrin (ß-CD) as a chiral recognizing element on a glassy carbon electrode (GCE). The changes in the MIP-layer related to removal and rebinding of the target ESOM were performed via differential pulse voltammetry (DPV) and cyclic voltammetry (CV) by using [Fe(CN)6]3-/4- as the redox probe. The structures of the developed sensor surface were characterized by using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Electrochemical impedance spectroscopy (EIS) was also utilized for a complementary electrochemical characterization. The calibration curve was obtained in the range 1.0 × 10-14-2.0 × 10-13 M with a limit of detection (LOD) of 1.9 × 10-15 M. The developed method has improved the accessibility of binding sites by producing the porous material via hydrolysis/condensation reaction of TEOS in presence of CTAB. The selectivity tests of the developed SiO2-ß-CD@MIP/GCE sensor indicated a high specificity towards ESOM compared with structurally related competitor molecules such as R-omeprazole (R-OM), R-lansoprazole, and S-lansoprazole. The developed sensor was successfully used to determine ESOM in tablets and commercial human serum samples with satisfactory recoveries (100.25 to 100.60%) and precision (RSD 0.46 to 0.66%).

A porous molecularly imprinted electrochemical sensor for specific determination of bisphenol S from human serum and bottled water samples in femtomolar level.

In this study, a porous molecularly imprinted electrochemical sensor was successfully fabricated for the selective assay of bisphenol S (BPS) by introducing N-methacryloyl-L tyrosine functional monomer. The molecularly imprinted polymer (MIP)-based sensor (MA-Tyr@MIP/GCE) was prepared via photopolymerization on the glassy carbon electrode and subsequently characterized by using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR). The analytical performance of the sensor was evaluated via CV and differential pulse voltammetry (DPV) measurements. Under the optimized conditions, the rebinding experiment demonstrated that the peak current of the porous MIP-based sensor obviously decreased with the increase of BPS concentration in the concentration range of 1-10 fM. Therefore, the detection limit was determined as 0.171 fM. It should be underlined that MA-Tyr@MIP/GCE exhibited high sensitivity and excellent selectivity because MA-TyrMA-Tyr@MIP/GCE sensor has a higher imprinting factor (IF) toward BPS in respect to competitive analogs, i.e., bisphenol A, bisphenol B, and bisphenol F. The practical application of the sensor also showed good reproducibility and stability for the detection of BPS in human serum and water samples. These results showed MA-Tyr@MIP/GCE successfully applied for the selective recognition of BPS in biological and water samples with high sensitivity and excellent selectivity.

A porous molecularly imprinted nanofilm for selective and sensitive sensing of an anticancer drug ruxolitinib.

A novel methodology has been applied to generate a porous molecularly imprinted material for highly selective and sensitive recognition of Janus kinase inhibitor ruxolitinib (RUX). The porous material-based nucleobase-derivative functional monomer was developed by a photopolymerization method. The thymine methacrylate (ThyM) as a functional monomer was synthesized and copolymerized with 2-hydroxyethyl methacrylate (HEMA) in the presence of ethylene glycol dimethacrylate (EGDMA) onto the glassy carbon electrode [glassy carbon electrode/molecularly imprinted polymer@poly(2-hydroxyethyl methacrylate-co-thymine methacrylate), (GCE/MIP@PHEMA-ThyM)] for the first time. The presence of ThyM results in the functional groups in imprinting binding sites, while the presence of poly(vinyl alcohol) (PVA) allows to generate porous materials for sensitive sensing. The characterization of GCE/MIP@PHEMA-ThyM was investigated by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), and impedance spectroscopy technique. Then, the porous MIP modified glassy carbon electrode was optimized with effecting parameters including removal agent, removal time, and incubation time to get a better response for RUX. Under well-controlled optimum conditions, the GCE/MIP@PHEMA-ThyM linearly responded to the RUX concentration up to 0.01 pM at the limit of detection (LOD) of 0.00191 pM. The non-imprinted polymer (NIP) was also prepared to serve as a control in the same way but without the template. The proposed method improves the accessibility of binding sites by generating the porous material resulting in highly selective and sensitive recognition of drugs in the pharmaceutical dosage form and synthetic human serum samples.

Interface imprinted polymers with well-oriented recognition sites for selective purification of hemoglobin.

In this study, we introduced a new strategy to design interface imprinted polymers for a novel aspect of molecular imprinting technique, utilization of sacrificial metal oxide particles. In the first step, bovine hemoglobin (BHb) was adsorbed on zinc oxide (ZnO) particles, which were then used to synthesize polyacrylic acid-based molecular imprinting membrane by bulk polymerization in the presence of ethylene glycol dimethacrylate as a cross-linking agent. After polymerization terminated, BHb-ZnO particles were removed to leave effective imprint sites onto the bulk polymeric network which is responsible for the formation of template orientation. The characterization of membranes was investigated by using Fourier transform infrared (FTIR), Raman spectroscopy (RS), scanning electron microscopy (SEM), surface area measurements (BET analyses) and thermogravimetric analysis (TGA). The interface molecularly imprinted membranes (iMIMs) have a relatively high specific rebinding capacity of 65.98 mg/g and excellent selectivity towards BHb with a separation factor of 6.78. The equilibrium adsorption isotherms fitted well to Langmuir isotherms (R2 = 0.9944) and the value of adsorption capability (Qmax) and equilibrium constant (b) were estimated to be 73.53 mg/g and 1.36 mg/mL for the iMIM, respectively. The kinetics of adsorption fitted best to pseudo-second order (R2 = 0.9912). The ZnO particles were used not only to ensure the preservation of the imprint cavities in the polymer network but also to lead to high template removal and better rebinding kinetics. This novel design with multiple recognition sites is quite simple and suitable for the separation of biomacromolecules.

Molecular imprinted magnetic nanoparticles for controlled delivery of mitomycin C.

Controlled drug delivery system is a technique which has considerable recent potential in the fields of pharmacy and medicine. Mitomycin C is commonly used drug in the treatment of superficial bladder and breast cancers. In the present study, mitomycin C-imprinted magnetic poly(hydroxyethyl methacrylate)-based nanoparticles (MIMNs) were prepared using surfactant free emulsion polymerization for controlled delivery of mitomycin C. The MIMNs were characterized by fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscopy, electron spin resonance, and elemental analysis. The average particle diameter of MIMNs was about 200 nm.

Preparation of molecular imprinted hydrophobic polymeric nanoparticles having structural memories for lysozyme recognition.

This study is related to the preparation of lysozyme-imprinted poly(hydroxyethyl methacrylate-N-methacryloyl-(L)-tyroptophan methylester) [nano-MIP] nanoparticles for purification of lysozyme. Nano-MIP particles were found to be 261 nm in diameter with a surface area of 1648 m(2)/g. According to the elemental analysis results, the particles contained 0.85 µmol MATrp/g polymer. The maximum lysozyme adsorption capacity was 1182.8 mg/g. Adsorbed lysozyme was desorbed with 94% recovery. It was observed that after five adsorption-desorption cycles there was no significant loss in adsorption capacity. In order to show the selectivity of the Lys-MIP nanoparticles, adsorption of lysozyme, bovine serum albumin (BSA), and cytochrome c were investigated.

Application of supermacroporous monolithic hydrophobic cryogel in capturing of albumin.

Supermacroporous poly{2-hydroxyethyl methacrylate-co-[N,N-bis(2,6-diisopropylphenyl)-perylene-3,4,9,10-tetracarboxylic diimide]} [poly(HEMA-co-DIPPER)] monolithic cryogel column was prepared by radical cryocopolymerization of HEMA with DIPPER as functional comonomer and N,N'-methylene-bisacrylamide (MBAAm) as crosslinker directly in a plastic syringe for adsorption of albumin. The monolithic cryogel contained a continuous polymeric matrix having interconnected pores of 10-50 µm size. Poly(HEMA-co-DIPPER) cryogel was characterized by swelling studies, FTIR, scanning electron microscopy, and elemental analysis. The equilibrium swelling degree of the poly(HEMA-co-DIPPER) cryogel was 14.7 g H2O/g dry cryogel. Poly(HEMA-co-DIPPER) cryogel was used in the adsorption/desorption of albumin from aqueous solutions. The nonspecific adsorption of albumin onto plain poly(HEMA) cryogel was very low (3.36 g/g polymer). The maximum amount of albumin adsorption from aqueous solution in acetate buffer was 40.9 mg/g polymer at pH 5.0. It was observed that albumin could be repeatedly adsorbed and desorbed with the poly(HEMA-co-DIPPER) cryogel without significant loss of adsorption capacity.