Adsorption and recognition of protein molecular imprinted calcium alginate/polyacrylamide hydrogel film with good regeneration performance and high toughness

Protein imprinted calcium alginate/polyacrylamide hydrogel film (CA/PAM MIP) with high toughness was prepared using bovine serum albumin (BSA) as template molecule, sodium alginate and acrylamide as functional monomers, N,N′-methylenebisacrylamide (MBAA) as the covalent cross-linker and CaCl₂ as the ionic cross-linker via UV radiation-reduced polymerization. Factors affecting the adsorption capacity and imprinting efficiency of the BSA-imprinted CA/PAM hydrogel films were investigated, such as ratio of polyacrylamide/sodium alginate, film thickness, MBAA concentration and CaCl₂ concentration. Results showed that the CA/PAM MIP exhibited an obvious improvement in terms of adsorption capacity for BSA compared with non-imprinted polymer (NIP). The adsorption capacity of MIP for BSA reached 22.49 mg/g, which was 2.7 times higher than NIP. The regeneration property of the BSA-imprinted CA/PAM hydrogel was distinctly improved and the imprinting efficiency of CA/PAM MIP maintained 77.95% of the initial value after five repetitions. Single and binary proteins rebinding indicated that the CA/PAM MIP exhibited good recognition performance. Cell culture experiments showed CA/PAM MIP was more suitable for cell culture than CA/PAM NIP. The residual sodium dodecyl sulfate (SDS) in the elution process leaded to the death of mouse fibroblast cells (L929) after 3 days. A moderate elution solution without residue eluent should be used to prepare MIP for cell culture.     

用于蛋白质BSA识别的温度/pH双敏印迹聚合物

用N-异丙基丙烯酰胺(NIPAM)和壳聚糖为功能单体,牛血清白蛋白（BSA）为模板蛋白,在改性SiO₂表面制备温度/pH双敏蛋白质印迹聚合物。TEM、FTIR和TG等结果证明印迹层已成功接枝在载体表面。系统研究了聚合物的温度/pH双敏性、吸附容量、吸附动力学、特异性、竞争吸附性及重复性。结果表明,印迹聚合物（MIP）的溶胀率和吸附容量受温度和pH影响较大,高温碱性收缩,低温酸性溶胀。在pH 4.6和35℃下,对0.6mg/mL BSA吸附4h时获得较大的吸附容量（83.74mg/g）,印迹因子为2.02。同时MIP也有较好的特异性和竞争吸附性。重复5次后,吸附容量仍能维持在88%,说明重复性良好。这种新型的温度/pH双敏蛋白质分子印迹合成方法简单,在蛋白质的分离和识别方面有较好的应用前景。     

Cyclodextrin‐based molecularly imprinted polymers for the efficient recognition of pyrethroids in aqueous media

Recent years have witnessed growing applications of the molecular imprinting technique for the detection of pesticide residues in environmental and food samples. In this study, molecularly imprinted polymers (MIPs) for pyrethroids, a class of popular insecticides, were synthesized by the crosslinking of β‐cyclodextrin (β‐CD) with 1,6‐hexamethylene diisocyanate (HMDI) or toluene‐2,4‐diisocyanate (TDI) in dimethyl sulfoxide, with lambda‐cyhalothrin (LCT) as a model template. Equilibrium batch‐rebinding tests were operated in different aqueous solutions. The results indicate that MIP prepared with TDI (MIP–TDI) possessed a much greater binding activity to LCT than MIP based on HMDI (MIP–HMDI), and MIP–TDI displayed a remarkably specific binding to LCT (with an imprinting factor of around 3) in an acetonitrile/water (4:7 v/v) mixture. The adsorption of LCT by MIP–TDI reached equilibrium after 3 h; this demonstrated comparatively rapid adsorption kinetics. Also, MIP–TDI could be regenerated eight times at least; this implied that the robust β‐CD polymer has the potential for practical applications. Furthermore, a cross‐selectivity study indicated that the high adsorption of LCT and its analogues by MIP–TDI in aqueous media must have been ascribed to the cooperative effects of CD inclusion interaction and stereoshape memory. This study paved the way for the use of β‐CD as a functional monomer for preparing smart artificial receptors for the efficient recognition of pyrethroids under aqueous conditions. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

One-step building of molecularly imprinted polymer microcapsules with multicore structure by Pickering emulsion polymerization

Novel molecularly imprinted polymer (MIP) microcapsules with multicore structure were prepared through one step Pickering emulsion polymerization combined with the polymerization driven phase separation. Bisphenol A (BPA) is found to play the part of heterogeneous nuclei besides template molecule, which offers opportunity for the building of the multicore structure inside of MIP microcapsules. The internal structure of MIP microcapsules could be regulated by choosing different kinds of template molecules. Rebinding experiments showed that the MIP with multicore structure possessed excellent binding properties toward BPA. The imprinting factor of MIP toward BPA is 1.96. The binding could reach equilibrium within 30 min. The fast rebinding kinetics was attributed to the unique multicore structure which reduced largely the mass transfer resistance of BPA in the MIP.     

红霉素分子印迹聚合物纳米微球的制备及其吸附特性

以红霉素为模板分子、甲基丙烯酸为功能单体、乙二醇二甲基丙烯酸酯为交联剂,采用沉淀聚合法制备了粒径均一的红霉素纳米分子印迹聚合物微球,优化了分子印迹聚合物的合成条件,确定了模板分子与功能单体的最佳摩尔比为1:3,对其进行了表征. 结果表明,所制聚合物对红霉素的实际最大吸附量可达202.12 mg/g,吸附约200 min达到平衡,对红霉素具有良好的选择性吸附能力.     

Supermacroporous poly(hydroxyethyl methacrylate) based cryogel with embedded bilirubin imprinted particles

Molecular imprinted polymers are artificial, template-made materials with the ability to recognize and to specifically bind the target molecule. The aim of this study is to prepare supermacroporous cryogel with embedded bilirubin-imprinted particles which can be used for the selective removal of bilirubin from human plasma. N-methacryloyl-(l)-tyrosinemethylester (MAT) was chosen as the pre-organization monomer. In the first step, bilirubin was complexed with MAT and the bilirubin-imprinted poly(hydroxyethyl methacrylate-N-methacryloly-(l)-tyrosine methyl-ester) [MIP] monolith was produced by bulk polymerization. MIP monolith was smashed and the particles ground and sieved through 100 μm sieves. In the second step, the supermacroporous poly(hydroxyethyl methacrylate) (PHEMA) cryogel with embedded MIP particles [PHEMA/MIP composite cryogel] was produced by free radical polymerization initiated by N,N,N′,N′-tetramethylene diamine (TEMED) and ammonium persulfate (APS) pair in an ice bath. After that, the template (i.e., bilirubin) molecules were removed using sodium carbonate and sodium hydroxide. Compared with the PHEMA cryogel (0.2 mg/g polymer), the bilirubin adsorption capacity of the PHEMA/MIP composite cryogel (10.3 mg/g polymer) was improved significantly due to the embedded MIP particles into the polymeric matrix. The relative selectivity coefficients of PHEMA/MIP composite cryogel for bilirubin/cholesterol and bilirubin/testosterone were 8.6 and 4.1 times greater than the PHEMA cryogel, respectively. The PHEMA/MIP composite cryogel could be used many times without decreasing the bilirubin adsorption capacity significantly.     

Computer simulation and preparation of molecularly imprinted polymer membranes with chlorogenic acid as template

A computational approach was developed for screening functional monomers for rational design of molecularly imprinted polymer (MIP) membranes. It was based on a comparison of the binding energy of complexes between a template and various functional monomers. According to the results of theoretical calculations, MIP membranes with chlorogenic acid as a template were prepared with a UV irradiation polymerization method, using 4‐vinylpyridine as a functional monomer and N,N′‐methylenebisacrylamide as a crosslinker, with poly(vinylidene fluoride) microfiltration membranes as the support. Membranes covered with a thin layer of imprinted polymer selective to chlorogenic acid were then obtained and tested using the equilibrium‐adsorption method. The high affinity of these synthetic membranes to chlorogenic acid, together with their straightforward and inexpensive preparation, provides a good basis for the development of applications of imprinted polymers in separation processes such as solid‐phase extraction. Copyright © 2011 Society of Chemical Industry     

Selective molecularly imprinted polymer nanofiber sorbent for the extraction of bisphenol A in a water sample

Novel molecularly imprinted polymer nanofibers (MIP‐NFs) were prepared for the adsorption of bisphenol A (BPA) in a water sample using the sol–gel process and the electrospinning technique. The effects of a number of synthesis parameters on the adsorption efficiency were investigated. The successful removal of BPA from MIP‐NFs was studied using UV–visible spectroscopy. The prepared MIP‐NFs were characterized by Fourier transform infrared, field emission SEM, TEM and energy dispersive X‐ray analysis. The results showed that the required molar ratio of 3‐aminopropyltriethoxysilane (APTES) to BPA was 15:1, which indicates a good performance in the rebinding test. Likewise, the molar ratio of APTES:acid:water was 1:2:9. The nylon 6 polymer solution, with a concentration of 12 wt%, showed a maximum adsorption capacity for BPA due to a decrease in the nanofiber diameter and an increase in the accessible sites. Furthermore, the maximum adsorption capacity of BPA was achieved at pH 7. Concerning the binding of BPA on MIP‐NFs, the experimental data matched well with the pseudo‐second‐order kinetics data and the Sips isotherm model. The saturated binding capacity for MIP‐NFs was predicted to be 115.1 mg g^?1, which was more than twice as high as that for non‐imprinted polymer nanofibers (46.82 mg g^?1). The results obtained in this study confirmed that the prepared MIP‐NFs showed considerable binding specificity for BPA in comparison with similar structural compounds such as phenol, naphthol and Naphthol AS, in aqueous solution. The binding capacity of MIP‐NFs remained almost constant after five cycles of reuse. The real sample analysis indicated that MIP‐NFs could be utilized as a useful sorbent material for the extraction of BPA from a water sample.     

A convenient synthesis of NiO-CuS/molecularly imprinted polymer nanocomposites with highly enhanced adsorption activity and selectivity for removal of Letrozole

ABSTRACT

In this study, Novel NiO-CuS nanocomposites were prepared by simple chemical method. The goal of this project was to apply the Letrozole (Anti-estrogen drug) template molecularly imprinted polymer (MIP) for the selective removal of Letrozole from aqueous samples. The NiO-CuS nanocomposites and NiO-CuS/MIP nanocomposites were specified by field emission scanning electron microscopy, X-ray diffraction, photoelectron spectroscopy, N₂ adsorption-desorption, and thermogravimetric analysis. The performance of the NiO-CuS and NiO-CuS/MIP nanocomposites was analyzed by optimizing various removal factors. The optimized data for adsorption process were 0.01 g/L: MIP, contact time: 40 min and pH: 7.0. The data was evaluated best by pseudo 1st and 2nd order equation which revealed a chemical adsorption of letrozole onto NiO-CuS and NiO-CuS/MIP particles, respectively. The result of R² values indicated that the adsorption data followed the Langmuir isotherm equation which defined that the binding agent happened on the homogeneous sites of adsorbent.     

Preparation of pH and temperature dual‐sensitive molecularly imprinted polymers based on chitosan and N‐isopropylacrylamide for recognition of bovine serum albumin

pH and temperature dual‐sensitive protein imprinted microspheres with high absorption capacity have been successfully synthesized on the surface of SiO₂ using chitosan grafted N‐isopropylacrylamide (CS‐g‐NIPAM) as the pH and temperature sensitive monomer, with acrylamide as comonomer, N,N′‐methylenebisacrylamide as the crosslinking agent and bovine serum albumin (BSA) as the template protein. The pH and temperature dual‐sensitivity was also investigated. The results showed that the adsorption capacity and imprinting factor improved slowly with increasing incubation pH from 4.6 to 7.0, and then decreased sharply in alkaline conditions due to the reduction of non‐specific binding from electrostatic and hydrogen bonding interactions. Fourier transform infrared spectroscopy, thermogravimetric analysis and transmission electron microscopy were used to characterize the polymers. The as‐prepared SiO₂@BSA molecularly imprinted polymers were also found to have high adsorption capacity (119.88 mg g^?1) within 2 h, an excellent imprinting factor (α = 2.25), specific selectivity and good reusability. © 2019 Society of Chemical Industry     

沉淀聚合法制备磺胺二甲嘧啶分子印迹聚合物

以磺胺二甲嘧啶为模板分子,采用沉淀聚合法制备了分子印迹聚合物,并对其选择性和吸附性能进行了研究.等温静态平衡实验结果表明,该印迹聚合物与相应的空白聚合物相比具有高的选择性和亲和性;Scatchard模型分析结果表明,该印迹聚合物对印迹分子存在一种均匀的结合位点,最大表观结合量为31.866 mg/g.     

The Preparation of BHb-Molecularly Imprinted Gel Polymers and Its Selectivity Comparison to BHb and BSA

Molecularly imprinted gel polymer (MIP) for the selective imprinting of bovine hemoglobin (BHb) was prepared in aqueous media by bulk polymerization using polyacrylamide matrix. The synthesis conditions of BHb-MIP were investigated, which involved the interaction of functional monomers and template protein in different molar ratio, solution pH, and ionic strength. The adsorption experiments indicated that BHb-MIP had a high affinity for BHb over the non-imprinted polymers. The selectivity of BHb-MIP for BHb and bovine serum albumin (BSA) with similar molecular weight was compared. It was demonstrated that BHb-MIP had better selective adsorption and recognition properties to BHb especially in the presence of BSA as competing protein. It might be helpful for selectively separating template protein with MIP from the proteins mixture with similar molecular weight.     

Synthesis and characterization of the molecularly imprinted mesoporous silica based on the self-assembly technique for selective recognition of lomefloxacin in aqueous solution

Based on double-imprinting (surfactant and lomefloxacin templates) concept and self-assembly technique, a new molecularly imprinted mesoporous silica (MIP-MS) was prepared to understand and characterize the mechanism of fast binding and selective recognition of lomefloxacin (LOM) by the adsorption isotherms model, the adsorption kinetic models, and the competitive adsorption. The MIP-MS was prepared by using LOM and surfactant micelles as the templates formed through self-hydrolyzed, self-condensed, and co-condensation of tetraethoxysilane and methyltriethoxysilane in alkaline media, and with the covalently anchored organic groups in the mesoporous silica matrix. Both the molecularly imprinted polymer (MIP) and non-imprinted mesoporous polymer (NIP) were prepared for comparison. The surface area, pore size and pore volume of the MIP-MS are 270 m² g^?1, 4.42 nm and 0.28 cm³ g^?1, respectively. The kinetics studies showed that the pseudo-second-order model was consistent with the kinetic data of the MIP-MS with the fast binding templates (the 95 % uptake of LOM within 10 min). The equilibrium data, at various temperatures, were described successfully by the Langmuir and Freundlich isotherm models. The Freundlich model was found to fit the experiment data well. The thermodynamics parameters (positive values of ΔS, negative values of ΔH and ΔG) indicated that the binding system for the MIP-MS was entropy-gained, exothermic, and the spontaneous adsorptive forces were stronger on MIP-MS than on NIP and MIP. The MIP-MS showed fast binding, higher affinity, and selectivity for the template of LOM compared with the NIP and MIP.     

Protein adsorption and separation with chitosan-based amphoteric membranes

A macroporous amphoteric membrane was successfully prepared by solution blending of a natural polymer chitosan (CS) and its derivative carboxymethylchitosan (CMCS). The adsorption of two model proteins (ovalbumin and lysozyme) with very different pI values on this CS/CMCS blend membrane was investigated in batch systems. The results showed that both proteins could be effectively adsorbed on the membrane, but the adsorption capacities were influenced by the pH, the initial protein concentration and the CMCS content in the membrane. Because of the amphoteric nature of the protein and the CS/CMCS membrane, the pH for the maximum adsorption of ovalbumin and lysozyme was different, which is the basis for the separation of these proteins from binary mixtures. As the CS/CMCS blend membrane also showed good desorption properties for those two proteins, both ovalbumin and lysozyme were successfully separated from binary mixtures by adjusting only the pH of the feed and the desorption solutions.     

Removal of copper(II) from an aqueous solution with copper(II)‐imprinted chitosan microspheres

Ion‐imprinted chitosan (CS) microspheres (MIPs) were prepared with Cu(II) as a template and epichlorohydrin as a crosslinker for the selective separation of Cu(II) from aqueous solution. The microspheres showed a higher adsorption capacity and selectivity for the Cu(II) ions than nonimprinted chitosan microspheres (NMIPs) without a template. The results show that the adsorption of Cu(II) on the CS microspheres was affected by the initial pH value, initial Cu(II) concentration, and temperature. The kinetic parameters of the adsorption process indicated that the adsorption followed a second‐order adsorption process. Equilibrium experiments showed very good fits with the Langmuir isotherm equation for the monolayer adsorption process. The maximum sorption capacity calculated from the Langmuir isotherm was 201.66 mg/g for the Cu–MIPs and 189.51 mg/g for the NMIPs; these values were close to the experimental ones. The selectivity coefficients of Cu(II) and other metal ions on the NMIPs indicated a preference for Cu(II). © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis of a Temperature-Sensitive Matrine-Imprinted Polymer and Its Potential Application for the Selective Extraction of Matrine from Radix Sophorae Tonkinensis

A temperature-sensitive matrine-imprinted polymer was prepared in chloroform by free-radical cross-linking copolymerization of methacrylic acid at 60 °C in the presence of ethylene glycol dimethacrylate as the cross-linker, N-isopropyl acrylamide as the temperature-responsive monomer and matrine as the template molecule. Binding experiments and Scatchard analyses revealed that two classes of binding sites were formed on molecular imprinted polymer (MIP) at 50 °C. Additionally, the thermoresponsive MIP was tested for its application as a sorbent material for the selective separation of matrine from Chinese medicinal plant radix Sophorae tonkinensis. It was shown that the thermoresponsive MIP displayed different efficiency in clean-up and enrichments using the SPE protocol at different temperatures.     

以乙烯基吡咯烷酮为功能单体的金属配合印迹聚合物的制备及水相识别

Using nickel（II） acetate.-2,2＇-dipyridyl complex as template and N-vinyl-2-pyrrolidone （NVP） as coordinate functional monomer,.a new kind of metal-compiexing template molecularly impnnted polymer （MIP） was prepared..The results of equilibri.um binding experiments in. aqueous solution showed that the MIP had higher＇binding capacity for nickel（ II ）-2,2＇-dipyridyl than the non-imprinted polymer with the same chemical composition. Theinfluences of metal ions and pHof solution on the recognition performance of MIP were investigated. The bindingcharacteristics of MIP were evaluated by the Scatchard analysis with one-site and two-site binding equations, respectively. The results on substrate selectivity of imprinted polymer revealed that MIP had better binding affinityfor template among thetested compounds.     

氨基化MIL-101表面印迹聚合物的制备及其吸附行为

研究了金属有机骨架材料MIL-101表面印迹聚合物的制备方法及其吸附行为。以MIL-101为载体,先通过化学修饰氨基制备了ED-MIL-101材料,再以京尼平苷为模板,甲基丙烯酸为功能单体,二乙烯基苯为交联剂,表面接枝京尼平苷分子印迹聚合物制备了MIPs@MIL-101印迹聚合物。通过傅里叶红外光谱（FTIR）、X射线衍射光谱（XRD）、扫描电镜（SEM）对聚合物进行结构表征,测试了聚合物的等温吸附及吸附动力学性能,探讨了聚合物的固相萃取性能。红外光谱及XRD衍射分析表明了MIL-101氨基化修饰及表面接枝复合材料的成功制备。吸附动力学研究表明当分子印迹聚合物用于吸附京尼平苷时,可在270min内达到吸附平衡。当温度为298K、308K、318K、328K时,印迹聚合物对模板的吸附量分别为55.94mg/g、46.16mg/g、38.98mg/g、31.47mg/g。吸附热ΔH为26.997kJ/mol。分子印迹固相萃取杜仲提取物中的京尼平苷时,总回收率达95.0%。     

Preparation and evaluation of a molecularly imprinted polymer for tolazoline

A uniformly sized molecularly imprinted polymer for the peripheral vasodilator drug tolazoline (T‐MIP) was prepared, and a nonimprinted polymer (NIP) was also synthesized in the same way but in the absence of the template. The T‐MIP was prepared with methylacrylic acid as functional monomer and ethylene glycol dimethacrylate as crosslinker by a multistep swelling and polymerization method. These imprinted materials were characterized by scanning electron microscopy, nitrogen adsorption, and static adsorption experiments. Binding studies were also performed to evaluate the uptake of T‐MIP and NIP with the results that T‐MIP had a significantly higher binding capacity for tolazoline (T) than did NIP. The maximum static adsorption capacities of T‐MIP and NIP for T were 78.9 and 38.8 μmol/g, respectively. The T‐MIPs and NIPs were used as stationary phases of solid‐phase extraction (SPE), and a relative selectivity coefficient (k′) value of 5.21 was obtained, which showed that the T‐MIP sorbent had higher selectivity than the NIP sorbent. The method was applied to the determination of T in urine samples. The prepared polymer sorbent showed promise for SPE for gas chromatography determination of T in urine samples. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis of molecularly imprinted polymers from AnAc for the separation of γ-oryzanol

The selectivity of gamma-oryzanol (γ-oryzanol) was recognized by molecularly imprinted polymer (MIP). Polymeric materials were successfully synthesized via thermal polymerization method using γ-oryzanol as template, anacardic acid (AnAc) as functional monomer, toluene as porogen, benzoyl peroxide (BPO) as initiator and divinylbenzene as crosslinker. Binding performance of MIPs was evaluated by MINITAP 14 for variance of analysis, linear regression analysis and adequating model through full factorial experimental technique in terms of adsorption capacity. Analysis of variance with 95% confidence level suggested significant interaction effect (amounts of template, porogen, crosslinker) on adsorption capacity of MIPs. The strongest interaction is between the amount of porogen and the amount of crosslinker. It was also found that a linear regression model for adsorption capacity represents the experimental data with the correlation coefficients (R²) greater than 0.9. The MIP synthesis with 0.8 mmol of template, 6 ml of porogen and 10 ml of crosslinker provided the highest adsorption capacity of MIP (1.14 mg/g-adsorbent). The proposed method is relatively rapid and easy to perform for the separation of γ-oryzanol in non-aqueous systems.