Effect of electrostatic functional monomers on lysozyme recognition by molecularly imprinted hydrogel

Electrostatic functional monomers (EFMs) play an important role in noncovalent molecular imprinting due to their formed complexes with the complementary segment(s) of the template molecule. In this work using UV difference spectroscopy, interaction saturations of methacrylic‐acid and 2‐dimethyl‐amino‐ethyl‐methacrylate in complex formation with lysozyme (Lyz) surface was found to occur at molar ratios to Lyz of 400 and 100, respectively. Based on these results and the estimated free to total EFMs ratios, four sets of imprinted/nonimprinted hydrogel samples were synthesized alongside the two sets based on lysozyme surface charges and equal EFMs. Comparisons showed that the highest absorption capacity of 59 mg/g and imprinting effect of 1.58 correspond to samples with EFM/Lyz ratios at saturation and minimum free to total EFM/Lyz ratios, respectively. Minimization of free monomers is hence important in recognition of proteins by avoiding the nonspecific binding. This can have generic application for specific separation of other macromolecules. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41366.     

Development of dieldrin,endosulfan, and hexachlorobenzene‐imprinted polymers for dye‐displacement array sensing

Due to the toxicity associated with the exposure to organochlorine pesticides, new materials capable of selectively capturing and detecting these compounds are highly desirable. In this study, imprinted polymers were prepared using three organochlorine pesticides—dieldrin (DE), endosulfan (EN), or hexachlorobenzene (HCB) as templates. The MIPs were polymerized via precipitation polymerization. The yields were over 90% with particle sizes ranging from 62 to 214 nm. Binding studies combined with GC‐ECD analysis showed that each template is more selective to its corresponding MIP compared with the other two structurally homologous templates. These results were consistent with those obtained using UV–vis where more bromocresol green (BCG) dye was released when higher template concentrations were introduced to the corresponding BCG‐impregnated MIPs. Since unique selectivity response pattern for each of the MIPs was obtained, this demonstrated that the MIPs were selective and can be potentially used in dye‐displacement array sensing. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44401.     

Increasing the adsorption capacity and selectivity of poly(vinyl alcohol) hydrogels by an alternative imprinting technique

In this work, we report an innovative alternative imprinting method for obtaining chemically crosslinked poly(vinyl alcohol) hydrogels with β‐cyclodextrin as template. The materials present high affinity toward the template that imprinted them, revealed by the higher sorption yield of β‐cyclodextrin and higher selectivity factors of the imprinted material, by comparing with the nonimprinted reference. The imprinting kinetic and mechanism has been demonstrated by adsorption studies, binding isotherms and Scatchard analysis and is in good correlation with the information regarding the morphology of the materials, determined by fluorescence microscopy and atomic force microscopy. By using a novel fluorescence spectroscopy method of the starting polymer solution, the optimum amount of imprinting template could be determined. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42024.     

杨梅黄素分子印迹聚合物的制备及其识别性能研究

以杨梅黄素(MYR)为模板分子、2-乙烯基吡啶(2-VP)为功能单体、二甲基乙二醇丙烯酸酯(EDMA)为交联剂,偶氮二异丁腈(AIBN)为引发剂,甲醇为致孔剂,采用分子印迹技术制备了杨梅黄素分子印迹聚合物(MYR-MIP)。通过红外光谱、扫描电镜、热重分析等技术表征了MYR-MIP的理化性能;采用紫外光谱分析研究了MYR-MIP对MYR的等温吸附和动力学吸附特性,研究结果表明MYR-MIP对MYR具有良好的特异性吸附,并且在2 h内达到平衡吸附;高效液相色谱分析表明MYR-MIP对MYR具有优良的选择识别特性。     

Synthesis of novel photoresponsive molecularly imprinted polymer microspheres with special binding properties

An azobenzene‐containing molecularly imprinting polymer microsphere with photoresponsive binding properties toward 2,4‐dichlorophenoxyacetic acid (2,4‐D) was successful prepared via silica surface polymerization. The number‐average diameters of silica and imprinting polymer microsphere are 0.5 and 0.7 μm, respectively. The static adsorption, binding and selectivity experiments were performed to investigate the adsorption properties and recognition characteristics of the polymers for 2,4‐D. The equilibrium adsorptive experiments indicated that 2,4‐D‐SMIP(surface molecularly imprinted polymers) has significantly higher adsorption capacity for 2,4‐D than its nonimprinted polymers (SNIP).The binding constant K_d and apparent maximum number Q_max of the imprinted polymer were determined by Scatchard analysis as 0.054 mmol L^?1 and 0.167 mmol g^?1_, respectively. The result of photoregulated release and uptake of 2,4‐D experiment demonstrated that azo‐containing SMIP can make use of light and change it into mechanical properties to release and take up the template molecules. It means that the SMIP can be controlled by light. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 869‐876, 2013     

Solvent‐free synthesis of chiral molecularly imprinted polymers: Porosity control using a nano‐sized solid porogen

Molecularly imprinted polymers (MIPs) have been synthesized in the absence of a solvent using fumed silica nanoparticles to create a porous network. The method employed led to a chiral imprinting effect and allowed for an excellent control over the internal morphology of imprinted and non‐imprinted polymer (NIP) materials. The polymers possess high surface areas (>300 m²) and identical pore size (112 Å). The MIP exhibited an imprinting factor (IF) of 9 and a selectivity value (α) of 1.83 for (?)‐ephedrine. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44104.     

Poly ionic liquid cryogel of polyethyleneimine: Synthesis,characterization, and testing in absorption studies

Here, we report the synthesis of polyethyleneimine (PEI) cryogels for the first time via cryopolymerization technique. The crosslinking of amine groups on the branched PEI chains is accomplished with epoxy groups of glycerol diglycidyl ether (GDE) based on epoxy–amine reactions in excess water at ?18 °C in about 16 h. Superporous PEI cryogels with pore sizes >100 μm were shown to have very fast equilibrium swelling behavior, e.g., 10 s to reach maximum swelling in DI water. Furthermore, the synthesized PEI cryogels were exposed to anion exchange reaction after protonation by HCl treatments to generate PEI ionic liquid cryogels containing hexafluorophosphate, thiocyanate, dicyanamide, and tetrafluoroborate. It was also demonstrated that PEI cryogels modified with [PF₆]^? absorbed 47.8 ± 5.7 mg/g of bovine serum albumin (BSA). Moreover, PEI cryogels were shown to be very useful as simple filtration filling materials for the direct removal of organic dyes such as methyl orange (MO) and eosin Y (EY) from their corresponding aqueous solutions with 98.5 and 98.6% yields, respectively. The separation of methylene blue (MB) from MO and EY mixture by using PEI cryogels as column filler materials was also demonstrated. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43478.     

Synthesis of macroporous polymer foams via pickering high internal phase emulsions for highly efficient 2,4,5‐trichlorophenol removal

Macroporous polymers foams (MPFs) were prepared by W/O Pickering high internal phase emulsions (HIPEs) stabilized by oleic acid (OA) modified silica nanoparticles (SPs), and then as‐prepared MPFs were applied to highly efficient adsorption of 2,4,5‐trichlorophenol (TCP). The characterization demonstrated that MPFs possessed macropore (50–150 μm) and interconnected pores (0.5–2 μm), and also had slightly hydrophobic nature (contact angle was 116°) and excellent thermal stability especially bellow 200°C. The influence of pH value, temperature, initial concentration, and contact time for the batch mode adsorption process was investigated, and the results showed that the maximum adsorption capacity and equilibrium time at 25°C were 167.7 mg g^?1 and 30 min, respectively. Moreover, the experimental data indicate that equilibrium isotherms for TCP fitted to the non‐linear Langmuir model, and both the adsorption and desorption kinetics can be represented by the pseudo‐second‐order model. The possible adsorption mechanism was considered to be the dispersion and hydrophobic interaction, simultaneously. The regeneration of the MPFs for one cycle was 94%. The results above strongly proved that this method reached the effect of highly efficient TCP removal. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41430.     

Molecular imprinting of dibenzothiophene using vinyl pyridine monomers: Fabrication and performance

Molecular imprinting process was proposed for the sulfur removal from fuels. The novel network‐structured molecularly imprinted polymers (MIPs) were fabricated by arranging 4‐vinyl pyridine functional monomers around dibenzothiophene template compounds, and fixing them with ethylene glycol dimethacrylate as crosslinking agent. The effects of dispersed phase, washing after treatment, content of template molecule, and crosslinking agent on the recognition ability of MIPs have been investigated. The practical performance is obtained by the FT‐IR, morphology, and thermal analysis as well as the recognition ability for dibenzothiophene under various feed sulfur concentrations and recognition time. The recognition ability of MIPs under 1000 mg/L feed sulfur concentration was 4.53 mg S/g. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44552.     

Fabrication and properties of anisotropic polyimide aerogels with aligned tube-like pore structure

Polyimide (PI) aerogels with highly aligned tube-like pores were fabricated by unidirectional ice crystal-induced self-assembly method. During this process, the mold bottom contacted with the freezing medium, the aqueous solution of poly(amic acid) (PAA) ammonium salt in the mold was unidirectionally frozen, the ice crystals grew from the bottom to top of PAA ammonium salt (PAS) solution along the freezing direction, which endowed PI aerogels with aligned tube-like pores after sublimation of ice crystals and thermal imidization of PAS. The obtained aerogels had low densities (0.077–0.222 g cm⁻³) and high porosities (83.8–94.2%) and exhibited anisotropic morphology and properties. Their compression strength in vertical direction (parallel to freezing direction) was higher than that in horizontal direction (perpendicular to freezing direction). Their heat transport in horizontal direction was much slower than that in vertical direction; the aerogels had better thermal insulating property in horizontal direction. This facile approach contributed to prepare new type of PI aerogel materials. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48769.     

Synthesis of polymer particles with specific lysozyme recognition sites by a molecular imprinting technique

To prepare silica beads covered with a lysozyme‐imprinted polymer layer, we polymerized acrylamide and acrylic acid or acrylamide and N,N‐dimethylaminopropylacrylamide with (NH₄)₂S₂O₈ in a phosphate buffer containing the lysozyme, surface‐modified silica beads, and crosslinkers; the result was the formation of a polymer layer with a lysozyme recognition site on the silica‐bead surface. By quantitative analysis of the supernatant of the solution containing the silica beads, we confirmed that modified silica beads, in contrast to unmodified silica beads, can selectively adsorb lysozymes. The process of binding and releasing the lysozyme to and from the modified silica beads can be repeated several times without degradation of the rebinding ability. A quartz‐crystal microbalance sensor fabricated with a molecularly imprinted polymer layer with a lysozyme recognition site was prepared. When a lysozyme aqueous solution was added to the solution in which the sensor was immersed, a high level of sensitivity and response was observed. High selectivity was also demonstrated by tests with other protein solutions. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3378–3387, 2001     

Dual application of cryogel as solid support in peptide synthesis and subsequent protein‐capture

The use of a cryogel in a combined application as a solid support for automated synthesis of a peptide ligand followed by affinity chromatography of a target protein is evaluated. The advantage, of synthesizing the ligand directly on the cryogel, is the circumvention of the standard process of synthesizing a peptide on a solid support, followed by cleavage, purification, analysis, and finally immobilization on the cryogel. To demonstrate the application, a peptide affinity ligand is synthesized directly on a cryogel with a yield of 28.4 μmol g^?1 dry polymer and purity of 45% of crude product. The affinity capture of an antipeptide antibody reveals a specific binding capacity of 0.86 mg g^?1 dry polymer. To further elucidate the general availability of a peptide ligand to a macromolecular interaction, a trypsin substrate is synthesized on a cryogel. Trypsin cleavage of immobilized substrate is determined to 1.5 μmol g^?1 dry polymer. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4383–4391, 2013     

硅胶衍生尼古丁印迹整体柱的制备及其识别

采用原位聚合并表面接枝制备了硅胶衍生尼古丁印迹整体柱。红外光谱和扫描电镜研究了聚合物的结构,基于尺寸排阻色谱原理测定了整体柱的总孔和微孔体积。在高效液相色谱系统中,考察了色谱条件对整体柱选择性的影响;用前沿色谱法测试了MIP整体柱的等温吸附,并研究了整体柱的吸附热力学。结果表明： MIP整体柱对尼古丁的选择因子相对8-羟基喹啉和吡啶分别为4.31和2.95;当流动相中pH值为7.5时,选择性最好;Freundlich模型比Langmuir模型更适合描述尼古丁在印迹整体柱上表面位点分布,位点异化指数为0.841;吸附热力学分析表明尼古丁在印迹整体柱上的自发放热吸附过程。     

Preparation and characteristics of a dummy molecularly imprinted polymer for phenol

A dummy molecularly imprinted polymers (DMIP) for phenol was synthesized by a thermal polymerization method with acrylamide as the functional monomer, ethylene dimethacrylate as the crosslinker, 2,2‐azobisisobutyronitrile as the free‐radical initiator, acetonitrile as the porogenic solvent, and sulfadiazine, a phenol analogue, as the template. In comparison to other adsorbents, the synthesized DMIP showed a higher capacity and rate of adsorption. The adsorption amount of the DMIP adsorbents for phenol reached 6.09 ± 0.15 mg/g, and the adsorption rate of the DMIP was about 0.406 ± 0.01 mg g^?1·min^?1. The results indicate that the Freundlich model fit the adsorption model of DMIP for phenol. The adsorption model of DMIP for phenol was multilayer adsorption. This showed that the DMIP synthesized by bulk polymerization could be used as a novel adsorbent for the removal of phenol from contaminated water. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Binding and recognition ability of molecularly imprinted polymer toward p-nitrophenol

p-Nitrophenol is a hazardous phenolic compound and its separation and determination is very necessary to protect public health and environmental quality. In this article, macromolecule polyethyleneimine (PEI) grafted on the surface of silica particles was crosslinked using p-nitrophenol as a template and diepoxyalkyl (669) as a crosslinking agent, and molecularly imprinted polymer on the surfaces of silica gel MIP-PEI/SiO₂ was prepared. The binding and recognition ability of MIP-PEI/SiO₂ for p-nitrophenol were researched using batch and dynamic methods. The experimental results showed that MIP-PEI/SiO₂ had high affinity, specific recognition ability, and excellent selectivity for p-nitrophenol. The saturated binding amount could reach to 155.5 mg g⁻¹. The selectivity coefficients relative to m-nitrophenol and chlorophenol were 45.80 and 117.5, respectively. The empirical Freundlich isotherm was found to describe well the equilibrium binding data. pH of sample solution was found to have a strong influence on the binding amount. MIP-PEI/SiO₂ was regenerated easily using diluted hydrochloric acid solution as eluent and MIP-PEI/SiO₂ possesses better reusability. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis of novel polyaniline/MgO composite for enhanced adsorption of reactive dye

In this investigation, the porous structure of polyaniline/MgO (PANI/MgO) composites has been successfully synthesized by in‐situ oxidative polymerization method. The as‐prepared materials were characterized by Ultraviolet–visible absorption spectroscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, and scanning electron microscopy. The obtained composites, for the first time, are used as an adsorbent for the removal of the sulfonated anionic dye reactive orange 16 (RO) from aqueous solution. The equilibrium adsorption isotherms of RO on the PANI/MgO composites were analyzed by Langmuir and Freundlich models, suggesting that the Langmuir model provides the better correlation of the experimental data and maximum adsorption capacity was found to be 558.4 mg g^?1. In addition, adsorption kinetics was followed by both pseudo‐first‐order and pseudo‐second‐order, but the latter model matches the results much better than the former one. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40210.     

Comparative analysis of atrazine molecularly imprinted polymers using acetonitrile and toluene as solvents

Acetonitrile and toluene are solvents commonly used for the synthesis of atrazine molecularly imprinted polymers (MIPs), but their effects have seldom been compared in the same imprinting system. In this paper, effects of the two solvents in an atrazine molecular imprinting system were evaluated theoretically and experimentally. A polarizable continuum model was adopted, and it was found that using the two solvents, the energy difference for the atrazine–methacrylic acid complex between vacuum and solution was not the same. The two types of MIPs prepared using different solvents vary in morphology, porosity, binding capacity, and specificity. All of these results suggest that the abilities of the solvents used to form hydrogen bonds with other compounds in the system are different. The porogen imprinting effect of the solvents also has an influence on binding capacity. Compared to MIPs synthesized using acetonitrile as solvent (MIPs-ACN), MIPs synthesized using toluene as solvent (MIPs-PhMe) have fewer but larger pores and exhibit much higher adsorption capability but less rigorous specificity. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47190.     

Self‐healing hydrogel of poly(vinyl alcohol)/graphite oxide with pH‐sensitive and enhanced thermal properties

Supramolecular hydrogel is a fascinating polymeric material composed of three‐dimensional noncovalent networks with many outstanding properties, especially reversible relevant performances. A self‐healing supramolecular hydrogel of poly(vinyl alcohol)/graphite oxide, with reversible pH responsiveness and good thermal stability, was prepared. The morphology, functional group changes, swelling performance, thermal stability, rheological performance, and self‐healing property of the PVA/GO hydrogel were investigated. A probable mechanism between the components and potential applications were also examined in our study. The experimental results show that the PVA/GO hydrogel was not only self‐healable without external stimulus or addition of any healing agents, but also pH sensitive and with good thermal stability. Green ingredients (PVA and GO) and a simple synthesis method (a freezing/thawing treatment) may pose little threat to the environment and also promote the production of such hydrogels. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46143.     

Preparation of ordered macroporous cinchonine molecularly imprinted polymers and comparative study of their structure and binding properties with traditional bulk molecularly imprinted polymers

Three‐dimensionally ordered macroporous molecularly imprinted polymers (MMIPs) were prepared by a combination of the colloidal crystal template method and the molecular imprinting technique. Traditional bulk molecularly imprinted polymers (BMIPs) were simultaneously synthesized with the same recipe as the MMIPs by using methacrylic acid as functional monomer, ethylene glycol dimethacrylate as crosslinker and chloroform as porogen. SEM and Brunauer ? Emmett ? Teller measurements show that MMIPs have a more regular macroporous structure, a narrower macropore distribution and a greater surface area and porosity compared with BMIPs. The isothermal and kinetic data of both polymers can be fitted with the Freundlich model and a pseudo‐second‐order equation, respectively. Their specificities to the template molecules are also similar. However, the binding capability, adsorption rate coefficient and internal effective diffusion coefficient of the MMIPs are higher than for the BMIPs when the particle size is above 54 µm. © 2015 Society of Chemical Industry     

Synthesis and properties of a ternary polyacrylate copolymer resin for the absorption of oil spills

A high‐oil‐absorption resin of a ternary copolymer for the absorption of oil spills was successfully prepared by suspension polymerization, and characterizations of the oil‐absorption resin were also examined in this study. The high‐oil‐absorption resin, a ternary copolymerized long‐chain polyacrylate with styrene (St), butyl methacrylate (BMA), and stearyl methacrylate (SMA) as the monomers and synthesized by suspension polymerization, was introduced. The oil‐absorption resin of St/BMA/SMA was characterized by Fourier transform infrared spectrometry. The particle morphology of the resin was observed by scanning electron microscopy. The effects of different polymerization technological parameters, such as the mass ratios of the monomer, the benzoyl peroxide initiator, and the crosslinking agent of divinylbenzene; the sort and concentrations of the dispersing agent of hydroxyl ethyl cellulose, sodium dodecyl benzene sulfonate, and gelatin, and the polymerization temperature, on the oil absorbency of St/BMA/SMA are discussed in detail. The optimum polymerization conditions of the St/BMA/SMA copolymer were obtained as follows: m_St/m_monomer = 50 wt %, m_BMA/m_{soft monomer} = 60 wt %, m_water/m_oil = 3:1, m_DVB/m_monomer = 1.0 wt %, m_BPO/m_monomer = 1.5 wt %, m_HEC/m_monomer = 0.07 wt %, m_SDBS/m_monomer = 0.03 wt %, m_gelatin/m_monomer = 0.14 wt % (where m is the mass), temperature = 85°C. With increasing content of these factors, the oil absorbency increased at first and then decreased. Compared with binary copolymer St/BMA prepared in previous research, the highest oil absorbencies to dichloromethane were 12.80 and 23.00 g/g in the St/BMA and St/BMA/SMA copolymers, respectively. St/BMA/SMA had a higher oil absorbency and faster oil‐adsorbing rate than St/BMA. The oil absorption in the oil–water mixture and the recovery of the resin were also studied in detail. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40180.