Copolymers Of 2-hydroxyethyl Methacrylate Research Articles

Investigation of polymer hydrogels with memory effect for cefazolin immobilization by small-angle neutron scattering

The method of small-angle neutron scattering has been used for the investigation of hydrogels synthesized on the basis of a cross-linked copolymer of 2-hydroxyethyl methacrylate and functional monomers (acrylic acid or dimethylaminoethyl methacrylate) which possess the memory effect with respect to the target pharmaceutical substance — cefazolin. The difference in the structure of anionic, cationic and amphiphilic hydrogels has been shown as well as the relation between the structure and the ability of a hydrogel for water sorption in the presence and in the absence of cefazolin. Certain structural features of the hydrogels confirmed the conditions for the appearance of the memory effect for the sorption and liberation of cefazolin.

Fabrication of Supramolecular Structured Hydrogels Based on Diels-Alder Click Reaction

A novel kind of supramolecular structrued hydrogels were fabricated by Diels-Alder click reaction between furan-functionalized polypseudorotaxanes and polymeric dienophiles. Firstly, polypseudorotaxanes were prepared by supramolecular self-assembly of furan-terminated poly(ethylene glycol)(PEG) and α-cyclodextrins (CDs) in water. And polymeric dienophiles were synthesized by a coupling reaction between copolymer of hydroxyethyl methacrylate and N,N-dimethyl acrylamide and N-maleoyl alanine (AMI). The supramolecular structured hydrogels were prepared by Diels-Alder reaction in water.

Synthesis, characterization and properties of amphiphilic block copolymers of 2-hydroxyethyl methacrylate and polydimethylsiloxane prepared by atom transfer radical polymerization

A series of amphiphilic poly(2-hydroxyethyl methacrylate)-b-polydimethylsiloxane-b-poly(2-hydroxyethyl methacrylate) (pHEMA-b-PDMS-b-pHEMA) (A-B-A) triblock copolymers were synthesized with varying block molecular weights. Control over the polymerization, micellar size and size distribution, dynamic mechanical properties, and film morphology of nine triblock copolymers was investigated as a function of block length. The polymerization resulted in copolymers with polydispersity index below 1.5. The self-assembly behavior of the triblock copolymers was studied in selective solvents for A and B blocks. The micellar diameter was determined by dynamic light scattering and transmission electron microscopy. The film morphologies were investigated by small angle X-ray scattering. Phase separation was observed when the blocks had similar molecular weights (symmetry). However, the ordering of the morphology was disrupted when the blocks lengths were asymmetric. Phase separation was observed by atomic force microscopy when the block molecular weights were symmetric. The viscoelastic properties were examined using dynamic mechanical analysis. The modulus and crosslink density increased with increasing pHEMA content. Number of aggregations is very small when THF was used compared with methanol and methanol–water. Aggregation of copolymers was difficult in THF due to back-folding and looping of PDMS block. This was unfavorable as it increases free energy of system. This probably resulted in higher CMC of pHEMA-b-PDMS-b-pHEMA copolymers in THF than in methanol. Micellar size of most of triblock copolymers in THF was smaller than in methanol.

Biomimetic Silver-Containing Colloids of Poly(2-methacryloyloxyethyl phosphorylcholine) and Their Film-Formation Properties

The synthesis of stable dispersions of hybrid colloids comprising copolymers of biocompatible 2-hydroxyethyl methacrylate (HEMA) and zwitterionic, biomimetic 2-methacryloyloxyethyl phosphorylcholine (MPC) incorporating antibacterial AgBF(4) by inverse miniemulsion is described. The prepared hybrid colloids were designed to provide both antibacterial and antifouling properties for the formation of interesting, multifunctional films. The obtained particles had sizes in the range of 130-160 nm with two different weight ratios of MPC to HEMA (1:10 and 2:5) and AgBF(4) contents between 0% and 15%. The silver salt takes on the role of the lipophobe in stabilizing the miniemulsion droplets against Ostwald ripening and is reduced after polymerization to Ag nanoparticles by gaseous hydrazine. Subsequently, the hybrid particles are transformed into smooth and stable films with thicknesses between 145 and 225 nm by simple drop casting and solvent annealing. The dispersions and films were thoroughly characterized by DLS, TEM, SEM, EDX, TGA, UV-vis spectroscopy, ICP-OES, XRD, AFM, and contact angle measurements. After immersion into water, the films did not show detectable leakage of silver, so they could be employed as dual-functional antifouling and antibacterial coatings.

Preparation, characterization, and drug‐release properties of PEG‐DA‐based copolymer hydrogel microspheres

AbstractThe research was to design a carrier used in tissue engineering and drug‐release system. In this article, a new dispersion polymerization system without organic solvent was described to prepare poly(ethylene glycol) diacrylate/2‐hydroxyethyl methacrylate (PEG‐DA/HEMA) copolymer hydrogel microspheres as carrier, which introduced chitosan (CS) as reaction medium and costabilizer, polyvinylpyrrolidone (PVP) as steric stabilizer and benzoy peroxide (BPO) as initiator. The effects of mass ratios of monomers, concentration of stabilizer and initiator on partilcle size and polydispersity index (PDI) of microspheres were investigated. Furthermore, bovine serum albumin (BSA) as protein model, the composition of copolymer, size, and polydispersity index of microspheres were employed to study the amount and released ratio of loaded BSA in this article. The results showed that hydrogel microspheres with 3.26 ± 0.24 μm in particle size and 1.03 ± 0.008 in PDI, obtained with mass ratios of PEG‐DA 60/HEMA 40, 2 wt % of stabilizer content and 2 wt % of initiator content (relative to total mass of monomers), had 124.57 ± 3.14 mg/g in the amount of loaded BSA and 59.09 ± 1.43% of released ratio. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Immobilization of lysozyme on poly(N-isopropyl acrylamide)/2-hydroxyethyl methacrylate copolymer core–shell gel beads

The immobilization of chicken egg white lysozyme (Lyz) molecules on poly(N-isopropyl acrylamide) gel beads containing 2-hydroxyethyl methacrylate (HEMA) (PGBH) was studied as a function of temperature and HEMA content. Using dynamic and static light scattering measurements, nanometer-sized PGBH particles were shown to exhibit thermo-responsive behavior, and aggregate formation occurred during temperature changes from 25 to 40 °C. The radii of PGBH and Lyz-immobilizing PGBH, the amount of immobilized Lyz and the activity of immobilized Lyz depended on both HEMA content and temperature. Moreover, the activity of immobilized Lyz also depended on the molecular size of the substrates, and the Lyz immobilized on PGBH particles with higher HEMA content showed activity toward low molecular weight substrates at 40 °C nearly equal to that of native Lyz, which indicates that no conformational change in the Lyz molecule occurred after immobilization. These results demonstrate that changes in the activity of the immobilized Lyz were due to a balance of an increase in the affinity between the substrate and Lyz resulting from concentration effects and the steric hindrance between the substrate and Lyz incorporated into the PGBH aggregates with increasing HEMA content and temperature. Furthermore, these results demonstrate that PGBH is a useful material as an enzyme immobilization carrier.

Influence of gradient strength and composition profile on the onset of the cloud point transition in hydroxyethyl methacrylate/dimethylaminoethyl methacrylate gradient copolymers

We examined the onset of the cloud point in dilute aqueous solutions of gradient copolymers of 2-hydroxyethyl methacrylate and dimethylaminoethyl methacrylate. Dynamic Light Scattering (DLS) and transmittance measurements both indicate that the copolymer solution cloud point decreases with increasing copolymer gradient strength, defined as the largest difference in the instantaneous composition along the copolymer. While transmittance measurements suggest that macroscopic clouding does not set in until 30% of the polymer chain becomes insoluble, DLS experiments, which are more sensitive to the onset of aggregation, indicate that the onset of aggregation occurs at the point where the least soluble polymer chain end becomes insoluble. Collectively, our data indicate that the macroscopic cloud point transition is highly sensitive to co-monomer sequence distribution of the copolymers, with its onset and transition breadth tunable through copolymer gradient strength.

Preparation of PHEMA Copolymers Containing Cell-binding Peptides as Graft Chains and Their Cell Adhesive Properties

In this study, poly(2-hydroxyethyl methacrylate) (PHEMA) copolymers containing cell-binding peptides (Arg-Gly-Asp-Ser (RGDS), Pro-His-Ser-Arg-Asn (PHSRN) or PHSRNG6RGDS) as graft chains were newly designed and prepared by radical copolymerization of HEMA with various peptide-macromonomers, which were prepared by solid phase synthesis using Fmoc-chemistry. Thin films of these copolymers were prepared on PSt-dishes by spin-coat method and their interaction with NIH/3T3 cells were investigated. Cell adhesive properties onto these copolymer films were found to depend strongly on the type of peptides and copolymer composition. More interestingly, PHSRNG6RGDS segment, at which PHSRN and RGDS epitopes were connected through Gly spacer, showed most effective cell adhesion and spreading properties in the series of PHEMA copolymers. These results should provide useful information to construct novel peptide-based nano-surfaces for the design of artificial extra cellular matrix.

New crosslinked hydrogels derivatives of 2-hydroxyethyl methacrylate: Synthesis, modifications and properties

This paper presents the synthesis, physicochemical properties and modifications of 2-hydroxyethyl methacrylate copolymers. It describes the new 2-hydroxyethyl methacrylate hydrogels in the form of microbeads of different degrees of crosslinking (2, 5, 8, 10, 15 and 20% mol). As crosslinking monomers bis(4(2-hydroxy-3-methacryloyloxypropoxy) phenyl)-sulfide and ethylene glycol dimethacrylate were used. The new hydrogels were obtained by two alternative meth- ods in a suspension copolymerisation procedure. The copolymers were modified with diethylenetriamine in an epoxide opening reaction. Thermal properties (differential scanning calorimetry, thermogravimetric analysis) and swelling charac- teristic in typical solvents of the obtained functional hydrogels were examined. The chemical structure of the copolymers before and after modification was confirmed by Fourier transform infrared spectroscopy and elemental analyses. Moreover, their sorptive properties in removal of Cu(II), Zn(II), Cd(II), and Pb(II) ions from aqueous solutions were also presented. The Langmuir and Freundlich isotherm models are used to describe the adsorption characteristics of the selected modified hydrogels.

Bioactive support for cell cultivation and potential grafting. Part 1: Surface modification of 2-hydroxyethyl methacrylate hydrogels for avidin immobilization

AbstractSynthetic hydrogels are often used in biomedical applications as many of them are compatible with living tissue and moreover they can meet most criteria for artificial tissue properties. For applications in tissue engineering modification of polymer surface using some bioactive compounds (e.g. saccharides, proteins) for promoting the process of cell adhesion and proliferation is widely used. In this work, a series of modified hydrogels was prepared by three different methods: by copolymerization of 2-hydroxyethyl methacrylate with methacrylic acid, by hydrolysis and oxidation of poly(2-hydroxyethyl methacrylate) to obtain carboxyl-rich supports. The influence of the reaction conditions of the hydrogel surface treatment on the total carboxylic group content and the swelling degree was studied. The modified hydrogels were characterized by attenuated total reflectance FT-IR spectroscopy and refractive index measurements. Obtained carboxylic groups on the hydrogel surface have allowed the immobilization of avidin in two ways: 1) electrostatically through dissociated carboxylic groups and 2) covalently bonded through activated carboxylic groups by Nhydroxysuccinimide. The capacity of hydrogels for avidin immobilization was determined by Bradford spectrophotometric method. The results so far obtained from the preliminary biological tests showed that immobilized avidin on the hydrogel surface provides better adhesion and proliferation of keratinocytes compared to supports without avidin.

The influence of the synthesis pressure on the chromatographic properties of poly(divinylbenzene-co-ethylvinylbenzene-co-2-hydroxyethyl methacrylate) monolithic columns

Monolithic columns based on copolymer of divinylbenzene (DVB), ethylvinylbenzene (EVB), and 2-hydroxyethyl methacrylate (HEMA) were prepared and applied to the separation of low-molecular-weight aromatic compounds. The monoliths were synthesized via thermally initiated free-radical polymerization in confines of stainless steel tubes with dimensions of 100 × 4.3 mm. In order to compensate for the polymer shrinkage during the synthesis and prevent the monolith from detachment from the column wall, the polymerization was conducted under nitrogen pressure. The excess pressure was varied from 0 bar to 9 bar. The synthesis under pressure was shown to improve the peak shapes and column efficiency in comparison with the synthesis in the closed tube. The optimum pressure for poly(DVB-co-EVB-co-HEMA) monoliths was found to be 3 bar. The efficiency of the column obtained at 3 bar is 13 500 TP/m for propylbenzene (k′ = 6) and 38 300 TP/m for uracil (k′ = 0).

Small-angle neutron scattering from polymer hydrogels with memory effect for medicine immobilization

Hydrogels synthesized based on cross-linked copolymers of 2-hydroxyethyl methacrylate and functional monomers (acrylic acid or dimethylaminoethyl methacrylate), having a memory effect with respect to target medicine (cefazolin), have been investigated by small-angle neutron scattering. The hydrogels are found to have a two-level structural organization: large (up to 100 nm) aggregates filled with network cells (4–7 nm in size). The structural differences in the anionic, cationic, and amphiphilic hydrogels and the relationship between their structure and the ability of hydrogels to absorb moisture are shown. A relationship between the memory effect during cefazolin immobilization and the internal structure of hydrogels, depending on their composition and type of functional groups, is established.

The Copolymer P(HEMA-co-SS) Binds Gluten and Reduces Immune Response in Gluten-Sensitized Mice and Human Tissues

Copolymers of hydroxyethyl methacrylate and styrene sulfonate complex with isolated gliadin (the toxic fraction of gluten) and prevent damage to the intestinal barrier in HLA-HCD4/DQ8 mice. We studied the activity toward gluten and hordein digestion and biologic effects of poly(hydroxyethyl methacrylate-co-styrene sulfonate (P(HEMA-co-SS)). We also investigated the effect of gliadin complex formation in intestinal biopsy specimens from patients with celiac disease. We studied the ability of P(HEMA-co-SS) to reduce digestion of wheat gluten and barley hordein into immunotoxic peptides using liquid chromatography-mass spectrometry. The biodistribution and pharmacokinetic profile of orally administered P(HEMA-co-SS) was established in rodents using tritium-labeled polymer. We assessed the capacity of P(HEMA-co-SS) to prevent the immunologic and intestinal effects induced by a gluten-food mixture in gluten-sensitized HLA-HCD4/DQ8 mice after short-term and long-term administration. We measured the effects of gliadin complex formation on cytokine release ex vivo using intestinal biopsy specimens from patients with celiac disease. P(HEMA-co-SS) reduced digestion of wheat gluten and barley hordein in vitro, thereby decreasing formation of toxic peptides associated with celiac disease. After oral administration to rodents, P(HEMA-co-SS) was predominantly excreted in feces, even in the presence of low-grade mucosal inflammation and increased intestinal permeability. In gluten-sensitized mice, P(HEMA-co-SS) reduced paracellular permeability, normalized anti-gliadin immunoglobulin A in intestinal washes, and modulated the systemic immune response to gluten in a food mixture. Furthermore, incubation of P(HEMA-co-SS) with mucosal biopsy specimens from patients with celiac disease showed that secretion of tumor necrosis factor-α was reduced in the presence of partially digested gliadin. The copolymer P(HEMA-co-SS) reduced digestion of wheat gluten and barley hordein and attenuated the immune response to gluten in a food mixture in rodents. It might be developed to prevent or reduce gluten-induced disorders in humans.

EPR study of radical annihilation kinetics of γ-ray-irradiated acrylic (PMMA) at elevated temperatures

High-energy irradiations of polymers may cause bond cleavage or crosslinking and change the structures and physical properties of the polymers, which may offer various applications. Despite wide investigation, relationship between the kinetics and mechanism of annihilation after irradiations and the structure and some physical properties of irradiated polymers is still poorly established. We have been exploring such possible relationship and report herein investigation of the kinetics of radical annihilation of γ-ray irradiated acrylic, i.e., poly(methylmethacrylate) or PMMA, at elevated temperatures with EPR spectroscopy. The EPR spectra consist of three components, a quintet Ra, a quartet Rb, and a broad singlet Rc. Ra and Rb follow second-order annihilation kinetics, while the decay of the radical Rc is comprised of at least two parallel kinetic processes, a slow second-order pathway and a fast pathway which can be equally well fitted to first- or second-order kinetics. The kinetics is analogous to that for the radical decays in irradiated 2-hydroxyethyl methacrylate copolymer. On the basis of the large hyperfine coupling constant of 2.3 mT, Ra may be assigned to a radical adjacent to two groups of protons, such as a doublet of quartet with similar coupling constants due to an anti-methylene proton and a methyl group; the Rb signal, possibly a methyl radical; and the broad singlet Rc, a magnetically coupled combination species. Alternative assignments of the radicals have also been suggested. The rate constant increases with increasing dose for each radical at a given temperature, possibly due to increase in radical concentrations at higher doses. The rate constants satisfy the Arrhenius equation, suggesting a single mechanistic pathway for the annihilation process in the temperature range; wherein the activation energy decreases with increasing dose for all radicals, possibly due to higher concentrations of free radicals in close proximity produced at higher doses.

Nano-network with dual temperature and pH responsiveness based on copolymers of 2-hydroxyethyl methacrylate with 3,9-divinyl-2,4,8,10-tetraoxaspiro[5.5]-undecane

This study refers to the synthesis of a nano-network with dual temperature and pH responsiveness based on the 2-hydroxyethyl methacrylate (HEMA) copolymers with a comonomer with spiroacetal moiety and crosslinking capacity, namely 3,9-divinyl-2,4,8,10-tetraoxaspiro[5.5]-undecane (U). The copolymers were synthesized by radical emulsion polymerization, using 4,4′-azobis(cyanopentanoic acid) as initiator, in the presence of sodium lauryl sulfate as tensioactive agent and poly(vinyl alcohol) as protective colloid. Three copolymer variants were taken into study resulted from the different ratio between the comonomers (HEMA/U), which was about 98/2, 95/5, and 90/10, respectively. The copolymers were characterized by FTIR and thermal analysis. The copolymers sensitivity was evidenced by studying the evolution of the hydrodynamic radius and zeta potential of the polymeric particles as a function of pH. Thus, the particles size increases with the comonomer amount, from 193 nm in case of the homopolymer up to 253 nm for the copolymer with maximum content of the comonomer (10%). The increase of the particle hydrodynamic radius with the growth of temperature was also put into evidence.

Synthesis of full and semi Interpenetrating hydrogel from polyvinyl alcohol and poly (acrylic acid‐co‐hydroxyethylmethacrylate) copolymer: Study of swelling behavior, network parameters, and dye uptake properties

AbstractSemi and full interpenetrating network (IPN) hydrogels were synthesized by allowing free radical copolymerization of acrylic acid (AA) and hydroxyethyl methacrylate (HEMA) in the matrix of polyvinyl alcohol (PVOH). Accordingly, four different semi IPN hydrogels were prepared with PVOH: copolymer mass ratio of 1 : 1, 1 : 0.75, 1 : 0.5, and 1 : 0.25. These hydrogels were designated as SEMIIPN1, SEMIIPN2, SEMIIPN3, and SEMIIPN4, respectively. In all of these SEMIIPN, after polymerization PVOH was crosslinked with 2 mass % glutaraldehyde to form the semi IPN structure. In a similar way, sequential full IPN were prepared from PVOH and copolymer of AA and HEMA (designated as PAAHEMA) with same composition except in this case apart from crosslinking of PVOH by 2 mass % glutaraldehyde the PAAHEMA copolymer was further crosslinked with N,N′‐methylenebisacrylamide (NMBA) to produce four full IPN hydrogels designated as FULLIPN1, FULLIPN2, FULLIPN3, and FULLIPN4. All of these semi and full IPN type hydrogels were characterized by carboxylic %, FTIR, UV, DTA‐TGA, XRD, SEM, and mechanical properties. The network parameters, swelling and diffusion characteristics of these hydrogels were also studied. The performance of these semi and full IPNs were compared in terms of their relative abilities for removing varied concentration of rhodamine B (RB) and methyl Violet (MV) dyes from water. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Wetting Behavior of Oleophobic Polymer Coatings Synthesized from Fluorosurfactant-Macromers

Architecturally similar monomers were copolymerized with a water-oil discriminate fluorosurfactant to create hydrophilic-oleophobic coatings. Acrylic acid, hydroxyethyl methacrylate, and methyl methacrylate were used as comonomers with the fluorosurfactant macromer. The homopolymers of the selected comonomers are water-soluble, water-swellable, and water-insoluble, respectively, thus coupling the surfactant monomer in varying concentration within polymers of varying hydrophilicity. Wetting behavior of water and hexadecane were examined as a function of copolymer composition, thus revealing critical structure-property relationships for the surfactant-based system. Acrylic acid copolymers and hydroxyethyl methacrylate copolymers both exhibited a hexadecane contact angle which exceeded the water contact angle. This condition predicted an ability to "self-clean" oil-based foulants. The most oleophobic of the self-cleaning copolymers had an advancing hexadecane contact angle of 73° and an advancing water contact angle of 40°. It was determined that the advancing and receding water and hexadecane contact angle response varies montonically for each copolymer type as the surface concentration of the surfactant is varied. Comparing between copolymer types revealed large differences in wetting response. Methyl methacrylate copolymers with 2.8 mol % surfactant had advancing water contact angle 82° and advancing hexadecane contact angle 26°, which is neither oleophobic nor self-cleaning. In contrast, acrylic acid copolymers with 3.1 mol % surfactant had advancing water contact angle of 44° and advancing hexadecane contact angle of 52°, creating a self-cleaning coating. Thus, the nature of the comonomer exerts a greater influence than the surfactant content on the wetting behavior and self-cleaning ability of the final coating.

Surface-Initiated Polymerization of 2-Hydroxyethyl Methacrylate from Heterotelechelic Oligoperoxide-Coated γ-Fe2O3 Nanoparticles and their Engulfment by Mammalian Cells

Novel heterotelechelic poly(N-vinylpyrrolidone) (CPA-PVP-IBMB) oligoperoxide containing anchoring carboxyl group from 4-cyanopentanoic acid (CPA) and peroxide end-group from 1-isopropyl-3(4)-[1-(tert-butyl peroxy)-1-methylethyl]benzene (IBMB) chain transfer agent was synthesized and investigated as a surface-active macroinitiator for tailored functionalization of maghemite (γ-Fe2O3) nanoparticles. CPA-PVP-IBMB initiated polymerization of 2-hydroxyethyl methacrylate (HEMA) in ethanol yielding CPA-PVP-block-poly(2-hydroxyethyl methacrylate) (CPA-PVP-block-PHEMA) copolymer. γ-Fe2O3 nanoparticles obtained by precipitation technique were modified by the CPA-PVP-IBMB macroinitiator and CPA-PVP-block-PHEMA copolymer by “grafting-to” approach to the surface using carboxyl end groups of both polymers. Second method, “grafting-from” approach, consisted in polymerization of HEMA initiated from the surface of CPA-PVP-IBMB-coated γ-Fe2O3 nanoparticles yielding CPA-PVP-IBMB-coated γ-Fe2O3/PHEMA nanoparticles. Tests wit...

Encapsulated hydrophilic polymer beads containing indomethacin as controlled release drug delivery systems.

Encapsulated hydrophilic polymer beads containing indomethacin were prepared by a combined technique of bead polymerization and phase separation. The drug delivery system consisted of the copolymer of 2-hydroxyethyl methacrylate and acrylamide as the core matrix and ethyl cellulose as the barrier membrane. The drug was incorporated into the polymer matrix during the formation of the beads. The system was found to be useful as a sustained release dosage form. Release of drug from the coated beads followed a zero-order rate up to 40% of the drug released. A linear relationship exists between the rate of release and the reciprocal amount of ethyl cellulose used for coating, indicating that the drug release was controlled by the coating thickness. Addition of polyvinyl pyrrolidone in the formulation significantly increased the amount of drug released. Blood level studies showed that drug absorption from the encapsulated beads was lower than that of indomethacin powder. It appeared that indomethacin was completely absorbed from the encapsulated beads.

Polymer hydrogels with the memory effect for immobilization of drugs

Hydrogels with the memory effect are synthesized from crosslinked copolymers of 2-hydroxyethyl methacrylate and functional monomers (acrylic acid or dimethylaminoethyl methacrylate) via the method of template synthesis with the use of the drug cephazoline as a matrix. It is shown that the hydrogels show an increased sorption activity against the target drug and a slow rate of drug release from the hydrogel (the memory effect) under certain conditions. In combination with cephazoline, these hydrogels may be regarded as a new prolonged-drug-release system for the treatment of infectious diseases.