Poly Ethylene Glycol Methacrylate Research Articles

Engineering of new crosslinked functional PEG micrometer-sized particles of narrow size distribution for enzyme immobilization

New functional crosslinked poly(ethylene glycol) (PEG) micrometer-sized particles of narrow size distribution were prepared by dispersion co-polymerization in an aqueous continuous phase of the monomers methacrylate polyethylene glycol carboxylic acid (MA-PEG-COOH) or methacrylate polyethylene glycol amine (MA-PEG-NH2) with polyethylene glycol methacrylate ether (MA-PEG-OCH3) and the crosslinker monomer polyethylene glycol dimethacrylate (PEDMA). The effect of various polymerization parameters, e.g., total monomer concentration, crosslinker monomer concentration, initiator concentration and stabilizer concentration and Mw on the size, size distribution and polymerization yield of the produced particles has been studied. As a model for enzyme immobilization, trypsin was covalently bound to the functional PEG particles. A substantial loss in the activity and an increase in the stability of the conjugated enzyme, as compared to the free one, were demonstrated.

Physicochemical and biological evaluation of poly(ethylene glycol) methacrylate grafted onto poly(dimethyl siloxane) surfaces for prosthetic devices

Poly(dimethyl siloxane) (PDMS) was surface-polymerized with poly(ethylene glycol)methacrylate (PEGMA) by surface-initiated atom transfer radical polymerization (SI-ATRP) in aqueous media at room temperature. Modification of the PDMS surface followed a three-step procedure: (i) PDMS surface hydroxylation by UV/ozone exposure, immediately followed by (ii) covalent attachment of the initiator, 1-trichlorosilyl-2-(chloromethylphenyl)ethane, onto the hydroxylated PDMS, via chemical vapor deposition; finally (iii) PDMS surface-polymerization of PEGMA by ATRP. Modified PDMS was characterized by water contact angle measurement, SEM, FTIR-ATR, and XPS. Results showed that modified surfaces had a hydrophilic character, given the water contact angles around 60°; FTIR-ATR and XPS analysis confirmed the presence of polymerized PEGMA on the surface of PDMS and the adhesion of Staphylococcus aureus GB 2/1 and Streptococcus salivarius GB 24/9 onto the modified surfaces was inhibited 94% and 81%, respectively. Finally, the modified PDMS showed no evidence of cytotoxic effects in in vitro assays using human skin fibroblasts.

Variations in polyethylene glycol brands and their influence on the preparation process of hydrogel microspheres

Hydrogel microspheres, e.g. for the use as protein carriers, can be prepared without the use of organic solvents via an emulsified aqueous two-phase system (ATPS) that is based on two immiscible polymer solutions. The type and concentration of the polymers can affect the ATPS and finally the distribution of incorporated drugs between the aqueous phases. For the preparation of hydrogel microspheres based on hydroxyethyl starch–hydroxyethyl methacrylate (HES–HEMA), hydroxyethyl starch–methacrylate (HES–MA), and hydroxyethyl starch–polyethylene glycol methacrylate (HES–P(EG)6MA), polyethylene glycol 12,000 (PEG 12,000) was used as second polymer. The particle size distribution and encapsulation efficiency of the microspheres depended dramatically on the type of PEG 12,000 that was used in the second phase of the ATPS. Analysis of different PEG 12,000 brands by various methods revealed differences in the salt composition and molecular weight distribution of the polymers which can explain the effects on the production process. The results illustrate that the range of product specifications may not always be tight enough to avoid variability in pharmaceutical processes like the preparation of hydrogel microspheres by an aqueous two-phase preparation process.

Polycarboxylate-Lignosulfonate Copolymerized High Performance Water Reducing Agent: Preparation and Application

A new polycarboxylate-lignosulfonate copolymerized high performance water reducing agent (PCL) was synthesized by polymerizing self-made methoxy polyethylene glycol methacrylate (MPEGMA), methacrylic acid (MAA), lignosulfonate (LS) and sodium methyl acryl sulfonate (SMAS) in aqueous solution. Influence of LS dosage used in synthesis on the performance of the product was investigated. The performance of the new polymer and compounds prepared by polycarboxylate based superplasticizer (PC) and LS were compared, which revealed that the former has better properties of plasticizing and strength improving. Engineering applications indicated that concrete incorporating the new superplasticizer has advantages on its cohesiveness and pumpability. Moreover, it’s not easy to bleed, segregate and stick to the ground.

Injection Moulding of Tungsten Carbide-Nickel Powders Prepared by Electroless Deposition

Tungsten carbide with nickel (WC-Ni) is generally used in applications in which high wear and corrosion resistance are required. In most cases, WC is mixed with Ni powder through a powder-processing route. In the present study, an electroless deposition technique was employed in order to prepare Ni coated WC particles prior to forming specimens by powder injection moulding method. The starting WC powders were subjected to surface activation followed by electroless Ni coating. The effects of a variety of processing parameters, including coating time and powder to electrolyte content ratio, were examined. The characteristics of the prepared powders were assessed by scanning electron microscopy and laser particle size analysis. It has been found that the fabrication of WC powder coated with Ni can be achieved through the electroless deposition technique. The amount of Ni introduced to the WC particles can be controlled by the powder to electrolyte content ratio and the deposition duration. The use of small particle loadings can ensure relatively large deposition and uniformity of the coatings. It is widely known that powder injection moulding (PIM) is an effective process for fabrication of small and complex shaped components of high performance materials. The PIM process includes 4 main steps: feedstock preparation, injection moulding, debinding and sintering. In this work, the WC-Ni powders were mixed with polyethylene glycol (PEG) and polymethyl methacrylate (PMMA) binder to form feedstock for injection moulding. The injection moulding process was carried out by a laboratory scaled, plunger-type machine. The mouldings were subjected to debinding and sintering. It was found that the PEG could be removed by water leaching. Specimens retained their shapes during and after leaching of the PEG. The remaining binder could be removed through pyrolysis. The mouldings were sintered under vacuum at 1400 °C for 1 hour. The sintered density achieved was at 88% of the theoretical value due to the low powder loading employed in the study.

Preliminary studies on pH-sensitive hydrogels and in vitro release profiles of two model drugs

The main aim of the present study was to develop a series of pH-sensitive hydrogels for targeted releasing drugs under simulated intestinal environment instead of stomach condition. These hydrogels were prepared via free radical polymerization with polyethylene glycol methacrylate 475 (PEGMA475), PEGMA950 and methacrylic acid as monomers, triethylene glycol dimethacrylate (TRGDMA), and ethylene glycol dimethacrylate as cross-link agents. The surface morphology and internal structures of hydrogels were detected by scanning electron microscope. The swelling experiments were also performed and the results revealed that the smart hydrogels were pH sensitive and their sensitiveness was reversible. Diclofenac sodium and bull serum albumin used as model drugs were loaded in the hydrogels to target releasing them in simulative intestinal tract. In vitro releasing studies showed that medicated hydrogels released model drugs slowly in acid conditions (pH 1.2), while the cumulated release amounts of drugs increased greatly when ambient pH value increased to 7.4. These phenomena indicated that these hydrogels tended to target release stimulating and destructible drugs in intestinal canal instead of gastric environment.

Optimised ‘on demand’ protein arraying from DNA by cell free expression with the ‘DNA to Protein Array’ (DAPA) technology

We have previously described a protein arraying process based on cell free expression from DNA template arrays (DNA Array to Protein Array, DAPA). Here, we have investigated the influence of different array support coatings (Ni-NTA, Epoxy, 3D-Epoxy and Polyethylene glycol methacrylate (PEGMA)). Their optimal combination yields an increased amount of detected protein and an optimised spot morphology on the resulting protein array compared to the previously published protocol. The specificity of protein capture was improved using a tag-specific capture antibody on a protein repellent surface coating. The conditions for protein expression were optimised to yield the maximum amount of protein or the best detection results using specific monoclonal antibodies or a scaffold binder against the expressed targets. The optimised DAPA system was able to increase by threefold the expression of a representative model protein while conserving recognition by a specific antibody. The amount of expressed protein in DAPA was comparable to those of classically spotted protein arrays. Reaction conditions can be tailored to suit the application of interest. DAPA represents a cost effective, easy and convenient way of producing protein arrays on demand. The reported work is expected to facilitate the application of DAPA for personalized medicine and screening purposes.

Adhesion of endothelial cells and endothelial progenitor cells on peptide-linked polymers in shear flow.

The initial adhesion of human umbilical vein endothelial cells (HUVECs), cord blood endothelial colony-forming cells (ECFCs), and human blood outgrowth endothelial cells (HBOECs) was studied under radial flow conditions. The surface of a variable shear-rate device was either coated with polymer films or covered by synthetic fibers. Spin-coating was applied to produce smooth polymer films, while fibrous scaffolds were generated by electrospinning. The polymer was composed of hexyl methacrylate, methyl methacrylate, poly(ethylene glycol) methacrylate (PEGMA), and CGRGDS peptide. The peptide was incorporated into the polymer system by coupling to an acrylate-PEG-N-hydroxysuccinimide comonomer. A shear-rate-dependent increase of the attached cells with time was observed with all cell types. The adhesion of ECs increased on RGD-linked polymer surfaces compared to polymers without adhesive peptides. The number of attached ECFCs and HBOECs are significantly higher than that of HUVECs within the entire shear-rate range and surfaces examined, especially on RGD-linked polymers at low shear rates. Their superior adhesion ability of endothelial progenitor cells under flow conditions suggests they are a promising source for in vivo seeding of vascular grafts and shows the potential to be used for self-endothelialized implants.

Synthesis and characterization of NIR-responsive Aurod@pNIPAAm-PEGMA nanogels as vehicles for delivery of photodynamic therapy agents

A near-infrared (NIR)-responsive Aurod@pNIPAAm-PEGMA nanogel was synthesized in two steps, growing a PEGMA monolayer on the surface of gold nanorods (AuNRs), followed by in situ polymerization and cross-linking of N-iso-propylacrylamide (NIPAAm) and poly-(ethylene glycol)-methacrylate (PEGMA). The AuNRs and Aurod@pNIPAAm-PEGMA nanogel were characterized by UV–vis spectroscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, and transmission electron microscopy, respectively. The lower critical solution temperature of the Aurod@pNIPAAm-PEGMA nanogel could be tuned by changing the molar ratio of NIPAAm/PEGMA. The NIR-mediated drug release behavior of the Aurod@pNIPAAm-PEGMA nanogel was studied with zinc phthalocyanines (ZnPc4) as a drug model. It was also demonstrated that the loaded ZnPc4 could keep the capability of generating singlet oxygen, and the in vitro study showed a great photodynamic therapy (PDT) effect on Hela cells. It thus indicated the potential of this Aurod@pNIPAAm-PEGMA nanogel for application as a drug carrier in PDT, which might make contributions to oncotherapy.

Selectively grafting polymer from the interior and/or exterior surfaces of bioreducible and temperature-responsive nanocapsules

A novel strategy is reported for selectively grafting polymer brushes from the interior and/or exterior surfaces of bioreducible and temperature-responsive nanocapsules. Poly(N-isopropylacrylamide-co-poly(ethylene glycol) methacrylate) (P(NIPAM-co-PEGMA)) nanocapsules with hydroxyl groups at the interior surface, exterior surface or both surfaces were first prepared via seeded precipitation copolymerization of N-isopropylacrylamide and poly(ethylene glycol) methacrylate using N,N′-cystaminebisacrylamide (CBA) as the shell crosslinker, respectively. The location of hydroxyl groups at the interior surface or exterior surface or both surfaces was controlled via the addition time of poly(ethylene glycol) methacrylate (PEGMA). Then, Ce4+/mediated redox initiated polymerization was used to graft poly(2-(dimethylamino)ethyl acrylate) (PDMAEA) brushes from the surfaces of P(NIPAM-co-PEGMA) nanocapsules with the selectivity of the grafting position (the interior and/or exterior surfaces) being controlled via hydroxyl location. The resulting nanocapsules are temperature, pH and redox responsive.

Waterborne polymer nanogels non-covalently crosslinked by multiple hydrogen bond arrays

Synthetic colloidal hydrogel particles of sub-micron dimensions, often referred to as microgels and/or nanogels, generally consist of water-soluble polymers held together through chemical crosslinking by covalent bonds in order to preserve the distinct colloidal particle identity. Here we demonstrate the synthesis of non-covalently crosslinked nanogel particles in which the crosslinking through covalent bonds is replaced by physical crosslinking induced by strong self-complementary quadruple hydrogen bond interactions. The multiple hydrogen bond (MHB) arrays were introduced in the form of a 2-ureido-4[1H]pyrimidinone (UPy) functionalized polyethylene glycol methacrylate (PEGMA) comonomer, which was employed in the synthesis of colloidal nanogels made from N-isopropylacrylamide (NIPAm) or a mixture of 2-(2-methoxyethoxy)ethyl methacrylate and oligo(ethylene glycol) methacrylate (MEO2MA-co-OEGMA) following conventional free radical polymerization routes. The temperature-dependent swelling properties of the non-covalently crosslinked nanogels with differences in UPy loadings were studied, clearly demonstrating that MHB arrays can work as crosslinking moieties warranting the colloidal particle identity of the prepared hydrogels.

PEGylation of fluoridated hydroxyapatite (FAp):Ln3+ nanorods for cell imaging

PEGylation is a popular approach for the surface functionalization of nanoparticles to achieve improved properties and better performance. Herein, we developed a facile method for surface PEGylation of hydrophobic fluoridated hydroxyapatite (FAp):Ln3+ (Ln = Eu or Tb) nanorods via hydrophobic interactions between oleic acid and amphiphilic synthetic copolymers, which were synthesized through reversible addition-fragmentation chain transfer (RAFT) polymerization using stearyl methacrylate (SMA) and poly(ethylene glycol) methacrylate (PEGMA) as monomers. Our results demonstrated that the morphology and fluorescent properties of the FAp nanorods are not significantly changed by the PEGylation procedure, and the resulting FAp nanorods were found to be stable in aqueous solution. More importantly, these PEGylated FAp nanorods are biocompatible with cells and could be utilized for cell imaging applications. Therefore, we believe that the method described in this work is a simple, efficient and general strategy for the surface PEGylation of hydrophobic nanoparticles.

Crosslinked PEG mats for peptide immobilization and stem cell adhesion.

We have designed a lightly crosslinked PEG based copolymer coating with compositional flexibility as well as extended stability for studying human mesenchymal stem cells (hMSCs). Copolymers contain a majority of poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) as a cytophobic background with poly(ethylene glycol) methacrylate (PEGMA) for peptide coupling, and less than 10% glycidyl methacrylate (GMA) for crosslinking. Copolymer thin films were crosslinked into 30 nm thick mats by either thermal treatment or ultraviolet light and were stable for 35 days in water at 37 °C. The amount of PEGMA in the copolymer was optimized to ∼11% to minimize non-specific cell-protein interactions while maximizing the amount of total bound peptides. Following the binding of RGDSP to the mat, hMSCs were seeded. The hMSC adhesion, spreading and focal adhesion complex formation were promoted in a concentration dependent manner. Mats coupled with a non-adhesive scramble (RDGSP) maintained their cytophobicity. Competitive detachment experiments further demonstrated that cell adhesion was mediated by receptor binding to the RGDSP peptide. Cell culture experiments performed at 1 and 2 weeks show that mats can still resist cell adhesion after incubation in a serum containing medium. X-ray photoelectron spectroscopy (XPS) was effectively used to quantify the average total peptide concentration as 12.6 ± 6.14 pmol cm-2. A square 2.2 mm N (1s) element map shows an average value of 17.9 pmol cm-2 of RGDSP, which correlates well with the multipoint high resolution data. The stability of the copolymer, compositional flexibility, ease of application and the ability to precisely quantify bound peptides on the mats make these materials ideal for the study of cellular processes, where stability, functionality and topography of the biointerface are relevant.

Dually responsive multinetworked hydrogels with improved performances by covalently bonding poly(N‐isopropylacrylamide)‐based microgels and poly(vinyl alcohol) skeleton

AbstractTo prepare intelligent hydrogels with both good mechanical performance and fast response, a series of multinetworked composite hydrogels with pH and thermo‐responsivity were designed and fabricated combining the advantages of both interpenetrating polymer network hydrogels and microgels. To begin with, precipitation polymerization of N‐isopropylacrylamide, methacrylic acid and polyethyleneglycol methacrylate was carried out in poly(vinyl alcohol) (PVA) aqueous solution, yielding thermo‐ and pH‐responsive copolymeric microgels. Then glutaraldehyde was added to the obtained microgel dispersion to covalently bond the microgel particles and PVA through acetal reaction, leading to the formation of multinetworked hydrogels with dual responses. The morphology of microgels and the internal microstructure of composite hydrogels were characterized by transmission electron microscope and scanning electron microscope, respectively. The influence of the PVA content and glutaraldehyde dosage on the mechanical behavior of the prepared hydrogels was investigated by means of uniaxial compressive tests. Experimental results reveal that the as‐prepared composite hydrogels exhibit enhanced mechanical performance compared to conventional hydrogels. Investigation onthe swelling and deswelling behaviors shows that they possess good temperature‐ and pH‐sensitivity andswell/deswell more rapidly than conventional hydrogels. POLYM. COMPOS., 2012. © 2013 Society of Plastics Engineers

High Viability of Cells Encapsulated in Degradable Poly(carboxybetaine) Hydrogels

In this study, we report a degradable poly(carboxybetaine) (pCB) hydrogel, produced via a thiol-disulfide exchange reaction for cell encapsulation. A pCB dithiol was synthesized as a cross-linker and reacted with a pyridyl dithiol-containing CB copolymer to form a hydrogel. We evaluated the biocompatibility of the pCB-based hydrogel via encapsulation of three cell types, including NIH3T3 fibroblasts, MG63 osteoblast-like cells, and HepG2 hepatocarcinoma cells. Up to 90% of cells retained their viability in the pCB hydrogel even at low cell-seeding densities under serum-free conditions after a 9-day culture. Results are compared with a degradable poly(ethylene glycol) methacrylate (PEGMA) hydrogel, which showed very low cell viability under serum-free condition after a 3-day culture. We incorporated an RGD peptide into the CB hydrogel using a cysteine-terminated cross-linker, which was shown to promote cell proliferation.

Designing polyethylene glycol (PEG) – plasticized membranes of poly(vinyl alcohol-g-methyl methacrylate) and investigation of water sorption and blood compatibility behaviors

Polyethylene glycol (PEG)-based semi-IPNs have been widely used as hydrogel matrices in tissue engineering applications because of their inherent hydrophilicity and biocompatibility. Today, synthetic scaffolds are being widely used in tissue engineering and allied applications because they offer the ability to precisely control the mechanical properties, morphology, and blood compatibility of the materials. In this regard, an attempt has been made to develop scaffolds membranes by judiciously combining PEG, polyvinyl alcohol, and polymethyl methacrylate. The so prepared hydrogel membranes were undertaken for structural, morphological, and thermal characterization using FTIR, scanning electron microscope (SEM), and DSC techniques, respectively. The hydrogel films were investigated for water sorption capacity under various experimental conditions such as changing chemical composition of the membrane, different pH, and temperature of the swelling media and varying simulated biological fluids. The hydrogel membranes were also studied for their catholicity and in vitro blood compatibility property by following several tests such as blood clot formation, percent haemolysis, and protein adsorption.

Characterisation of hydroxyapatite surface modified by poly(ethylene glycol) and poly(hydroxyethyl methacrylate) grafting

AbstractHydroxyapatite (HA) has many applications in medicine as a biocompatible and bioactive biomaterial. Numerous studies have shown that modification of the HA surface can improve its biological and chemical properties. However, little is known about the surface properties of modified materials. In this paper the influence of organic polymers: polyethylene glycol (PEG) and polyhydroxyethyl methacrylate (pHEMA) on the surface properties and surface chemistry of hydroxyapatite (HA) is presented. The surface properties of modified HA were characterised by the FT-IR, XPS, BET, and zeta potential measurements. Specific surface area was determined by BET. Infrared and XPS spectra confirmed the presence of PEG and pHEMA on the surface of HA. The BET N2 adsorption revealed slight changes in the HA surface chemistry after grafting modification. The surface chemical properties of the HA were considered to be based on the zeta potential. The decrease in zeta potential results in the increasing stability of the modified material and also in the reduction of bacterial adhesion. The reaction for surface modification of HA is proposed and described.

New hyaluronic acid based brush copolymers synthesized by atom transfer radical polymerization

In this work, an efficient method for the synthesis of hyaluronic acid based brush copolymers using atom transfer radical polymerization (ATRP) has been reported. At first, two different hyaluronic acid (HA) based macroinitiators have been prepared and then they have been used for the polymerization via ATRP of hydrophilic or hydrophobic molecules carrying vinyl portions.In particular, by linking 2-bromo-2-methylpropionic acid (BMP) to the primary hydroxyl groups of tetrabutyl ammonium salt of HA (HA–TBA) or to amino groups of the ethylenediamino derivative of HA–TBA (HA–TBA–EDA), two macroinitiators (HA–TBA–BMP and HA–TBA–EDA–BMP) have been obtained. Then they have been used for the ATRP of poly(ethylene glycol) methacrylate (PEGMA), butyl methacrylate (BUTMA) or N-isopropylacrylamide (NIPAM) using a complex of Cu(I) and 2,2′-Bipyridyl (Bpy), as a catalyst.Both macroinitiators and final copolymers, named as HA–BMP–pPEGMA, HA–BMP–pBUTMA, HA–BMP–pNIPAM, HA–EDA–BMP–pPEGMA, HA–EDA–BMP–pBUTMA and HA–EDA–BMP–pNIPAM, have been characterized by spectroscopic analysis and size exclusion chromatography to confirm the success of the polymerization process.

Crosslinked gel polymer electrolytes based on polyethylene glycol methacrylate and ionic liquid for lithium ion battery applications

Gel polymer electrolytes were synthesized by copolymerization polyethylene glycol methyl ether methacrylate with polyethylene glycol dimethacrylate in the presence of a room temperature ionic liquid, methylpropylpyrrolidinium bis(trifluoromethanesulfonyl)imide (MPPY·TFSI). The physical properties of gel polymer electrolytes were characterized by thermal analysis, impedance spectroscopy, and electrochemical tests. The ionic conductivities of the gel polymer electrolytes increased linearly with the amount of MPPY·TFSI and were mainly attributed to the increased ion mobility as evidenced by the decreased glass transition temperatures. Li||LiFePO4 cells were assembled using the gel polymer electrolytes containing 80wt% MPPY·TFSI via an in situ polymerization method. A reversible cell capacity of 90mAhg−1 was maintained under the current density of C/10 at room temperature, which was increased to 130mAhg−1 by using a thinner membrane and cycling at 50°C.

Synthesis and Performance Research of Ester Polycarboxylate Superplasticizer

Using methoxy polyethylene glycol methacrylate (MPEGMA), butyl acrylate (BA), Methyl allyl sulfonate (SMAS) as the raw materials, we can compose them to multipolymer in redox system. Through analyzing the factors and adjustment of orthogonal experimental results, the optimum technology of synthesis are shown as follows: n(MPEGMA):n(BA):n(SMAS)=5:12:2, n(H2O2)/n(Vc)=6, and the reaction temperature is 30°C. When the volume of superplasticizer is 0.42%, water cement ratio is 0.3; the initial fluidity of cement paste can get to 238mm, and within 1 hour without any loss.