Poly(ethylene Glycol) 400 Dimethacrylate Research Articles

Surface imprinted thin polymer film systems with selective recognition for bovine serum albumin

Molecularly imprinted polymers are synthetic antibody mimics formed by the crosslinking of organic or inorganic polymers in the presence of an analyte which yields recognitive polymer networks with specific binding pockets for that biomolecule. Surface imprinted polymers were synthesized via a novel technique for the specific recognition of bovine serum albumin (BSA). Thin films of recognitive networks based on 2-(dimethylamino)ethyl methacrylate (DMAEMA) as the functional monomer and varying amounts of either N,N′-methylenebisacrylamide (MBA) or poly(ethylene glycol) (400) dimethacrylate (PEG400DMA) as the crosslinking agent were synthesized via UV free-radical polymerization and characterized. A clear and reproducible increase in recognition of the template BSA was demonstrated for these systems at 1.6–2.5 times more BSA recognized by the MIP sample relative to the control polymers. Additionally, these polymers exhibited selective recognition of the template relative to competing proteins with up to 2.9 times more BSA adsorbed than either glucose oxidase or bovine hemoglobin. These synthetic antibody mimics hold significant promise as the next generation of robust recognition elements in a wide range of bioassay and biosensor applications.

Molecularly imprinted polymers for the recognition of sodium dodecyl sulfate denatured creatine kinase

Micro-contact imprinting methodology was used to prepare the molecule recognition film for denatured creatine kinase-MM (CK-MM), which was denatured by sodium dodecyl sulfate. Interpretation of thermo-calorimetry measurements suggested the use of poly(ethylene glycol) 400 dimethacrylate (PEG400DMA) as a crosslinking molecule. The selected functional monomer, methyl methacrylate (MMA), produced the highest imprinting factor from a panel of five candidates. The molecularly imprinted polymers (MIPs) formed with 5% MMA, 95% PEG400DMA and denatured CK-MM showed excellent imprint recognition, with the imprinting factor of 8.66. The dissociation constant calculated from Scatchard plot was 3.25×10−8M. MIPs had little affinity with non-template proteins, such as native CK-MM, a native and denatured form of human serum albumin (HSA) and immunoglobulin G (IgG). The competitive study in a two-protein environment showed that the selectivity of MIP was 96.8% and 98.7% for denatured CK-MM/denatured HSA and denatured CK-MM/denatured IgG, respectively. The results suggested that MIPs prepared in this work recognize not only the protein sequences but also the protein secondary structure.

A systematic approach to forming micro-contact imprints of creatine kinase

A systematic approach has been used to form molecular imprints of creatine kinase (CK) using micro-contact imprinting. Using thermocalorimetry data, we selected poly(ethylene glycol) 400 dimethacrylate (PEG400DMA) as our crosslinker, on the basis that it would be expected to have minimal specific recognition when incorporated into the imprinted polymer. The functional monomer used, methacrylic acid (MAA), was chosen from a panel of six candidates on the basis of it giving the highest differential affinity with respect to a non-imprinted polymer. A polymer formed with 5% MAA and 95% PEG400DMA showed excellent imprint recognition, with CK binding to the imprinted material being 2.05 +/- 0.07 x 10(-10) mol cm(-2) compared to 9.1 +/- 4.5 x 10(-12) mol cm(-2) control binding. The imprinted polymers (approximate thickness 22.6 mum as measured by Alpha-step) showed clear two-phase binding with maximum absorption achieved after approximately 2 hours. Data extracted from Scatchard plots showed the K(d) for the high affinity binding site population to be 2.56 x 10(-10) M and the binding site population to be 1.97 x 10(-10) mol cm(-2), corresponding data for low affinity binding sites shows the K(d) = 3.27 x 10(-9) M and the binding site population to be 2.32 x 10(-10) mol cm(-2). Re-binding the molecularly imprinted polymers (MIPs) with non-template proteins, namely myoglobin, human serum albumin (HSA) and immunoglobulin G (Ig G), showed these proteins to have comparatively little affinity for the CK imprinted films. The percentage re-binding figures, relative to CK binding, were: 18.7, 3.5, and 3.5 for myoglobin, HSA, and Ig G respectively. This pattern of binding was maintained in competitive binding protocols with two proteins in solution at equal concentrations, where the percentage re-binding figures, relative to CK binding (4.5 +/- 0.06 x 10(-10) mol cm(-2)), were 17.2, 4.5, and 2.9 for myoglobin, HSA, and Ig G respectively. The presence of multiple competing analytes in undiluted human serum did not significantly decrease template protein recognition. Finally, we used circular dichroism to monitor protein denaturation, and showed that the denatured template protein loses a significant proportion (76.8%) of its MIP affinity after being heated at 80 degrees C for 10 minutes.

Poly(n-isopropylacrylamide)-based hydrogel coatings on magnetite nanoparticles via atomtransfer radical polymerization

Core magnetite (Fe3O4) nanoparticles have been functionalized with a model intelligent hydrogel systembased on the temperature responsive polymer poly(n-isopropyl acrylamide)(PNIPAAm) to obtain magnetically responsive core–shell nanocomposites.Fe3O4 nanoparticles were obtained from a one-pot co-precipitation method which provided eitheroleic acid (hydrophobic) or citric acid (hydrophilic) coated nanoparticles. Subsequentligand exchange of these coatings with various bromine alkyl halides and a bromo silaneprovided initiating sites for functionalization with NIPAAm using atom transfer radicalpolymerization (ATRP). The bromine alkyl halides that were used were 2-bromo-2-methylpropionic acid (BMPA) and 2-bromopropionyl bromide (BPB). The bromo silane that wasused was 3-bromopropyl trimethoxysilane (BPTS). The intelligent polymeric shell consistsof NIPAAm crosslinked with poly(ethylene glycol) 400 dimethacrylate (PEG400DMA).Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), andtransmission electron microscopy (TEM) were used to confirm the presence of thepolymeric shell. Dynamic light scattering (DLS) was used to characterize thenanocomposites for particle size changes with temperature. Their magnetic andtemperature responsiveness show great promise for further biomedical applications. Thisplatform for functionalizing magnetic nanoparticles with intelligent hydrogels promises toimpact a wide range of medical and biological applications of magnetic nanoparticles.

The microcontact imprinting of proteins: The effect of cross-linking monomers for lysozyme, ribonuclease A and myoglobin

The performance of molecularly imprinted polymers (MIPs) is of interest to researchers in the field of analytical chemistry, and in the pharmaceutical and food industries. Because the choice of the functional monomer(s) plays a key role in the selectivity of a MIP, the synthesis of an effective, tight-binding MIP can be difficult and time-consuming, involving the evaluation of the binding performance of MIPs of many different compositions. In this study, we report an express method combining molecular imprinting and microcontact printing techniques to prepare a polymer thin film as an artificial antibody. In addition to the microcontact printing technique, isothermal titration of monomers to proteins stamps was investigated to screen the functional monomer for MIPs. Finally, the importance of the choice of cross-linking monomers in MIPs was studied, and these studies suggest that monomers containing an optimal length PEG spacer give higher imprinting effectiveness. Several model antigens (lysozyme, ribonuclease A and myoglobin) were adsorbed on a cover glasses that were pretreated with hexamethyldisilazane (HMDS). These protein stamps were then contacted with different monomer solutions (cross-linking monomers) on a glass slide substrate. Photopolymerization yielded the molecularly imprinted polymer. This technique, analogous to microcontact printing, allows for the rapid, parallel synthesis of MIPs of different compositions, and requires very small volumes of monomers (ca. 4 microL). The technique also avoids potential solubility problems with the molecular targets. Of several cross-linking monomers screened, tetraethyleneglycol dimethacrylate (TEGDMA) gave the most selective lysozyme binding, while polyethyleneglycol 400 dimethacrylate (PEG400DMA) were most selective for ribonuclease A and myoglobin.

Synthesis and temperature response analysis of magnetic‐hydrogel nanocomposites

Magnetically responsive hydrogel networks based on composites of magnetic nanoparticles and temperature responsive hydrogels were developed. These systems show great promise as active components of microscale and nanoscale devices and are expected to have a wide applicability in various biomedical applications. Specifically, nanocomposite hydrogel systems based on the temperature sensitive N-isopropylacrylamide hydrogels crosslinked with ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and poly(ethylene glycol) 400 dimethacrylate (PEG400DMA) were synthesized and characterized. The composite systems were synthesized by UV free-radical polymerization. Iron oxide magnetic nanoparticles were incorporated into the hydrogel systems by polymerizing mixtures of the nanoparticles and monomer solutions. The swelling response of these composite systems to different crosslinking molecular weights, temperature, and the effect of the presence of the magnetic nanoparticles were examined.

Incorporation of styrene enhances recognition of ribonuclease A by molecularly imprinted polymers

Ribonuclease A (RNase A) is an RNA-cleaving enzyme characterized by its high conformational stability and strong catalytic activity. This enzyme is ubiquitous in living organisms and is difficult to inactivate. In polymerase chain reaction (PCR) RNase activity is removed by adding inhibitors. Molecularly imprinted polymers (MIPs) with high selectivity, high stability, low cost and facile synthesis could prove useful in extraction of target molecules, such as RNase A, from reaction mixtures. In this investigation, MIPs were synthesized from the monomers styrene and polyethyleneglycol 400 dimethacrylate (PEG400DMA) in several different ratios. Styrene as a functional monomer gave MIPs with a higher affinity for RNase A than other functional monomers tested, according to both enzyme-linked immnuosorbent assay (ELISA) and isothermal titration calorimetry (ITC). The optimum volume ratio of styrene/PEG400DMA was 20/100 at 25 degrees C, and this ratio maximized the rebinding efficiency of RNase A to MIPs. Isothermal titration calorimetry was also used, and could be useful to design the composition of molecularly imprinted polymers for various target molecules.

Synthesis of and recognition by ribonuclease A imprinted polymers

Ribonuclease (RNase), an enzyme which degrades RNA, is ubiquitous in living organisms,can renature after autoclaving, and is difficult to inactivate. The removal of RNase isespecially necessary for the reverse transcription–polymerase chain reaction (RT-PCR) andfor in vitro transcription and translation. Typically, RNase inhibitors must be added tothese reactions nowadays. Molecularly imprinted polymers (MIPs) could offer manyadvantages for removal of undesired enzymes, including high binding selectivity, stability,low cost, and facile synthesis. Surface imprinting, employing immobilized RNase, was usedin this study to make the most effective use of the template molecules—clearly, inaccessiblebinding sites, no matter how well imprinted, are not useful for target binding. Differentmonomers and cross-linkers were used to synthesize RNase-templated MIPs, andthe rebinding capacity of each composition was characterized. We found thatusing polyethylene glycol 400 dimethacrylate (PEG400DMA) gave the highestimprinting effectiveness (i.e. the highest RNase binding ratio between imprinted andnon-imprinted polymers). However, including styrene monomer (50 wt%) gavepolymers with the highest overall affinity for ribonuclease A (RNase A). Finally,isothermal titration calorimetry was used as an auxiliary tool to help elucidatethe mechanisms of the binding of monomers to templates, and ligands to MIPs.

Polymerized (ethylene glycol) dimethacrylate–cholesteryl methacrylate liposomes: preparation and stability studies

In this study, preparation of stable polymerized liposomes using monomeric mixture of poly(ethylene glycol) 400-dimethacrylate (PEG.DM) and cholesteryl methacrylate (ChMA) was carried out. Liposomes containing PEG.DM–ChMA monomers were prepared by a sonication method and subsequently polymerized using an ammonium persulfate/sodium metabisulfite redox system. Liposomes containing PEG.DM monomer was also prepared for comparative studies. Both monomeric and polymerized liposomes were characterized by Fourier transform (FT) IR, FT nuclear magnetic resonance (NMR) spectroscopy, transmission electron microscopy and turbidity measurement. The spectroscopic studies clearly confirmed the polymerization of ChMA and PEG.DM monomers in the liposomes. The transmission electron micrograph showed the spherical shape of both monomeric and polymerized liposomes. The average sizes of the PEG.DM and PEG.DM–ChMA containing monomeric liposomes are 420 nm and 400 nm, respectively, and the average sizes of the polymerized PEG.DM and PEG.DM–ChMA liposomes are 450 nm and 460 nm, respectively. The turbidity measurement indicated that both the polymerized liposomes are more stable than the monomeric liposomes. Vincristine sulfate (VCR), a water-soluble anticancer drug, was chosen as a model drug for incorporation in both the monomeric and polymerized liposomes. The percentage encapsulation was determined by completely breaking the liposome bilayers using Triton X-100. In vitro release of the encapsulated VCR from monomeric and polymerized liposomes were carried out in phosphate-buffered saline, pH 7.4 and in 1% (v/v) human plasma at 37°C. In both media, the polymerized liposomes released the drug in a sustained manner for prolonged period of time compared to the monomeric liposomes. Among the polymerized liposomes, the polymerized PEG.DM–ChMA liposomes released the drug for longer period of time than the polymerized PEG.DM liposomes. These results clearly suggested that the more stable polymerized PEG.DM–ChMA liposomes appear to be a better carrier for the delivery of therapeutic molecules.

A Comparative Study of Coordination in Gel Electrolytes Quantitative Analysis

Changes in lithium ion coordination in polymer gel electrolyte materials have been studied by Fourier transform infrared (FTIR) spectroscopy as a function of composition. Two plasticizers, propylene carbonate and dimethyl sulfoxide, and two polymers, polyvinylidene fluoride‐co‐hexafluoropropylene (Kynar flex), and poly(ethylene glycol 400)dimethacrylate (PEG400DMA), have been compared, and their coordination to the cation has been determined. The salt used in all samples is lithium bis(trifluoromethane sulfone)imide, Li(TSFI). In order to determine the changes of lithium coordination from the resulting FTIR spectra, a quantitative band‐shape analysis of these spectra has been performed. © 1999 The Electrochemical Society. All rights reserved.