muramidase and acrylic-acid

A polymeric platform for immunodiagnostic bioassay was constructed based on biostable polymeric support and two functional monomers, low-fouling methacryloyloxyethyl phosphorylcholine (MPC) and acrylic acid (AAc), by a photografting polymerization approach. Covalent binding of antibody to pAAc chains was achieved by activating carboxyl with NHS/EDC partner. The resultant surface showed obvious suppression of nonspecific protein adsorption and platelet adhesion relative to the control sample, exhibiting good anti-bioadhesion performances. Based on the polymer-supported matrix, a highly sensitive antibody-antigen specific recognition was confirmed in both native plasma and diluted human plasma due to the enhanced antibody loading capacity and lowered bioadhesion as compared to the reference.

Topics: Acrylates; Adhesiveness; Adsorption; Antibodies; Antigens; Enzyme-Linked Immunosorbent Assay; Fibrinogen; Humans; Immobilized Proteins; Light; Muramidase; Phosphorylcholine; Photoelectron Spectroscopy; Platelet Adhesiveness; Polymerization; Polymers; Polymethacrylic Acids; Serum Albumin, Bovine; Spectroscopy, Fourier Transform Infrared

Poly(hydroxyethyl methacrylate) (pHEMA) hydrogels were functionalized with pendant alpha-, beta- and gamma-cyclodextrins (CD) with the aim of improving the biocompatibility and increasing the ability to host drug molecules. Pendant alpha-, beta- and gamma-CDs did not affect swelling of the hydrogels but slightly decreased the water contact angle. Protein deposition was notably dependent on the nature of the CD, due to their different affinities for hydrophobic moieties of proteins. Lysozyme and albumin sorption was hindered by gamma-CD. Functionalization with beta-CD also reduced protein sorption, although less so, while alpha-CD decreased lysozyme deposition but enhanced albumin sorption compared with control pHEMA hydrogels. Loading of the hydrogels with miconazole was carried out by immersion in drug suspension followed by autoclaving. Functionalization with gamma-CD doubled the affinity of the network for the drug and resulted in the highest amount loaded (up to 170 mgg(-1)). Sustained delivery was observed for several days. Some miconazole-loaded hydrogels completely prevented Candida albicans biofilm formation as assayed in an in vitro microbiological test.

Topics: Acrylates; Adsorption; Albumins; alpha-Cyclodextrins; Antifungal Agents; beta-Cyclodextrins; Biocompatible Materials; Biofilms; Candida albicans; Drug Delivery Systems; gamma-Cyclodextrins; Hydrogels; Materials Testing; Miconazole; Microbial Sensitivity Tests; Muramidase

The interaction between lysozyme and colloidal poly(NIPAM-co-acrylic acid) microgels is investigated in aqueous solutions at neutral pH. Lysozyme binding isotherms, obtained within the ionic strength range 10-220 mM, indicate that the maximum uptake at 10 mM is 2.4 g lysozyme per gram dry gel, and that the uptake capacity decreases with increasing ionic strength to approximately 0 at 220 mM. Swelling isotherms, obtained from photon correlation spectroscopy measurements, show that the binding is accompanied by a substantial deswelling of the microgels. The microgel suspension is stable up to a protein-to-polymer charge ratio in the microgels of about 0.6, largely independent of ionic strength, whereas flocculation/sedimentation occurs at higher charge ratios. The charge ratio 0.6 corresponds to a zeta-potential of about -6 mV, as obtained from measurements of electrophoretic mobility. Binding and swelling isotherms are analyzed in detail and compared with predictions of theoretical model calculations. The influence of protein-protein attraction is highlighted, as well as the interplay between electrostatic interactions and network elasticity.

Topics: Acrylates; Acrylic Resins; Colloids; Elasticity; Gels; Muramidase; Static Electricity

This paper presents a study of EOF properties of plasma-polymerized microchannel surfaces and the effects of protein (fibrinogen and lysozyme) adsorption on the EOF behavior of the surface-modified microchannels. Three plasma polymer surfaces, i.e. tetraglyme, acrylic acid and allylamine, are tested. Results indicate EOF suppression in all plasma-coated channels compared with the uncoated glass microchannel surfaces. The EOF behaviors of the modified microchannels after exposure to protein solutions are also investigated and show that even low levels of protein adsorption can significantly influence EOF behavior, and in some cases, result in the reversal of flow. The results also highlight that EOF measurement can be used as a method for detecting the presence of proteins within microchannels at low surface coverage (<1 ng/cm(2) on glass). Critically, the results illustrate that the non-fouling tetraglyme plasma polymer is able to sustain EOF. Comparison of the plasma-polymerized surfaces with conventionally grafted polyelectrolyte surfaces demonstrates the stabilities of the plasma polymer films, enabling multiple EOF runs over 3 days without deterioration in performance. The results of this study clearly demonstrate that plasma polymers enable the surface chemistry of microfluidic devices to be tailored for specific applications. Critically, the deposition of the non-fouling tetraglyme coating enables stable EOF to be induced in the presence of protein.

Topics: Acrylates; Adsorption; Allylamine; Electroosmosis; Ethylene Glycols; Fibrinogen; Humans; Microfluidic Analytical Techniques; Muramidase; Plasma; Polymers; Proteins; Spectrum Analysis; Surface Properties

Molecularly imprinted polymers (MIPs) selective for lysozyme were prepared on SPR sensor chips by radical co-polymerization with acrylic acid and N,N'-methylenebisacrylamide. Gold-coated SPR sensor chips were modified with N,N'-bis(acryloyl)cystamine, on which MIP thin films were covalently conjugated. The presence of NaCl during the polymerization and the re-binding tests affected the selectivity and the optimization of NaCl concentration in the pre-polymerization mixture and the re-binding buffer could enhance the selectivity in the target protein sensing. When the lysozyme-imprinted polymer thin films were prepared in the presence of 40 mM NaCl, the selectivity factor (target protein bound/reference protein bound) of MIP in the re-binding buffer containing 20 mM NaCl was 9.8, meanwhile, that of MIP in the re-binding buffer without NaCl was 1.2. A combination of SPR sensing technology with protein-imprinted thin films is a promising tool for the construction of selective protein sensors.

Topics: Acrylamides; Acrylates; Gold; Muramidase; Surface Plasmon Resonance

The complex formation between the basic protein lysozyme and anionic polyelectrolytes: poly acrylic acid and poly vinyl sulfonic acid was studied by turbidimetric and isothermal calorimetric titrations. The thermodynamic stability of the protein in the presence of these polymers was also studied by differential scanning calorimetry. The lysozyme-polymer complex was insoluble at pH lower than 6, with a stoichiometric ratio (polymer per protein mol) of 0.025-0.060 for lysozyme-poly vinyl sulfonic acid and around 0.003-0.001 for the lysozyme-poly acrylic acid. NaCl 0.1M inhibited the complex precipitation in agreement with the proposed coulombic mechanism of complex formation. Enthalpic and entropic changes associated to the complex formation showed highly negative values in accordance with a coulombic interaction mechanism. The protein tertiary structure and its thermodynamic stability were not affected by the presence of polyelectrolyte.

Topics: Acrylates; Calorimetry, Differential Scanning; Chemical Precipitation; Egg Proteins; Hydrogen-Ion Concentration; Macromolecular Substances; Muramidase; Nephelometry and Turbidimetry; Polyethylene Glycols; Polyglycolic Acid; Polymers; Polyvinyls; Protein Binding; Solubility; Thermodynamics

Many commercial soft contact lenses are based on poly-2-hydroxyethyl methacrylate (HEMA) and acrylic acid (AA) hydrogels. The adsorption of proteins, albumin and lysozyme, on such contact lens surfaces may cause problems in their applications. In this work the adsorption of proteins, albumin and lysozyme, on hydrogel surfaces, AA and HEMA, was investigated as a function of concentration of protein. Also the effects of pH and ionic strength of protein solution on the adsorption of protein were examined. The obtained results indicated that the degree of adsorption of protein increased with the concentration of protein, and the adsorption of albumin on HEMA surface at the studied pHs (6.2-8.6) was higher than AA surface, whereas the adsorption of lysozyme on AA surface at the same pHs was higher than HEMA. The change in ionic strength of protein solution affected the proteins adsorption on both AA and HEMA surfaces. Also, the amount of sodium ions deposited on the AA surface was much higher than HEMA surface. This effect can be related to the negative surface charge of AA and its higher tendency for adsorption of sodium ions compared to the HEMA surface.

Topics: Acrylates; Adsorption; Albumins; Animals; Chickens; Egg Proteins; Hydrogen-Ion Concentration; Methacrylates; Muramidase; Osmolar Concentration; Sodium Chloride; Surface Properties

Thermoprecipitation of lysozyme from egg white was demonstrated using copolymers of N-isopropylacrylamide with acrylic acid, methacrylic acid, 2-acryloylamido-2-methylpropane-sulfonic acid and itaconic acid, respectively. Polymers synthesized using molar feed ratio of N-isopropylacrylamide:acidic monomers of 98:2 exhibited lower critical solution temperatures in the range of 33--35 degrees C. These polymers exhibited electrostatic interactions with lysozyme and inhibited its bacteriolytic activity. The concentration of acidic groups required to attain 50% relative inhibition of lysozyme by the polymers, was 10(4)--10(5) times lower than that required for the corresponding monomers. This was attributed to the multimeric nature of polymer-lysozyme binding. More than 90% lysozyme activity was recovered from egg white. Polymers exhibited reusability up to at least 16 cycles with retention of >85% recovery of specific activity from aqueous solution. In contrast, copolymer comprising natural inhibitor of lysozyme i.e. poly (N-isopropylacrylamide-co-O-acryloyl N-acetylglucosamine) lost 50% recovery of specific activity. Thermoprecipitation using these copolymers, which enables very high recovery of lysozyme from egg white, would be advantageous over pH sensitive polymers, which generally exhibit lower recovery.

Topics: Acetylglucosamine; Acrylamides; Acrylates; Animals; Binding Sites; Chemical Precipitation; Egg White; Hydrogen-Ion Concentration; Ions; Methacrylates; Muramidase; Osmolar Concentration; Polymers; Solutions; Succinates

A silica-based, polyacrylate ion-exchange stationary phase has been prepared using Ce(IV) as the initiator. Analysis of the physical properties of the polymeric layer separated from the silica surface indicates that the polymeric coating is cross linked to some extent. The polymerization carried out at different concentrations of Ce(IV) demonstrated that the effective surface area can be increased by lowering the Ce(IV) concentration at higher monomer concentrations of the reaction mixture. These materials are quite reproducible and of high electrostatic binding capacity; 1.485 mumol/m2. The electrostatic binding capacity of a non-polymeric stationary phase reached the theoretical limit for a monolayer (0.16 mumol/m2). However, the covalent binding capacity of the same stationary phase was only 50% of the electrostatic binding capacity. The same trend was observed in all the polymeric stationary phases tested. This shows that the mechanism of protein binding in polymeric and conventional stationary phases is similar, and multilayer electrostatic binding is highly unlikely in these sorbents examined. Z numbers revealed that the contact area of the protein is independent of the polymeric character of the stationary phase and therefore, the increased loading of these polymeric stationary phases is due to the increased surface area.

Topics: Acids; Acrylamides; Acrylates; Alkanesulfonates; Animals; Catalysis; Cation Exchange Resins; Cattle; Cerium; Chickens; Chromatography, Ion Exchange; Enzymes, Immobilized; Hemoglobins; Hot Temperature; Muramidase; Oxidation-Reduction; Polymers; Protein Binding; Silanes; Silicon Dioxide; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Static Electricity; Surface Properties; Time Factors; Tissue Adhesives