Regularities of Albumin Sorption on Carboxylic Cation-Exchanger

Regularities of bovine serum albumin sorption on carboxylic cation-exchanger have been studied. The porous cation-exchanger was synthesized by terpolymerization of methacrylic and acrylic acids and cross-agent. The influence of sodium chloride concentration in interval 0-0.3 M and the solution pH value (4.5, 5.0, and 5.5) on albumin sorption has been considered. Sodium chloride concentration influence on protein sorption was shown to have different character depending of solution pH value. Salt concentration increase in studied interval causes protein sorption increase at pH 4.5. The cation-exchanger capacity dependence from salt concentration at pH 5.0 is characterized by curve with slight maximum. The increase of sodium chloride concentration from 0.1 till 0.3 M in solution having pH 5.5 leads to sharp decrease of protein sorption. The interpretation of regularities found was done considering functional groups` ionization degree change. Sodium chloride concentration and solution pH influence on the sorbent specific swelling has been shown. Specific swelling of cation-exchanger changes differently with salt concentration increase at different solution pH values

Ionization of Carboxylic Cation-Exchanger and Sorption of Proteins

Porous carboxylic cation-exchanger has been synthesized by one-stage synthesis – suspension polymerization of methacrylic and acrylic acids (molar ratio 3:1) and triethyleneglycol dimethacrylate (15%) in the presence of a diluent. Ionization parameters (at different ionic strength) were defined from potentiometric curves as pKα – lg[(1- α)/ α] (α –ionization degree) dependence using Henderson-Hasselbach equation. The morphology of sorbent beads has been observed using SEM. Bovine serum albumin (IP 4.8) and lysozyme (IP 11.2) were model proteins for investigation of ionic strength influence at different pH on protein binding. Sorption regularities might be partially explained by carboxylic groups ionization increase with the increase of ionic strength, while the change affected sorption differently at different pH values

Sorption of Organic Compounds Onto Carboxylic Cation-Exchangers

Sorption onto carboxylic cation exchangers is an effective and widely used method for purification, isolation and concentration of biologically active compounds. The process and efficiency of sorption depends on structure and physicochemical properties of sorbent and bio-compound, as well as pH, composition and temperature of sorption solution.The most important characteristic of the ion-exchanger is the ionization of its functional groups. The ionization process depends on pH, neutral salt concentration and temperature. Binding of organic compounds occurs mostly via electrostatic interactions. Therefore the condition of functional groups has a significant influence on sorption ability. Three weak acidic cation exchangers with different structures were investigated - two of them (K-120, K-10) were synthesized by water-dispersion polymerization, but the third is a commercially available sorbent Amberlite IRC-50. The method of potentiometric titration was used to describe the ionization of functional groups. Ionization parameters were found from titration results using the Henderson-Hasselbach equation. Sorption properties and kinetics were studied in batch experiments with different organic compounds. To choose the optimal conditions for the sorption process, correlation between sorption efficiency, pH value and neutral salt concentration has been studied for each compound

Akrila kaulu cementa modificēšana ar biosaderīgām piedevām

Metilmetakrilāta un n-heksilakrilāta suspensijas kopolimerizācijas rezultātā iegūta polimēru dispersija. Izpētīta biosaderīgo piedevu ievadīšanas ietekme uz kaulu cementa īpašībām

Sorptive Immobilization and Subsequent Release of Hen Egg Lysozyme

For lysozyme immobilization, synthesized carboxylic ion-exchanger has been used. Lysozyme immobilization was performed both from model solution and from diluted hen egg white. Enzymatic activity of lysozyme containing solutions was evaluated by Micrococcus lysodeiktikus cell lysis. Reversibly conjugated lysozyme release was ascertained to depend on the contacted medium composition. Lysozyme release from conjugates was stable for the duration of experiment (11 days). To evaluate the stability of conjugate over time, samples were stored at ambient temperature for 72 days. Lytic activity of desorbates was practically unchanged as compared to the initial activity

Structural peculiarities of ter-polymeric carboxylic ion-exchanger designed for sorption of proteins.

Carboxylic cation-exchanger K-120 has been developed for sorption of proteins. It has aliphatic matrix containing methacrylic and acrylic acid units and thermodynamically flexible crosslinking agent. The introduction of acrylic acid units together with methacrylic changes the ionization parameters of cation-exchanger and enhances essentially sorption ability towards proteins. The defined level of functional groups ionization provides high binding capacity and reversibility. Enhanced content of cross-linking agent ensures appropriate osmotic stability of the network. Spherical polymeric beads are permeable for protein molecules. Scanning electron microscopy testifies about micro globular structure of synthesized carboxylic ion-exchanger

Sorbent for Lysozyme Based on Acrolein Copolymer

Ion exchange resin with bis(carboxymethyl) amino groups synthesized on the base of acrolein copolymer is found to be effective sorbent of lysozyme and does not absorb bovine serum albumine. Sorption of lysozyme is characterized by high values of distribution coefficients increasing with equilibrium concentration decrease, the sorption being performed from the solutions with 0.15 M salt concentration at pH value about 7. Lysozyme can be desorbed quantitatively from the resin by buffered weak acidic solution, completely remaining enzymatic activity

Acrylic Bone Cements Modified with Starch

The successful result of restorative and replacement surgical operation depends significantly on properties of used bone cement. Acrylic bone cements are usually based on methylmethacrylate polymer, while monomer polymerization begins after mixing of components in mixing device and terminates in living tissue. Polymerization of methylmethacrylate is exothermic process, and temperature increase might cause tissue necrosis with concomitant implant aseptic loosening. Developed non-ionogenic and containing carboxylic groups of acrylic acid bone cements on the base of poly(methylmethacrylate-2-ethylhexylmethacrylate) – ethylmethacrylate- triethyleneglycol dimethacrylate system have appropriate setting parameters. The influence of polysaccharide nature additive introduction on main properties of developed bone cements has been studied. Starch was used as biocompatible and biodegradable component. The introduction of 20% starch into solid phase of bone cements aroused the change of setting profiles: polymerization peak temperature decreased and setting time increased. The mechanical properties of bone cements determined by pour-point bending and uniaxial compression tests were not worsened by starch introduction. The morphology of fracture of bone cements specimens was studied using electron microscopy. The data obtained testify that bone cements modification with starch additive is perspective for further achieving of bone tissue regeneration

Bone Cements with Dietary Fibre Additive

Acrylic bone cement setting as the result of exothermic reaction of polymerization is accompanied by high temperature growth. This temperature shock may cause living tissue necrosis with subsequent implant loosening. Bioactivity lack of bone cements on the base of poly(methylmethacrylate) – methylmethacrylate also may be the reason of implant loosening. Developed bone cements on the base of poly(methylmethacrylate-2-ethylhexylmetharylate) – ethylmethacrylate-triethyleneglycol dimethacrylate as well as carboxylic groups containing cement on that base are the cements with less expressed temperature increase during polymerization. Isolated from pea beans and wheat bran dietary fibre was used as additive which was introduced into bone cement solid phase. The introduction of 20% of additive influenced bone cements setting parameters: peak temperature decreased and setting time increased. The mechanical properties of formed cements were determined from four- point bending tests and uniaxial compression. Pea beans dietary fibre introduction did not worsen mechanical properties of bone cements, whereas enhancement was noticed in some results. The introduction of the same amount of wheat bran dietary fibre caused the decrease of ultimate stress of both bone cements in bending and in compression. This additive introduction caused the decrease of apparent density of carboxylic groups containing cement what might compensate polymerizing mixture shrinkage. The changes probably were caused by difference in morphology of isolated pea beans and bran dietary fibre what was established by scanning electron microscopy. The data show that bone cement modification with pea beans and bran dietary fibre is promising for bioactivity rise of non ionogenic bone cement and bioactivity increase of carboxylic groups containing cement. Bran dietary fibre additive introduction might be proper only in small amount (3-9% in solid phase), also to diminish bone cement shrinkage