Synthetic Hydrophilic Polymers Research Articles

Photochemically immobilized polymer coatings: effects on protein adsorption, cell adhesion, and leukocyte activation

Amphiphilic chains of 4-benzoylbenzoic acid moieties and polymer were photochemically immobilized onto silicone rubber to ask whether the covalently coupled polymers would passivate the silicone rubber by inhibiting protein adsorption and subsequent cell adhesion and activation. Three groups of polymers were utilized: the hydrophilic synthetic polymers of polyacrylamide, polyethylene glycol, and polyvinylpyrrolidone; the glycosaminoglycan, hyaluronic acid; and poly(glycine-valine-glycine-valine-proline), a polypeptide derived from the sequence of clastin. Each coating variant decreased the adsorption of fibrinogen and immunoglobulin G compared to uncoated silicone rubber. All except the methoxy-polyethylene glycol coating nearly abolished fibroblast growth, but none of the coating variants inhibited monocyte or polymorphonuclear leukocyte adhesion. Interleukin-1β, interleukin-1 receptor antagonist, and tumor necrosis factor-α secretion by leukocytes were not statistically different between any of the coating variants and uncoated silicone rubber. However, the methoxy-polyethylene glycol and elastin-based polypeptide coatings, which supported the highest numbers of adherent monocytes, also elicited the lowest levels of pro-inflammatory cytokine secretion. When these in vitro data were collectively evaluated, the coating that most effectively passivated silicone rubber was the polypeptide derived from elastin.

Interaction of cells with polymers

AbstractThis paper summarizes the results of our experiments studying the effect of functional chemical groups of synthetic hydrophilic polymers on the recognition of these materials by macrophages in in vivo experiments. The interaction of keratinocytes with synthetic hydrophilic polymers in vitro is also demonstrated. The implants containing anionic groups (carboxylates) were shown to be better tolerated by nonspecific immunity. The keratinocytes are able to grow on hydrophilic polymer supports and migrate to surfaces with improved adhesivity (in vitro). The clinical applications of these experiments are demonstrated.

Study on slow release anti-cancer drugs prepared by radiation induced polymerization

This paper reports the research results which the anticancer drugs Ara-C with controlled slow release were made by radiation induced polymerization of monomers such as methacrylates at room temperature. Our studies showed that not only hydrophilic synthetic polymers but also hydrophobic polymers such as hydrophobic methacrylates (including MMA, EMA, and BMA) could be used to the immobilization. In vitro the rate of drugs release was controlled by the many factors such as the content of drugs, the monomer material, the crosslinking agent, the irradiation dose and the water content, etc.

Synthetic macronet hydrophilic polymers as soil conditioners. I. kinetic characterization of macro‐net sulfonated polystyrene resins

Abstract Polystyrene‐based macronet polymers, bearing ionic groups on their chains, have shown properties that can characterize them as soil conditioners. This study is based on their capability to retain water in their structure in amounts that equal many times the polymer's dry weight. The kinetics of water retention indicated that the velocity with which they act in polymer‐soil systems is high. The water capacity as well as the apparent density of the polymer‐soil mixtures was determined. At the same time, the performance of these mixtures was identified using soil column experiments under free water flow. The final values for the mixtures’ water capacity were found to depend on the swelling ratio and the water capacity of the polymer itself.

Synthetic macronet hydrophilic polymers as soil conditioners. II. The effect of the final ion form of crosslinked sulfonated polystyrene on seedling growth

Abstract Hydrophilic polymers were obtained via modification of linear polystyrene and were applied to various plant‐soil systems. Sandy‐loam soil and quartz sand were used as substrates for tomato and lettuce cultivation. Three different ion species were studied as the final form of the sulfonic group attached to the polystyrene backbone. The sodium (Na+), ferrous‐iron (Fe2+), and hydrogen (H+) forms were employed in order to determine the influence of the ion‐exchange processes in which the conditioner is involved. The results showed slightly improved growth in the presence of Fe2+ form, while there was significant growth response of seedlings to the acid form of the sulfonated polystyrene resins. The ion‐exchange behaviour of the polymers in the acid form was studied by pH measurements employing water suspensions. Finally, the influence of the new polymers on the growth of seedlings was compared to that of a known commercial product based on polyacrylamide.

Hybrid Copolymers for Controlled Release of Contraceptive Steroids

Biodegradable and biocompatible hybrid copolymeric implants for the controlled release of contraceptive steroids were prepared and characterized. These hybrid copolymers were developed from a natural macro molecule, collagen, and the hydrophilic synthetic polymers poly(ethylene gly col) and poly(vinyl pyrrolidone) for imparting biocompatibility as well as bioac tiveness to the implant. The characterization of these gels was carried out using techniques such as FT-IR, SEM and TGA. The in vitro release studies of testosterone entrapped within the hybrid were carried out at physiological pH and temperature. It was found that the testosterone gave a large release ini tially and then levelled off to release the same quantity every day in a zero- order pattern. About 44% of the steroid was released in the first ten days and thereafter the release was very slow. The total amount of drug released by 90 days was about 66%.

Attachment of staphylococci to various synthetic polymers

Attachment of staphylococci to different synthetic polymers used for medical purposes was studied in applying the bioluminescent technique. The number of attached bacterial cells was determined by measuring the light emission resulting from the reaction between firefly luciferase and ATP present in adhered staphylococcal cells. It was shown that staphylococci attach to synthetic polymers within a few minutes, although one hour incubation is required to reach a constant maximum value of attached cells. Ten different synthetic polymers and five Staphyloccocus epidermidis strains were investigated in our study. The relationship between surface properties of polymers and bacterial attachment was studied. Various physicochemical parameters of synthetic polymers and bacteria were determined (contact angle, surface tension). It was demonstrated that bacterial attachment decreases with decreasing contact angle and with increasing surface tension of synthetic materials. Modifications of surface charge and hydrophobicity of solid materials were also investigated. It could be proved that especially negatively charged and hydrophilic synthetic polymers show very decreased staphylococcal attachment.

Cervical dilatation by Lamicel--studies on the mechanism of action.

Lamicel is a synthetic hydrophilic polymer tent which produces cervical softening and dilatation when inserted into the endocervical canal. To investigate the mechanism of action of Lamicel, the intrauterine pressure and levels of 6-keto-prostaglandin F1 alpha, 13-14-dihydro-15-keto-prostaglandin F2 alpha, oestradiol and progesterone in plasma and amniotic fluid were measured in patients undergoing second trimester abortion. There was no significant change in any of the measured hormones during a 2-h treatment with Lamicel, but uterine activity increased significantly for 10 min after insertion, then settled spontaneously to below pre-treatment levels. Peripheral plasma levels of magnesium sulphate measured in patients undergoing first trimester abortion were not significantly raised after insertion of Lamicel. Light microscopic examination of cervical specimens, obtained at hysterectomy from patients pre-treated with Lamicel for 24 h, revealed minimum increase in vascularity, mast cell population and ground substance mucopolysaccharides.

Lamicel: a new technique for cervical dilatation before first trimester abortion

Mechanical dilation of the cervix can be both difficult and dangerous and has potentially serious complications. Lamicel, a synthetic hydrophilic polymer, was inserted into the cervix between 2 and 24 h before termination by vacuum aspiration in the first trimester in 48 nulliparae. A control group of 12 nulliparae were not treated with Lamicel. The force needed to dilate the cervix, accurately measured with a specifically designed force-measuring instrument, was found to be significantly reduced in all treated groups. The greatest rate of dilatation occurred within the first 2 h after insertion.

Suppression of IgE antibody production in sensitized mice and rats by tolerogenic conjugates of synthetic hydrophilic polymers with antigen or hapten: effect on antigen-induced histamine release from peritoneal mast cells.

IgE antibodies were produced in mice and rats by immunization with ragweed pollen extract (RAG) or dinitrophenylated ovalbumin (DNP3-OA). Treatment of these animals with tolerogenic conjugates of (i) the antigen (RAG or OA) with monomethoxypolyethylene glycol (mPEG), or (ii) DNP with polyvinyl alcohol (DNP-PVA) resulted, within 7-14 days, in a fall in circulating IgE antibodies and in mast cell sensitivity, as assessed by the radioallergosorbent test (RAST) and in the in vitro antigen-induced histamine release (HR) test, respectively. The reduction in responsiveness was more marked in mice than rats; 10 days after a booster immunization, the IgE antibody titres in the RAG-mPEG-treated group of mice were approximately 10-fold lower than in the saline-treated group, with a 100-fold difference in cell sensitivity. DNP-PVA treatment of mice produced a more than 10-fold reduction in IgE anti-DNP titres with a substantial reduction in histamine release.

Synthetic hydrophilic polymers

Synthetic hydrophilic polymers find promising applications in pharmacology, biotechnology and chemistry. The biocompatibility, biodegradability and pharmacological activity of these polymers depend much on their hydrophilic nature. This article summarizes the recent developments in the utilization of the different classes of these hydrophilic polymers as pharmacologically active agents, for enzyme modification and as catalysts and supports for chemical reactions.

Some Remarks on the Viscometric Behaviour of the Systems Couplers-Gelatin and Couplers-Synthetic Polymers

AbstractSome aspects of the mechanism of the interactions between nondiffusing couplers and gelatin or hydrophilic synthetic polymers were investigated by viscometry, studying (a) the role played by the polymer; (b) the effect of the solvent; (c) the influence of operative factors.The interactions between the polymers and the couplers examined depended on the type, molecular size and structure of the polymer and on the chemical structure of the coupler. In most cases a threshold polymer concentration was found, above which the interactions began to be evident.Polar surface active solvents seem to interact with the coupler aliphatic side chain, hindering the coiling up of the polymer- coupler aggregates, while pre-warming of the samples hinders the building up of intermolecular aggregates.An ageing effect of the polymer-coupler solutions was detected, which probably means that the aggregates undergo some structural and configurational changes during the storage time.