We have demonstrated that the optimal surface treatment of a polyvinylalcoholcopolymer hydrogel for epithelial cell migration and proliferation is an argon radio frequency (rf) plasma treatment. The surface chemistry of the material was determined prior to each cellular evaluation, allowing us to compare the biological response with a known surface chemistry. The cellular response was carried out in a consistent manner a minimum of three separate runs. We found that the optimal conditions required culturing the cells under constant rotation. Cells became confluent on argon-plasma-treated surfaces coated under several different reactions pressures, and after 2 weeks they became multilayered. Our experiments demonstrated that cells proliferated and extracellular matrix and adhesion proteins were present only when the surface was treated with an argon rf plasma; acetone- and ammonia-treated surfaces did not yield the desired results. Organ culture experiments further demonstrated the efficacy of the argon-treated surfaces. In these experiments, intact keratoprosthetic devices with modified hydrogel surfaces were implanted into rabbit corneas. The excised corneas containing the devices were cultured, and 3 weeks later, using confocal laser scanning microscopy, confluent epithelium was detected on the modified hydrogel surface. This is the first demonstration that rabbit limbal epithelial cells can migrate onto a synthetic cornea containing a modified hydrogel-treated surface and form a confluent surface of epithelium.

No abstract

No abstract

Our goal was to: 1) modify poly(vinyl alcohol) hydrogels intended for use in a synthetic cornea to absorb ultraviolet light and 2) develop molding procedures for the fabrication of the device. Two ultraviolet light-absorbing monomers were incorporated by copolymerization. The resulting hydrogels protected against ultraviolet light, were not toxic to corneal fibroblasts, and the protection did not diminish during prolonged aqueous exposure. A novel keratoprosthesis molding procedure was developed that made use of the phase transition properties of mixtures of poly(vinyl-trifluoroacetate) and acetonitrile. In this procedure the keratoprosthesis was shaped and a fibrous skirt was bonded to it in a single operation. Composite keratoprostheses were designed and prepared for in vivo testing.

Oleophilic ion-exchange resins are ones capable of appreciable swelling in most organic solvents, and thus they have functional ion-exchange properties in these solvents. These resins were prepared by introduction into the polymer structure of hydrophobic or oleophilic groups which reduce the polarity of an ion-exchange polymer and make f o r its swelling in organic solvents. Oleophilic ion-exchange polymers were prepared by the copolymerization of methacrylic acid and dodecyl methacrylate; by the copolymerization of styrene and isobutylene, followed b y sulfonation; by the formation of a cage polymer of polystyrene about a linear, oil-soluble polymer of isobutylene or butyl rubber, followed by cross linking (sometimes) and sulfonation; by the acylation (with lauroyl groups, as an example) of polystyrene, followed by sulfonation; by the quaternerization with long-chain alkyl halides of polyvinylimidazole; by the chloromethylation of polystyrene, followed by treatment with a long-chain tertiary amine. In this manner, polymers were prepared which had appreciable swelling in a wide range of solvents varying f r o m hexane or benzene on one hand to water on the other. The rates of exchange of certain of these oleophilic ion-exchange polymers in apolar solvents were shown to be comparable to those of conventional ion-exchange resins in aqueous media.