{
    "protocol": "The synthesis of hydrophilic polymers involves the following steps: 1. Utilize gamma or electron beam irradiation to initiate the polymerization process; 2. Employ N-vinylpyrrolidone (NVP) or copolymerize NVP with 2-hydroxyethyl-methacrylate (HEMA) to form coatings; 3. Apply the polymerized and chemically grafted coating on the surfaces of articles intended for contact with living tissue; 4. Ensure that appropriate process conditions and parameters are maintained to achieve thin, hydrophilic layers on various polymeric materials.1. Prepare a mixture of pre-polymerized hydrophilic polymers and monomers suitable for surface modification, such as PVP, PHEMA, NVP, and HEMA. 2. Subject the mixture to high energy radiation to induce graft polymerization on surfaces of articles such as contact lenses. 3. Ensure that the resulting graft coating entraps or enmeshes the pre-polymerized polymer as it forms. 4. Maintain the grafting solution with osmolarity similar to that of normal saline (iso-osmolar) to keep contact lenses in the grafting solution after irradiation until use.Place silicone copolymer contact lenses in tubes containing 10 ml of a deionized water (DI) solution of polyvinylpyrrolidone (PVP/K-90) and N-vinylpyrrolidone (NVP) in a w/w ratio of 4:1 and a total concentration of 10 wt %. Use a carousel holder to rotate the tubes around a gamma source at a distance of approximately 4 inches. Irradiate the samples to a total dose of 0.1 Mrad at a dose rate of approximately 480 rads/min. Wash the contact lenses in DI water.1. Conduct gamma- or electron beam-irradiation induced graft polymerization in an aqueous solution containing a hydrophilic polymer. 2. Ensure that the hydrophilic polymer is at least partially entrapped in the graft polymerized coating. 3. Use a hydrophilic polymer selected from a diverse group including polyalkylene oxides, polyols, and other hydrophilic or hydrophobic materials. 4. Utilize a hydrophilic monomer from a range of ethylenically unsaturated C3–C6 carboxylic acids, allylamines, and other specified monomers with at least one hydrophilic functionality. 5. Optionally, incorporate an ionic monomer, salt of an ionic monomer, or mixture thereof in the total monomer weight. 6. The polymer-monomer mix ratio is varied from 1:4 to >4:1 with total solution concentrations ranging from 1% to 25%. 7. Conduct the process under a pH of high aqueous solution (2% KOH or NaOH)."
}