5264
Reda Mohammed Mourad
Modified Silicon Rubber Of Controlled Bacterial Contamination For Contact Lenses Applications
silicone rubber, PDMS, SiH, ultraviolet-curable PDMS-PU prepolymer, IPN, Grafting copolymerization, NAgSiH composites, AgNPS, antimicrobial activities.
This thesis deals with the modification of silicone rubber based hydrogels manifesting the comfort and wearability for use in contact lenses application. Silicone rubber was modified by three different techniques to obtain silicone hydrogel (SiH) biomaterials possessing hydrophilic and antibacterial properties for contact lenses application. First technique: Interpenetrating polymer network (INP) Polydimethylsiloxane (PDMS), a type of silicone rubbermostly used in biomedical devices, was modified into ultraviolet-curable PDMS- polyurethane (PDMS-PU) prepolymer, then INP silicone hydrogels consisting of ultraviolet- curable PDMS-PU prepolymer, 3- methacryloxypropyl tris(trimethylsoloxy silane) (TRIS) and hydrophilic monomers N,N-dimethyl acrylamide (DMA) and polyethylene glycol methacrylate PEGMA were formed. Second technique: Graft copolymerization of PDMS through photo-polymerizationGrafting copolymerization of PDMS, having methacryloxy side chain, with different concentrations of DMA and N-vinyl pyrrolidone was done by free radical polymerization. The chemical groups of these silicone hydrogels formed by IPN and grafting copolymerization techniques were characterized by FTIR. Their tensile modulus, protein adsorption, equilibrium water content and water contact angle were also measured. It was found that the equilibrium water content enhanced when the hydrophilic monomer content increased, while their protein adsorption, tensile modulus and water contact angle decreased. Third technique: The impregnation of silver nanoparticles into the prepared silicone hydrogelNanosilver- silicone hydrogel (NAgSiH) composites were synthesized by impregnation of the prepared SiH films (containing PDMS dimthacrylate macromer) in silver nitrate followed by diffusion and in-situ chemical reduction of silver ions loaded in SiH film.The silver nano particles (AgNPS) were identified by UV-Vis absorption spectroscopy, Energy-dispersive X-ray spectroscopy (EDX) mapping and EDX spectrum. The physico-mechanical and chemical properties of NAgSIH films were studied. The antimicrobial effect of the hydrogels was evaluated. It was found that UV-Vis absorption spectroscopy and EDX mapping and spectrum emphasized that AgNPS were in spherical shape. The light transmittance decreased as the concentration of AgNPS increased, while the Young’s modulus increased gradually. NAgSiH composites possessed an excellent antimicrobial activities.
2016
Ph.d
Ain Shams
Science