Synthesis of Soft Polysiloxane-urea Elastomers for Intraocular Lens Application
| Autor: | Andreas Kandelbauer, Günter E. M. Tovar, Günter Lorenz, Natascha Riehle, Sibylle Thude |
|---|---|
| Přispěvatelé: | Publica |
| Rok vydání: | 2019 |
| Předmět: |
Materials science
Siloxanes Cell Survival Proton Magnetic Resonance Spectroscopy General Chemical Engineering 02 engineering and technology 010402 general chemistry Elastomer 01 natural sciences Octamethylcyclotetrasiloxane Catalysis General Biochemistry Genetics and Molecular Biology Cell Line chemistry.chemical_compound Dogs Elastic Modulus Transmittance Copolymer Animals Humans Urea Composite material Lenses Intraocular Cell Death General Immunology and Microbiology Polydimethylsiloxane General Neuroscience 021001 nanoscience & nanotechnology 0104 chemical sciences Molecular Weight Refractometry Elastomers chemistry Siloxane Stress Mechanical 0210 nano-technology Refractive index |
| Zdroj: | Journal of Visualized Experiments. |
| ISSN: | 1940-087X |
| Popis: | This study discusses a synthesis route for soft polysiloxane-based urea (PSU) elastomers for their applications as accommodating intraocular lenses (a-IOLs). Aminopropyl-terminated polydimethylsiloxanes (PDMS) were previously prepared via the ring-chain equilibration of the cyclic siloxane octamethylcyclotetrasiloxane (D4) and 1,3-bis(3-aminopropyl)-tetramethyldisiloxane (APTMDS). Phenyl groups were introduced into the siloxane backbone via the copolymerization of D4 and 2,4,6,8-tetramethyl-2,4,6,8-tetraphenyl-cyclotetrasiloxane (D4Me,Ph). These polydimethyl-methyl-phenyl-siloxane-block copolymers were synthesized for increasing the refractive indices of polysiloxanes. For applications as an a-IOL, the refractive index of the polysiloxanes must be equivalent to that of a young human eye lens. The polysiloxane molecular weight is controlled by the ratio of the cyclic siloxane to the endblocker APTMDS. The transparency of the PSU elastomers is examined by the transmittance measurement of films between 200 and 750 nm, using a UV-Vis spectrophotometer. Transmittance values at 750 nm (upper end of the visible spectrum) are plotted against the PDMS molecular weight, and > 90% of the transmittance is observed until a molecular weight of 18,000 g·mol-1. Mechanical properties of the PSU elastomers are investigated using stress-strain tests on die-cut dog-bone-shaped specimens. For evaluating mechanical stability, mechanical hysteresis is measured by repeatedly stretching (10x) the specimens to 5% and 100% elongation. Hysteresis considerably decreases with the increase in the PDMS molecular weight. In vitro cytotoxicity of some selected PSU elastomers is evaluated using an MTS cell viability assay. The methods described herein permit the synthesis of a soft, transparent, and noncytotoxic PSU elastomer with a refractive index approximately equal to that of a young human eye lens. |
| Databáze: | OpenAIRE |
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