聚乙烯醇水凝胶模拟自然玻璃体的实验研究

目的　筛选与自然玻璃体性能相似的聚乙烯醇［poly（vinyl alcohol），PVA］水凝胶，为探索寻找新的玻璃体替代物提供依据。方法　采用γ-射线（Co⁶⁰）辐照交联得到1%PVA水凝胶、3%PVA水凝胶、7%PVA水凝胶。通过检测PVA水凝胶的物理光学性能（比重、含水率、透光率、屈光率、pH值、溶胀性能）和流变性能及细胞毒性，筛选与自然玻璃体性能相似的PVA水凝胶。结果　（1）物理光学性能:1%PVA水凝胶的含水率、屈光指数、透光率、pH值、比重分别为98.90%、1.335 5、94.80%、7.22、1003.9 g·L^-1；3%PVA水凝胶的各指标分别为98.10%、1.336 1、93.20%、7.25、1014.4 g·L^-1；7%PVA水凝胶的各指标分别为93.50%、1.342 5、88.20%、7.41、1114.7 g·L^-1，3%PVA和1%PVA水凝胶与自然玻璃体有相似的光学物理性能。（2）流变性能:三种浓度PVA水凝胶储存模量（G′）均大于损耗模量（G″），表明三种物质均为有黏弹性能的凝胶体，且其弹性性能大于黏性性能。1%PVA:G′、G″分别为（3.2±1.1）Pa、（0.8±0.5）Pa；3%PVA:G′、G″分别为（6.1±1.3）Pa、（1.3±0.9）Pa；7%PVA:G′、G″分别为（106.5±18.6）Pa、（18.3±12.8）Pa。在顺应性方面，7% PVA＞3% PVA＞1% PVA；在蠕变方面，3% PVA＞7% PVA＞1% PVA。（3）细胞毒性:MTT比色实验结果显示细胞在1%PVA、3%PVA、7%PVA浸泡液中培养72 h后，各组间吸光度（A值）值比较差异均无统计学意义（均为P>0.05），表明三种水凝胶均无明显细胞毒性，拥有良好的生物相容性。结论　3%PVA水凝胶具有与自然玻璃体相似的光学、物理和流变性能，拥有良好的生物相容性，能很好地模拟自然玻璃体的性能。

A study of polyvinyl alcohol hydrogel simulating human vitreous body

Objective　To screen a kind of polyvinyl alcohol (PVA) hydrogel with similar physical properties to human vitreous body as to provide basis for exploring new vitreous substitutes.Methods　Different concentrations (1%，3%，7%) PVA solution were crosslinked by γ-irradiation (Co⁶⁰)，and 1%，3% and 7% PVA hydrogels were harvested.Then PVA hydrogels with similar properties to natural vitreous were screened by detecting the physical and optical properties (density，water content，light transmittance，refractive index，pH value，swelling property) and rheological properties and cytotoxicity of PVA hydrogels.Results　As for the physical and optical properties of the hydrogels，the water content，refractive index，light transmittance，pH value and density of 1%，3% and 7% PVA hydrogel was 98.90% vs.98.10% vs.93.50%，1.335 5 vs.1.336 1 vs.1.342 5，94.80% vs.93.20% vs.88.20%，7.22 vs.7.25 vs.7.41 and 1003.9 g·L^-1d vs.1014.4 g·L^-1 vs.1114.7 g·L^-1，respectively.Finally，1% and 3% PVA hydrogels had the similar physical and optical properties to the human vitreous.As for rheological properties，the storage modulus (G′) of the three PVA hydrogels was larger than the loss modulus (G″)，indicating that these three hydrogels were viscoelastic gel，and the elastic properties was greater than the viscosity.1% PVA:G′ was (3.2±1.1)Pa，G″ was (0.8±0.5)Pa；3% PVA:G′ was (6.1±1.3)Pa，G″ was (1.3±0.9)Pa；7% PVA:G′ was (106.5±18.6)Pa and G″ was (18.3±12.8)Pa.According to resilience，the hydrogels can be ranked as follows:7% PVA>3% PVA>1% PVA；in terms of creep，3% PVA>7% PVA>1% PVA.Additionally，MTT colorimetric assay showed that there was no significant difference in A values among the three groups by cells culture in 1%，3% and 7% PVA for 72 hours (all P>0.05)，suggesting that all the three hydrogels showed no obvious cytotoxicity and had good biocompatibility.Conclusion　3% PVA hydrogel has similar optical，physical and rheological properties to the human vitreous，and shows good biocompatibility，which can be one of vitreous substitutes.