Department of Ophthalmology and Visual Science, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8574, Japan.
Biomaterials. 2011 Feb;32(4):1080-90. doi: 10.1016/j.biomaterials.2010.10.002. Epub 2010 Nov 4.
This study manipulates both clear cornea and opaque sclera by two dehydration processes for revealing the relationship between altered tissue structures and change in optical functions. In contrast to the high levels of light scattering in dehydrated tissues by critical point dry, a simple dehydration at 4-8 °C effectively and significantly improved their visible-light transmission, even in the sclera, with accompanying dense fiber packing. Further improvement in visible-light transmission, from 40-50% to 80-90%, has been achieved by flatting tissue surface with cover glasses during dehydration at low temperature. Such optical clearing of sclera by dehydration is reversible. However, chemical cross-linking effectively stabilizes their densely packed microscopic structures and visible-light transmission at over 50% irreversibly, even at wet conditions. Interestingly, the repetition of both low temperature dehydration/cross-linking treatments effectively reduced the required amounts of cross-linking reagents to keep a high transparency. Wet transparent cross-linked sclera can also show a characteristic strong tensile strength. Furthermore, rabbit corneal epithelium has regenerated on the transparent sclera with cross-linking in vitro.
本研究通过两种脱水过程来处理透明的角膜和不透明的巩膜，以揭示组织结构改变与光学功能变化之间的关系。与临界点干燥导致脱水组织中高水平的光散射相反，简单的 4-8°C 低温脱水可有效且显著提高其可见光透过率，即使在巩膜中也是如此，同时伴随着密集的纤维堆积。通过在低温脱水过程中用盖玻片将组织表面压平，可见光透过率进一步从 40-50%提高到 80-90%。巩膜的这种脱水光学透明性是可逆的。然而，化学交联可有效地稳定其密集堆积的微观结构和超过 50%的可见光透过率，即使在潮湿条件下也是如此。有趣的是，低温脱水/交联处理的重复有效地减少了所需的交联试剂的量，以保持高透明度。湿态透明交联的巩膜也可以表现出特征性的高强度拉伸强度。此外，在体外交联的透明巩膜上，兔角膜上皮已经再生。
