Myung David, Farooqui Nabeel, Waters Dale, Schaber Spencer, Koh Wongun, Carrasco Michael, Noolandi Jaan, Frank Curtis W, Ta Christopher N
Department of Ophthalmology, Stanford University, Stanford, California 94305, USA.
Curr Eye Res. 2008 Jan;33(1):29-43. doi: 10.1080/02713680701793930.
Epithelialization of a keratoprosthesis requires that the implant material be sufficiently permeable to glucose. We have developed a poly(ethylene glycol)/poly(acrylic acid) (PEG/PAA) interpenetrating polymer network (IPN) hydrogel that can provide adequate passage of glucose from the aqueous humor to the epithelium in vivo. A series of PEG/PAA IPNs with varying PEG macromonomer molecular weights were synthesized and evaluated through swelling studies to determine their water content and diffusion experiments to assess their permeability to glucose. One of the PEG/PAA hydrogels prepared in this study had a glucose diffusion coefficient nearly identical to that of the human cornea (approximately 2.5 x 10(-6) cm(2)/sec). When implanted intrastromally in rabbit corneas, this hydrogel was retained and well-tolerated in 9 out of 10 cases for a period of 14 days. The retained hydrogels stayed optically clear and the epithelium remained intact and multilayered, indicating that the material facilitated glucose transport from the aqueous humor to the anterior part of the eye. The results from these experiments indicate that PEG/PAA hydrogels are promising candidates for corneal implant applications such as keratoprostheses and intracorneal lenses, and that the PEG/PAA IPN system in general is useful for creating permeable substrates for ophthalmic and other biomedical applications.
角膜假体的上皮化要求植入材料对葡萄糖具有足够的渗透性。我们开发了一种聚乙二醇/聚丙烯酸（PEG/PAA）互穿聚合物网络（IPN）水凝胶，它能够在体内使葡萄糖从房水充分通过至上皮。合成了一系列具有不同PEG大分子单体分子量的PEG/PAA IPN，并通过溶胀研究评估其含水量，通过扩散实验评估其对葡萄糖的渗透性。本研究制备的一种PEG/PAA水凝胶的葡萄糖扩散系数与人角膜的几乎相同（约2.5×10⁻⁶ cm²/秒）。当将这种水凝胶基质内植入兔角膜时，10例中有9例在14天内保持留存且耐受性良好。留存的水凝胶保持光学透明，上皮保持完整且为多层，这表明该材料促进了葡萄糖从房水向眼前部的转运。这些实验结果表明，PEG/PAA水凝胶有望用于角膜假体和角膜内透镜等角膜植入应用，并且一般而言，PEG/PAA IPN系统可用于制造适用于眼科及其他生物医学应用的可渗透基质。
