Tissue Engineering Applied to the Retinal Prosthesis: Neurotrophin-Eluting Polymeric Hydrogel Coatings.
Tissue Engineering Applied to the Retinal Prosthesis: Neurotrophin-Eluting Polymeric Hydrogel Coatings.
复制标题
组织工程应用于视网膜假体：神经营养蛋白洗脱聚合物水凝胶涂层。
DOI：
10.1016/j.msec.2007.04.011
复制
发表时间：
2008
期刊：
影响因子：
--
通讯作者：
Rizzo3rd,JosephF
中科院分区：
文献类型：
--
作者：
Winter,JessicaO;Gokhale,Mrudula;Jensen,RalphJ;Cogan,StuartF;Rizzo3rd,JosephF
一些团体正在开发视觉假体来帮助视力丧失的患者。虽然这些设备在临床上取得了一些成功，但它们受到分辨率差的严重限制，并且在许多情况下只有 15 个电极。像素密度很差，因为高刺激阈值需要大电极来最小化电荷密度，否则会损坏电极和组织。高刺激阈值要求的一个重要原因是生物相容性差。我们研究了组织工程中流行的一种系统——药物释放水凝胶的应用，作为改善组织-电极界面的机制。研究的水凝胶（即 PEGPLA 可光交联聚合物）释放已知可促进视网膜神经元存活和神经突延伸的神经营养因子（即 BDNF）。水凝胶与视网膜外植体共培养 7 天和 14 天，同时测量神经突延伸和神经突密度。暴露于释放 BDNF 的水凝胶 7 天后，样品的神经突延伸得到增强；然而，到第 14 天时这些增加就消失了，表明药物释放下降。因此，PEGPLA 水凝胶是在视网膜中短期（<14 天）急性释放治疗因子的绝佳候选者，但需要进行额外的修改才能与神经假体一起应用。此外，这些结果表明，在缺乏额外支持线索的情况下，神经营养因子的作用是短暂的，并且采用此类因子的组织工程系统可能只会给患者带来短暂的益处。
Several groups are developing visual prostheses to aid patients with vision loss. While these devices have shown some success in the clinic, they are severely limited by poor resolution, and in many cases have as few as 15 electrodes. Pixel density is poor because high stimulation thresholds require large electrodes to minimize charge density that would otherwise damage the electrode and tissue. A significant contributor to high stimulation threshold requirements is poor biocompatibility. We investigated the application of one system popular in tissue engineering, drug-releasing hydrogels, as a mechanism to improve the tissue–electrode interface. Hydrogels studied (i.e., PEGPLA photocrosslinkable polymers) released neurotrophic factors (i.e., BDNF) known to promote neuron survival and neurite extension in the retina. Hydrogels were examined in co-culture with retinal explants for 7 and 14 days, at which time neurite extension and neurite density were measured. Neurite extension was enhanced in samples exposed to BDNF-releasing hydrogels at 7 days; however, these increases were absent by day 14 suggesting declining drug release. Thus, PEGPLA hydrogels are excellent candidates for short-term (<14 days) acute release of therapeutic factors in the retina, but will require additional modifications for application with neural prostheses. Additionally, these results suggest that the effects of neurotrophic factors are short-lived in the absence of additional support cues, and tissue engineering systems employing such factors may only produce transient benefits to the patient.