Bio-Enhanced Neural Electrodes Based on Porous Silicon

描述（由申请人提供）：该项目的总体目标是开发具有增强生物相容性的纳米结构多孔硅作为神经电极材料，特别是新型混合硅/陶瓷多位点神经记录电极阵列。我们之前已经证明，纯陶瓷基多位点神经电极阵列可以持续记录多个单个神经元的长期活动长达六周。这些结果与微丝电极相似，优于其他薄膜电极。然而，为了使任何电极系统作为神经义肢装置的神经接口组件，电极将需要连续记录多年。初步研究表明，通过在硅中引入多种孔隙度，硅的行为可以从相对生物惰性的材料转变为生物活性的材料，甚至是可吸收的材料。在这个提案中，我们计划研究两种类型的半柔性纳米结构硅/陶瓷混合神经电极。在一种类型中，电极材料将完全基于在薄硅衬底上电化学形成的纳米结构多孔硅。在第二种类型的电极中，额外的超薄陶瓷材料层将通过特殊的沉积工艺在纳米结构多孔硅上形成保形。后一种结构将使我们能够直接比较具有纳米结构陶瓷表面的电极与传统陶瓷基器件的性能。

DESCRIPTION (provided by applicant): The overall objective of this program is to develop nanostructured porous silicon as neural electrode materials with enhanced biocompatibility, in particular for novel hybrid silicon/ceramic multi-site neural recording electrode arrays. We have previously shown that the pure ceramic-based multi-site neural electrode arrays can consistently record multiple single neuron activity chronically for up to six weeks. These results are similar to microwire electrodes and better than other thin film electrodes. However, in order for any electrode system to act as neural interface components of neural prosthetic devices, the electrode will be required to record consistently for many years. Preliminary studies have shown that by introducing widely varying porosity into silicon, its behavior can be tuned from that of a relatively bio-inert material to one that is bioactive, and even resorbable. In this proposal, we plan to investigate two types of semi-flexible nanostructured hybrid silicon/ceramic neural electrodes. In one type, the electrode material will be based solely on nanostructured porous silicon formed electrochemically on a thin Si substrate. In the second type of electrode, an additional ultra-thin layer of ceramic material will be formed conformally onto the nanostructured porous silicon using a special deposition process. The latter structure will allow us to directly compare the performance of electrodes with essentially nanostmctured ceramic surface to conventional ceramic-based devices. In Phase I, the efficacy of nanostructured porous silicon neural electrodes will be evaluated in vivo using rat brain model. The neural tissue will be evaluated using histology methods to look for neural damage near the site of implantation and study the growth of neurons into the porous silicon electrodes. To promote neural growth at the electrode/tissue interface and for better contact of the recording sites on the array with neurons, we will test the ability of the porous silicon to deliver neurotrophic molecules. In Phase II, upon optimizing the parameters for nanostructured porous silicon electrodes, Spire and its collaborators will design, fabricate and test in vivo performance of a two dimensional array of porous silicon-based neural electrodes for chronic, long-term (greater than 6 months) multi-site recording.