Hermetically sealed coatings for neural implants

神经植入物是一种很有前途的方法，可以持续治疗一些目前无法治愈的严重疾病，如失明，帕金森病或闭锁综合征。这些系统由绝缘和导电层的非常薄且柔性的箔组成，其必须长期植入。它们必须在大脑中工作20年或更长时间。这需要一个稳定的气密密封，不能提供由今天的微型技术。该项目旨在找到一个薄膜封装和技术，提供可靠的操作20年的大脑液。申请人提出研究来自聚合物和氧化物夹层的夹层。作为聚合物，聚对二甲苯和聚酰亚胺将被研究。中间层将是金属氧化物，由原子层沉积制成。此外，还将准备和分析每个电气互连的完全气密密封系统。 创新首先是开发、分析和改进用于密封神经植入物的新概念。其次，创新是一种新的工艺流程，以各向同性和无缺陷的方式在柔性基板上沉积存款无机-有机屏障。选择的科学方法是首先制定测试程序，然后准备一系列样品并进行分析。主要测试程序将是加速浸泡测试，这意味着将穿刺针浸入热盐水中，并通过介电谱对其进行测量。制备具有不同形貌的样品。这些都涂有不同的屏障层，然后分析和评估。对于一个或几个选定的阻隔涂层，将组装和测试一个完整的系统。将通过基于活化能的模型对水扩散进行理论描述。由于如果存在液态水则会发生腐蚀，因此也将模拟扩散的水分子在微腔处的聚合物和金属氧化物层的边界处的冷凝。

Neural implants are a promising approach towards sustainable treatment of a number of severe illnesses which cannot be healed today, such as blindness, Parkinson’s disease or the locked-in syndrome. These systems consist of very thin and flexible foils of insulating and conducting layers, which must be chronically implanted. They have to work 20 years and more in the brain. This needs a stability of hermetic sealing which cannot be provided by today’s micro technology.The project aims at finding a thin film package and a technology which provide reliable operation for 20 years in the brains liquor. The applicants propose to investigate sandwich layers from polymers and oxidic interlayers. As polymers, Parylene and Polyimide will be investigated. The interlayers will be metallic oxides, made by atomic layer deposition. Also systems with full hermetic sealing for each electric interconnect separately will be prepared and analyzed. The innovation is first the development, analysis and the improvement of a new concept for hermetically sealing neural implants. Second, innovation is a new process flow to deposit anorganic-organic barriers on flexible substrates in an isotropic and flawless way. The scientific method chosen is first to develop test procedures, next to prepare a series of samples and to analyze them. The primary test procedure will be the accelerated soak test, which means immersing the probes in hot saline and measuring them by dielectric spectroscopy. Samples with different topographies are prepared. These are coated with different barrier layers, then analyzed and evaluated. For one or several selected barrier coatings a full system will be assembled and tested.Theoretical description of the water diffusion will be made by a model based on activation energies. Since corrosion happens if liquid water is present, the condensation of the diffused water molecules at the boundary of polymer and metal oxide layers at micro cavities will also be modelled.