基于可降解材料的植入式脑神经传感器研究

The long-standing engineering design goal of traditional electronics has been to maximize reliability and operation lifetime. An emerging new type of electronics built on biodegradable materials possesses a key characteristic that the major materials can completely dissolve in environmental and physiological aqueous solutions, which envisions a new path for electronic waste managements and implantable sensors. This proposal aims to develop such biodegradable implantable brain neural sensor composed of dissolvable materials, in a sense that the device can physically “disappear” and safely resorb by the body after functioning. Compared to traditional brain neural sensors, such as the inherently invasive intracranial electrocorticography (ECoG) and intracortical electrodes, the advantages of biodegradable neural sensors are that they help avoid secondary surgery for device removal, and therefore relieve the burden of patients and decrease potential risks. This project plans to investigate the degradation characteristics of various thin film materials including metals, semiconductors and polymers, and integrate them into implantable neural sensors through nonconventional micro-fabrication techniques. Biodegradable encapsulation materials with low water transmission rates will also be explored as well as their influences on the electrical properties of neural electrodes, in order to tune the lifetime of sensors to serve different applications. The research is expected to provide new perspectives for the diagnosis and treatment of neural diseases and the exploration of neuron activity.

传统的电子器械向来以提高器件的稳定性和寿命为目标，而基于可降解材料制备的电子器件，可在环境或者生理溶液中完全溶解，为废旧电子产品的处理以及植入式医用探测器的研究开辟了新的道路。本课题计划探索这种新型的由可降解材料制备的脑神经传感器，相比于传统器件（例如侵入式的颅内脑电图传感器以及扎入式脑神经传感器），其优势是器件使用完毕后可自行“消失”，安全地被人体吸收，从而避免了二次创伤手术移除器件，减轻病人的负担以及潜在的安全隐患。拟研究多样化的材料（金属、半导体等）的溶解性质，并通过新型的微纳加工工艺将材料以薄膜的形式集成神经传感器。同时探索低透水性的可降解薄膜封装材料，并在体外的溶液中测试其对传感器电学性能的影响，以调控器件的工作寿命适应不同的需求。希望该研究能为神经性疾病的诊疗以及神经元活动的探索提供新的思路。

可降解电子器件是新兴的研究领域，其特点是全由可降解材料制备，可在生理溶液中完全降解，在植入式医用监测、治疗器械领域具有潜在的重要价值，可避免二次取出手术，减轻病人负担。本课题系统探索了金属钼电极、聚乳酸-羟基乙酸共聚物(PLGA)以及封装防水单晶硅薄膜在不同生理缓冲溶液中的降解速率和透水性质。并基于可降解材料制备了可降解脑神经传感器，实现在体信号的测量，同时研究了神经传感器在体外溶液界面中的阻抗性质以及细胞相容性。这些研究表明薄膜单晶硅材料具有较好的防水性质，可用于延长、调控可降解电子的工作寿命。金属钼电极具有一定的稳定性，可与可降解高分子、单晶硅防水材料相结合，实现颅内脑皮层信号的探测，且在实现完功能后可完全降解。该研究为可降解材料及器件的制备奠定了重要的基础，为神经性疾病的诊断及治疗提供了新的思路。