Weltman Ahuva, Yoo James, Meng Ellis
Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA.
Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, CA 90089, USA.
Micromachines (Basel). 2016 Oct 4;7(10):180. doi: 10.3390/mi7100180.
The acquisition of high-fidelity, long-term neural recordings in vivo is critically important to advance neuroscience and brain⁻machine interfaces. For decades, rigid materials such as metal microwires and micromachined silicon shanks were used as invasive electrophysiological interfaces to neurons, providing either single or multiple electrode recording sites. Extensive research has revealed that such rigid interfaces suffer from gradual recording quality degradation, in part stemming from tissue damage and the ensuing immune response arising from mechanical mismatch between the probe and brain. The development of "soft" neural probes constructed from polymer shanks has been enabled by advancements in microfabrication; this alternative has the potential to mitigate mismatch-related side effects and thus improve the quality of recordings. This review examines soft neural probe materials and their associated microfabrication techniques, the resulting soft neural probes, and their implementation including custom implantation and electrical packaging strategies. The use of soft materials necessitates careful consideration of surgical placement, often requiring the use of additional surgical shuttles or biodegradable coatings that impart temporary stiffness. Investigation of surgical implantation mechanics and histological evidence to support the use of soft probes will be presented. The review concludes with a critical discussion of the remaining technical challenges and future outlook.
在体内获取高保真、长期的神经记录对于推动神经科学和脑机接口发展至关重要。几十年来，诸如金属微丝和微加工硅杆等刚性材料被用作神经元的侵入式电生理接口，提供单电极或多电极记录位点。大量研究表明，此类刚性接口的记录质量会逐渐下降，部分原因是组织损伤以及探针与大脑之间机械不匹配所引发的免疫反应。微制造技术的进步使得由聚合物杆构建的“软”神经探针得以发展；这种替代方案有可能减轻与不匹配相关的副作用，从而提高记录质量。本文综述了软神经探针材料及其相关微制造技术、由此产生的软神经探针及其应用，包括定制植入和电封装策略。使用软材料需要仔细考虑手术放置问题，通常需要使用额外的手术穿梭器或赋予临时刚度的可生物降解涂层。将介绍手术植入力学的研究以及支持使用软探针的组织学证据。本文综述最后对剩余的技术挑战和未来前景进行了批判性讨论。
