神经电极-脑组织界面微动环境力学特性仿真

Mechanical simulation of neural electrode-brain tissue interface under different micro-motion conditions

为了解决电极的长期寿命问题,采用有限元方法对电极-脑组织界面的微动进行静态分析和瞬态分析,基于商用电极A1x16-3-100-413进行建模,研究微动频率f和电极界面黏附状态对电极-脑组织界面力学状态的影响.结果表明,f对等效应力σ最大值有显著影响,高频率比低频率更不利于电极的长期稳定性,且存在临界值;f在20Hz左右时σ接近最大值,超过20Hz后f的影响减小;电极与脑组织之间的物理耦合度对界面力学状态有较大影响,增强电极和脑组织的黏附程度,可以有效减小微电极尖端和神经组织间的应力、应变以及分层,从而提高电极使用寿命.

In order to improve the long-term stability simulation had been used for the static analysis and tr of the brain anslent ana motion＇s frequency and friction state on the mechanical state of ly th implanted electrode, the finite-element sis. In particular, the effects of micro- e probe-brain tissue interface had been investigated based on the commercial electrode, A1x16-3-100-413. The results demonstrate that micro- motion frequency has a great effect on the maximal Vort Mises stress observed on the model, indicating that higher frequencies are more harmful than lower frequencies in terms of long-term stability of the electrode. And there exists a critical value： when the value of frequency is 20 Hz, the stress is nearly to the maximum, followed by the decreased influence of frequency. The results also show that physical coupling degree between the electrode and the brain tissue has a significant influence on the interface mechanical state. Enhancing the attachment between the electrode and the brain can effectively decrease the stress, strain and delamination of the microelectrode tip with respect to the adjacent neural tissue, thus improve the working life of implanted electrode.