神经电极的水凝胶涂层及楔形角对组织损伤的影响

目的研究水凝胶涂层的厚度以及电极楔形角对植入损伤的影响。方法基于植入损伤评估系统,进行模拟神经电极植入过程的实验,评估电极植入造成的组织损伤。用浸涂次数(分别为0、1、2、3)控制水凝胶涂层的厚度,选用30°、40°、50°、60°为电极楔形角的变量。以最大组织应变和最大植入力为组织损伤的衡量标准。结果水凝胶涂层越厚,电极植入损伤越大。楔形角越小,植入损伤也越小。同时,减小针尖的楔形角可以减小涂层对组织损伤的影响程度。3次浸涂时,楔形角为30°时,最大组织应变与最大植入力分别增加3.4%和3.8%,而楔形角为60°时,两者分别增加11.3%和18.1%。结论神经电极的水凝胶涂层将增大植入电极对生物组织的损伤,然而减小电极尖端楔形角的方法可以降低水凝胶涂层厚度对植入损伤的影响程度。

Effects of PVA-H Coating Thickness and Tip Angle on Tissue Injury

Objective To study the effects of PVA-H coating thickness and tip angle on the tissue injury caused by the implantation of neural electrodes. Methods Simulated implantation experiments were conducted based on a tissue injury evaluation system to evaluate the tissue injury caused by electrode implantation. The coating thicknesses were controlled by the number of dip coating times (0, 1, 2, and 3), whereas the tip angles were set as 30°, 40°, and 50°. The maximum tissue strain and insertion force were selected as the measurement of the tissue injury. Results thicker hydrogel coating and larger tip angle would cause more serious tissue injury. Simultaneously, reducing the tip angle of the neural electrode could reduce the degree of the hydrogel coating effect on the tissue injury. When the tip angle was 30°, the maximum strain and the peak insertion force increased by 3.4% and 3.8%, respectively, whereas when the wedge angle was 60°, the maximum strain and maximum insertion force increased by 11.3% and 18.1%, respectively. Conclusions The hydrogel coating of the neural electrode increased the injury of biological tissues caused by the implantation of the neural electrode. However, the method of decreasing the tip angle of the electrode could reduce the degree of the negative effects of the hydrogel coating thickness on the implantation injury.