ABSTRACT
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.