Modification of the surface of stimulating electrodes by electrospinning

耳蜗植入体（CI）用于治疗耳聋和极重度听力损失。作为对植入的自然反应，结缔组织在植入物插入后不久形成，包围整个植入物并因此使其电绝缘。这种组织形成导致不可预测的刺激传播和增加的能量消耗。在耳聋的过程中，电刺激靶向的听觉神经细胞（螺旋神经节神经元，SGN）也会死亡。以前的尝试，旨在改善CI电极集成，从事一般应用沿着电极阵列。根据目前的知识状态，在接触区域的局部应用将是更有前途的approaches.The本项目的目的是通过合并上述方法与基于纤维的加工方法静电纺丝的表面的局部改性。定制的基于纤维的表面特性操纵旨在（i）减少结缔组织细胞的粘附而不显著影响电特性，以及（ii）使物质（抗炎，神经营养）从接触表面释放。在项目过程中，医用级硅胶弹性体将通过静电纺丝进行加工，并沉积在测试样本和植入物上。随后将表征纤维结构对电极触点电性能的影响。阻抗的潜在增加不应超过5 kOhm的阈值。为了实现这一目标，产生和表征不同的纤维直径和纤维垫厚度。将开发其他技术，使外淋巴液浸透疏水性硅胶纤维结构。因此，目的是利用纤维垫的间隙作为待由电极施加的物质的储存器。在使用测试样本成功进行释放和生物相容性体外研究后，将方法转移到真实的电极载体（植入物）上。除了开发合适的制造策略外，还将研究纤维垫在插入耳蜗期间的分层稳定性。项目完成后，将获得广泛的知识和技术，这将允许（i）通过使用纤维结构化电极表面（ii）单纤维功能化以及具有活性剂的纤维结构和（iii）研究上述措施对电极性能以及生物相容性的影响。

Cochlear implants (CI) are used to treat deafness and profound hearing loss. As a natural reaction to implantation, connective tissue forms shortly after implant insertion, surrounding and therefore electrically insulating the entire implant. This tissue formation leads to unpredictable stimulus propagation and increased energy consumption. In the course of deafness, auditory nerve cells (spiral ganglion neurons, SGN), targeted by electrical stimulation, also die. Previous attempts, aiming at the improvement of CI electrode integration, engaged in a general application along the electrode array. According to the current state of knowledge, a local application in the area of the contacts would be more promising approach.The present project aims at the local modification of the surface by merging the aforementioned approaches with the fiber-based processing method electrospinning. Tailor-made fiber-based manipulation of the surface properties is intended to (i) reduce the adhesion of connective tissue cells without significantly affecting the electrical properties and (ii) enable substance release (anti-inflammatory, neurotrophic) from the surfaces of the contacts. In the course of the project, medical grade silicone elastomers will be processed by electrospinning and deposited on test specimens and implants. This will be followed by a characterization of the influence of the fiber structures on the electrical properties of the electrode contacts. Potential increases in impedance should not exceed a threshold of 5 kOhm. To achieve this goal, different fiber diameters and fiber mat thicknesses are generated and characterized. Additional techniques will be developed to saturate the hydrophobic silicone fiber structures with perilymph. Therefore, aiming to utilize the interstices of the fiber mats as a reservoir for the substances to be applied by the electrode. Following successful in vitro studies on release and biocompatibility using test specimens, the methods are transferred to real electrodes carriers (implants). In addition to the development of suitable manufacturing strategies, the delamination stability of the fiber mats during insertion into the cochlea will be investigated. After completion of the project, extensive knowledge and techniques will be available, which will allow (i) structuring of electrode surfaces by using fibers (ii) functionalization of single fibers as well as the fiber construct with active agents and (iii) investigation of the influence of the mentioned measures on the electrical electrode properties as well as biocompatibility.