Department of Otolaryngology-Head and Neck Surgery.
Department of Chemical and Biochemical Engineering, University of Iowa.
Otol Neurotol. 2021 Dec 1;42(10):1476-1483. doi: 10.1097/MAO.0000000000003288.
Application of photografted zwitterionic coatings to cochlear implant (CI) biomaterials will reduce friction and insertion forces.
Strategies to minimize intracochlear trauma during implantation of an electrode array are critical to optimize outcomes including preservation of residual hearing. To this end, advances in thin-film zwitterionic hydrogel coatings on relevant biomaterials may show promise, in addition to the potential of these materials for decreasing the intracochlear foreign body response.
Using a recently designed one-step process, thin-film coatings derived from zwitterionic sulfobetaine methacrylate (SBMA) were photopolymerized and photografted to the surface of polydimethylsiloxane (PDMS, silastic) samples and also to CI arrays from two manufacturers. Fluorescein staining and scanning electron microscopy with energy-dispersive X-ray spectroscopy verified and characterized the coatings. Tribometry was used to measure the coefficient of friction between uncoated and coated PDMS and synthetic and biological tissues. Force transducer measurements were obtained during insertion of uncoated (n = 9) and coated (n = 9) CI electrode arrays into human cadaveric cochleae.
SBMA thin-film coating of PDMS resulted in >90% reduction in frictional coefficients with steel, ceramic, and dermal tissue from guinea pigs (p < 0.0001). We employed a novel method for applying covalently bonded, durable, and uniform coating in geographically selective areas at the electrode array portion of the implant. Image analysis confirmed uniform coating of PDMS systems and the CI electrode arrays with SBMA polymer films. During insertion of electrode arrays into human cadaveric cochleae, SBMA coatings reduced maximum force by ∼40% during insertion (p < 0.001), as well as decreasing force variability and the overall work of insertion.
Thin-film SBMA photografted coatings on PDMS and electrode arrays significantly reduce frictional coefficients and insertional forces in cadaveric cochleae. These encouraging findings support that thin-film zwitterionic coating of CI electrode arrays may potentially reduce insertional trauma and thereby promote improved hearing and other long-term outcomes.
将光电接枝两性离子涂层应用于耳蜗植入物（CI）生物材料上，将减少摩擦和插入力。
在植入电极阵列过程中，最大限度地减少对内耳的创伤的策略对于优化结果至关重要，包括保留残余听力。为此，在相关生物材料上的薄膜两性离子水凝胶涂层的进步可能具有前景，此外，这些材料还有可能减少内耳异物反应。
使用最近设计的一步法，将光电接枝的两性离子磺基甜菜碱甲基丙烯酸酯（SBMA）薄膜涂层光聚合并光接枝到聚二甲基硅氧烷（PDMS，硅橡胶）样品和两个制造商的 CI 阵列的表面。荧光染色和带有能量色散 X 射线光谱的扫描电子显微镜验证并描述了这些涂层。摩擦测量用于测量未涂层和涂层 PDMS 与合成和生物组织之间的摩擦系数。在将未涂层（n=9）和涂层（n=9）CI 电极阵列插入人类尸体耳蜗期间，通过力传感器测量获得插入力。
PDMS 的 SBMA 薄膜涂层使与钢、陶瓷和豚鼠皮肤组织的摩擦系数降低了>90%（p<0.0001）。我们采用了一种新颖的方法，将共价键合的、持久的、均匀的涂层应用于植入物电极阵列部分的地理选择性区域。图像分析证实了 PDMS 系统和 SBMA 聚合物膜的 CI 电极阵列的均匀涂层。在将电极阵列插入人类尸体耳蜗期间，SBMA 涂层在插入过程中最大力降低了约 40%（p<0.001），同时降低了力变异性和插入的整体功。
PDMS 和电极阵列上的 SBMA 薄膜光电接枝涂层显著降低了尸体耳蜗中的摩擦系数和插入力。这些令人鼓舞的发现支持了 CI 电极阵列的薄膜两性离子涂层可能潜在地减少插入创伤，从而促进更好的听力和其他长期结果。
