Redolfi Riva Eugenio, D'Alessio Angela, Micera Silvestro
The BioRobotics Institute, Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, 56127 Pisa, Italy.
Translational Neuroengineering, Centre for Neuroprosthetics and Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1000 Lausanne, Switzerland.
Micromachines (Basel). 2022 Apr 28;13(5):692. doi: 10.3390/mi13050692.
Implantable flexible neural interfaces (IfNIs) are capable of directly modulating signals of the central and peripheral nervous system by stimulating or recording the action potential. Despite outstanding results in acute experiments on animals and humans, their long-term biocompatibility is hampered by the effects of foreign body reactions that worsen electrical performance and cause tissue damage. We report on the fabrication of a polysaccharide nanostructured thin film as a coating of polyimide (PI)-based IfNIs. The layer-by-layer technique was used to coat the PI surface due to its versatility and ease of manufacturing. Two different LbL deposition techniques were tested and compared: dip coating and spin coating. Morphological and physiochemical characterization showed the presence of a very smooth and nanostructured thin film coating on the PI surface that remarkably enhanced surface hydrophilicity with respect to the bare PI surface for both the deposition techniques. However, spin coating offered more control over the fabrication properties, with the possibility to tune the coating's physiochemical and morphological properties. Overall, the proposed coating strategies allowed the deposition of a biocompatible nanostructured film onto the PI surface and could represent a valid tool to enhance long-term IfNI biocompatibility by improving tissue/electrode integration.
可植入柔性神经接口（IfNIs）能够通过刺激或记录动作电位直接调节中枢和外周神经系统的信号。尽管在动物和人体的急性实验中取得了显著成果，但其长期生物相容性受到异物反应的影响，这会降低电性能并导致组织损伤。我们报道了一种多糖纳米结构薄膜的制备，该薄膜用作基于聚酰亚胺（PI）的IfNIs的涂层。由于其多功能性和易于制造，采用层层技术来涂覆PI表面。测试并比较了两种不同的层层沉积技术：浸涂和旋涂。形态学和物理化学表征表明，在PI表面存在非常光滑且具有纳米结构的薄膜涂层，对于这两种沉积技术，该涂层相对于裸露的PI表面显著提高了表面亲水性。然而，旋涂对制造特性的控制更多，有可能调整涂层的物理化学和形态学特性。总体而言，所提出的涂层策略能够在PI表面沉积生物相容性纳米结构薄膜，并且可以成为通过改善组织/电极整合来增强IfNI长期生物相容性的有效工具。
