PDF(Pubmed)
Abstract：
Invasive neural implants allow for high-resolution bidirectional communication with the nervous tissue and have demonstrated the ability to record neural activity, stimulate neurons, and sense neurochemical species with high spatial selectivity and resolution. However, upon implantation, they are exposed to a foreign body response which can disrupt the seamless integration of the device with the native tissue and lead to deterioration in device functionality for chronic implantation. Modifying the device surface by incorporating bioactive coatings has been a promising approach to camouflage the device and improve integration while maintaining device performance. In this work, we explored the novel application of a chondroitin sulfate (CS) based hydrophilic coating, with anti-fouling and neurite-growth promoting properties for neural recording electrodes. CS-coated samples exhibited significantly reduced protein-fouling in vitro which was maintained for up to 4-weeks. Cell culture studies revealed a significant increase in neurite attachment and outgrowth and a significant decrease in microglia attachment and activation for the CS group as compared to the control. After 1-week of in vivo implantation in the mouse cortex, the coated probes demonstrated significantly lower biofouling as compared to uncoated controls. Like the in vitro results, increased neuronal population (neuronal nuclei and neurofilament) and decreased microglial activation were observed. To assess the coating\'s effect on the recording performance of silicon microelectrodes, we implanted coated and uncoated electrodes in the mouse striatum for 1 week and performed impedance and recording measurements. We observed significantly lower impedance in the coated group, likely due to the increased wettability of the coated surface. The peak-to-peak amplitude and the noise floor levels were both lower in the CS group compared to the controls, which led to a comparable signal-to-noise ratio between the two groups. The overall single unit yield (% channels recording a single unit) was 74% for the CS and 67% for the control group on day 1. Taken together, this study demonstrates the effectiveness of the polysaccharide-based coating in reducing biofouling and improving biocompatibility for neural electrode devices.
摘要：
有创神经植入物允许与神经组织的高分辨率双向通信，并已证明能够记录神经活动，刺激神经元，并以高空间选择性和分辨率感知神经化学物种。然而,植入后，他们暴露于异物反应，这可能会破坏设备与天然组织的无缝集成，并导致慢性植入设备功能的恶化。通过结合生物活性涂层来修饰装置表面一直是伪装装置并改善集成同时保持装置性能的有前景的方法。在这项工作中,我们探索了硫酸软骨素（CS）基亲水涂层的新应用，神经记录电极具有防污和促进神经突生长的特性。CS包被的样品在体外表现出显著减少的蛋白质污染,其维持长达4周。细胞培养研究显示，与对照组相比，CS组的神经突附着和生长显着增加，小胶质细胞附着和活化显着降低。在小鼠皮质体内植入1周后，与未涂覆的对照相比,涂覆的探针显示出显著较低的生物污染。像体外结果一样，观察到神经元数量增加（神经元核和神经丝）和小胶质细胞活化减少。为了评估涂层对硅微电极记录性能的影响，我们在小鼠纹状体中植入有涂层和无涂层的电极1周，并进行阻抗和记录测量。我们观察到涂层组的阻抗明显降低，可能是由于涂层表面的润湿性增加。与对照组相比，CS组的峰峰值幅度和本底噪声水平均较低，这导致两组之间的信噪比相当。在第1天,CS的总单个单位产率(记录单个单位的通道%)为74%,对照组为67%。一起来看,这项研究证明了基于多糖的涂层在减少生物污染和改善神经电极装置的生物相容性方面的有效性。
