Du Zhanhong Jeff, Bi Guo-Qiang, Cui Xinyan Tracy
Department of Bioengineering, University of Pittsburgh, 5057 Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA.
Hefei National Laboratory for Physical Sciences at the Microscale, CAS Center for Excellence in Brain Science and Intelligence, Technology and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China.
Adv Funct Mater. 2018 Mar 21;28(12). doi: 10.1002/adfm.201703988. Epub 2017 Dec 11.
Implantable microelectrode arrays (MEAs) are important tools for investigating functional neural circuits and treating neurological diseases. Precise modulation of neural activity may be achieved by controlled delivery of neurochemicals directly from coatings on MEA electrode sites. In this study, a novel dual-layer conductive polymer/acid functionalized carbon nanotube (fCNT) microelectrode coating is developed to better facilitate the loading and controlled delivery of the neurochemical 6,7-dinitroquinoxaline-2,3-dione (DNQX). The base layer coating is consisted of poly(3,4-ethylenedioxythiophene/fCNT and the top layer is consisted of polypyrrole/fCNT/DNQX. The dual-layer coating is capable of both loading and electrically releasing DNQX and the release dynamic is characterized with fluorescence microscopy and mathematical modeling. In vivo DNQX release is demonstrated in rat somatosensory cortex. Sensory-evoked neural activity is immediately (<1s) and locally (<446 µm) suppressed by electrically triggered DNQX release. Furthermore, a single DNQX-loaded, dual-layer coating is capable of inducing effective neural inhibition for at least 26 times without observable degradation in efficacy. Incorporation of the novel drug releasing coating onto individual MEA electrodes offers many advantages over alternative methods by increasing spatial-temporal precision and improving drug selection flexibility without increasing the device's size.
可植入微电极阵列（MEA）是研究功能性神经回路和治疗神经疾病的重要工具。通过直接从MEA电极位点的涂层中可控地释放神经化学物质，可以实现对神经活动的精确调节。在本研究中，开发了一种新型的双层导电聚合物/酸功能化碳纳米管（fCNT）微电极涂层，以更好地促进神经化学物质6,7-二硝基喹喔啉-2,3-二酮（DNQX）的负载和可控释放。基层涂层由聚（3,4-亚乙基二氧噻吩）/fCNT组成，顶层由聚吡咯/fCNT/DNQX组成。双层涂层能够负载并电释放DNQX，其释放动力学通过荧光显微镜和数学建模进行表征。在大鼠体感皮层中证明了体内DNQX的释放。电触发的DNQX释放可立即（<1秒）且局部（<446微米）抑制感觉诱发的神经活动。此外，单个负载DNQX的双层涂层能够诱导有效的神经抑制至少26次，且疗效无明显下降。将新型药物释放涂层整合到单个MEA电极上，通过提高时空精度和改善药物选择灵活性，在不增加设备尺寸的情况下，比其他方法具有许多优势。
