For implantable neural interfaces, the functional and clinical outcomes of inorganic microelectrodes are challenged by limitations in specificity and long-term performance. A biological intermediary between micro-electrical devices and the brain may improve specificity and longevity through (1) natural synaptic integration with deep neural circuitry, (2) accessibility on the brain surface, (3) optogenetic manipulation for targeted, light-based readout/control. Accordingly, we have developed implantable "living electrodes", living cortical neurons and axonal tracts protected within soft hydrogel cylinders, for optobiological monitoring/modulation of brain activity. Here we demonstrate fabrication, rapid axonal outgrowth, reproducible cytoarchitecture, and simultaneous optical stimulation and recording of these tissue engineered constructs in vitro. We also present their transplantation, survival, integration, and optical recording in rat cortex as an in vivo proof-of-concept for this neural interface paradigm. The creation and characterization of these functional, optically-controllable "living electrodes" are critical steps in developing a new class of optobiological tools for neural interfacing.

中文翻译：

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具有长轴突的突触脑机接口的光控“活电极”的开发。

对于植入式神经接口，无机微电极的功能和临床结果受到特异性和长期性能的限制。微电子设备与大脑之间的生物中介可以通过（1）与深度神经回路的自然突触整合，（2）在大脑表面的可及性，（3）针对有针对性的，基于光的读出/控制。因此，我们开发了可植入的“活体电极”，活动的皮质神经元和轴突束，保护在软水凝胶圆柱体内，用于光学生物监测/大脑活动的调节。在这里，我们展示了虚构，轴突迅速生长，可重现的细胞结构，并同时在体外对这些组织工程构建物进行光刺激和记录。我们还介绍了它们在大鼠皮质中的移植，存活，整合和光学记录，作为这种神经接口范例的体内概念证明。这些功能性的，可光学控制的“活体电极”的创建和表征是开发用于神经接口的新型光生物学工具的关键步骤。