Current neural interfaces rely on electrical stimulation pulses to affect neural tissue. The development of a chemical delivery technology, which can stimulate neural tissue with the body's own set of signaling molecules, would provide a new level of sophistication in neural interfaces. Such technology should ideally provide highly local chemical delivery points that operate at synaptic speed, something that is yet to be accomplished. Here, the development of a miniaturized ionic polarization diode that exhibits many of the desirable properties for a chemical neural interface technology is reported. The ionic diode shows proper diode rectification and the current switches from off to on in 50 µs at physiologically relevant electrolyte concentrations. A device model is developed to explain the characteristics of the ionic diode in more detail. In combination with experimental data, the model predicts that the ionic polarization diode has a delivery delay of 5 ms to reach physiologically relevant neurotransmitter concentrations at subcellular spatial resolution. The model further predicts that delays of <1 ms can be reached by further miniaturization of the diode geometry. Altogether, the results show that ionic polarization diodes are a promising building block for the next generation of chemical neural interfaces.

中文翻译：

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微型离子极化二极管，用于神经递质在突触速度下的释放

当前的神经接口依靠电刺激脉冲来影响神经组织。化学传递技术的发展可以利用人体自身的信号分子集刺激神经组织，从而将神经接口的复杂性提高到一个新的水平。理想情况下，此类技术应提供以突触速度运行的高度局部的化学传递点，这仍有待实现。在此，报道了开发出对化学神经接口技术表现出许多理想特性的小型化的离子极化二极管。离子二极管显示正确的二极管整流，并且在生理上相关的电解质浓度下，电流在50 µs内从关闭切换到开启。开发了器件模型以更详细地说明离子二极管的特性。结合实验数据，该模型预测离子极化二极管的传递延迟为5毫秒，以亚细胞空间分辨率达到生理相关的神经递质浓度。该模型还预测，通过进一步缩小二极管的几何尺寸，可以达到<1 ms的延迟。总之，结果表明，离子极化二极管是下一代化学神经接口的有前途的构建基块。