Freeman Daniel K, O'Brien Jonathan M, Kumar Parshant, Daniels Brian, Irion Reed A, Shraytah Louis, Ingersoll Brett K, Magyar Andrew P, Czarnecki Andrew, Wheeler Jesse, Coppeta Jonathan R, Abban Michael P, Gatzke Ronald, Fried Shelley I, Lee Seung Woo, Duwel Amy E, Bernstein Jonathan J, Widge Alik S, Hernandez-Reynoso Ana, Kanneganti Aswini, Romero-Ortega Mario I, Cogan Stuart F
Draper, Cambridge, MA, United States.
Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States.
Front Neurosci. 2017 Nov 27;11:659. doi: 10.3389/fnins.2017.00659. eCollection 2017.
Wireless neural stimulators are being developed to address problems associated with traditional lead-based implants. However, designing wireless stimulators on the sub-millimeter scale (<1 mm) is challenging. As device size shrinks, it becomes difficult to deliver sufficient wireless power to operate the device. Here, we present a sub-millimeter, inductively powered neural stimulator consisting only of a coil to receive power, a capacitor to tune the resonant frequency of the receiver, and a diode to rectify the radio-frequency signal to produce neural excitation. By replacing any complex receiver circuitry with a simple rectifier, we have reduced the required voltage levels that are needed to operate the device from 0.5 to 1 V (e.g., for CMOS) to ~0.25-0.5 V. This reduced voltage allows the use of smaller receive antennas for power, resulting in a device volume of 0.3-0.5 mm. The device was encapsulated in epoxy, and successfully passed accelerated lifetime tests in 80°C saline for 2 weeks. We demonstrate a basic proof-of-concept using stimulation with tens of microamps of current delivered to the sciatic nerve in rat to produce a motor response.
正在研发无线神经刺激器，以解决与传统铅基植入物相关的问题。然而，在亚毫米尺度（<1毫米）上设计无线刺激器具有挑战性。随着设备尺寸缩小，输送足够的无线电力来操作设备变得困难。在此，我们展示了一种亚毫米级的电感供电神经刺激器，它仅由一个用于接收电力的线圈、一个用于调谐接收器谐振频率的电容器以及一个用于整流射频信号以产生神经刺激的二极管组成。通过用简单的整流器取代任何复杂的接收器电路，我们将操作该设备所需的电压电平从0.5至1伏（例如用于CMOS）降低到了约0.25至0.5伏。这种降低的电压允许使用更小的接收天线来获取电力，从而使设备体积达到0.3至0.5立方毫米。该设备用环氧树脂封装，并在80°C的盐水中成功通过了为期两周的加速寿命测试。我们通过向大鼠坐骨神经输送数十微安电流以产生运动反应的刺激，展示了一个基本的概念验证。
