Wireless power transfer to deep-tissue microimplants
Wireless power transfer to deep-tissue microimplants
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DOI：
10.1073/pnas.1403002111
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发表时间：
2014-06-03
影响因子：
11.1
通讯作者：
Poon, Ada S. Y.
中科院分区：
文献类型：
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作者：
Ho, John S.;Yeh, Alexander J.;Poon, Ada S. Y.
将电子系统植入人体的能力带来了许多医学进步。半导体技术的进步为毫米或更小规模的设备(“微植入物”)铺平了道路，但电源的小型化仍然具有挑战性。尽管已经证明了无线供电，但到目前为止，组织中浅层以外的能量转移受到不适合微型植入物的大线圈(至少一厘米直径)的限制。在这里，我们展示了一种称为中场供电的方法可以克服这种限制，这种方法可以在组织深处创建一个高能量密度区域，在其中能量收集结构可以变得非常小。不同于传统的近场(电感耦合)线圈，其耦合受到指数场衰减的限制，图案化的金属板被用来通过组织中的传播模式来诱导空间受限和自适应的能量传输。我们使用这种方法为一个微型植入物(2毫米，70毫克)提供动力，该植入物能够对心脏进行闭胸式无线控制，其体积比传统起搏器小一个数量级。当暴露水平低于人类安全阈值时，毫瓦级的能量可以转移到深层组织(>；5厘米)微植入物，以实现复杂的电子功能和生理刺激。这里开发的方法应该能够使新一代植入性系统能够以最低的成本和风险集成到人体中。
The ability to implant electronic systems in the human body has led to many medical advances. Progress in semiconductor technology paved the way for devices at the scale of a millimeter or less ("microimplants"), but the miniaturization of the power source remains challenging. Although wireless powering has been demonstrated, energy transfer beyond superficial depths in tissue has so far been limited by large coils (at least a centimeter in diameter) unsuitable for a microimplant. Here, we show that this limitation can be overcome by a method, termed midfield powering, to create a high-energy density region deep in tissue inside of which the power-harvesting structure can be made extremely small. Unlike conventional near-field (inductively coupled) coils, for which coupling is limited by exponential field decay, a patterned metal plate is used to induce spatially confined and adaptive energy transport through propagating modes in tissue. We use this method to power a microimplant (2 mm, 70 mg) capable of closed-chest wireless control of the heart that is orders of magnitude smaller than conventional pacemakers. With exposure levels below human safety thresholds, milliwatt levels of power can be transferred to a deep-tissue (>5 cm) microimplant for both complex electronic function and physiological stimulation. The approach developed here should enable new generations of implantable systems that can be integrated into the body at minimal cost and risk.