IEEE Trans Biomed Circuits Syst. 2017 Dec;11(6):1204-1215. doi: 10.1109/TBCAS.2017.2755596.
We present a sub-mm, fully wireless, implantable intraocular pressure monitor microsystem (IMM) that comprises a powering coil, an antenna, a piezoresistive micro-electro-mechanical system pressure sensor, and a pressure sensing IC. The system provides a 24-h intraocular pressure monitoring, which is not possible with currently used tonometric measurements. The IMM volume is limited to 0.38 mm (4 × smaller than previous state-of-the-art) for the studies on laboratory rodents prior to human use. A cavity resonator magnetic coupling delivers the wireless power to the chip with 4.89% efficiency. The chip senses a change in a differential sensor resistance by providing a low-power differential resistance to frequency conversion with the measured standard deviation in differential resistance sensing of . The data packets are wirelessly transmitted by an ultralow power 2.4-GHz ISM band OOK transmitter. The IMM is integrated on a 5-μm-thick biocompatible Parylene C substrate. Implemented in a 0.18-μm CMOS process, the system achieves 0.67-mmHg pressure sensitivity with differential resistance sensing and dissipates only 6.3 nW with 30 min of measurement intervals. We verify the IMM functionality in the in vivo biological experiment.
我们提出了一种亚毫米、完全无线、可植入的眼内压监测微系统（IMM），它包括一个供电线圈、一个天线、一个压阻式微机电系统压力传感器和一个压力感应 IC。该系统提供 24 小时的眼内压监测，这是目前使用的眼压测量方法所无法实现的。在用于人体之前，我们将系统体积限制在 0.38 毫米以内（比以前的最先进技术小 4 倍），以便在实验室啮齿动物身上进行研究。空腔谐振器磁耦合以 4.89%的效率将无线功率传输到芯片。芯片通过提供低功率差分电阻来实现差分传感器电阻的变化，从而将差分电阻感应的测量标准偏差转换为频率。数据包通过超低功耗 2.4GHz ISM 波段 OOK 发射器进行无线传输。IMM 集成在 5 微米厚的生物相容性聚对二甲苯 C 衬底上。该系统采用 0.18 微米 CMOS 工艺实现，差分电阻感应的压力灵敏度为 0.67mmHg，测量间隔为 30 分钟时仅消耗 6.3nW 的功率。我们在体内生物实验中验证了 IMM 的功能。
