IEEE Trans Biomed Circuits Syst. 2020 Jun;14(3):412-424. doi: 10.1109/TBCAS.2020.2971066. Epub 2020 Feb 3.
Accurate monitoring of physiological temperature is important for many biomedical applications, including monitoring of core body temperature, detecting tissue pathologies, and evaluating surgical procedures involving thermal treatment such as hyperthermia therapy and tissue ablation. Many of these applications can benefit from replacing external temperature probes with injectable wireless devices. Here we present such a device for real-time in vivo temperature monitoring that relies on "chip-as-system" integration. With an on-chip piezoelectric transducer and measuring only 380 μm × 300 μm × 570 μm, the 0.065-mm monolithic device, in the form of a mote, harvests ultrasound energy for power and transmits temperature data through acoustic backscattering. Containing a low-power temperature sensor implemented with a subthreshold oscillator and consuming 0.813 nW at 37 °C, the mote achieves line sensitivity of 0.088 °C/V, temperature error of +0.22/-0.28 °C, and a resolution of 0.0078 °C rms. A long-term measurement with the mote reveals an Allan deviation floor of <138.6 ppm, indicating the feasibility of using the mote for continuous physiological temperature monitoring.
准确监测生理温度对于许多生物医学应用非常重要，包括监测核心体温、检测组织病变以及评估涉及热疗（如高热疗法和组织消融）的手术过程。许多这些应用都可以受益于用可注射的无线设备代替外部温度探头。在这里，我们提出了一种实时体内温度监测的设备，它依赖于“芯片系统”集成。该设备具有一个片上压电换能器，尺寸仅为 380 μm × 300 μm × 570 μm，以 mote 的形式存在，可通过声反向散射传输温度数据并利用超声能量进行供电。该 mote 包含一个采用亚阈值振荡器实现的低功耗温度传感器，在 37°C 时仅消耗 0.813 nW，其线灵敏度为 0.088°C/V，温度误差为+0.22/-0.28°C，分辨率为 0.0078°C rms。通过 mote 进行的长期测量显示 Allan 偏差底<138.6 ppm，表明 mote 可用于连续生理温度监测。
