Taking your temperature from the inside

从体内测量体温

Oral and forehead thermometers may not accurately capture a person’s core body temperature, and the few ingestible temperature sensors on the market are so big they are hard to swallow and risk obstructing the GI tract. 口腔和额头温度计可能无法准确捕捉人体的核心体温，而市面上现有的少数可吞咽温度传感器体积过大，不仅难以吞咽，还存在阻塞胃肠道的风险。

But MIT engineers created one that can send continuous temperature updates at a size of just six by four millimeters. To create it, the researchers built a circuit that can fit on a one-square-­millimeter silicon chip and designed an oscillator based on leakage current—the small current that flows through a circuit when it’s off. 但麻省理工学院（MIT）的工程师们研发出了一种仅 6 毫米乘 4 毫米大小的传感器，可以持续发送体温数据。为了实现这一目标，研究人员构建了一个能够安装在 1 平方毫米硅芯片上的电路，并设计了一种基于“漏电流”（即电路关闭时流经电路的微小电流）的振荡器。

Its frequency varies depending on the temperature of the chip’s surroundings. The circuit detects temperature within 0.01 °C and can be powered with a 1.55-volt coin cell battery. A strategy known as backscattering further cuts energy consumption, allowing most of the power requirements to be outsourced to an antenna outside the body. 其频率会根据芯片周围的温度而变化。该电路的测温精度可达 0.01°C，并可由 1.55 伏的纽扣电池供电。一种被称为“反向散射”的策略进一步降低了能耗，使得大部分电力需求可以由体外的天线来承担。

It emits an ultra-high-frequency radio wave, which is modulated by an antenna within the sensor and sent back to the external one. By interpreting the changes in the radio wave, the external antenna can calculate the temperature value. 它会发射超高频无线电波，该波由传感器内部的天线进行调制，并发送回外部天线。通过解读无线电波的变化，外部天线即可计算出温度值。

The result is “the smallest ingestible capsule that we have seen for temperature-­sensing paradigms,” says Saransh Sharma, a former MIT postdoc now at the University of Cambridge, who is lead author of a paper on the work. 该研究论文的第一作者、曾在麻省理工学院担任博士后现就职于剑桥大学的 Saransh Sharma 表示，这是“我们所见过的用于体温传感模式的最小可吞咽胶囊”。

The researchers envision using it to monitor infection, observe patients during and after anesthesia, track fevers in children, help mark ovulation, and more. It could also be used to monitor athletes, soldiers, or anyone else exposed to extreme temperatures. 研究人员设想将其用于监测感染、观察麻醉期间及术后的患者、追踪儿童发烧情况、辅助标记排卵期等。它还可以用于监测运动员、士兵或任何暴露在极端温度下的人群。

“A sensor like this gives us the ability to monitor infections and identify them early,” says Giovanni Traverso, an associate professor of mechanical engineering and one of the paper’s senior authors, along with MIT provost Anantha Chandrakasan. “That’s very relevant, particularly for at-risk populations like people who are immunosuppressed.” “这样的传感器使我们能够监测感染并及早发现，”机械工程副教授 Giovanni Traverso 说道，他与麻省理工学院教务长 Anantha Chandrakasan 同为该论文的资深作者。“这非常有意义，特别是对于免疫抑制人群等高危群体而言。”

Ultimately, he hopes, it could replace other types of thermometers for everyone. 他希望最终这种传感器能够取代其他类型的温度计，惠及所有人。