The function of miniature wireless medical devices, such as capsule endoscopes, biosensors and drug-delivery systems, depends critically on their location inside the body. However, existing electromagnetic, acoustic and imaging-based methods for localizing and communicating with such devices suffer from limitations arising from physical tissue properties or from the performance of the imaging modality. Here, we embody the principles of nuclear magnetic resonance in a silicon integrated-circuit approach for microscale device localization. Analogous to the behaviour of nuclear spins, the engineered miniaturized radio frequency transmitters encode their location in space by shifting their output frequency in proportion to the local magnetic field; applied field gradients thus allow each device to be located precisely from its signal’s frequency. The devices are integrated in circuits smaller than 0.7 mm³ and manufactured through a standard complementary-metal-oxide-semiconductor process, and are capable of sub-millimetre localization in vitro and in vivo. The technology is inherently robust to tissue properties, scalable to multiple devices, and suitable for the development of microscale devices to monitor and treat disease.

微型无线医疗设备（例如胶囊内窥镜，生物传感器和药物输送系统）的功能主要取决于它们在体内的位置。但是，现有的基于电磁，声学和成像的用于定位和与这些设备通信的方法受到物理组织特性或成像模态性能的限制。在这里，我们将硅核方法中的核磁共振原理体现在微型器件的定位上。类似于核自旋的行为，工程化的微型射频发射机通过将其输出频率与局部磁场成比例地移动来编码它们在空间中的位置。因此，施加的场梯度允许从其信号频率精确定位每个设备。^{如图3所示，}并且通过标准的互补金属氧化物半导体工艺制造，并且能够在体外和体内亚毫米级定位。该技术固有地对组织特性具有鲁棒性，可扩展到多个设备，并且适合于开发用于监视和治疗疾病的微型设备。