Portable Electrochemical Sensor for Micromotor Speed Monitoring

Autonomous movement promotes practical applications of micromotors. Understanding the moving speeds is a crucial step in micromotor studies. The current analysis method relies on an expensive optical microscope, which is limited to laboratory settings. Herein, we have developed a lightweight (0.15 g), portable (2.0 x 3.5 cm(2)), and low-cost (approximately $0.26) micromotor sensor (mu-Motor sensor), composed of water-sensitive materials for micromotor speed monitoring. Moving micromotors induce fluid flow, enhancing the evaporation rate of the liquid medium. Consequently, a high correlation between motor speed and water molecule concentration above the moving medium has been established. The mu-Motor sensor enables a real-time readout of the moving speed in various settings, with high accuracy (>= 95% in the lab and >= 90% in field studies at a local beach). The mu-Motor sensor opens up a new way for detecting micro/nanomachine movements, illuminating future applications of micro/nanorobotics for diverse scenarios.

Automated summary

Understanding the speed of micromotors is essential for their practical applications. Current analysis methods rely on expensive optical microscopes, which are limited to laboratory settings. In this study, a lightweight, portable, and low-cost micromotor sensor was developed using water-sensitive materials. The sensor allows real-time monitoring of micromotor speed in various settings with high accuracy.