Scientists at Cornell University in the United States have for the first time created robots capable of sensing the temperature of their surroundings and "joining hands" to change the environment. These robots are only as thick as a human hair and are expected to be used in the medical and agricultural fields in the future. The related paper was published in the latest issue of Nature Electronics.

Micro-robots working in coordination. Photo credit: Kaitlyn Serrao/Cornell University Ithaca Campus and Cornell Tech

These robots can walk autonomously, sense their environment, perform imaging and measurements, and even "communicate" with one another. The research team arranged 54 of these robots in an array and paired them with temperature-sensing circuits, enabling liquid to flow between regions of different temperatures—pumped from hot to cold, or in the reverse direction. This is the first time micro-robots have been able to change their physical surroundings.

These robots function like artificial cilia, mimicking the ability of natural cilia to pump fluids—relying on the coordinated beating of cilia to drive directional liquid flow at the microscale. The human respiratory tract's clearance of mucus and the fallopian tubes' transport of eggs both rely on this mechanism.

However, rather than copying the structure of natural cilia, the team designed a more efficient dual-hinge structure that can be easily programmed via electronic signals. The two hinges move in sequence, creating an irreversible paddling motion that drives the surrounding liquid.

A single paddle cannot accomplish much—many robots must work together. The team arranged 54 hinged artificial cilia into an array, equipped with two temperature-sensing circuits—one "leader" and one "follower." The two communicate with each other, synchronizing the cilia in the array to pump liquid collectively as temperature changes. This circuit essentially determines when and which hinge the cilia array uses to pump: when the temperature is above a set value, it pumps forward; when the temperature is lower, it pumps in reverse.

The team emphasizes that sensing the environment, manipulating fluids, and enabling microchips to communicate with one another—these three key capabilities constitute a feedback loop inspired by natural systems, with potential future applications in medicine or agriculture. For example, the robots could respond to light or pH levels, triggering chemical reactions or mechanical motion.