The key to the new platform is the integration of three functions on a scale measured in tens of micrometres. Each robot carries a temperature sensor, a programmable CMOS control circuit and arrays of electrochemical actuators that beat like biological cilia. The actuators are built from a titanium–palladium stack that bends when voltage is applied, driving ions into and out of the palladium layer and causing controlled bending at engineered hinges. Because the cilia are hinged, with two rigid panels connected by rotational joints, their beat cycle can be programmed to break the time-reversal symmetry that governs fluid motion at low Reynolds number. At microscopic scales, where viscosity dominates over inertia, fluid flows are reversible unless the stroke and the recovery stroke differ in shape, a constraint famously articulated in Lighthill’s analysis of flagellar hydrodynamics. The hinged design allows the robots to sweep the fluid with a fast, extended stroke and a slow, folded recovery, producing net pumping in a chosen direction.

Powering and controlling such tiny machines is a formidable engineering challenge, and the team solved it with microscale photovoltaic regions that convert incident laser light at 635 nanometres into electrical current for both the logic and the actuators. The binary sensing circuit switches its output phase configuration at threshold temperatures of 26 and 30 degrees Celsius, and can deliver actuation frequencies ranging from 0.4 to 12.8 hertz, with 1.6 hertz used for cilium beating in the reported demonstrations. The photovoltaic supply generates currents of roughly 0.78 microamperes at one sun of illumination, rising to about 4.8 microamperes at ten suns, enough to run the circuit and drive the cilia without any tether. This architecture builds on earlier work from the same collaboration, including electronically integrated mass-manufactured microscopic robots, cilia metasurfaces for programmable microfluidic manipulation, and microscopic robots with onboard digital control, but it adds something those systems lacked: a genuine sensory loop in which the robot’s action depends on what it measures.

The researchers demonstrated three distinct temperature-responsive modalities, each producing a different coupling between robot behaviour and environmental cues. The first is binary sensing, in which the onboard sensor acts as a threshold detector. Below the threshold the cilia pump in one direction; above it, the circuit reconfigures the wiring to the actuators and the pumping reverses. The team showed that this simple switch can reverse unidirectional flow, reverse the rotation of a single vortex, or reverse both vortices in a symmetric counter-rotating pair, all in response to nothing more than the ambient temperature crossing a set point. Because the flow patterns are generated by arrays of individually wired cilia, the same sensing principle can be routed into dramatically different hydrodynamic outcomes simply by changing how the circuit output is distributed across the array.

The second modality replaces the sharp threshold with continuous sensing, implemented using pulse-coupled oscillator circuits built from dynamic-leakage-suppression logic gates. In this scheme, the oscillation frequency of the onboard circuit depends on temperature through the exponential dependence of subthreshold leakage currents, so the beat frequency of the cilia rises smoothly as the fluid warms. The pumping speed therefore tracks temperature continuously rather than switching between two states. The oscillator architecture also supports synchronisation: coupling pulses from a designated leader oscillator advance the follower until the two lock with a fixed phase offset, a mechanism related to the pulse-coupled designs previously used for coordinating autonomous microscopic machines through local electronic pulses. This phase-locking provides a route to coordinated actuation across a cilia array without any central controller.

The third modality exploits spatial temperature gradients rather than absolute temperature. Using a scalable ultra-low-power temperature gradient sensor based on pulse-coupled oscillators, the robot determines which side of its body is warmer and aligns its pumping accordingly. When the imposed gradient is reversed, the leader and follower roles in the oscillator network exchange, and the pumping direction flips. The result is a microscopic machine that orients its fluid-mechanical output along the local thermal landscape, in loose analogy to the way ciliated protists orient their swimming relative to environmental cues. Together, the three modalities, threshold switching, continuous modulation and gradient alignment, form a toolkit for programming how a microrobot’s behaviour responds to its surroundings.

The most striking demonstration is the closing of the loop. Because the cilia-driven flows move fluid around, they transport heat, and the team showed that a collective array of cilia can actively reshape the local thermal field. In their experiments, unidirectional pumping advected fluid from a cooler region towards a hotter region, flattening the temperature gradient that the sensors were measuring. As the temperature field changed, the oscillator frequencies shifted, which in turn altered the pumping, which further modified the thermal field. The researchers modelled this feedback with a reduced two-dimensional description of thermally advected flow and quantified it through a thermal stretching length that grows cycle by cycle, fitting the dynamics with an exponential law. The system thus exhibits a genuine closed-loop interaction among sensing, actuation and environment, the microscopic analogue of an organism modifying its own habitat.

The experimental platform itself is a tour de force of integration. The devices were fabricated at the Cornell NanoScale Facility, with the CMOS circuits exposed by etching the top dielectric, then interconnected with titanium–platinum leads, re-encapsulated in silicon dioxide, shielded with a grounded layer, and finally released with an aluminium nitride sacrificial layer before the titanium–palladium actuator stack and rigid panels were added. Fluid temperatures were controlled with a hotplate and characterised by infrared thermography on dry samples, which showed a uniform region with a spatial standard deviation of about 0.11 degrees Celsius and a gradient region of roughly 0.5 degrees Celsius per millimetre; in liquid, where phosphate-buffered saline strongly absorbs mid-infrared radiation, the team used a micro-thermocouple instead. Flow fields were measured with particle image velocimetry and compared against three-dimensional hydrodynamic simulations of the beating cilia, validating the theoretical model of the two-hinged kinematics.

The implications reach well beyond the laboratory demonstration. Artificial cilia that sense and respond to their environment could regulate temperature and chemical gradients in lab-on-chip systems, create fluid microhabitats for recruiting cells or controlling microbiomes in biomedical contexts, and serve as building blocks for emergent collective behaviours in swarms of autonomous micromachines. The theoretical framing, developed with physicists studying non-reciprocal phase transitions and adaptive active solids, suggests that populations of such robots could self-organise into patterns no single robot is programmed to produce, much as bacterial colonies generate large-scale spiral waves from local interactions. Because the platform is built with standard CMOS processes and mass-manufacturable techniques, scaling to larger and more capable microrobotic collectives appears feasible. The work was supported primarily by the National Science Foundation and the Army Research Office, with additional support from the Kavli Institute at Cornell and Westlake University, and the team has filed patent applications covering the actuators and control electronics.

What makes this advance conceptually important is the shift from open-loop microrobots, which execute fixed motions, to machines that participate in a dynamic dialogue with their world. In nature, the coupling between organism behaviour and environmental modification underlies nest construction, swarm thermoregulation and microbiome recruitment; until now, engineered microrobots could sense or act, but rarely both in a feedback loop. By embedding thermal sensing, programmable logic and ciliary actuation on a single chiplet smaller than a grain of salt, the Cornell-led team has created the first microscopic robotic platform in which the environment is not merely a medium the robot moves through but a variable the robot actively regulates. As the researchers and their collaborators refine the sensing modalities and extend them to chemical and mechanical cues, the boundary between living, environment-shaping matter and engineered machines at the microscale looks set to blur further.

Subject of Research: Microscopic robots with onboard sensing, logic and cilia actuators that couple their behaviour to thermal environmental cues in a closed loop

Article Title: Microscopic robots that sense and reshape their environment

Article References: Wang, W., Zhang, J., Chaudhari, P., Shim, K., Severn, J., Zheng, C., Liang, Z., Ji, Y., Pelster, J., Griniasty, I., Seara, D., Vitelli, V., Lauga, E., Apsel, A., & Cohen, I. (2026). Microscopic robots that sense and reshape their environment. Nature Electronics. https://doi.org/10.1038/s41928-026-01709-x

Image Credits: AI Generated

DOI: 10.1038/s41928-026-01709-x

Keywords: microrobotics, artificial cilia, CMOS, electrochemical actuators, temperature sensing, microfluidics, closed-loop control, NEMS, collective behaviour, thermal regulation, Cornell University, Nature Electronics

The concept of engineered cilia draws its inspiration directly from biology. Cilia are the tiny, hair-like appendages that line surfaces throughout living organisms, from the airways of the human lung, where they sweep mucus and trapped debris along in coordinated waves, to the surfaces of single-celled organisms that use them to swim and to feed. Biological cilia achieve their remarkable effectiveness through dense, coordinated arrays in which individual filaments beat in synchrony, generating directed fluid flow with exquisite efficiency. Replicating that behavior in artificial microsystems has been a long-standing goal of microfluidics and microrobotics, because arrays of artificial cilia could, in principle, replace bulky external pumps and valves with silent, solid-state surfaces that move fluids on demand.

What sets the new work apart is the marriage of actuation with sensing and with mainstream semiconductor manufacturing. CMOS technology is the workhorse of the modern electronics industry, responsible for the billions of transistors that power everything from smartphones to data centers. By integrating microrobotic cilia onto CMOS platforms, the researchers inherit the maturity, scalability and precision of chip fabrication. Each cilium can be addressed and driven by underlying circuitry, and the same silicon infrastructure that powers the actuators can also host the sensors that monitor local conditions. In the demonstration discussed by Hu, the relevant environmental variable is temperature: the cilia respond to thermal cues by adjusting their beating, and in doing so they pump fluid across the chip surface.

The technical significance of this sensing-actuation coupling is difficult to overstate. Most microscale actuators to date have been open-loop devices: they perform a prescribed motion when stimulated, blind to the consequences of that motion. A cilium that can detect temperature and then modify fluid flow creates a feedback system embedded in the material itself. Temperature affects fluid viscosity, density gradients and chemical reaction rates, so a surface that senses heat and stirs fluid in response can, for example, redistribute thermal energy, homogenize concentration gradients or deliver reagents to where they are needed. The microrobotic cilia thus function simultaneously as sensors, actuators and pumps — three components that traditionally occupy separate devices and separate design disciplines.

This achievement builds on a decade of steady progress in microrobotics. Earlier landmark work by Marc Miskin and colleagues, published in Nature in 2020, introduced microscopic robots small enough to be invisible to the naked eye, capable of crawling under external stimulation and fabricated using processes compatible with existing semiconductor foundries. Subsequent work by the same community, including studies published in Proceedings of the National Academy of Sciences in 2018 and by Wang and colleagues in Nature in 2022, pushed toward ever more capable and controllable microrobotic systems. The new CMOS-integrated cilia represent a conceptual step beyond locomotion: rather than robots that move themselves through an environment, these are robots that stay put and transform the environment around them, one fluid pulse at a time.

Coordination is the second pillar of the achievement. A single cilium, whether biological or artificial, moves very little fluid. The power of ciliary systems emerges from collective behavior — thousands or millions of filaments beating in metachronal waves, the traveling patterns of motion that make biological cilia so effective. The theoretical foundations for such collective synchrony were laid long ago: the Kuramoto model, formalized by Mirollo and Strogatz in 1990, describes how large populations of coupled oscillators spontaneously fall into step, and the elegant geometry of ciliary coordination was analyzed by King, Ocko and Mahadevan in 2015. Nature offers a striking biological parallel in the aggregation patterns of bacteria such as E. coli, documented by Budrene and Berg in 1991, where individual cells following simple rules produce elaborate collective structures. The new microrobotic cilia tap into this same physics, using engineered coupling — mediated in part by the fluid they share and in part by their CMOS control layer — to generate coordinated pumping from individually simple units.

The fluid itself plays a crucial role in this coordination. At the microscale, fluid dynamics is dominated by viscosity rather than inertia, a regime characterized by low Reynolds numbers where momentum essentially does not exist and motion is entirely determined by the forces applied at each instant. Hydrodynamic interactions between neighboring cilia are strong and long-ranged in this regime, so the beating of one filament physically influences its neighbors through the surrounding fluid. This creates natural pathways for synchronization and wave propagation, and it means that the cilia and the fluid form a single coupled dynamical system. When the cilia sense a temperature change and alter their beating, they are not merely responding to their environment — they are renegotiating their collective behavior with it, moment by moment.

Potential applications span several fields. In microfluidics, CMOS-integrated ciliary surfaces could replace external pumps in lab-on-a-chip diagnostic devices, enabling fully portable analysis systems in which fluid handling is performed by the chip surface itself. In thermal management, the ability to sense hot spots and direct cooling flow toward them could transform how heat is removed from densely packed electronics, from high-performance processors to power electronics. In biology and medicine, surfaces that sense local conditions and stir fluid accordingly could improve cell culture systems, tissue engineering scaffolds and implantable devices, where gentle, distributed fluid motion is often essential for nutrient delivery and waste removal. Because the technology is CMOS-compatible, it could in principle be scaled to large areas using existing foundry infrastructure, a decisive advantage over exotic microfabrication approaches that never leave the laboratory.

The work also signals a broader philosophical shift in how researchers think about microscale machines. The traditional paradigm treats sensing and actuation as separate subsystems, connected by a controller — an architecture inherited from macroscopic robotics. At the microscale, where power, space and computational resources are all severely constrained, that separation becomes a liability. Systems in which sensing, computation and actuation are fused into a single integrated platform, as the CMOS cilia demonstrate, point toward microrobots that behave less like programmed machines and more like adaptive materials — surfaces whose mechanical response is inseparable from their perception of the world. Hu’s commentary frames this as a demonstration of how microscale actuators can both sense and actively modify their surroundings, a formulation that captures the essence of embodied intelligence at the smallest scales.

Challenges remain before such systems become commonplace. Driving dense arrays of actuators requires careful power management on-chip; long-term reliability of moving micromechanical structures in fluid environments must be established; and the repertoire of sensed variables will need to expand beyond temperature to include chemical composition, pressure and biological signals if the full vision of environment-shaping microrobotic surfaces is to be realized. Yet the trajectory is clear. From the first demonstrations of microscopic robots to today’s CMOS-integrated cilia that feel heat and answer with fluid motion, the field is converging on machines that live in, understand and reshape their microscopic worlds. As the boundaries between sensors, actuators and electronics continue to dissolve, the humble cilium — nature’s oldest micromachine — may prove to be the blueprint for the next generation of intelligent surfaces.

Subject of Research: CMOS-integrated microrobotic cilia that sense temperature and pump fluid to modify their microscale environment

Article Title: Microrobotic cilia that sense and reshape their surroundings

Article References: Hu, W. (2026). Microrobotic cilia that sense and reshape their surroundings. Nature Electronics. https://doi.org/10.1038/s41928-026-01716-y

Image Credits: AI Generated

DOI: 10.1038/s41928-026-01716-y

Keywords: microrobotics, CMOS integration, artificial cilia, microfluidics, temperature sensing, actuators, fluid pumping, collective synchronization, lab-on-a-chip, thermal management, Nature Electronics, microscale robotics