The study, published in Science Advances, describes what the researchers call bulk ferroelectric heterostructures created within a bismuth ferrite-barium titanate ceramic. Rather than stacking ultrathin layers of different materials in a film, as is common in laboratory demonstrations of interface-driven phenomena, the team used a carefully controlled heat treatment to drive nanoscale elemental partitioning throughout the interior of a solid ceramic. The result is an interconnected network of bismuth-rich and barium-rich regions embedded within a coherent crystal lattice, effectively building millions of internal interfaces into a material that can be manufactured at scale.

Dr David Hall, Reader in Ceramics in the Department of Materials and the Henry Royce Institute at The University of Manchester, explained the significance of the approach. Many of the most interesting behaviours in ferroelectric materials have historically been confined to thin films, where interfaces can be carefully engineered, he noted. What the team has shown is that similar interfacial effects can be generated throughout a solid ceramic, creating new opportunities to control the electrical and mechanical behaviour of these materials. The distinction matters because thin films, however elegant their physics, are difficult to incorporate into the robust bulk components that real-world sensors and actuators demand.

The mechanism behind the transformation is as compelling as the outcome. Using atomic-resolution microscopy, spectroscopy and computational modelling, the researchers established that their heat treatment causes the constituent elements to segregate into chemically distinct nanoscale regions while the crystal lattice remains coherent across the boundaries between them. Because the two families of regions differ in composition, they generate local electric fields and elastic strain fields where they meet. Charged domain walls also form within this landscape. Together, these internal features act as built-in heterointerfaces, altering how the entire ceramic responds when electrical voltages or mechanical forces are applied to it.

The most striking consequence is thermal. The engineered material exhibits a Curie temperature of 824 degrees Celsius, the point above which ferroelectricity collapses, more than 350 degrees higher than the starting material. That margin is not an academic curiosity. Piezoelectric sensors are increasingly needed in engines, turbines, exhaust systems and industrial process monitoring, environments where temperatures routinely exceed the limits of conventional lead-free piezoceramics. The Manchester-led team reports that the ceramic maintained strong piezoelectric performance at temperatures relevant to industrial sensing and monitoring applications, suggesting the material could function where existing options struggle or fail outright.

Beyond temperature tolerance, the researchers demonstrated something arguably more conceptually provocative: programmable ferroelectric behaviour. By combining electrical or mechanical conditioning with thermal ageing, they were able to imprint preferred domain configurations into the material. Remarkably, these configurations remain recoverable even after the application of strong electrical fields, enabling reversible electromechanical responses that are often difficult to achieve in conventional bulk ferroelectrics. In one configuration, the team achieved large reversible shear strains, a property prized in actuator technologies where precise, repeatable mechanical displacement is the goal. The study also reports internal bias fields exceeding 8 megavolts per metre, substantially higher than those typically observed in traditional bulk ferroelectric materials, a characteristic that can stabilise performance against depoling and fatigue.

To appreciate why this matters, it helps to consider how the field arrived here. Piezoelectric ceramics function because their crystal structures lack a centre of symmetry, allowing mechanical stress to generate a voltage and vice versa. For decades, the dominant material has been lead zirconate titanate, or PZT, whose exceptional properties come partly from a morphotropic phase boundary, a compositional knife-edge where two crystal phases coexist and switching between them becomes extraordinarily easy. Designing lead-free systems around similar phase boundaries has been a central strategy, but the resulting materials often sacrifice temperature stability or require delicate compositional tuning. The heterostructure approach takes a different philosophical route: instead of adjusting the average composition of the material, it engineers functionality directly into the material’s internal architecture.

The work is the product of an international collaboration involving The University of Manchester, the Henry Royce Institute, ShanghaiTech University, the Chinese Academy of Sciences, Diamond Light Source, the University of Leeds and Sheffield Hallam University. It also builds on roughly a decade of sustained research into lead-free piezoelectric ceramics at Manchester, an investment that has already yielded intellectual property protection for the underlying materials and the manufacturing approach. The research team is now supporting translation of the concept toward potential industrial applications, a step that will test whether laboratory-scale heat treatments can be reproduced reliably in commercial ceramic processing lines.

The implications extend past a single material system. Bismuth ferrite and barium titanate are both well-studied ferroelectrics, and the principle of using thermal processing to drive controlled nanoscale self-organisation could in principle be applied to other ferroic materials, including magnetic and multiferroic systems where internal interfaces are known to host unusual physics. Dr Hall framed the work as introducing a new design framework: rather than focusing solely on changing composition, researchers can use controlled nanoscale self-organisation to build new functionality directly into a material, a concept he suggested could apply across a much wider range of ferroic materials in future.

Challenges remain before bulk ferroelectric heterostructures reach the factory floor. Scaling any thermally driven microstructural process requires tight control of processing windows, and the long-term stability of the imprinted domain configurations under years of cyclic electrical and mechanical loading will need to be verified. Yet the demonstration that interface-driven effects, once thought to require atomically engineered thin films, can be reproduced inside a scalable ceramic represents a genuine conceptual advance. If the approach matures, it could reshape how engineers design the sensors that monitor jet engines, the transducers that power medical ultrasound, and the actuators that drive precision machinery, all while removing lead from the supply chain. For a field that has spent two decades searching for a viable route beyond PZT, the idea that the answer may lie in teaching materials to organise themselves is an unexpectedly elegant one.

Subject of Research: Lead-free piezoelectric bulk ferroelectric heterostructures in bismuth ferrite-barium titanate ceramics

Article Title: Bulk ferroelectric heterostructures open new design route for lead-free piezoelectric materials

Article References: Bulk ferroelectric heterostructures open new design route for lead-free piezoelectric materials. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: ferroelectric, piezoelectric, lead-free ceramics, bismuth ferrite, barium titanate, heterostructures, Curie temperature, high-temperature sensors, actuators, ultrasonic transducers, domain engineering, Science Advances

Actuators are the components of a machine that generate force or torque, and in conventional robotic design they are the primary currency of mobility. A robot that can translate in three dimensions and reorient itself typically requires at least six independently controlled actuators to achieve that full range of motion. Jie Yin, corresponding author of the paper and a professor of mechanical and aerospace engineering at NC State, explains that the feather star robot achieves the same degrees of freedom with a fraction of that hardware. The key, he says, is intelligent design: by shaping the robot’s body so that its structure and its interaction with the surrounding water govern its behavior, the researchers dramatically reduced the input required from computers or human operators. The robot’s capabilities emerge from its geometry and material properties rather than from an elaborate control system.

The inspiration for the design came from feather stars, crinoid echinoderms that can move in any direction or hold themselves stationary in the water column by coordinating the movements of their flexible, feather-like limbs. The robot distills that biological principle into a remarkably simple architecture: four elastic wings protrude from a central disk that houses the two actuators. Each wing is monostable, a term from mechanics describing a structure that can be bent out of shape but will always snap back to a single preferred resting position. This snap-through behavior is the heart of the robot’s locomotion strategy, converting smooth actuator input into rapid, impulsive wing motion that pushes effectively against the water.

The robot’s repertoire is organized into three distinct modes, each produced by a different pattern of actuator activation. When both actuators are switched on, all four wings snap downward simultaneously; when the actuators are turned off, the monostable wings snap back up. Rapidly cycling the actuators on and off makes the robot flap all four wings in quick succession, driving it upward through the water column. Switching the actuators off entirely stops the flapping and lets the robot descend. And by flapping the wings slowly rather than rapidly, the robot can hover in place, a behavior the researchers have nicknamed jellyfish mode, since the slow pulsing motion and stationary hovering recall the swimming style of a jellyfish.

Horizontal travel relies on an even more economical trick. To move forward or backward, the researchers activate only one of the two actuators. This causes a single wing to flutter, functioning like a tailfin and pushing the robot in the opposite direction. The team calls this fish mode, and it means that steering and translation along the horizontal plane require no additional hardware whatsoever. The third mode, rotor mode, comes from alternating rapidly between the two actuators, which sets the robot spinning on its axis. By combining jellyfish mode, fish mode, and rotor mode, the operators can maneuver the robot through all three dimensions, climbing, descending, translating, hovering, and turning with a machine that carries only two sources of actuation.

The project grew out of an earlier effort that illustrates exactly what mechanical intelligence is meant to solve. Haitao Qing, first author of the paper and a postdoctoral researcher at UC Berkeley who began the project as a Ph.D. student at NC State, previously helped create a soft aquatic robot inspired by the manta ray. That robot could move quickly through the water, but it lacked three-dimensional maneuverability. The goal of the new work was to design a robot with far greater agility without resorting to unduly complicated mechanisms. The feather star concept delivered that agility by shifting the burden from actuator count to structural design, letting the elastic wings and their snap-through dynamics generate a rich set of behaviors from minimal input.

The practical implications of reducing actuator count extend well beyond elegance. Every actuator on an underwater robot adds mass, wiring, power draw, and a potential point of failure, and in marine environments where maintenance is difficult and expensive, simplicity translates directly into reliability and endurance. A two-actuator platform is lighter, easier to seal against water intrusion, cheaper to manufacture, and simpler to control than a six-actuator equivalent. Because the robot’s modes are selected by simple activation patterns rather than complex coordinated control of many motors, the computational demands are correspondingly modest, which matters for small autonomous vehicles with limited onboard processing and battery capacity.

The researchers also demonstrated concrete uses for the robot. In tests, the machines were shown exploring underwater spaces while carrying a camera, and lifting objects underwater, either operating alone or working in concert with other robots. That cooperative capability hints at a future in which fleets of inexpensive, simply actuated soft robots swarm through shipwrecks, aquaculture pens, coral reefs, or submerged infrastructure, performing inspection and light manipulation tasks that would currently require larger, costlier, and more fragile vehicles. Qing describes the design as a versatile platform for integrating with other technologies across a range of underwater applications, and notes that the team’s future directions include developing a fully wireless version of the robot, freeing it from the tether that currently connects it to its power and control source.

Qing also extends an open invitation to other disciplines. The team members are mechanical engineers, he notes, and they have produced a novel design for aquatic robotics; they would welcome collaborations with experts in other fields to explore what the platform might accomplish in practice. That collaborative posture is fitting, because the underlying idea, mechanical intelligence, is relevant far beyond one robot. It suggests a broader design principle in which morphology, elasticity, and environmental interaction substitute for actuation and computation, a lesson that could inform everything from search-and-rescue vehicles to biomedical devices that must navigate constrained, fluid-filled spaces.

The paper, titled Minimal-Actuation Feather Star Inspired Soft Swimmers for Multimodal 3D Maneuverability, was published on October 7 in Science Advances. In addition to Yin and Qing, the co-authors are Caizhi Zhou and Haoze Sun, both Ph.D. students at NC State; Yuanhang Zhu of the University of Virginia and the University of California, Riverside; and Jiacheng Guo, Haibo Dong, and Daniel Quinn of the University of Virginia. The research was supported by the National Science Foundation under grants 2126072 and 2329674, and by the Office of Naval Research under MURI grant N00014-22-1-2616. For a field that has often equated capability with complexity, the feather star robot makes a quietly radical argument: sometimes the smartest machine is the one whose body already knows what to do.

Subject of Research: A feather star-inspired soft underwater robot achieving 3D maneuverability with two actuators through mechanical intelligence

Article Title: Feather star-inspired underwater robot gets 3D maneuverability from only two actuators

Article References: Feather star-inspired underwater robot gets 3D maneuverability from only two actuators. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: soft robotics, feather star, underwater robot, mechanical intelligence, actuators, bioinspired design, marine robotics, Science Advances, North Carolina State University, 3D maneuverability, monostable wings, swimming robot

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

The central molecular player is azobenzene, a photoswitchable aromatic compound that undergoes a reversible transformation between two geometric isomers. In its thermodynamically stable trans form, the molecule is elongated and relatively flat; absorption of ultraviolet or near-ultraviolet light promotes it into the bent, kinked cis state. Because this isomerization changes molecular length, dipole moment, and packing geometry by a substantial margin, a polymer matrix loaded with azobenzene units physically deforms wherever light is absorbed. When the light is removed, thermal relaxation or exposure to a different wavelength drives the molecules back toward the trans configuration, allowing the deformation to reverse. This back-and-forth molecular shape change, repeated millions of times, is the engine that powers the entire actuator.

What distinguishes a hydrogel from a conventional azopolymer film is the presence of water as a substantial fraction of the material volume. Hydrogels are three-dimensional polymer networks swollen with aqueous fluid, which makes them mechanically similar to soft biological tissue. That similarity matters for applications: a hydrogel actuator can operate in physiological saline, interface with living cells with minimal mechanical mismatch, and transport ions or small molecules through its swollen network. The challenge has always been that typical hydrogels are mechanically weak and that incorporating enough hydrophobic azobenzene to produce strong photoresponse tends to make the material brittle and poorly swollen. The new work addresses this tension directly through network design.

According to the study, the researchers engineered copolymer networks in which azobenzene-containing monomers are covalently integrated with hydrophilic building blocks that maintain water uptake. The result is a material that remains highly swollen while still concentrating enough photoswitchable units near the surface and throughout the bulk to generate meaningful mechanical stress under illumination. The authors report that the balance between hydrophilic matrix content and azobenzene loading is the key design variable: too little azobenzene and the photomechanical response is feeble; too much and the network collapses or cracks. Their optimized compositions achieve large, reversible bending curvature at irradiation intensities compatible with inexpensive light-emitting diodes, a practical threshold for real-world deployment.

The mechanics of actuation in these materials are governed by a steep gradient in light absorption. Because azobenzene units near the illuminated surface absorb photons preferentially, the cis-rich layer forms at the exterior of the gel while the interior remains largely trans. This through-thickness asymmetry in molecular shape produces a differential strain, with the surface layer trying to expand or contract relative to the unconverted core. The mismatch forces the whole strip to bend toward or away from the light source, depending on the sign of the strain induced by isomerization. Classical bimetal-strip physics describes the resulting curvature, but in azopolymer hydrogels the active layer is continuously graded rather than sharply defined, which smooths the stress distribution and improves fatigue resistance over repeated switching cycles.

One of the most striking capabilities demonstrated in the paper is photo-guidance, meaning that the direction, speed, and geometry of motion can be steered in real time by repositioning or reshaping the illumination. A focused spot applied to one edge of a gel strip produces bending toward the light; sweeping the spot along the strip propagates a traveling deformation wave. Polarized light adds another control dimension, because azobenzene units preferentially absorb photons polarized along their molecular axis and undergo reorientation into directions perpendicular to the polarization. This photoinduced alignment, known as the Weigert effect, allows the researchers to inscribe anisotropic order into the gel surface and thereby program complex deformation modes, including twisting and helical coiling, without ever touching the material with a mold or a mechanical fixture.

The study further shows that these programmed deformations can be harnessed for locomotion. When a gel strip is placed on a wetted substrate and illuminated with an asymmetric, moving light pattern, the combination of cyclic bending and frictional asymmetry with the surface generates net displacement, effectively turning the material into a light-driven crawler. The authors characterize the dependence of crawling speed on irradiation intensity, spot size, and scan velocity, mapping out the operating envelope in which locomotion is fastest and most stable. Such light-steered motion at small scales is precisely what engineers have sought for microrobotic swimmers and delivery platforms that must navigate confined, cluttered environments where wires and onboard power are impractical.

Reversibility and endurance are perennial concerns for photoswitchable materials, and the paper devotes careful attention to both. Azobenzene isomerization is intrinsically fatigue-resistant because it involves no bond breaking, only bond-angle rearrangement, and the authors report that their hydrogel actuators sustain many repeated light on-off cycles with only modest degradation in bending amplitude. Thermal relaxation of the cis isomer back to trans occurs on timescales that depend on the local polymer environment, and the team exploits this by choosing substituent chemistry that tunes the thermal half-life, allowing them to dial in how quickly the actuator recovers its rest shape once the light is switched off. Fast-recovery variants suit rapid cycling applications, while slow-recovery compositions can hold a deformed shape as a light-written temporary configuration.

The implications extend well beyond laboratory demonstrations of bending strips. In biomedicine, hydrogel actuators that respond to light could drive minimally invasive devices such as self-steering catheters, cell-culture substrates that mechanically stimulate tissue on demand, and drug-release valves that open and close under transdermal illumination. In microfluidics, arrays of photoresponsive gel pillars could serve as pumpless mixers and check valves actuated by a scanned laser or a digital projector. In soft robotics more broadly, the ability to program three-dimensional shape changes purely through light patterns suggests a manufacturing paradigm in which a single flat gel sheet is transformed into many different functional geometries simply by rewriting the illumination script, echoing the principles of four-dimensional printing without the need for multi-material fabrication.

Challenges remain before azopolymer hydrogel actuators leave the laboratory. The strong absorption of azobenzene in the ultraviolet limits penetration depth and raises phototoxicity concerns for biological use, motivating ongoing efforts toward red-shifted azo derivatives and two-photon activation schemes that would allow near-infrared light to drive the switch through optically transparent tissue. Actuation forces, while sufficient for microscale manipulation, still fall short of what is needed to deform stiff structures, and operating in fully dry environments remains difficult because the hydrogel depends on water plasticization for its soft mechanics. Nevertheless, the demonstration that network architecture, illumination geometry, and polarization control can be combined into a coherent photo-guidance toolkit marks a significant step. It points toward soft machines that are powered, programmed, and steered by light alone, a vision that this study brings measurably closer to reality.

Subject of Research: Photo-responsive azopolymer hydrogel actuators driven and steered by patterned light

Article Title: Photo-guided azopolymer hydrogel actuators

Article References: Urban, D., Toyohara, R., Rey, M., Martella, D., Hjelme, D. R., Alessandrini, A., Ohashi, T., & Descrovi, E. (2026). Photo-guided azopolymer hydrogel actuators. Light: Science & Applications, 15(1), Article 383. https://doi.org/10.1038/s41377-026-02411-5

Image Credits: AI Generated

DOI: 10.1038/s41377-026-02411-5

Keywords: azopolymer, hydrogel, actuators, azobenzene, photoisomerization, soft robotics, photomechanics, light-driven materials, smart materials, locomotion, microfluidics, biomedical devices