When exposed to a beam of near-infrared light, these micromotors absorb energy via the gold coating, which subsequently heats the adjacent air. This heat-induced energy transfer generates soft convection currents, akin to the uplifting of warm air, thereby propelling the micromotors upward and enabling precise directional movement. Researchers can effectively steer these tiny devices by manipulating the position of the light source, showcasing an impressive level of control that has previously been unattainable in airborne micromotor technologies.

Historically, micromotors have been restricted to motion in liquid environments, where buoyancy lends support to their movement. However, achieving controlled propulsion in air presents far more complex challenges due to gravitational forces alongside the absence of supportive fluids. The team’s success in overcoming these obstacles signifies a pivotal leap in the design and application of micromotor technologies, which could potentially revolutionize a variety of fields ranging from environmental sensing to micro-aerial delivery systems.

The leader of this innovative research initiative, John Capobianco, is a professor emeritus at Concordia University, specializing in the fields of chemistry and biochemistry. Capobianco has dedicated his academic career to advancements in nanoscience, and his recent work with these micromotors marks a high point in his research endeavors, particularly as he approaches retirement in May 2025. His contributions have not only shaped the future of nanotechnology but have also paved the way for new methodologies in experimental physics.

This groundbreaking research has been published in the esteemed journal Advanced Materials, signaling the importance and relevance of the findings to the scientific community. The research received crucial funding from the Natural Sciences and Engineering Research Council of Canada (NSERC) and CMC Microsystems, backed by the Government of Canada’s FABrIC project, which supports innovative research in the fields of materials science and engineering. The collaboration demonstrates a unified effort among various academic and governmental institutions dedicated to promoting scientific progress.

The implications of these light-activated micromotors extend well beyond mere academic curiosity—their potential applications are numerous and varied. For instance, these devices could be utilized in creating microscopic sensors that can detect environmental pollutants, thus contributing to efforts aimed at improving air quality. Additionally, the technology could lead to the development of nanomachines that perform targeted tasks in the atmosphere, such as delivering therapeutics for airborne diseases or monitoring climate phenomena at an unprecedented scale.

Moreover, understanding how these micromotors operate at the nanoscale opens avenues for further research into other potential light-driven technologies. The intrinsic relationship between light and matter at the nanoscale could provide new insights into energy efficiency, offering environmentally friendly solutions to energy acquisition, especially in areas where traditional energy sources are either impractical or unsustainable.

With the ever-growing focus on sustainability and the environment, these micromotors represent a new frontier in ecological technology. The ability to navigate and manipulate particles in air without chemical fuels not only promises a decrease in pollution outputs associated with powered movements but also aligns with broader goals of developing green technologies. This innovation stands to inspire further exploration into similar mechanisms that could convert light into motion, fostering a renewed interest in photonics and materials science.

As the authors of the study declare no conflict of interest, it underscores the integrity and motive of research aimed solely at benefiting society. This transparent approach cultivates an environment of trust and accountability within the scientific community, fostering collaborations that prioritize innovation and discovery. The nexus of collaboration between academia and funding bodies further signifies a commitment to scientific integrity and the drive to address global challenges.

Moving forward, it will be essential to investigate the scalability of this technology, evaluating the potential for developing larger or more efficient micromotor systems. The challenges of scaling nanotechnology often lie in the complexity of replicating nanoscale conditions at a larger scale while maintaining functionality. Understanding these limitations will be crucial for translating laboratory successes into real-world applications.

In summary, the creation of light-activated micromotors that operate in air presents a transformative opportunity within the realms of both nanotechnology and environmental science. As research continues to unfold and applications are explored, the potential for these micromotors to influence a wide array of industries becomes increasingly apparent. As we witness the advancement of technology that harnesses the power of light, we stand on the cusp of a new era in engineering and environmental sustainability.

Subject of Research: Micromotors powered by light for use in air
Article Title: Light-Activated Micromotors in Air Propelled by Thermal Convection
News Publication Date: 18-Sep-2025
Web References: Advanced Materials
References: DOI: 10.1002/adma.202505959
Image Credits: Image courtesy Impact Research Comms, created for Wiley for the publication in Advanced Materials

Keywords

Nanotechnology, Micromotors, Air Pollution, Environmental Science, Green Technology, Photonics, Energy Efficiency

Natural organisms have evolved highly specialized morphologies and behaviors to adapt to their intricately changing habitats. By translating these biological inspirations into artificial designs, scientists have sought to replicate the remarkable efficiency and versatility observed in nature. The suckerfish-shark relationship serves as a compelling model: suckerfishes cling to sharks or boats during transit but detach upon arrival in prey-rich waters to forage independently. Mimicking this dynamic behavior, the researchers engineered a core-satellite micro@nanomotor system that operates through two distinct stages—a large micromotor host carrying numerous small nanomotor satellites, which release selectively in response to environmental pH changes.

At the heart of this system is a yolk-shell structured micromotor composed of polydopamine-mesoporous silica (PDA-MS), which acts as the “host.” This core is functionalized with many Janus gold-platinum (Au-Pt) nanomotors—analogous to the “suckerfish” satellites—that are capable of autonomous propulsion driven by hydrogen peroxide (H₂O₂) decomposition. The coordinated bonding between the nanomotors and the PDA-MS surface is sensitive to weakly acidic conditions, allowing the nanomotors to detach precisely when the micro@nanomotor encounters specific chemical cues.

The micro@nanomotor achieves directional motion by exploiting self-thermophoresis when illuminated with low-power NIR light. This photothermal effect generates a localized temperature gradient, propelling the micromotor host along a predetermined path. Upon encountering a weakly acidic microenvironment, similar to tumor extracellular spaces, the coordinated bonds weaken, triggering the release of the active nanomotors. Once released, these smaller nanomotors engage in self-diffusiophoretic movement fueled by the low concentrations of hydrogen peroxide present, enabling independent navigation and enhanced coverage at the target site.

This innovative two-stage propulsion mechanism represents a profound leap in micro/nanorobotics, combining remote light actuation with environmentally responsive release. The bionic design strategy addresses a long-standing challenge in the field: developing flexible micro/nanomotors capable of adapting to and functioning within the diverse, complex biological milieus encountered in vivo. Such responsiveness is critical for performing sophisticated tasks such as targeted drug delivery, biosensing, and environmental detoxification, where precise control over motor behavior and cargo release is paramount.

Moreover, the core-satellite architecture allows for a high payload capacity of functional nanomotors loaded onto a single micromotor platform. This hierarchical system maximizes efficiency by enabling the controlled liberation of numerous Janus nanomotors at the site of interest, vastly improving the potential for targeted therapeutic applications. In particular, the researchers propose that this system could be adapted for theranostic functions within tumor microenvironments, where the mild acidity acts as a natural trigger for motor deployment and therapeutic payload release.

Fundamentally, the incorporation of Janus nanomotors—named for their dual-faced asymmetric design—provides directional propulsion through catalytic decomposition of low-concentration hydrogen peroxide fuel, generating localized chemical gradients. By decorating the PDA-MS micromotor surface with these Janus nanomotors via coordinated bonds sensitive to pH, the team creates a responsive system that can switch propulsion modes seamlessly. This adaptability enhances operational flexibility in fluctuating biological or chemical environments, overcoming critical limitations of conventional unistage micro/nanomotor systems.

The research, supported by major funding bodies including China’s Fundamental Research Funds for the Central Universities and the Natural Science Foundation of Jiangsu Province, represents a significant milestone in artificial micro/nanomotor engineering. It also highlights the synergy between biomimetic design principles and advanced materials chemistry in constructing functional devices with high intelligence and autonomy. Such advancements pave the way for next-generation smart nanomachines that intelligently interact with biological systems for applications spanning precision medicine, diagnostics, and beyond.

Professor Xin Du, the lead scientist on this project, emphasized the transformative potential of integrating biologically inspired motion strategies with smart material components. According to Du, the ability to remotely control micromotor motion via NIR light combined with environmentally triggered nanomotor release offers unprecedented operational versatility. His group’s extensive publication record across high-impact journals attests to their pioneering role in this rapidly evolving domain.

The prospects for this two-stage micro@nanomotor extend beyond medical applications. Environmental remediation stands to benefit from the autonomous release of numerous catalytic nanomotors capable of degrading pollutants, enhancing water treatment technologies, and monitoring environmental variables in situ. The responsive release mechanism enables a dynamic adaptation to contaminants, triggering motor deployment only when necessary, thus conserving fuel and avoiding unintended dispersal.

In the broader context, this breakthrough underscores the importance of investigating natural cooperative behaviors and translating them into engineered microsystems. By imitating the cooperative locomotive and release behaviors of marine species, researchers can overcome existing design challenges associated with control, fuel efficiency, and environmental adaptability in micro/nanomotors. This bench-to-nature approach signifies a new paradigm in the design of intelligent nanomachines and multifunctional therapeutic platforms.

As nanotechnology continues to push the frontiers of miniaturization and autonomy, such smart biomimetic micro@nanomotors herald a future where artificial systems not only coexist harmoniously within biological niches but actively respond and adapt to microenvironmental cues. The dynamic interplay between NIR light propulsion and chemical stimuli response in this system offers a versatile framework potentially extensible to other stimuli-responsive materials including enzymatic, magnetic, and acoustic modulation.

Ultimately, the core-satellite PDA-MS@Au-Pt micro@nanomotor system crafted by this research team represents a compelling synthesis of materials engineering, catalytic propulsion chemistry, and biomimetic design. It exemplifies the transformative impact of biologically inspired mechanisms powered by intelligent materials to realize multifunctional, adaptable, and controllable micro/nanomachines. As such, it opens new vistas for soft robotic devices capable of performing complex biological tasks with precision and minimal invasiveness.

Subject of Research: Biomimetic micro/nanomotors inspired by suckerfish-shark interaction for intelligent, two-stage propulsion and weak acid-triggered release of nanomotors.

Article Title: Biomimetic two-stage micro@nanomotor with weak acid-triggered release of nanomotors

News Publication Date: 7-Apr-2025

Web References: http://dx.doi.org/10.26599/NR.2025.94907309

Image Credits: Nano Research, Tsinghua University Press

Keywords

Biomimetic micro/nanomotors, two-stage propulsion, Janus nanomotors, near-infrared light propulsion, weak acid-triggered release, hydrogen peroxide decomposition, polydopamine-mesoporous silica, tumor microenvironment, smart nanomachines, self-thermophoresis, self-diffusiophoresis, active cargo delivery