Publications

Self-propelled micromotors have shown promise for applications in environmental remediation, sensing, and biomedicine. However, assessing their performance in realistic, 3D microenvironments with dynamic boundaries and complex topography remains a key challenge. Achieving controlled motion and enhanced reactivity under such confinement is critical for both technological applications and fundamental studies on active matter. Here, the integration of light-driven micromotors with liquid marbles is presented, which are gas-permeable droplets encased by hydrophobic particles that act as dynamic, flow-active microreactors. By tuning the coverage of the particulate shell, partially covered liquid marbles are developed that exhibit robust evaporation-induced flows, increasing the average micromotor velocity by approximately threefold compared to sessile droplets. Under illumination, photocatalytic self-propulsion provides an additional velocity component and promotes micromotor dispersion. The combined circulation enhances mass transfer, guiding micromotor accumulation and transport while providing an optical transparent, soft-confinement platform for studying active particles and confined catalytic reactions.

JTD Keywords: Active matter, Liquid marbles, Marangoni flow, Photocatalysis, Self-propelled micromotors

Inspired by Richard Feynman's 1959 lecture and the 1966 film Fantastic Voyage, the field of micro/nanorobots has evolved from science fiction to reality, with significant advancements in biomedical and environmental applications. Despite the rapid progress, the deployment of functional micro/nanorobots remains limited. This review of the technology roadmap identifies key challenges hindering their widespread use, focusing on propulsion mechanisms, fundamental theoretical aspects, collective behavior, material design, and embodied intelligence. We explore the current state of micro/nanorobot technology, with an emphasis on applications in biomedicine, environmental remediation, analytical sensing, and other industrial technological aspects. Additionally, we analyze issues related to scaling up production, commercialization, and regulatory frameworks that are crucial for transitioning from research to practical applications. We also emphasize the need for interdisciplinary collaboration to address both technical and nontechnical challenges, such as sustainability, ethics, and business considerations. Finally, we propose a roadmap for future research to accelerate the development of micro/nanorobots, positioning them as essential tools for addressing grand challenges and enhancing the quality of life.

JTD Keywords: Catalytic nanomotor, Chemically powered nanomotors, Collective behavior, Drug-delivery, Functionality, Humans, Intelligence, Janus micromotors, Low-reynolds-number, Metal-organic frameworks, Micro/nanorobots, Motion control, Multiparticle collision dynamics, Nanotechnology, Near-infrared light, Propulsion, Robotics, Self-propelled micromotors, Smart materials, Technological translatio, Technological translation

The presence of organic pollutants in the environment is a global threat to human health and ecosystems due to their bioaccumulation and long-term persistence. Hereby a micromotor-in-sponge concept is presented that aims not only at pollutant removal, but towards an efficient in situ degradation by exploiting the synergy between the sponge hydrophobic nature and the rapid pollutant degradation promoted by the cobalt-ferrite (CFO) micromotors embedded at the sponge's core. Such a platform allows the use of extremely low fuel concentration (0.13% H2 O2 ), as well as its reusability and easy recovery. Moreover, the authors demonstrate an efficient multicycle pollutant degradation and treatment of large volumes (1 L in 15 min) by using multiple sponges. Such a fast degradation process is due to the CFO bubble-propulsion motion mechanism, which induces both an enhanced fluid mixing within the sponge and an outward flow that allows a rapid fluid exchange. Also, the magnetic control of the system is demonstrated, guiding the sponge position during the degradation process. The micromotor-in-sponge configuration can be extrapolated to other catalytic micromotors, establishing an alternative platform for an easier implementation and recovery of micromotors in real environmental applications.© 2022 Wiley-VCH GmbH.

JTD Keywords: effective removal, fabrication, microbots, microjets, organic pollutants, propelled micromotors, self-propelled micromotors, sponges, water treatment, Oil-water separation, Organic pollutants, Water treatment

Self-propelled micromotors have previously shown to enhance pollutant removal compared to non-motile nano-micro particles. However, these systems are expensive, difficult to scale-up and require surfactant for efficient work. Efficient and inexpensive micromotors are desirable for their practical applications in water treatment technologies. We describe cobalt-ferrite based micromotors (CFO micromotors) fabricated by a facile and scalable synthesis, that produce hydroxyl radicals via Fenton-like reaction and take advantage of oxygen gas generated during this reaction for self-propulsion. Once the reaction is complete, the CFO micromotors can be easily separated and collected due to their magnetic nature. The CFO micromotors are demonstrated for highly efficient advanced oxidative removal of tetracycline antibiotic from the water. Furthermore, the effects of different concentrations of micromotors and hydrogen peroxide on the antibiotic degradation were studied, as well as the generation of the highly reactive hydroxyl radicals responsible for the oxidation reaction.

JTD Keywords: Degradation, Fenton reaction, Microbots, Nanomotors, Self-propelled Micromotors, Water treatment