Epitaxial-assembled monolayer superlattices for efficient micromotor propulsion

Abstract

Exploring micromotors with outstanding propulsion efficiency is of great importance for aspects ranging from enhancement of performance to realization of applications. Improvements in propulsion efficiency lead to a lower fuel requirementand broadens the potential application areas for higher environment compatibility. In this article, a tubular micromotor with catalytic nanoparticle superlattices is fabricated through a simple epitaxial assembly method. A high surface-to-volume ratio due to the use of catalytic nanoparticles, a carbon outer layer and cooperative propulsion of multitubes enables the micromotor to move in biocompatible environment with a low concentration of fuel. In addition, magnetic nanoparticles are integrated into the micromotor to offer effective control of the direction of movement by using a magnetic field. This work provides a simple and low-cost fabrication method for a micromotor with high performance, which is expected to meet practical demands.

Smart Materials for Microrobots

“…Another locally powered mechanism of chemical locomotion consists of the continuous ejection of gas microbubbles generated in internal cavities of the microrobot engine, akin to rockets used to propel into space. − To achieve directional motion, the catalytic surface is enclosed by an inert material (silicon, parylene, polypyrrole, graphene), leaving an opening for the fuel to enter and the chemical reaction to occur. Typical engine designs include a hollow tube with a catalytic interior and an inert exterior, and Janus microspheres with diverse degrees of coverage (half coating or nearly complete shell with a small opening). , To increase the bubble production and enhance the microengine propulsion, composite materials, surface roughness, and geometric design have been integrated into the engine. − A limitation of chemically powered engines is that some of the common fuels, e.g., hydrogen peroxide, − hydrazine, , sodium borohydride, , are toxic, while other biocompatible microengines (based on magnesium, zinc, calcium carbonate) have short lifetimes. Moreover, the byproduct of the chemical reaction might change the local pH environment or increase the concentration of charged species.…”

An Overview of Recent Progress in Micro/Nanorobots for Biomedical Applications

“…Therefore, micro/nanorobot driven by chemical and magnetic driving will have higher control precision and faster movement speed than single driving. [ 130–134 ] Enzyme‐based chemically‐driven micro/nanorobots are more biocompatible; therefore, the combination of enzyme‐driven and magnetic‐driven is also more promising in the biomedical field. For example, Wu et al.…”

“…Therefore, micro/nanorobot driven by chemical and magnetic driving will have higher control precision and faster movement speed than single driving. [130][131][132][133][134] Enzyme-based chemically-driven micro/ nanorobots are more biocompatible; therefore, the combination of enzyme-driven and magnetic-driven is also more promising in the biomedical field. For example, Wu et al [38] fabricated enzymatic/magnetically driven micromotors for synergistic treatment of chemotherapy and starvation therapy, as shown in Figure 5A.…”

Broadband and large-depth terahertz modulation by self-assembly monolayer silver nanoparticle arrays

“…Nanoparticle-based structures, which are generally composed of nanoparticle films and substrates, have attracted significant attentions because of their unique physico-chemical properties for diverse applications, e.g. photodetection, sensing, photocatalysis, photovoltaics and so on [34][35][36][37]. These nanostructures are particularly effective in improving the performance of THz devices.…”