High‐Motility Visible Light‐Driven Ag/AgCl Janus Micromotors

Abstract

The research field of man-made nano/micromotors is growing significantly at the level of new materials and fabrication, as well as numerous exciting demonstrations, ranging from Visible light-driven nano/micromotors are promising candidates for biomedical and environmental applications. This study demonstrates blue light-driven Ag/AgCl-based spherical Janus micromotors, which couple plasmonic light absorption with the photochemical decomposition of AgCl. These micromotors reveal high motility in pure water, i.e., mean squared displacements (MSD) reaching 800 µm 2 within 8 s, which is 100× higher compared to previous visible light-driven Janus micromotors and 7× higher than reported ultraviolet (UV) light-driven AgCl micromotors. In addition to providing design rules to realize efficient Janus micromotors, the complex dynamics revealed by individual and assemblies of Janus motors is investigated experimentally and in simulations. The effect of suppressed rotational diffusion is focused on, compared to UV light-driven AgCl micromotors, as a reason for this remarkable increase of the MSD. Moreover, this study demonstrates the potential of using visible light-driven plasmonic Ag/AgCl-based Janus micromotors in human saliva, phosphate-buffered saline solution, the most common isotonic buffer that mimics the environment of human body fluids, and Rhodamine B solution, which is a typical polluted dye for demonstrations of photocatalytic environmental remediation. This new knowledge is useful for designing visible light driven nano/micromotors based on the surface plasmon resonance effect and their applications in assays relevant for biomedical and ecological sciences. Janus Micromotors

Recent Advances in Nano‐ and Micromotors

“…iv) Extracted trajectories ( X – Y maps) for the motion of the Janus micromotors formed by 1, 2, 3 and >3 particles, and their corresponding v) experimental and vi) simulated MSD plots. Reproduced with permission . Copyright 2018, Wiley–VCH.…”

“…In addition to quantum dots, other inorganic photosensitive materials were considered to generate motion including Au/TiO 2 nanocaps and Janus swimmers made of Ag/AgCl deposited onto polystyrene spheres (Figures C‐i,ii), taking advantage of the surface plasmon resonance of Au and Ag, reaching velocities up to ≈2.8 and 4.9 µm s −1 , respectively. The trajectories of swimmers were assessed (Figure C‐iii), showing a general decrease in velocity, ranging from 3.5–4.0 µm s −1 , or 2.5–3.5 µm s −1 for two‐ and three‐particle assemblies, respectively.…”

Biocompatible and pH‐Responsive Colloidal Surfactants with Tunable Shape for Controlled Interfacial Curvature

“…However, the preparation of biocompatible amphiphilic Janus particles through a facile method has barely been addressed, which greatly limits their biorelated application . Therefore, there remains strong demand for new classes of biocompatible Janus particles with tunable morphology and functionality, which could enable the design of applications in food, cosmetics, drug delivery, and biomedicine …”

Bubble‐Enabled Underwater Motion of a Light‐Driven Motor

“…Compared with other physical sources, light is becoming an attractive external stimulus to propel both nano/micromotors and macromotors owing to its unlimited, nonintrusive, clean, and easily controllable capability. Light‐driven nano/micromotors are promising candidates for biomedical and environmental applications . For example, Baraban and co‐workers.…”

“…has demonstrated blue light‐driven Ag/AgCl‐based spherical Janus micromotors, which revealed high motility in pure water. Their results could be used in bioenvironments demanding low toxicity and nondestructive illumination conditions, such as water purification and antibacterial action . As for macro‐robotics community, Shi and co‐workers.…”