Chemotaxis of catalytic silica–manganese oxide “matchstick” particles

Abstract

Particles that can undergo directed self-propulsion are desirable for colloidal cargo delivery and self-assembly. Herein we describe the synthesis of silica-manganese oxide "matchstick" colloids that undergo catalytic self-propulsion by consumption of hydrogen peroxide. Chemotaxis is observed when particles are placed in a fuel gradient. Movement opposes convective flow which is tracked by following inert polymer microspheres simultaneously.

Nanoconfined Atomic Layer Deposition of TiO2/Pt Nanotubes: Toward Ultrasmall Highly Efficient Catalytic Nanorockets

“…Collective behavior driven by a uniform response to an external field is a notable characteristic of biological and artificial micro‐ and nanomotors, with the self‐organization driven by local interactions between individual motors in the assembly and the environment. In particular, the collective motion of self‐propelled swimmers due to an imposed chemical gradient is a rich topic because of the complexities introduced by the interplay between self‐propulsion, Brownian motion, and chemotactic effects.…”

“…Inspired by these efforts, the collective motion of the fabricated nanorockets, with a very high concentration in the suspension, is also investigated. The fuel concentration dependence of the catalytic swimmer on their velocities can promote chemotactic migration toward higher fuel concentration in the presence of an imposed peroxide gradient . The scheme in Figure C illustrates how this net nanorocket flux is used to achieve large‐scale directed transport of passive cargos, where individual nanorockets accumulate along the side of the tracer and move the tracer with their collective thrust.…”

Finite‐Sized One‐Dimensional Silica Microstructures (Rods): Synthesis, Assembly, and Applications

“…Reproduced with permissions from Ref. . Copyright (2012, 2015, 2015, 2016) American Chemical Society.…”

“…Matchstick‐like rods were made by first aligning the rods in an electric field followed by gold deposition on one end using electron‐beam coating (Figure a). Though these matchsticks were highly monodisperse, scalability remains an issue . Matchstick‐like rods were also prepared by preforming the metal oxide nanoparticles in the emulsion droplets before growing the rods (Figure b) .…”

“…Though thesem atchsticks were highly monodisperse, scalability remains an issue. [29] Matchstick-like rods were also prepared by preforming the metal oxide nanoparticles in the emulsion droplets before growingt he rods (Figure 4b). [30,31] The nanoparticles acted like stabilizers concentrated at the periphery of the emulsion droplets.…”