Titania-Based Micro/Nanomotors: Design Principles, Biomimetic Collective Behavior, and Applications

Autonomous micro/nanomotors (MNMs) serve as models for biologically active matter and have potential applications in nanomachinery, nanoscale assembly, robotics, fluidics, and chemical/biochemical sensing. Using light to power and direct the motion of MNMs is particularly advantageous since the light source can provide spatiotemporal control over transport. Because of its superior stability and photocatalytic and photothermal properties, titanium dioxide (titania, TiO₂) is an especially attractive material for the design of MNMs. We discuss the progress to date in the fabrication and use of titania-based MNMs. These show biomimetic swarming behavior and have potential applications in microfluidics, cargo delivery, and environmental remediation. We end with limitations of the current MNMs and the challenges that need to be overcome for the field to move forward.