# Photocatalytic Micro/Nanomotors Functioning in the Near‐Infrared Window for Biomedical Applications

## TL;DR

This review explores how near-infrared light-powered micro/nanomotors can be used for non-invasive biomedical treatments by improving their photocatalytic efficiency.

## Contribution

The paper systematically reviews innovative material strategies for enhancing near-infrared responsiveness in photocatalytic micro/nanomotors.

## Key findings

- NIR light enables biocompatible operation but requires advanced materials to overcome low photon energy limitations.
- Heterostructures, upconversion coupling, and defect modulation are effective strategies for improving photocatalytic performance.
- Potential applications include photodynamic therapy and neural stimulation, though challenges like immune evasion remain.

## Abstract

Near‐infrared (NIR) light‐driven photocatalytic micro‐ and nanomotors are emerging as a new class of self‐propelled micro/nanodevices for minimally invasive biomedical applications. By operating within the biological transparency window, they enable autonomous motion and light‐induced redox reactions under biocompatible illumination conditions. Yet, the low photon energy of NIR light imposes fundamental constraints on photocatalytic efficiency and propulsion, requiring innovative materials design. This review systematically discusses recent progress in materials strategies for achieving NIR responsiveness, including heterostructure formation, upconversion coupling, defect modulation, and photosensitization via dyes or plasmonic nanostructures. The relationships between material composition, optical absorption, charge separation, and motion behavior are analyzed, with emphasis on photocatalytic propulsion. Particular attention is given to their potential application in photodynamic therapy, neural stimulation, and redox‐based treatments, while discussing remaining challenges related to fuel‐free propulsion, ionic tolerance, and immune system evasion. Finally, key design principles and future research directions are outlined, positioning NIR‐responsive photocatalytic micro/nanomotors as a versatile platform for minimally invasive therapeutic treatments and remote‐controlled catalysis.

This review focuses on near‐infrared responsive photocatalytic micro/nanomotors based on inorganic materials, with particular emphasis on minimally invasive biomedical applications. It discusses material strategies for achieving near‐infrared responsiveness, including heterostructure construction, upconversion nanoparticle integration, defect engineering, and photosensitization techniques. The review further highlights emerging therapeutic applications, key challenges and opportunities, and future design principles.