Preparation and biomedical applications of Janus nanomotors.

Janus nanomotors (JNMs), as a forefront nanotechnology research focus, demonstrate great potential due to their special asymmetric structure and outstanding performance in disease diagnosis and treatment. These "two-faced" nanoparticles exhibit propulsion by leveraging asymmetric physicochemical properties, functioning as biological motors. In the biomedical field, they provide important applications, including targeted drug delivery, precision biosensing, and minimally invasive therapies, offering new directions and novel strategies for disease diagnosis and treatment. This paper reviews the current JNM fabrication methods and analyzes the advantages and limitations of each method as well as their respective advances in biomedical applications. Given the existence of multiple propulsion modes for JNM, they can be categorized into three types based on the quantitative characteristics of their power sources: externally field-driven JNMs, fuel-driven JNMs, and composite-driven JNMs. Based on the distinct origins of driving forces, externally field-driven JNMs are further categorized into light-driven, magnetically-driven, ultrasound-driven, and electric-driven types. Fuel-driven JNMs are classified into enzyme-driven and self-driven variants. Furthermore, this paper specifically highlights composite-driven JNMs, which achieve functional enhancement in complex biological environments by integrating multiple stimulus sources. Finally, we discuss future prospects and challenges for differently propelled JNMs, anticipating their significant influence on human health.