Nanozymatic magnetic nanomotors for enhancing photothermal therapy and targeting intracellular SERS sensing

Abstract

Self-propelled micro/nanomotors (MNMs) have emerged as promising tools for biomedical applications owing to their active and controllable movement, which is achieved by converting energy derived from chemical reactions or external physical fields into mechanical forces. However, it remains a challenge to develop all-in-one MNMs that integrate multiple bio-friendly engines and biomedical functions. In this study, we present a nanozymatic magnetic nanomotor capable of self-propulsion, driven by its intrinsic engines, and possessing inherent biomedical functions. The nanomotors with a core-island structure are fabricated by a general scalable chemistry synthesis approach. The core of the nanomotors is magnetic Fe₃O₄ nanoparticles, while the surrounding islands consist of Au nanostars. Such components naturally equip the nanomotors with the dual engine of the magnetic core and gold nanozyme. In addition, the localized surface plasmon resonance (LSPR) effect of the Au nanostar imparts the nanomotors with favourable photothermal conversion and surface-enhanced Raman scattering (SERS) properties. The nanomotors exhibit glucose concentration-dependent motion behavior of enhanced diffusion, leading to improved endocytosis for enhanced photothermal treatment. When exposed to a magnetic field, the nanomotors demonstrate both directional locomotion towards target cells and up-and-down oscillatory movement, enabling the efficient gathering of intracellular analytes for SERS sensing. To conclude, the as-prepared nanomotors represent an active and controllable nanoplatform with a simple structure and are naturally equipped with dual engines and dual biomedical functions, providing new perspectives to the development of all-in-one biomedical MNMs.