Biocompatible Nanomotors as Active Diagnostic Imaging Agents for Enhanced Magnetic Resonance Imaging of Tumor Tissues In Vivo

Abstract The limited penetration of imaging agents in solid tumor tissue and cells remains a great challenge to achieve ideal visibility in cancer diagnosis. Herein, a near infrared (NIR) light‐driven Janus mesoporous silica nanomotor (JMS nanomotor) to promote magnetic resonance (MR) imaging in vivo is developed. The JMS nanomotors are prepared by depositing Au on the half‐sphere surface of gadolinium‐doped mesoporous silica nanoparticles. Under NIR irradiation, the nanomotors achieve efficient propulsion through thermophoresis in biological media. To prove the ability of nanomotors as active diagnostic imaging agents, both in vitro and in vivo experiments are carried out. In vitro studies confirm that NIR light can actively propel the JMS nanomotors to effectively seek, adhere to, and mechanically perforate the tumor cells to enhance the cellular uptake and MR imaging. To move a step further, in vivo investigations show that the JMS nanomotors also exhibit improved accumulation and deep penetration in the solid tumor model when exposed to NIR laser, where the MR imaging contrast is significantly enhanced in the majority of tumor tissue. Such JMS nanomotors provide new insight in precise cancer diagnosis and meanwhile MR imaging offers a new tool for real‐time tracking of nanomotors in vivo.