Near-infrared-driven fluorescent nanomotors for detection of circulating tumor cells in whole blood.

It is of great significance to develop micro/nanomotors with good biosafety and high efficiency for biomedical detection. In order to enhance the contact chances between the biosensors and the analytes in the complex blood sample, we report a near-infrared light (NIR)-driven fluorescent nanomotor, which can safely and efficiently capture and detect circulating tumor cells (CTCs) in the whole blood environment without pretreating procedures. Firstly, the structure of the fluorescent nanomotor was characterized and its motion behavior in different environments was analyzed. Subsequently, CTCs detection conditions were optimized to explore the effect of nanoscale autonomous mixing provided by nanomotor's motion behavior on the efficiency of CTCs capture. The results showed that the NIR-driven fluorescent nanomotor can keep moving in the complex biological medium so as to increase their contact chances with CTCs and improve the binding efficiency with the target analyte (the capture efficiency increased from 67.5% - 85% (no NIR irradiation) to 93.75-98.75% (under NIR irradiation)). Finally, due to the excellent fluorescence properties of the nanomotors, they can be applied to the visual detection of the whole blood samples obtained from clinical cancer patients. The NIR-driven nanomotor designed in this paper can detect CTCs in whole blood environment, which is a beneficial extension of the existing cell detection system of most micro/nanomotors in water phase environment.