Cancer-Targeting and Viscosity-Activatable Near-Infrared Fluorescent Probe for Precise Cancer Cell Imaging.

ABSTRACT

Small-molecule fluorescent probes have emerged as potential tools for cancer cell imaging-based diagnostic and therapeutic applications, but their limited selectivity and poor imaging contrast hinder their broad applications. To address these problems, we present the design and construction of a novel near-infrared (NIR) biotin-conjugated and viscosity-activatable fluorescent probe, named as QL-VB, for selective recognition and imaging of cancer cells. The designed probe exhibited a NIR emission at 680 nm, with a substantial Stokes shift of 100 nm and remarkably sensitive responses toward viscosity changes in solution. Importantly, QL-VB provided an evidently enhanced signal-to-noise ratio (SNR 6.2) for the discrimination of cancer cells/normal cells, as compared with the control probe without biotin conjugation (SNR 1.8). Moreover, we validated the capability of QL-VB for dynamic monitoring of stimulated viscosity changes within cancer cells and employed QL-VB for distinguishing breast cancer tissues from normal tissues in live mice with improved accuracy (SNR 2.5) in comparison with the control probe (SNR 1.8). All these findings indicated that the cancer-targeting and viscosity-activatable NIR fluorescent probe not only enables the mechanistic investigations of mitochondrial viscosity alterations within cancer cells but also holds the potential as a robust tool for cancer cell imaging-based applications.