Fluorescence-Based Ratiometric Nanosensor for Selective Imaging of Cancer Cells

Herein, we report the synthesis and characterization of a nanosensor developed from a group of uniform materials based on organic salts (GUMBOS). This sensor is composed of three ionic species, namely, fluorescein, rhodamine B, and tetradecyltrihexyl phosphonium (P₆₆₆₁₄) ions. Nanoparticles prepared from this three-component GUMBOS, termed nanoGUMBOS, exhibited increased fluorescence at two wavelengths with increases in pH values. The ratio of fluorescence emission corresponding to FL and RhB components of these nanoGUMBOS also changed with pH, allowing ratiometric analysis of pH through fluorescence measurements. Peak ratios were significantly different at pH 5 and pH 7, indicating potential applications of this nanomaterial as a cancer diagnostic tool. In this regard, in vitro fluorescence microscopy was employed to image cancerous and normal breast cells incubated with nanoGUMBOS. Fluorescence imaging of cancer cells showed higher uptake of these nanoGUMBOS and more pervasive fluorescence intensity in comparison with normal cells. Thus, the synthesized novel nanomaterial shows a great potential for rapid visual imaging of cancer cells.