Organic-Dye-Modified Upconversion Nanoparticle as a Multichannel Probe to Detect Cu²⁺ in Living Cells

The development of an inorganic-organic hybrid probe to more accurately detect ions in living systems is very challenging but highly desirable. Here we combined upconversion nanoparticles with the electrically active ferrocene group to detect Cu²⁺ in living cells. The as-prepared probe displays three different signal changes in absorption, emission, and electrochemical behavior, respectively, during Cu²⁺ ion detection. Moreover, this new probe has been demonstrated to show high stability and adaptability. In addition, bioimaging testing reveals that this probe is suitable for detecting and visualizing Cu²⁺ in A549 cells with low cytotoxicity.