Rapid and multimodal in vivo bioimaging of cancer cells through in situ biosynthesis of Zn & Fe nanoclusters

Early diagnosis remains highly important for efficient cancer treatment, and hence, there is significant interest in the development of effective imaging strategies. This work reports a new multimodal bioimaging method for accurate and rapid diagnosis of cancer cells by introducing aqueous Fe²⁺ and Zn²⁺ ions into cancer cells (i.e., HeLa, U87, and HepG2 cancer cells). We found that the biocompatible metal ions Fe²⁺ and Zn²⁺ forced the cancer cells to spontaneously synthesize fluorescent ZnO nanoclusters and magnetic Fe₃O₄ nanoclusters. These clusters could then be used for multimodal cancer imaging by combining fluorescence imaging with magnetic resonance imaging and computed tomography imaging. Meanwhile, for normal cells (i.e., L02) and tissues, neither fluorescence nor any other obvious difference could be detected between pre- and post-injection. This multimodal bioimaging strategy based on the in situ biosynthesized Zn & Fe oxide nanoclusters might therefore be useful for early cancer diagnosis and therapy.