Green Fabrication of Carbon Dots upon Photoirradiation and Their Application in Cell Imaging

The green and low-cost preparation of carbon dots (CDs) with excellent fluorescence plays a key role in cell-imaging applications. Herein, we develop a green photochemical approach for fabricating CDs. The produced CDs can be used directly in lung cancer A549 cell imaging without any tedious post-treatments. As nontoxic and green alternatives to prevent pollution, fatty acids in sole aqueous media are the only reactants used to synthesize CDs. Furthermore, the green process of photoirradiation avoids harsh conditions, such as strong acids and bases, strong oxidants, and high temperatures and pressures. In addition, the by-products remaining in the aqueous environment are fatty acid dimers in the form of vesicles, which can also be recycled as gemini surfactant resources. We demonstrate that this green synthetic method for fabricating CDs is suitable for fatty acids with different chain lengths, and therefore, exhibits considerable universality. Fatty acids, as readily available green resources in nature, and the green and simple synthesis method without additional pollution provides a new approach and perspective for the green synthesis of CDs for bioimaging.