Sustainable synthesis of carbon dots via bio‐waste recycling for biomedical imaging

Bio‐waste is a side product of biomedical research containing carbon, which can be utilized for developing carbon dots (CDs). CDs are known to be useful for a variety of applications because of their unique photoluminescence, low toxicity, and straightforward synthesis. In this paper, we employed a one‐step hydrothermal method to prepare CDs from bio‐waste as the only reactant. The as‐synthesized Cell‐CDs were found to be chemically stable and biocompatible. In addition, the spectra of Cell‐CDs’ emissions covered the visible light, which is ideal for super‐resolution imaging. Particularly, dual‐color imaging can be achieved, for example, by staining the plasma membrane with Cell‐CDs emitting one color and staining cytosolic organelles with Cell‐CDs emitting a different color of fluorescence. Here, we demonstrate such applications by studying the subcellular dynamics of live cells. Cell‐CDs were synthesized from bio‐hazard waste via a one‐step hydrothermal method, yielding photoluminescent, chemically stable, and biocompatible probes. These Cell‐CDs enabled super‐resolution live‐cell imaging with dual‐color capability, distinguishing plasma membranes and lysosomes by emitting different fluorescent colors.