Facile synthesis of carbon dots from wheat straw for colorimetric and fluorescent detection of fluoride and cellular imaging

Colorimetric and fluorescent detection of F − have attracted enormous interest owing to their simplicity, low-cost and high selectivity. However, traditional colorimetric and fluorescent sensors mainly based on the insoluble and toxic organic molecules, which is not favorable for sensing F − in water media and living cells. In this work, we designed fluorescent carbon dots (CDs) with excellent water solubility and good biocompatibility as a colorimetric and fluorescent dual-model probe for the detection of F − . The CDs were prepared by a green, one-step hydrothermal strategy from wheat straw without any additives and surface passivation . The obtained CDs exhibited a bright blue fluorescence, special response to F − and low cytotoxicity. More interestingly, a significant color change from light yellow to red can be observed by the naked eye upon addition of F − ions to the CDs solution probably due to the formation of hydrogen bonding between CDs and F − . Besides, the fluorescence of CDs also can be selectively quenched by F − with the detection limit of about 49 μM. Additionally, the CDs are also applied to intracellular imaging and sensing of F − in living cells. This strategy may provide a new method for the detection of F − in water media and biological systems.