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

Abstract 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.