Facile synthesis of red dual-emissive carbon dots for ratiometric fluorescence sensing and cellular imaging. Issue 9 (24th February 2020) - Hu, Yang
Abstract : Carbon dots synthesized by the hydrothermal treatment of dicyandiamide and o -phenylenediamine in dilute H2 SO4 exhibit efficient excitation-independent red dual-emission useful for ratiometric fluorescence sensing and cellular imaging. Abstract : Recently, widespread attention has been paid to red emissive carbon dots (CDs) which have desirable optical properties, low toxicity, and biocompatibility. Despite great efforts, the facile preparation of red dual-emissive CDs useful for ratiometric detection and bioimaging remains challenging. Here, we report a facile synthesis of red dual-emissive CDs and their potential for ratiometric fluorescence sensing and cellular imaging. Derived from the hydrothermal treatment of dicyandiamide and o -phenylenediamine in dilute sulfuric acid, the CDs are surface-tailored with nitrogen-, oxygen-, and sulfur-containing functional groups. The as-prepared CDs show various good features, including good water solubility, biocompatibility, excitation-independent dual-emission with two photoluminescence (PL) peaks centered at 630 and 680 nm, and an absolute quantum yield (QY) of 30.2% in water. The CDs exhibit a selective, sensitive, rapid, and stable ratiometric fluorescence response toward methyl blue, giving a linear relationship in the range of 0.5–300 μM with a correlation coefficient ( R 2 ) of 0.997. We also study ratiometric fluorescence sensing for the accurate detection of pH. Moreover, the CDs possess good cellular imaging ability, indicating their promising applicability for biomedical applications. These results pave a way toward the fabrication of red dual-emissive carbon-based nanomaterials useful for both ratiometric sensing and bioimaging.