Facile, ultrafast synthesis of up- and down-conversion fluorescent carbon dots for highly sensitive detection of hematin

Fluorescent carbon dots (CDs) are promising zero-dimensional carbon nanomaterials with semiconductor-like properties, which have attracted tremendous attention owing to their fascinating features such as excellent optical performance, chemical inertness, and low toxicology. In this investigation, Mg-doped CDs (Mg-CDs) with up- and down-conversion fluorescence (FL) were prepared within 2 min through a one-pot, facile and ultrafast microwave method. The obtained Mg-CDs showed excitation-independent blue emission and were potentially applied for the detection of hematin based on the strong inner filter effect (IFE). The FL intensity ratio (I0/I) of the synthesized Mg-CDs were proportional to the concentration of hematin in the range of 0.1–75 μM with the limit of detection of 25 nM for Mg-CDs-0.1 and 0.01–25 μM with the limit of detection of 1 nM for Mg-CDs-0.5. Overall, this selective and sensitive assay using Mg-CDs obtained through the current microwave method was believed to demonstrate significant application prospects in complex matrices owing to its simplicity and specificity for hematin. In this work, we developed a highly sensitive method of detecting hematin by Mg-CDs based on the strong inner filter effect. [Display omitted] •The Mg-CDs with up- and down-conversion FL can be prepared through a facile, ultrafast microwave synthesis within 2 min.•The FL of Mg-CDs can be quenched by hematin based on IFE, with the LOD of 25 nM (Mg-CDs-0.1) and 1 nM (Mg-CDs-0.5).•The proposed method is highly sensitive and selective, which can be used to detect hematin in healthy human red cells.