Microwave-assisted ultra-fast synthesis of carbon quantum dots from linter: Fluorescence cancer imaging and human cell growth inhibition properties

Abstract The water dispersed-fluorescent carbon quantum dots (CDs) were synthesized using microwave-assisted hydrothermal process in the closed system from the waste cotton linter as a new carbon source. This method provided an ultra-fast, more effective, economical and easier synthesis for cancer-imaging applications compared to the other methods presented in literature. The morphological and optical properties of the hydrothermally produced carbon quantum dots were characterized by using FT-IR, transmission electron microscopy (TEM), SEM, EDX, UV–vis and fluorescent spectrophotometry techniques. An emission peak was observed at 420 nm when the CDs were excited at 376 nm. CDs were calculated to have an average particle diameter of 10.14 nm by TEM. In order to determine the usability of the CDs in cell imaging, two different concentrations (50 μL/mL and 100 μL/mL) of the CDs colloidal solution were applied to a human mesothelioma cell line, H2452, and human umbilical vein endothelial cells (HUVEC) for varying durations. While the fluorescent photos revealed that 2 h of exposure was sufficient for the cells to take the C-dots in and higher concentrations appeared brighter in the wavelengths studied (red channel (excitation/emission 586/646 nm), blue channel (390/446 nm) and the green channel (482/532 nm)), cell viability and proliferation assays indicated that the material was cytotoxic against the both cell lines and inhibited the cell growth in a time- and dose- dependent manner.