Hydrothermal synthesis of carbon nanodots from waste wine cork and their use in biocompatible fluorescence imaging

A low-cost and simple method is reported for the synthesis of carbon nanodots (CDs) from waste wine cork using hydrothermal treatment. The structural and optical properties of the CDs were characterized by TEM, FTIR, Raman, UV-Vis absorption, and photoluminescence (PL) spectroscopy. Results indicate that the CDs have an average diameter of ~ 6.2 ± 2.7 nm and their excitation-dependent PL is related to the functional groups on their surface. The CDs have a quantum yield of 1.54%, estimated using quinine sulfate as a reference. They have been successfully applied in the bioimaging of mesenchymal stem cells (MSCs). After treatment with the CDs, the MSCs fluoresce green, yellow and red colors under the excitation wavelengths in the ranges 320-380 nm, 450-490 nm, and 515-560 nm, respectively, demonstrating their potential use in the field of fluorescence imaging.