Development of nitrogen and sulfur-doped carbon dots for cellular imaging

In this study, a new synthetic method for nitrogen (N) and sulfur (S) -doped CDs was developed via a hydrothermal method using methionine and citric acid as raw materials. The s-prepared CDs exhibit excellent optical properties and good biocompatibility. The spherical N, S - doped CDs have an average diameter of 5 nm. They consist of C, O, N and S elements, and take on excellent water solubility due to the hydroxyl and carboxyl, amino groups on the surface. The CDs have a photoluminescence quantum yield of 13.8% using quinine sulfate as a reference, and the average fluorescence lifetime of CDs is 3.67 ns. The CDs solution present good photoluminescence properties, and the maximum excitation wavelength and emission wavelength locate at 330 nm and 405 nm, respectively. In addition, their fluorescence intensity almost does not change under the conditions of acid, alkali, and high salt, which indicates its anti-photobleaching property and good light stability. Based on the good biocompatibility and strong fluorescence emission of the CDs, they were used as fluorescent imaging reagents.
Source: Journal of Pharmaceutical Analysis - Category: Drugs & Pharmacology Source Type: research