One-step hydrothermal-assisted synthesis of highly fluorescent N-doped carbon dots from gum tragacanth: Luminescent stability and sensitive probe for Au3+ ions

Abstract

Water-soluble nitrogen-doped carbon dots (N-CDs) were fabricated by one-step hydrothermal treatment of mixture of gum tragacanth (GT) and ethylenediamine (EDA). The as-prepared N-CDs were highly fluorescent generator depending on the excitation wavelength and pH. The quantum yield (at 436 nm) was 66.74% at excitation 365 nm and pHs 2–4. The fluorescent intensity of N-CDs solution (5 μg/mL) irradiated at 365 nm for 60 min and stored at −4 °C. Also, the fluorescent intensity decreased slightly (~10%) after 20 weeks of storage. The as-prepared N-CDs showed good antioxidant activity, and the cytotoxicity test against human fibroblast cells using MTT assay indicated the cell survival rate of ~94% in <125 μg/mL concentration of N-CDs. The resulting N-CDs showed a remarkably sensitive and selective quenching effect of fluorescent emission toward Au3+ ions with the detection limit reached 2.69 μM and a linear range extended in the range of 0–100 μM.