An assessment of the toxicity of carbon dot nanoparticles to Pichia pastoris

The excellent physical and chemical properties of carbon dots (CDs) such as their extra small size, large surface-to-volume ratio, inherent fluorescence, etc. provides them great potential in many biomedical applications. However, their biosafety issues are still indistinct. In the present study, the toxicity of CDs to a unicellular eukaryotic model organism was investigated. The CDs were prepared through pyrolysis of citric acid and characterized by means of dynamic light scattering (DLS), UV-vis spectrophotometry and spectrofluorimetry. Results show that the synthesized CDs have blue emission around 470 nm and the mean diameter of CDs was obtained to be 3.1±0.4 nm. Moreover, addition of CDs to the culture medium revealed dose-dependent toxicity to Pichia pastoris.