Preparation of Highly Luminescent Carbon Quantum Dots and Study of Bioimaging

Abstract

Using ammonium citrate as the carbon source and urea, ammonia and ethylenediamine as the nitrogen sources, CQDs with different nitrogen sources were prepared by hydrothermal method, and the preparation conditions were optimized to obtain CQDs with the best fluorescence performance for three different nitrogen sources.The fluorescence colors of the three CQDs were not significantly different, all of them were blue, indicating that different nitrogen sources did not have significant differences on the fluorescence color, but had some effects on the fluorescence intensity, and the yields of 1-CQDs, 2-CQDs and 3-CQDs were 0.22, 0.29 and 0.529, respectively.The UV, natural light, pH and ionic stability of CQDs with different nitrogen sources were investigated, and the results showed that 3-CQDs have UV, natural light and ionic stability, and all three CQDs have pH instability.The MTT method shows that 3-CQDs have lower cytotoxicity than the other two CQDs, and the bioimaging experiments show that 3-CQDs bind to yeast in greater numbers and have stronger fluorescence intensity, which proves that they are more suitable for bioimaging, laying a theoretical foundation for the bioimaging of CQDs at a later stage.