Abstract:
Carbon Dots (CDs) are one of the most important nanomaterials ever known to
humanity. They have been widely concerned in recent years because of their
biocompatibility, low cytotoxicity, photostability, easy surface functionalization, and
eco-friendliness. CDs have a wide range of applications in the fields of bio-imaging,
bio-sensing, photocatalysis and optoelectronics, etc. In the present study, nitrogen
doped carbon dots (N-CDs) were prepared by thermal decomposition method with citric
acid as the carbon source and urea as a nitrogen source. Various sources of citric acid
were used to synthesize N-CDs as well as the citric acid was isolated from lemon juice
by chemical method and also synthesized by fermentation using the filamentous fungus
Aspergillus niger. The Fourier transform infrared spectrometer and UV-visible
spectrophotometer were used to discover surface functional groups and luminescence
properties of N-CDs. The results of N-CDs synthesized from various sources of citric
acid were analyzed. The sensing application of the prepared N-CDs as a reducing agent
was tested, demonstrating the reduction of ferric ions (Fe3+). Some applications of CDs
are monitoring blood glucose levels, identification of cancer cells, heavy metal
detection in polluted water, and usage of CDs in drug development will be conducted
in the future.
