Novel Silicon-Based Carbon Quantum Dots: An Efficient Fluorescent Probe for Precise Tryptophan Detection

Tryptophan, an essential amino acid for the human body, plays a crucial role in various physiological processes, including protein synthesis, fatty acid metabolism, enhancing energy levels, and being converted into neurotransmitters to regulate sleep and mood. It is also used in the prevention and treatment of pellagra. However, excessive intake of tryptophan can cause adverse effects, so detecting its concentration is of great significance. In this paper a silicon-based carbon quantum dot (N,Si-CDs) tryptophan probe was prepared. The structure and composition of N,Si-CDs were characterized by TEM, FT-IR, and XPS. Fluorescence studies revealed that N,Si-CDs exhibited high selectivity for tryptophan with minimal interference from other substances. There was a good Linear relationship between the fluorescence intensity of N,Si-CDs and the concentration of tryptophan in the range of 5–25 μM, and the detection Limit was as low as 19 nM. N,Si-CDs were successfully applied to detect tryptophan in complex Matrices such as honey, Yili milk powder, water-soluble vitamin C, sour plum soup, and lemon tea, with recovery rates ranging from 81.3% to 106.4%. Cell experiments demonstrated that N,Si-CDs had low toxicity to T24 cells and could be used for live-cell imaging. This N,Si-CDs shows great potential in fields such as food safety, environmental monitoring, and biomedical research.