Both carbon dots precursor and organic bridge ligands for coordination polymers: AMP-based ratiometric fluorescent probes and its application in bovine serum albumin detection.

Bovine serum albumin (BSA) is one of the most abundant proteins in serum, and its high-throughput detection is still one of the current challenges. Nitrogen‑phosphorus co-doped carbon dots (CDs) were synthesized by a hydrothermal method. Adenosine monophosphate (AMP) was used as a precursor for the synthesis of CDs, providing the required carbon, nitrogen and phosphorus sources for the CDs. It was also used as an organic bridge ligand for coordination polymers. Upon addition of the lanthanide metal ion Tb, the AMP molecules formed lanthanide coordination polymers in solution, resulting in fabrication of the novel ratiometric fluorescent probe AMP-CDs@Tb with dual emission centers. This fabricated method greatly reduced the complexity of dual-emission CDs doped with lanthanide metals. The designed ratiometric fluorescent probe only needed one precursor AMP to realize the synthesis of CDs and bound to lanthanide metal ions as an organic ligand, this probe could be used for rapid and sensitive analysis of BSA. The linear relationship was good when the concentration of BSA was 0.1 to 650 μM, and the LOD was 0.042 μM. In addition, the possible detection mechanism of BSA was explored through fluorescence lifetime and density functional theory calculations.