Spectroscopic cyclic voltammetry, and molecular docking study on the molecular interaction between synthesized blue emitting nitrogen‐doped carbon dots and human serum albumin

Abstract

AbstractFluorescent carbon dots are a promising drug carrier and bio‐sensor material. The study between human serum albumin and carbon dots could explore the possible interaction mechanism. In this paper, melamine was adopted as passivating agent and citric acid as carbon source, high fluorescence nitrogen doped carbon dots (N‐CDs) were synthetized by one‐pot solid phase pyrolysis successfully. The obtained blue emissive N‐CDs with an average particle size of 2.8 ± 0.7 nm displayed an excitation‐dependent photoluminescence behavior, and the fluorescence quantum yield was estimated to be 12.8%. Moreover, the N‐CDs contained abundant hydroxyl, carboxyl, and amine groups. The molecular interaction between as‐prepared N‐CDs and HSA was systematically investigated in vitro through several spectroscopic methods associated with cyclic voltammetry (CV) and molecular docking. The quenching mechanism of HSA by N‐CDs was static through forming the HSA‐N‐CDs complex, and both hydrogen bonding and van der Waals forces were the fundamental driving forces in the spontaneous binding process. The distance between N‐CDs and HSA was 2.2 nm on the basis of Förster's theory. The competitive binding experiment showed that the binding of N‐CDs was primarily in site I of HSA. Through the analysis of circular dichroism (CD), synchronous fluorescence, and three‐dimensional fluorescence spectra, the secondary structure of HSA was altered in the presence of N‐CDs and the polarity around the amino acid residues of HSA was not changed. Besides, molecular simulation was applied to determine the possible binding situation. Our study explored the interaction mechanism of N‐CDs with HSA, which provided some valuable information for understanding the structure and function of proteins as well as the transport and metabolism of N‐CDs.