Coordination Nanoparticles Formed by Fluorescent 2-Aminopurine and Au 3+ : Stability and Nanozyme Activities

Nucleobase–metal coordination polymers (CPs) have been the target of much recent research owing their interesting properties and ease of preparation. Natural nucleobases are nonfluorescent, and 2-aminopurine (2AP) is a strongly fluorescent analog of adenine. In this work, we compared the CPs formed by adenine, 2AP and adenosine with various metals. Only Au3+ produced CP nanoparticles with both adenine and 2AP. Both products were similar in terms of size, suggesting that the position of the exocyclic amine is unimportant for coordination with gold. Since 2AP is fluorescent, the dissolution of the nanoparticles in the presence of various chemicals including KCN, GSH, iodide, bromide and chloride, was studied and compared to fluorescent adenosine–Au nanoparticles. It appears that the 2AP CP was more robust than the adenosine one since even chloride can quench the fluorescence of the adenosine/Au complex. Finally, the adenine and 2AP nanoparticles exhibited weak oxidase-like activity for oxidation of TMB possibly by the Au3+ exposed on the surface.