Development of morin-conjugated Au nanoparticles: exploring the interaction efficiency with BSA using spectroscopic methods.

Abstract In order to enhance its interaction efficiency with biomacromolecules for the usage as a therapeutic agent, we have conjugated morin, an antioxidant activity and anti-tumor drug, with citrate-coated Au nanoparticles (M-C-AuNPs). M-C-AuNPs were prepared by reducing chloroauric acid using trisodium citrate in the boiling condition, and the resulted M-C-AuNPs were characterized by UV–vis absorption spectroscopy, Transmission Electron Microscopy (TEM), X-ray diffraction (XRD) and FTIR analysis. In this article, UV–vis absorption spectroscopy in combination with fluorescence spectroscopy, and circular dichroism (CD) spectroscopy were employed to investigate the interactions between M-C-AuNPs and bovine serum albumin (BSA), C-AuNPs and BSA in a phosphate buffer at pH 7.4. By comparing the quenching constant K SV , effective quenching constant K a , binding constant K b and the number of binding sites n , it is clearly suggested that M-C-AuNPs could enhance the binding force of morin with BSA, which would pave the way for the design of nanotherapeutic agents with improved functionality.