Self-Assembly of an Europium-Containing Polyoxometalate and the Arginine/Lysine-Rich Peptides from Human Papillomavirus Capsid Protein L1 in Forming Luminescence-Enhanced Hybrid Nanoparticles

Abstract

Through a self-assembly of arginine/lysine-rich peptide from human papillomavirus (HPV) capsid protein and an Eu-containing polyoxometalate (POM), Na9[EuW10O36]·32H2O (EuW10), the formation of well-defined hybrid nanospheres in aqueous solution is presented, showing large luminescence enhancement of POM and use as a potential “turn-on” fluorescence probe in biology. The binding mechanisms between them have been explored at the molecular level by using transmission electron microscopy (TEM), scanning electron microscopy (SEM), fluorescence spectra, isothermal titration calorimetry (ITC), ζ-potential, and nuclear magnetic resonance (1H NMR) titration spectra. ITC study confirmed the assembly was completely enthalpy driven, and ζ-potential proved that the driving force was governed mainly by the electrostatic interaction. 1H NMR spectroscopy indicated changes in hydrogen bond of EuW10 and the peptide segment, and the binding model was clarified. Our design constructed the self-assembly fabrication of well-de...