Incorporation of gold nanoparticles into the bilayer of polydiacetylene unilamellar vesicles

Abstract

Gold nanoparticles made with three different alkanethiol surface passivating agents were loaded into the hydrophobic bilayers of polydiacetylene liposomes. The physical and optical properties of the vesicles were compared to each other and a nanoparticle-free control. Small gold nanoparticles were utilized to minimize the plasmon absorption and thereby minimize the effects of energy transfer processes on the optical behavior of the polydiacetylene moiety. The size and structure of the liposomes were examined with dynamic light scattering and electron microscopy, while the stability of the bilayer was investigated through differential scanning calorimetry. Optical spectroscopy was used to monitor the photopolymerization of the vesicles as well as the stress-induced polydiacetylene blue to red transition. Specifically, changes to the absorption frequency, fluorescence frequency, and the fluorescence intensity were monitored. This system can serve as a model system for the optimization of liposomes containing nanoparticles with specialized optical, magnetic, or chemical functionality.