Solution Phase Interactions Controlled Ordered Arrangement of Gold Nanoparticles in Dried State

Gold (Au) nanoparticles (NPs) were synthesized in the presence of water soluble biomolecules such as DNA, chitosan, phospholipids, and BSA by using seed-mediated approach at room temperature. All reactions produced mostly spherical geometries with comparable size (<= 20 nm). The NPs were arranged in a typical pearl-necklace type arrangement except in the presence of BSA. Different measurements such as UV-visible, TEM, XRD, and XPS were used to characterize the Au NPs. Fluorescence spectroscopy was used to identify the interactions between biomolecules and blank (uncapped) Au NPs in aqueous colloidal solutions. It was concluded that the favorable interactions between Au NPs and biomolecules in aqueous phase, in fact, drive them into pearl-necklace type arrangement in the dried state.