One step synthesis and phase transition of phospholipid-modified Au particles into toluene

We demonstrated that phospholipid (l-α-dipalmitoylphosphatidylcholine, DPPC)-capped gold nanoparticles could be synthesized with one step by reduction of HAuCl4 in aqueous solution using sodium citrate and simultaneously accompanying with the phase transition across the water/toluene interface into the organic phase. Such a transition process has been observed by the color changes and verified by the UV-visual adsorption. Transition electron microcopy (TEM) image shows that the one-step synthesized gold nanoparticles obtained in the toluene phase has approximately 10 nm. Fourier transfer infrared reflectivity (FT-IR) study on the lipid-capped particles demonstrates that DPPC has adsorbed onto the gold nanoparticle surface. Extention of this work to other metals with even smaller sizes and use of different lipids would be possible.