Photochemical deposition of noble metal ultrafine particles onto liposomes

Composite particles consisting of liposomes loaded with silver or gold ultrafine particles have been prepared by UV irradiation (λ=253.7 nm) of AgClO 4 or NaAuCl 4 aqueous solutions in the presence of l-α-dimyristoyl phosphatidylcholine liposomes. The diameter of the metal particles was <5–7 nm. The absorption peak of the composite particles was observed at λ=380–390 (silver) or 540 nm (gold). The absorption spectra of the liposome/silver composite particles were broad and weak. The quantum yield of photoreduction of silver ions increased in the presence of liposomes. The usefulness of the liposome as a matrix for loading and stabilizing the noble-metal ultrafine particles has been demonstrated.