title: Wavelength-programmed solute release from photosensitive liposomes.
abstract: Liposomes of dipalmitoylphosphatidylcholine containing a photochromic lipid "Bis-Azo PC" release entrapped solutes on exposure to UV light. We have now demonstrated that on addition of cholesterol (up to 25 mol%) to the liposomal membrane the liposomes also release their contents in response to visible light in the region of 470 nm, to which liposomes lacking steroid are insensitive. In a mixed population of liposomes prepared with and without cholesterol, this enables wavelength-dependent release of entrapped solutes on sequential exposure to visible and UV light. Furthermore, the cholesterol-containing liposomes allow stepped partial release of entrapped solute following multiple periods of short visible illumination. It is suggested that the cholesterol-containing liposomes may be potentially useful for drug delivery and for "caging" of reagents.
authors.affiliation: Division of Biological Sciences, School of Environmental and Life Sciences, University of Salford, Salford M5 4WT, United Kingdom. r.h.bisby@salford.ac.uk
authors.forename: R H
authors.initials: RH
authors.lastname: Bisby
authors.forename: C
authors.initials: C
authors.lastname: Mead
authors.forename: C G
authors.initials: CG
authors.lastname: Morgan
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine; D002784:Cholesterol; D004337:Drug Carriers; D016503:Drug Delivery Systems; D008027:Light; D008081:Liposomes; D010775:Photic Stimulation
chemical_list: D004337:Drug Carriers; D008081:Liposomes; D015060:1,2-Dipalmitoylphosphatidylcholine; D002784:Cholesterol