Photo-responsive liposomes decorated with hydrophobically modified poly(vinyl alcohol)–coumarin conjugate

Photo-responsive liposome was developed by modifying the surface of egg yolk phosphatidylcholine (egg PC) liposomes with hydrophobically modified poly(vinyl alcohol)–epoxypropoxy coumarin conjugate (HmPVA-EPC). Decanoyl chloride (DC) was used as a hydrophobic pendant for the hydrophobic modification of PVA. The fluorescence quenching of liposomes was more than 65% when the ratio of lipid/HmPVA-EPC was 1:0.01–1:0.1, but the value was less than 35% in the ratio range of 1:0.2–1:1. Under UV irradiation (λ = 254 nm), egg PC liposomes of which lipid/HmPVA-EPC ratio was 1:0.1 readily release their content for 60 min possibly due to the photo-dimerization of EPC residues.