Valduga G, Reddi E, Jori G, Cubeddu R, Taroni P, Valentini G
Department of Biology, University of Padova, Italy.
J Photochem Photobiol B. 1992 Dec;16(3-4):331-40. doi: 10.1016/1011-1344(92)80020-v.
Zinc(II) phthalocyanine (ZnPc), a potential second-generation phototherapeutic agent for tumours, has been incorporated into small unilamellar vesicles (SUVs) (diameter, 52 nm) and large unilamellar vesicles (LUVs) (diameter, 84 nm) of dipalmitoyl-phosphatidylcholine (DPPC). Absorption spectroscopy, as well as steady state and time-resolved fluorescence emission studies, indicate that ZnPc is monomeric in SUVs at a stoichiometric concentration below 0.25 microM (corresponding to an actual endoliposomal concentration of about 0.5 mM), while in LUVs it is monomeric below 2 microM. The fluorescence lifetime of the monomer is 3-3.5 ns. Upon increasing the ZnPc concentration, aggregated derivatives are formed, which are characterized by shorter fluorescence lifetimes (1.2-1.5 ns; 0.4-0.6 ns). The possible implications of these observations for the phototherapeutic efficiency of ZnPc are briefly discussed.
锌（II）酞菁（ZnPc）是一种潜在的肿瘤第二代光疗剂，已被载入二棕榈酰磷脂酰胆碱（DPPC）的小单层囊泡（SUVs）（直径52纳米）和大单层囊泡（LUVs）（直径84纳米）中。吸收光谱以及稳态和时间分辨荧光发射研究表明，在化学计量浓度低于0.25微摩尔（对应于约0.5毫摩尔的实际脂质体内浓度）时，ZnPc在SUVs中呈单体状态，而在LUVs中，其在低于2微摩尔时呈单体状态。单体的荧光寿命为3 - 3.5纳秒。随着ZnPc浓度的增加，会形成聚集衍生物，其特征是荧光寿命较短（1.2 - 1.5纳秒；0.4 - 0.6纳秒）。简要讨论了这些观察结果对ZnPc光疗效率的可能影响。
