Simultaneous measurements of K+ and calcein release from liposomes and the determination of pore size formed in a membrane
Simultaneous measurements of K+ and calcein release from liposomes and the determination of pore size formed in a membrane
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DOI：
10.2116/analsci.23.517
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发表时间：
2007-05-01
影响因子：
1.6
通讯作者：
Mizushima, Tohru
中科院分区：
文献类型：
--
作者：
Katsu, Takashi;Imamura, Tomonori;Mizushima, Tohru
同时测量由生物活性物质诱导的由卵磷脂和胆固醇组成的脂质体对K+和钙黄绿素的渗透性的变化，以使用不同尺寸的标记物快速筛选膜中形成的孔的尺寸。在本研究中检查的物质被分为三种类型的基础上，在K+和钙黄绿素释放率的差异。第一种类型仅释放K+，并且包括短杆菌肽A。第二类主要释放K+，在释放钙黄绿素之前，包括放线菌素B和制霉菌素。第三种类型，包括抗菌肽，如短杆菌肽S，丙甲霉素和蜂毒肽，以及几种膜活性药物，如塞来昔布（非甾体抗炎药），1-十二烷基氮杂环庚烷-2-酮（名为氮酮;皮肤渗透促进剂）和氯丙嗪（镇静剂），引起K+和钙黄绿素的同时释放。因此，在脂质体膜中形成的孔的大小按以下顺序增加：类型一、类型二和类型三。我们通过进行渗透保护实验，测量在不同大小的渗透保护剂存在下钙黄绿素的释放，更精确地确定了大小。第二种类型的细菌素B和制霉菌素形成的孔的半径为0.36 - 0.46 nm，而第三种类型形成的孔的半径大得多，为0.63 - 0.67 nm或更大。第三种类型的物质引起的渗透性变化进行了讨论，在与一个瞬时孔形成的脂质包装不匹配发生在二棕榈酰磷脂酰胆碱脂质体的相变过程中。
The changes induced by biologically active substances in the permeability to K+ and calcein of liposomes composed of egg phosphatidylcholine and cholesterol were measured simultaneously in order to rapidly screen the sizes of pores formed in a membrane, using different sized markers. The substances examined in the present study were classified into three types based on differences in the rates at which K+ and calcein were released. The first type released only K+, and included gramicidin A. The second type predominantly released K+, preceding the release of calcein, and included amphotericin B and nystatin. The third type, including antimicrobial peptides, such as gramicidin S, alamethicin, and melittin, and several membrane-active drugs, like celecoxib (non-steroidal anti-inflammatory drug), 1-dodecylazacycloheptan-2-one (named azone; skin permeation enhancer), and chlorpromazine (tranquilizer), caused the release of K+ and calcein simultaneously. Thus, the sizes of pores formed in a liposomal membrane increased in the following order: types one, two, and three. We determined the size more precisely by conducting an osmotic protection experiment, measuring the release of calcein in the presence of osmotic protectants of different sizes. The radii of pores formed by the second type, amphotericin B and nystatin, were 0.36 - 0.46 nm, while the radii of pores formed by the third type were much larger, 0.63 - 0.67 nm or more. The permeability changes induced by substances of the third type are discussed in connection with a transient pore formed in a lipid packing mismatch taking place during the phase transition of dipalmitoylphosphatidylcholine liposomes.