Egbaria K, Friedman M
School of Pharmacy, Hebrew University of Jerusalem, Israel.
Pharm Res. 1992 May;9(5):629-35. doi: 10.1023/a:1015897909739.
The surface characteristics of bovine and egg albumin microspheres were examined using four anionic dyes; sodium fluorescein, eosin, erythrosin, rose bengal, and the cationic dye rhodamine B. The adsorption isotherms of the dyes on unloaded albumin microspheres exhibited Langmuir behavior for dilute solutions of rose bengal, erythrosin, and eosin, suggesting monolayer formation in the initial stages of the sorption process. The adsorption capacity of the microspheres for the dyes (k2) and the affinity constants of the dyes for the microspheres (k1) were found to depend on both the polarizability and the hydrophobic properties of the dye, presumably reflecting the heterogeneous character of the microsphere surface. Further, the extent of sorption at higher dye concentrations was found to depend on the ability of the dye to form stable aggregates inside the microspheres and on environmental long-range forces acting at these sites. At both low and high dye concentrations, the amount adsorbed to the microsphere surface increased with increasing hydrophobicity of the dyes. The lowest adsorption was observed for the nonsubstituted dye fluorescein, whereas the most hydrophobic dye used, rose bengal, was completely adsorbed onto the microsphere surface. The data suggest that the bovine albumin microsphere surfaces are highly hydrophobic and less porous than egg albumin microsphere surfaces.
使用四种阴离子染料（荧光素钠、曙红、赤藓红、孟加拉玫瑰红）和阳离子染料罗丹明B检测了牛血清白蛋白和卵清蛋白微球的表面特性。对于孟加拉玫瑰红、赤藓红和曙红的稀溶液，染料在未负载白蛋白微球上的吸附等温线呈现朗缪尔行为，这表明在吸附过程的初始阶段形成了单分子层。发现微球对染料的吸附容量（k2）和染料对微球的亲和常数（k1）取决于染料的极化率和疏水特性，这大概反映了微球表面的异质性。此外，发现在较高染料浓度下的吸附程度取决于染料在微球内部形成稳定聚集体的能力以及作用于这些位点的环境长程力。在低染料浓度和高染料浓度下，微球表面吸附的量均随染料疏水性的增加而增加。对于未取代的染料荧光素，观察到的吸附量最低，而所使用的疏水性最强的染料孟加拉玫瑰红则完全吸附到微球表面。数据表明，牛血清白蛋白微球表面比卵清蛋白微球表面具有更高的疏水性且孔隙率更低。
