A new clay-liposome complex was developed for reducing leaching of herbicides and contamination of groundwater. The liposomes were composed of the neutral and Environmental Protection Agency approved phospholipid phosphatidylcholine (PC). Adsorption of PC liposomes on the clay mineral montmorillonite could exceed the cation exchange capacity of the clay, and was well simulated by the Langmuir equation. X-ray diffraction results for 6 mM PC and 1.6 g/L clay (3 day incubation) yielded a basal spacing of 7.49 nm, which was interpreted as the formation of a supported planar bilayer on montmorillonite platelets. Fluorescence methods demonstrated structural changes which reflected adsorption of PC followed by loss of vesicle integrity as measured by the penetration of dithionite into the internal monolayer of fluorescently labeled liposomes, resulting in a decrease in fluorescence intensity to 18% of initial after 4 h. Energy transfer was demonstrated after 1 h from labeled liposomes to montmorillonite labeled by an acceptor. The neutral herbicide alachlor adsorbed on the liposome-clay complex, yielding a formulation of upto 40% active ingredient, and 1.6-fold reduction in herbicide release in comparison to the commercial formulation. Hence, the PC-montmorillonite complex canform a basisfor environmentally friendly formulations of herbicides, which would yield reduced leaching.
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机译：开发了一种新的粘土-脂质体复合物，以减少除草剂的浸出和地下水的污染。脂质体由中性和环境保护局批准的磷脂磷脂酰胆碱（PC）组成。 PC脂质体在粘土矿物蒙脱土上的吸附可能超过粘土的阳离子交换能力，并通过Langmuir方程进行了很好的模拟。 6 mM PC和1.6 g / L粘土的X射线衍射结果（孵育3天）产生7.49 nm的基本间距，这被解释为在蒙脱石血小板上形成了支撑的平面双层。荧光方法显示出结构变化，反映了PC的吸附，继之以囊泡完整性的丧失，这是通过连二亚硫酸盐渗入荧光标记脂质体内部单层所测得的，从而使荧光强度降低至最初4小时后的18％。从标记的脂质体到受体标记的蒙脱石1小时后证实了能量转移。与市售制剂相比，中性除草剂甲草胺吸附在脂质体-粘土复合物上，可制得高达40％活性成分的制剂，除草剂释放减少1.6倍。因此，PC-蒙脱土复合物可为环保的除草剂配方奠定基础，从而减少浸出。
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