Chitosan-Sodium Alginate Polyelectrolyte Complex Coating Pluronic® F127 Nanoparticles Loaded with Citronella Essential Oil

Pluronic® F127 nanoparticles were loaded with citronella essential oil (CEO) and then covered with chitosan-sodium alginate polyelectrolyte complex (PEC). The system was characterized according to size, zeta potential and stability over time. Dynamic light scattering (DLS) in different proportions of water/ethanol as a dispersive medium was important in confirming that PEC covered the F127 nanoparticles. Infrared spectroscopy also indicated interaction of F127 with PEC. The nanoparticle size evaluated by transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM) corroborated the value observed in DLS (hydrodynamic radius (RH) range of 100-200 nm). Encapsulation efficiency of 80% for CEO was determined by UV-Vis spectroscopy. The release profile of the CEO was evaluated in phosphate buffer saline (PBS) containing 20% of ethanol and in simulated sweat fluid, achieving 74 and 81%, respectively. The releasing mechanism fitted the Korsmeyer-Peppas mathematical model, indicating Fickian diffusion behavior for both studied media.将香茅精油（citronella essential oil，CEO）负载至泊洛沙姆®F127（Pluronic® F127）纳米粒中，再以壳聚糖-海藻酸钠聚电解质复合物（chitosan-sodium alginate polyelectrolyte complex，PEC）对其进行包覆。本体系通过粒径、Zeta电位（zeta potential）与长期稳定性开展表征工作。通过设置不同水/乙醇比例作为分散介质的动态光散射（Dynamic light scattering，DLS）实验，证实了PEC可成功包覆F127纳米粒。红外光谱（Infrared spectroscopy）分析结果同样证实，F127与PEC之间存在相互作用。通过透射电子显微镜（transmission electron microscopy，TEM）与场发射扫描电子显微镜（field emission scanning electron microscopy，FESEM）测得的纳米粒粒径，与动态光散射观测得到的结果（流体动力学半径（hydrodynamic radius，RH）范围为100~200 nm）一致。采用紫外-可见（UV-Vis）光谱法测定，香茅精油的包封率可达80%。分别在含20%乙醇的磷酸盐缓冲液（phosphate buffer saline，PBS）与模拟汗液体系中考察香茅精油的释放行为，最终释放率分别达74%与81%。该释放过程符合Korsmeyer-Peppas数学模型，表明两种介质中的释放均呈现菲克扩散（Fickian diffusion）行为。