Sanchez Christian, Renard Denis
Laboratoire de Physico-Chimie et Génie Alimentaires, ENSAIA-INPL BP 172, 54505 Cedex, Vandoeuvre-les-Nancy, France.
Int J Pharm. 2002 Aug 21;242(1-2):319-24. doi: 10.1016/s0378-5173(02)00174-6.
We have studied at pH 4.2 and three protein (Pr):polysaccharide (Pol) weight ratios (8:1, 2:1 and 1:1) the structure and stability of beta-lactoglobulin/acacia gum/water dispersions containing protein aggregates (BLG/AG/W) or free from aggregates (AF-BLG/AG/W). Phase diagrams were characteristic of complex coacervation. BLG/AG/W dispersions displayed a larger biphasic area than AF-BLG/AG/W dispersions, that moved towards the protein axis. It was concluded that protein aggregates affected complex coacervation both by entropic (size and molecular masses of aggregates) and enthalpic (surface properties of aggregates) effects. Laser light scattering measurements revealed that the particles diameter (d(43)) induced by demixing was controlled by protein aggregates in AF-BLG/AG/W dispersions. At 1 wt.% biopolymer concentration, particles were 15-20 times larger in AF-BLG/AG/W dispersions than in BLG/AG/W dispersions at (Pr:Pol) ratios of 2:1 or 1:1. Confocal scanning laser microscopy showed that AF-BLG/AG/W dispersions only contained spherical coacervates. BLG/AG/W dispersions contained both coacervates and aggregates coated with AG or/and BLG/AG coacervates. At a (Pr:Pol) ratio of 2:1 and 1:1, coacervates were vesicular or multivesicular. Coacervates were smaller in BLG/AG/W dispersions than in AF-BLG/AG/W dispersions. It was concluded that protein aggregates have the intrinsic ability to stabilize complex coacervates and could be used to design multifunctional delivery systems. This study showed that composite dispersions containing both protein aggregates embedded in protein-polysaccharide coacervates and free coacervates may be performed. In this respect, the design of protein aggregates with controlled size distribution and surface properties could open new possibilities both in the non-chemical control of coacervates stability and in the development of multifunctional delivery systems.
我们在pH 4.2以及三种蛋白质（Pr）与多糖（Pol）的重量比（8:1、2:1和1:1）条件下，研究了含有蛋白质聚集体的β-乳球蛋白/阿拉伯胶/水分散体系（BLG/AG/W）或不含聚集体的体系（AF-BLG/AG/W）的结构和稳定性。相图具有复合凝聚的特征。BLG/AG/W分散体系比AF-BLG/AG/W分散体系呈现出更大的双相区域，且该区域向蛋白质轴方向移动。得出的结论是，蛋白质聚集体通过熵效应（聚集体的大小和分子量）和焓效应（聚集体的表面性质）影响复合凝聚。激光光散射测量表明，在AF-BLG/AG/W分散体系中，由分层诱导的颗粒直径（d(43)）受蛋白质聚集体控制。在生物聚合物浓度为1 wt.%时，在（Pr:Pol）比为2:1或1:1的情况下，AF-BLG/AG/W分散体系中的颗粒比BLG/AG/W分散体系中的颗粒大15至20倍。共聚焦扫描激光显微镜显示，AF-BLG/AG/W分散体系仅包含球形凝聚层。BLG/AG/W分散体系包含凝聚层以及被AG或/和BLG/AG凝聚层包裹的聚集体。在（Pr:Pol）比为2:1和1:1时，凝聚层呈泡状或多泡状。BLG/AG/W分散体系中的凝聚层比AF-BLG/AG/W分散体系中的凝聚层小。得出的结论是，蛋白质聚集体具有稳定复合凝聚层的内在能力，可用于设计多功能递送系统。本研究表明，可以制备出既含有嵌入蛋白质-多糖凝聚层中的蛋白质聚集体又含有游离凝聚层的复合分散体系。在这方面，设计具有可控尺寸分布和表面性质的蛋白质聚集体，可能为凝聚层稳定性的非化学控制以及多功能递送系统的开发开辟新的可能性。
