The influence of polymeric shell formed by the layer-by-layer (LbL) assembly technique using chitosan or its grafted copolymers with dextran or poly(ethylene glycol) and dextran sulfate on physico-chemical properties and aggregation kinetics of silver nanoparticles (AgNP) was investigated. It is shown that the hydrodynamic diameter of encapsulated AgNP increases linearly with increasing the number of polyelectrolyte layers without sufficient aggregation. The critical concentrations of coagulation (CCC) and Hamaker constants (H) were determined in dependence on electrolyte charge, structure of polycation, and number of bilayers in the shells. While a shell consists of more than two bilayers, the values of critical electrolyte concentration and energy of interparticle interactions H are influenced mainly by copolymer structure. In all cases, the CCC value is more than doubled after formation of two or more bilayers over silver nanoparticle surface. The shells based on chitosan-poly(ethylene glycol) graft copolymer were proven to be the most effective in increasing aggregation stability in NaCl solutions, while chitosan-dextran graft copolymer effectively decreases van der Waals interaction between nanoparticles. Application of grafted copolymers allows one to obtain encapsulated colloids that are stable over a wide range of NaCl concentrations including the isotonic one and improve biocompatibility and targetability of nanovehicles engineered for therapeutic or imaging purposes.

Graphical abstract

使用壳聚糖或其与葡聚糖或聚乙二醇和硫酸葡聚糖的接枝共聚物通过层接（LbL）组装技术形成的聚合物壳对银纳米颗粒（AgNP）的理化性质和聚集动力学的影响为调查。结果表明，包封的AgNP的水动力直径随聚电解质层数的增加而线性增加，而没有足够的聚集。凝固的临界浓度（CCC）和Hamaker常数（H）取决于电解质的电荷，聚阳离子的结构以及壳中双层的数量。虽然壳由两个以上的双层组成，但临界电解质浓度和粒子间相互作用的能量H的值主要受共聚物结构影响。在所有情况下，在银纳米粒子表面形成两个或更多双层后，CCC值增加了一倍以上。壳聚糖-聚乙二醇接枝共聚物的壳被证明是最有效的增加NaCl溶液中的聚集稳定性，而壳聚糖-葡聚糖接枝共聚物则有效地降低了纳米粒子之间的范德华相互作用。接枝共聚物的应用使人们可以获得包囊的胶体，该胶体在包括等渗的NaCl的广泛的NaCl浓度范围内是稳定的，并改善了为治疗或成像目的而设计的纳米载体的生物相容性和靶向性。壳聚糖-聚乙二醇接枝共聚物的壳被证明是最有效的增加NaCl溶液中的聚集稳定性，而壳聚糖-葡聚糖接枝共聚物则有效地降低了纳米粒子之间的范德华相互作用。接枝共聚物的应用使人们可以获得包囊的胶体，该胶体在包括等渗的NaCl的广泛的NaCl浓度范围内是稳定的，并改善了为治疗或成像目的而设计的纳米载体的生物相容性和靶向性。壳聚糖-聚乙二醇接枝共聚物的壳被证明是最有效的增加NaCl溶液中的聚集稳定性，而壳聚糖-葡聚糖接枝共聚物则有效地降低了纳米粒子之间的范德华相互作用。接枝共聚物的应用使人们可以获得包囊的胶体，该胶体在包括等渗的NaCl的广泛的NaCl浓度范围内是稳定的，并改善了为治疗或成像目的而设计的纳米载体的生物相容性和靶向性。

图形概要