|
In this study, natural polysaccharides and their derivatives were used to prepare nanoparticle drug delivery systems. The preparation was based on the static electric interaction between positive polyelectrolyte and negative polyelectrolyte and was conducted on mild conditions, i.e. at room temperature and in aqueous solutions. The obtained five nanoparticle drug delivery systems were carboxymethyl chitosan/chitosan, heparin/chitosan, carboxymethyl chitosan/phosphonic chitosan, heparin/phosphonic chitosan and phosphonic chitosan/DNA nanoparticles. In preliminary experiments, we prepared calcium-crosslinked carboxymethyl chitosan hydrogel beads.By means of IR, TEM and zeta potential analyzer etc., the physicochemical characteristics of these drug delivery systems were characterized, including the formation mechanism, the particle size, polydispersity, zeta potential and morphology of the nanoparticles. The pH and ion strength stability of nanoparticles were also evaluated. In addition, we further investigated the effects of the pH of chitosan solution, the molecular weight of chitosan, the concentration of chitosan solution and the concentration of loaded protein on the particle size, polydispersity, zeta potential, protein entrapment efficiency of the nanoparticles. As the results showed, the molecular weight and the concentration of polysaccharides were important factors to affect the size of nanoparticles. Prepared with suitable molecular weight and solution concentration of polysaccharides, the particle size ranged from 100nm to 500nm. The entrapment efficiency of drug is a key factor to evaluate drug delivery systems. We found that, increasing the concentration of both components in nanoparticles could prepare more nanoparticle carriers and hence efficiently improve the entrapment efficiency of drug.Furthermore, we investigated the effect of doxorubicin-loading nanoparticles on HeLa cells and satisfactory results were obtained. As a potential gene carrier, phosphonic chitosan were evaluated in terms of the entrapment, protection and transfection of plasmid DNA.
|