Preparation of nanoparticles composed of chitosan/poly-gamma-glutamic acid and evaluation of their permeability through Caco-2 cells.

In this study, a novel nanoparticle system for paracellular transport was prepared using a simple and mild ionic-gelation method upon addition of a poly-gamma-glutamic acid (gamma-PGA) solution into a low-molecular-weight chitosan (low-MW CS) solution. The particle size and the zeta potential value of the prepared nanoparticles can be controlled by their constituted compositions. The results obtained by the TEM and AFM examinations showed that the morphology of the prepared nanoparticles was spherical in shape. Evaluation of the prepared nanoparticles in enhancing intestinal paracellular transport was investigated in vitro in Caco-2 cell monolayers. It was found that the nanoparticles with CS dominated on the surfaces could effectively reduce the transepithelial electrical resistance (TEER) of Caco-2 cell monolayers. After removal of the incubated nanoparticles, a gradual increase in TEER was noticed. The confocal laser scanning microscopy observations confirmed that the nanoparticles with CS dominated on the surface were able to open the tight junctions between Caco-2 cells and allowed transport of the nanoparticles via the paracellular pathways.