Preparation, Structural Characterization, Toxicity Test, and DNA Release Study of Low Molecular Weight Chitosan-g-L-Phenylalanine/DNA Complex

Abstract

The preparation of low molecular weight chitosan-g-L-phenylalanine (LMWCts-g-Phe) was successfully carried out by the coupling reaction using carbodiimide as a coupling agent. The complex of the LMWCts-g-Phe and DNA (LMWCts-g-Phe/DNA), prepared by a complex coacervation method,
exhibited various shapes, i.e., sphere, square, rectangle, and rod with an average size of ~ 50-150 nm as observed by SEM and a zeta potential in the range from -5.9 to -8.9 mV. The in vitro cytotoxicity test showed that the LMWCts-g-Phe and LMWCts-g-Phe/DNA were less toxic to fibroblast cells with the %viability of 76-111. The in vitro release of DNA from the complex was very fast in high pH medium (tris buffer, pH 8.0) and completed within 3 days, while the sustained release was achieved in neutral (PBS, pH 7.4) and low pH media (citric acid/sodium citrate buffer, pH 3.0).