Buffer solution can control the porosity of DNA-chitosan complexes.

The current studies examine the pore properties and biological effects of DNA-chitosan complexes, which may be useful as scaffolds for tissue engineering. The porosity of the DNA-chitosan complexes was controlled by rinsing them with several different pH 7.2 buffer solutions, including phosphate-buffered saline (PBS), Tris-HCl, boric acid, and N-(2-hydroxyethyl)piperazine-N'-(2-ethanesufonic acid) (HEPES). Rinsing with PBS resulted in 84% porosity, whereas rinsing with Tris-HCl produced 94% porosity. It was further found that daunorubicin hydrochloride complex intercalated with and bound to the groove of the DNA-chitosan complexes, indicating that DNA in the complexes maintains its double-stranded helical structure. The DNA-chitosan complexes were not toxic to MG-63 osteoblast-like cells and caused only a mild tissue response when implanted subcutaneously in the backs of rats. These results suggest that buffer-rinsed DNA-chitosan complexes may be useful as a scaffold material in tissue engineering.