PBS buffer solutions with different pH values can change porosity of DNA-chitosan complexes

We examined the effect of phosphate-buffered saline (PBS) solution with different pH values on the formation of porosity in the DNA/chitosan complexes, and evaluated the intercalation behavior of the complexes. Four different PBS solutions with pH = 6.0, 7.0, 7.4, and 7.8 were used for rinsing water-insoluble DNA-chitosan complexes. All complexes showed high porosities ranging from 83 to 95%. Rinsing with PBS at pH 7.0, 7.4, and 7.8 reduced the porosity of the DNA-chitosan complexes. Re-rinsing with PBS at pH 7.4 reduced the porosity of the DNA-chitosan complex rinsed with PBS at pH 6.0. The appearances for porous formation were influenced by the differences in pH of PBS. Daunorubicin hydrochloride intercalated and bound in the grooves of DNA within all of the DNA-chitosan complexes, indicating that DNA in the complexes maintained its double-stranded helical structure. These results suggested that PBS-rinsed DNA-chitosan complex is promising as a scaffold material in tissue engineering.