Membrane coating of alginate-DNA microspheres

DNA was immobilized within alginate gels using either the emulsification/internal gelation or external gelation/droplet formation technique. Microspheres were coated with chitosan or poly-L-lysine membrane materials. The membrane coated alginate-DNA microspheres were examined under the light microscope. The thickness of both chitosan and poly-L-lysine membranes was measured, with chitosan forming a thicker membrane. The thickness of the chitosan membranes ranged from 30 $ mu$m to 50 $ mu$m, while that of the poly-L-lysine membranes ranged from 3 $ mu$m to 13 $ mu$m. Factors affecting the thickness of poly-L-lysine membranes included: the concentration of alginate, poly-L-lysine and calcium chloride, treatment time with saline, membrane formation time and the molecular weight and pH of poly-L-lysine. The retention of DNA within poly-L-lysine coated alginate-DNA microspheres was also studied. It was found that alginate concentration, poly-L-lysine concentration and pH of the saline all affected the retention of DNA. The poly-L-lysine coated microspheres could retain 78% of the DNA initially encapsulated