Protective effect of liposomal formulation containing pDNA against nuclease degradation. (a) Liposomal formulations containing chitosan-GFP (N/P 5). Lane a, naked pGFP; lane b, naked pGFP+DNase I; lanes c-f, Plain-, Tf-, Pen-, and PenTf- chitosan-GFP liposomes, respectively + DNase I. (b) Liposomal formulations containing chitosan-βgal (N/P 5). Lane a, naked pβgal, lane b naked pβgal+DNase I, lane c-f, Plain-, Tf-, Pen-, PenTf- chitosan-βgal liposomes, respectively, + DNase I.