Abstract

In the present study, poly(N-[3-(dimethylaminopropyl)] methacrylamide) (PDMAPMAAm) grafts/blocks and chitosan (Cs) backbone bearing tertiary and primary amine groups, respectively, were copolymerized by the conventional free-radical solution method to prepare novel nonviral cationic carriers covering a pH range between 4.0 and 9.0. All of the chain parameters calculated by experimental and theoretical methods indicated that with increasing KPS concentration, the structures of Cs-PDMAPMAAm (Cs/D) copolymers changed from graft to block copolymer. The constants of the Mark–Houwink–Sakurada (MHS) equation K and a were also determined to calculate the molecular weights of synthesized PDMAPMAAm and its hydrolyzed grafts. For physico-biochemical properties, FTIR, GPC, and ¹H NMR techniques, ζ-potential, particle size, hemolytic activity, buffering capacity, and cell viability measurements were performed to discuss that at least one of the Cs/D products demonstrates an acceptable transfection efficiency as in vitro. To investigate the cytotoxicity and gene transfection properties of Cs/D copolymers and their polyplexes with small interfering RNA (siRNA) by MTS assay on L929 and MDA-MB-231, which are healthy mouse fibroblast cells and a triple-negative human breast cancer cell line, respectively, binding capacity and serum stability by agarose gel electrophoresis, cellular uptake by confocal microscopy, and transfection efficiency of siRNA in vitro on the MDA-MB-231 cell line were studied.