Efficient polycation non-viral gene delivery system with high buffering capacity and low molecular weight for primary cells: Branched poly (beta-aminoester) containing primary, secondary and tertiary amine groups

Abstract

Gene transfer studies, preferred in many biotechnology studies such as in vitro transgenic cell modeling systems, gene therapy, transgenic animal production by cloning, etc., are quite limited due to transfection difficulties on primary cell lines. The main purpose of this study is on the production of biocompatible gene carrier systems with high transfection efficiency for Primary Ovine Fibroblast cell lines (POF). To achieve this goal, the synthesis of the branched poly(beta-aminoester) (PBAE) containing primary, secondary and tertiary amino groups in their molecular structures was carried out via step-growth polymerization by a typical Michael addition reaction between bisphenol A-ethoxylate diacrylate (BPAEDA) and ethylenediamine (EDA) for the first time. PBAEs were characterized using FTIR and NMR techniques. GPC-SEC system was used to determine the molecular weight of these polymers. Proton buffering capacity of the PBAE was also determined. In order to optimize the preparation of the PBAE nanoparticles (nPBAE), two different methods, which are solvent evaporation and solvent displacement techniques, were used. Their physicochemical properties such as particle size, polydispersity index (PDI), zeta potential and stability were identified. nPBAE-gene complexes (gnPBAE) were obtained according to the adsorption or encapsulation mechanisms and their properties were evaluated by comparative surface charge and gel electrophoresis. In vitro studies including gene binding capacity, cytotoxicity and the transfection effi-ciency for primary ovine fibroblast (POF) cell lines were also realized. Consequently, (egnPBAE)(dw) formulation, which is obtained from PBAEEDA with the lowest Mw by encapsulation method in this study, have very high in vitro transfection efficiency up to 78.3% in POF cells and it was also exhibited almost 1.5 times more transfection efficiency against commercial product Lipofectamine because of its low Mw and the presence of the secondary and tertiary amine structures as well as primary amine end groups in its backbone.