Development of Cationic Dextran Nanoparticles via Reductive Amination: Enhanced Cellular Uptake and Low Cytotoxicity in Gene Transfection

Abstract

Purpose: The development of safe and efficient non-viral carriers remains critical for gene therapy. Biocompatible polysaccharides such as dextran are attractive candidates for novel delivery platforms. This study reports the synthesis, characterization, and evaluation of a cationic dextran derivative for pDNA delivery. Methods: Cationic Dextran was synthesized through periodate oxidation and reductive amination with 1,6-Hexamethylenediamine. Its structure was confirmed using ¹H NMR and FT-IR spectroscopy. Nanoparticles, formed via self-assembly with pDNA, were analyzed for size, zeta potential (DLS), and morphology (SEM). Functional properties, including buffering capacity, pDNA condensation (gel retardation assay), DNase I protection, cytotoxicity in NIH3T3 cells (MTT assay), and cellular uptake, were assessed. Results: Nanoparticles showed uniform size (207–245 nm) and strong positive zeta potential (+57.2 to +73.7 mV). The polymers demonstrated a substantial buffering capacity within the endosomal pH range, efficiently condensed pDNA, and provided partial protection against DNase I. Cytotoxicity was low at both 24 and 48 hours. Flow cytometry confirmed high cellular uptake, with over 95% of NIH3T3 cells internalizing polyplexes. Conclusion: These cationic Dextran nanocarriers demonstrate efficient pDNA condensation, low cytotoxicity, and high cellular uptake, making them promising for gene delivery. Although nuclease protection needs optimization, it offers a versatile platform for non-viral gene therapy.