A new nano hyperbranched β-pinene polymer: Controlled synthesis and nonviral gene delivery

Recently, an extensive research effort has been directed toward the improvement of nonviral transfection vectors, such as polymeric materials. The macromolecular structure of polymers has a substantial effect on their transfection efficacy. In this context, the modern advances in polymer production techniques, such as the deactivation-enhanced radical atom transfer polymerization (DE-ATRP), have been fundamental for the synthesis of controlled architecture nanomaterials. In this study, hyperbranched poly(β-pinene)-PDMAEMA-PEGDMA nanometric copolymers were synthesised at high conversion via DE-ATRP using different concentrations of β-pinene for gene delivery applications. The structural characterization and the biological performance of the materials were investigated. The copolymers' molar mass (10,434-16,438 mol l^-1), dispersity, and conversion (90-95%) varied significantly with β-pinene proportion on the polymerizations. The polymer-gene complexes generated (280-110 nm) presented excellent solution stability due to the β-pinene segment on the copolymers. Gene delivery and transfection were highly dependent on the copolymer composition. The copolymers containing the highest β-pinene proportions exhibited the best results with high transfection effectivity. In conclusion, the incorporation of β-pinene in DMAEMA-PEGMA copolymer formulations is a renewable option to improve the materials' branching ratio, polyplex stability, and gene delivery performance without causing cytotoxic effects.