Polyglycerol-functionalized nanodiamond as a platform for gene delivery: Derivatization, characterization, and hybridization with DNA

A gene vector consisting of nanodiamond, polyglycerol, and basic polypeptide (ND-PG-BPP) has been designed, synthesized, and characterized. The ND-PG-BPP was synthesized by PG functionalization of ND through ring-opening polymerization of glycidol on the ND surface, multistep organic transformations (-OH ->-OTs (tosylate)->-N-3) in the PG layer, and click conjugation of the basic polypeptides (Arg(8), Lys(8) or His(8)) terminated with propargyl glycine. The ND-PG-BPP exhibited good dispersibility in water (> 1.0 mg/mL) and positive zeta potential ranging from + 14.2 mV to + 44.1 mV at neutral pH in Milli-Q water. It was confirmed by gel retardation assay that ND-PG-Arg(8) and ND-PG-Lys(8) with higher zeta potential hybridized with plasmid DNA (pDNA) through electrostatic attraction, making them promising as nonviral vectors for gene delivery.