Functionalized polyesters based on valerolactones and [12]aneN3 as effective non-viral gene vectors in HepG2 cells

Abstract

Polymer vectors hold great promise for application in gene therapy. However, some challenges such as low transfection efficiency, high toxicity, and insufficient cell selectivity still need to be addressed. Here, we proposed a simple and efficient approach to synthesize polyester vectors via a ring-opening polymerization (ROP) process. Three distinct block copolymers, TMN-1/2/3, were prepared by using valerolactones with alkyl sulfide chains (6, 8, and 10 carbon side chains, respectively) and propargyl valerolactone as monomers and BODIPY derivatives as fluorescent units and polymerization initiators, and further modification through a click reaction with 3-azidopropyl-[12]aneN₃ as positive units. The three block copolymers integrate multiple functionalities, including imaging capability, degradability, and DNA condensation ability. Their DNA binding ability and gene transfection efficiency were systematically studied and showed good structure–activity relationship. Among them, TMN-3 with a 10 carbon alkyl sulfide chain was the most effective in DNA binding ability and gene transfection efficiency, which was 18.9 times higher than that of 25 kDa PEI in the HepG2 cell line. The efficient cellular uptake, lysosomal escape, and nuclear entry of the TMN-3-DOPE/pDNA polyplex resulted in its excellent performance. Moreover, it was demonstrated that TMN-3-DOPE/pDNA exhibited significant anticancer effects upon internalization into HepG2 cells. The results indicated that TMN-3 has the potential to serve as an effective non-viral gene vector for tumor treatment.