Construction of ROS-Responsive Poly(β-amino ester)-poly(β-thioether ester) Copolymer for Enhancing Gene Delivery and Gene Therapy

Gene therapy is often limited by gene vectors. To reduce the impact of intracellular reactive oxygen species and improve transfection efficiency, thioether bonds were introduced in poly(β-amino ester) (PBAE), a well-known nonviral gene vector, to synthesize PBAE-poly(β-thioether ester) copolymer (PBAE-TE). By varying the monomer feeding ratio and reaction time, the optimized copolymer (PBAE-TE2-5) showed the highest transfection efficiency in SiHa and HeLa cells (75.00 and 78.70%) with a 75:1 copolymer/GFP ratio. PBAE-TE2-5 also demonstrated superior transfection performance compared to PBAE in multiple cell lines (HeLa, Me180, C666-1, and HEK 293T) and better penetration capability in 3D spheroid cell models (SiHa and HEK 293T). The PBAE-TE2-5-CRISPR/Cas9 plasmid polyplexes could effectively edit target genes in HEK 293T (<i>MUC2</i>) and SiHa (<i>HPV16 E7</i>) cells, and inhibit cancer cell proliferation both <i>in vitro</i> and <i>in vivo</i>. These findings highlight the promising potential of PBAE-TE as an effective gene delivery system.