Influence of block sequences in polymer vectors for gene transfection in vitro and toxicity assessment of zebrafish embryos in vivo

Abstract

In this study, a triblock copolymer PDMAEMA-b-poly(PEGMA)-b-PDMAEMA (DED) and a diblock copolymer PDMAEMA-b-poly(PEGMA) (DE) were synthesized by atom transfer radical polymerization (ATRP) with the initiators bis(2-bromoisobutyryl) hexanediamide (BiBH) and ethyl 2-bromoisobutyrate (EBiB), respectively. Their molecular weights and chemical compositions were almost the same with only difference being in the block sequences. The influence of the block copolymer structures on the gene transfection results was investigated systematically. Gel retardation assay, atomic force microscopy (AFM) observation, particle size and zeta potential measurements with dynamic light scattering (DLS) were used to characterize the properties of the polymer/pDNA complexes. DED showed moderate aggregation behavior with far less cytotoxicity to in vitro and in vivo to zebrafish than DE, which indicates that DED would be a promising vector for gene therapeutic applications.