Precision Tuning of DNA- and Poly(ethylene glycol)-based Nanoparticles via Co-assembly for Effective Antisense Gene Regulation

Development of safe and effective delivery vectors remains a critical challenge for oligonucleotides-based biopharmaceuticals. In this work, we incorporate antisense oligonucleotides into micellar nanoparticles via co-assembly of two block copolymers, DNA-b-poly(ɛ-caprolactone) and poly(ethylene glycol)-b-poly(ɛ-caprolactone), and the hydrophobic homopolymer, poly(ɛ-caprolactone). By fine-tuning the spacing of particle surface moieties through adding a diluent homopolymer to the micellar core, we conduct a systematic investigation of structure-property correlations among hybridization kinetics, nuclease resistance, cellular uptake, and antisense efficacy. It is found that, when an intermediate density is achieved, nuclease access of the DNA is greatly hindered, but formation of double-stranded DNA is nearly unaffected. Remarkably, micelles showing the highest selectivity (good nuclease resistance while still maintaining hybridization kinetics) also exhibit the highest antisense gene silencing efficacies. ...