Muscular dystrophies are genetic disorders caused by mutations in more than 30 genes, with no cure or effective treatment. Duchenne muscular dystrophy (DMD) is caused by frame-shift mutations in the dystrophin gene with little or no functional dystrophin protein in muscles. One of the most effective experimental therapies for DMD is antisense oligonucleotide (AON) therapy, which corrects the disrupted reading-frame by skipping the mutated exon(s) during pre-messenger RNA splicing resulting in truncated but functional dystrophin protein. Proof of principle has been obtained with the most effective phosphorodiamidate morpoholino (PMO) chemistries in animal models and clinical trials. However, low efficiency and non-specific delivery remain critical barriers for AON therapy to achieve long-term efficacy. My thesis has tested two hypothesis driven approaches to overcome these barriers: developing new polymers for effective delivery with low toxicity, and identifying ligands for tissue specific targeting. I have evaluated a new class of poly (ester-amine) (PEAs) primarily as vehicles for PMO delivery. The results demonstrate a significantly enhanced delivery and exon skipping efficiency in cell culture and in vivo with reduced toxicity compared with cationic polymer alone as delivery vehicles, providing a base to further optimize for clinical applications.Applying a novel approach of phage array in combination with powerful next generation sequencing (NGS), my study revealed obstacles to identification of peptide ligands and allowed me to design a novel procedure with potential to rejuvenate the technique for ligand identification with phage array both in vitro and in vivo. Collectively, these experiments address the most challenging issues currently in translational research.