Cationic Polymer Based Gene Delivery: Uptake and Intracellular Trafficking

To date, low transfection efficiency remains the major drawback of polymer based gene delivery. Many cell types including stem cells, fibroblast and neurons are known to be poorly transfected with polymer based gene carriers and the high toxicity severely restrict their utility in gene delivery. Continual efforts are made to identify cellular barriers to efficient transfection as these carriers have low immunogenicity, ease of manufacturing and scalability. Here, we summarize the current status of understanding on uptake mechanism of polymer-DNA complexes (polyplexes), their endosomal escape, cytosolic transport and nuclear entry of pDNA.