Redox-sensitive, cholesterol-bearing PEGylated poly(propyleneimine)-based dendrimersomes for drug and gene delivery to cancer cells

Stimuli-responsive nanocarriers have attracted increasing attention for drug and gene delivery in cancer therapy. The present study reports the development of redox-sensitive dendrimersomes made of disulphide-linked cholesterol-bearing PEGylated dendrimers, that can be used as drug and gene delivery systems. Two disulphide-linked cholesterol-bearing PEGylated generation 3-diaminobutyric polypropylenimine dendrimers have been successfully synthesized through in situ two-step reaction. They were able to spontaneously self-assemble into stable, cationic, nanosized vesicles (or dendrimersomes), with lower critical aggregation concentration values for high cholesterol-bearing vesicles. These dendrimersomes were able to entrap both hydrophilic and hydrophobic dyes, and also showed a redox-responsive sustained release of the entrapped guests in presence of a glutathione concentration similar to that of the cytosolic reducing environment. The high cholesterol-bearing dendrimersome was found to have a higher melting enthalpy, an increased adsorption tendency on mica surface, was able to entrap a larger amount of hydrophobic drug and was more resistant to redox-responsive environment in comparison with its low cholesterol counterpart. In addition, both dendrimersomes were able to condense more than 85% of the DNA at all tested ratios for the low-cholesterol vesicles, and at dendrimer: DNA weight ratios of 1:1 and higher for the high-cholesterol vesicles. These vesicles resulted in an enhanced cellular uptake of DNA, by up to 15-fold compared with naked DNA with the low-cholesterol vesicles. As a result, they increased gene transfection on PC-3 prostate cancer cell line, with the highest transfection being obtained with low-cholesterol vesicle complex at a dendrimer: DNA weight ratio of 5:1 and high-cholesterol vesicle complex at a dendrimer: DNA weight ratio of 10:1. These transfection levels were about 5-fold higher than that observed when treated with DNA. These cholesterol-bearing PEGylated dendrimer-based vesicles are therefore promising as redox-sensitive drug and gene delivery systems for potential applications in combination cancer therapy