PEG-Assisted DNA Solubilization in Organic Solvents for Preparing Cytosol Specifically Degradable PEG/DNA Nanogels

DNA was dissolved in selected organic solvents in the presence of poly(ethylene glycol) (PEG). Nanoscale PEG/DNA complex (∼100 nm) was produced in dimethylsulfoxide (DMSO) phase. Using a thiol-functionalized six-arm branched PEG for DNA solubilization, the PEG/DNA nanocomplex was cross-linked through the formation of disulfide linkages between the thiol groups, resulting in the production of stable PEG/DNA nanogels in aqueous solution. DNA release from the nanogels could be modulated by changing the concentration of an external reducing agent. The released plasmid DNA from the nanogels maintained intact structural integrity and exhibited appreciable gene transfection efficiency. The PEG/DNA nanogels could be potentially applied for gene therapy including DNA vaccination.