PEGylated chitosan complexes DNA while improving polyplex colloidal stability and gene transfection efficiency

► Low degree of chitosan PEGylation does not suppress DNA polyplex formation. ► Polyplexes with low degree PEGylated chitosans and DNA are less prone to colloidal instability. ► Polyplexes between low degree PEGylated chitosans and DNA show increased transfection ability.