The molecular structures of poly(ethylene glycol)-modified nonviral gene delivery polyplexes.

Polycations can complex with DNA and form compact nanoparticles (polyplexes) to facilitate gene transfection. Recently, poly(ethylene glycol) (PEG) was incorporated in the polyplexes to improve their in vivo stability and defer body clearance. This work provided a direct look using atomic force microscopy at the molecular conformation of PEG molecules on the polyplex surfaces. Individual PEG strands were seen to extend from the compact cores and intertwined with each other to form the protective surface layer.