Treating polyplexes with PEG, a process called "PEGylation," prevents them from sticking together; however, applying PEG in a controlled, consistent manner to the polyplex surface is very difficult.

Pegylation of polypeptide drugs protects them and improves their pharmacodynamic and pharmacokinetic profiles. The pegylation process attaches repeating units of polyethylene glycol (PEG ...