Chemically Stimulated DNA Uptake by Protoplasts - Direct DNA uptake by protoplasts can be stimulated by chemicals like polyethylene glycol (PEG). The technique is so efficient that virtually every protoplast system has proven transformable.

PEG is also used to stimulate, the uptake of liposomes ,and to improve the efficiency, of electroporation see below for details). PEG at high concentration (15-25%) will precipitate ionic macromolecules such as DNA and stimulate their uptake by endocytosis without any gross damage to protoplasts.

This is followed by cell wall formation and initiation of cell division. These cells can now be plated at low density on selection medium.
Initial studies using the above method were restricted to Petunia and Nicotiana.