Table 14.1 Techniques for loading molecules into the cytoplasm.

Method of Plasma Membrane Breach Size of Molecules Loaded (MW) *
Chemical
ATP ref 1000
Cell-penetrating peptides ref (CPP) 150,000; (DNA)
Influx pinocytic cell-loading reagent ref (I14402) 150,000
α-Toxin of Staphylococcus aureus ref 1000
Vehicle
Red blood cell fusion ref 300,000
Cationic lipids ref (Lipofectamine reagents) (DNA)
Mechanical
Microinjection ref 150,000
Whole-cell patch clamping ref Very high
Carbon nanotubes and nanowires ref 150,000; (DNA)
Scrape loading ref 500,000; (DNA)
Ultrasonication ref 70,000; (DNA)
Microprojectile bombardment ref 10,000; (DNA)
Glass beads ref 150,000
Electrical
Electroporation ref † 150,000; (DNA)
* Molecular weight (MW) of largest molecules reported loaded (DNA is listed separately if it has been successfully introduced by a technique). † We recommend the Neon® Transfection System (www.invitrogen.com/neon) for efficient electroporation of cultured cell lines, primary cells and stem cells.