Last November, van der Gun et al. published an article high-lighting the unique advantages of the SAINT protein delivery reagent: SAINT-PhD.

1. Delivery of the protein is independent of the
   size and charge.
2. Delivery efficiency is high: up to 98% of
   adherent cells, up to 83% of suspension
   cells and up to 70% of primary cells are
   shown to have taken up the protein
   transported by SAINT-PhD into the cells.
3. Intracellular delivery of proteins by SAINT-PhD
   is not significantly affected by the presence
   of serum. This is a major advantage,
   because most competitors (e.g. Bioporter)
   are not able to deliver proteins into cells
   in the presence of serum. Furthermore, the
   presence of serum is self-evident in in vivo
   protein delivery experiments and applications.
4. The delivered protein can exert its function
  both in the cytoplasm and in the nucleus. For
  example, a methyltransferase enzyme was
  delivered using SAINT-PhD resulting in
  DNA methylation leading to a decrease in
  expression.
5. SAINT-PhD does not affect cell viability.

B.T.F. van der Gun et al., Serum insensitive, intranuclear protein delivery by the multipurpose cationic lipid SAINT-2, J. Control. Release. (2007), doi:10.1016/j.jconrel.2007.08.014