•  Liposomes Mediated

Liposomes are spherical vesicles which are made up of synthetic lipid bilayers which imitate the structure of biological membranes. DNA to be transferred is packaged into the liposome in vitro and transferred to to the targeted tissue . The lipid coating helps the DNA to survives in vivo and enters into the cell by endocytosis. Cationic liposomes, where the positive charge on liposomes is stabilized by binding of negatively charged DNA, are popular vehicles for gene transfer in vivo. For more detail see lecture 2 of module 5.

Figure 8-1.7.2.4: In vivo liposome mediated gene transfer- (A) formation of lipid bilayer in water (B) Structure of anionic and cationic liposome (C) Use of liposome to transfer genes into cells.

Adapted and modified from:

http://www.ncbi.nlm.nih.gov/books/NBK7569/figure/A2924/?report=objectonly

Advantage:

• The liposomes with the foreign DNA are easy to prepare.
• There is no restriction in the size of DNA that is to be transferred.

Disadvantage :

• Efficiency of gene transfer is low and transient expression of the foreign gene is obtained as they are not designed to integrate into the chromosomal DNA.