Question

Why are non-viral vehicles often lipid based?

Describe how cationic liposomes can specifically target DNA.

Answer 1

There are multiple reasons why non-viral vehicles are often lipid-based (liposomes). They are versatile in that they can incorporate both hydrophobic and hydrophilic drugs due to the nature of the liposomes. They have very less toxicity when compared to other DNA delivery vehicles since they are made from biological lipids similar to the lipids of the plasma membrane. Delivery of target DNA or drug into the cell also becomes easier as the liposomes can easily integrate with the plasma membrane. Also, The immunogenicity of the liposomes is very less meaning chances of rejection decreases.

Lipid molecules used in liposomes are conserved entities with a head group and hydrophobic hydrocarbon tails connected via a backbone linker. Cationic lipids commonly attain a positive charge through one or more amines present in the polar head group. The presence of positively charged amines facilitates binding with anions such as those found in DNA. The liposome thus formed is a result of energetic contributions by Van der Waals forces and electrostatic binding to the DNA.

In layman terms, cationic liposomes with an inherent positive charge can easily bind with and attract the negatively charged DNA.