20.8 Nuclear import

Nuclear import through passive process occurs when nuclear membrane disassembles during cell division. Transfection efficiency depends on cell cycle state. Such as linear PEI transfection does not depend on cell cycle state while branched chain polyplex does. PEI has the ability to facilitate nuclear translocation of DNA because microinjected PEI-DNA polyplexes have higher transfection ability when compared to naked DNA or lipoplexes.

20.9 Summary

Lipoplexes and polyplexes can be optimally designed to be used as an efficient non-viral vectors for gene therapy and disease control. There is a need for development of an ideal vector for gene delivery, which could be tailored according to the need considering its in vivo use, stability, and easy transport across membrane. Lipoplexes and polyplexes are such molecules which could be used as vector. Lipoplexes transformed into hexagonal H 11 phase have high transfection activity when compared to those in lamellar L phase. DOPE containing complexes aggregate in blood and thus cannot be used for systemic application but are good for cell culture work. Serum resistant lipoplexes and polyplexes are being formulated which are more stable in blood. Completely condensed DNA with the polymer has advantages of being protected from degradation, enhanced binding ability and improved endocytosis. But the problem lies with the dissociation of DNA from carrier inside cell. Thus there is a need of rational designing of vectors with efficient transfection ability.