Question

You are asked to produced a stealth liposome with the ability to carry cDNA into the nucleus of a targeted cell carrying a specific type of receptor on its membrane.How would you design it?

Answer 1

Liposomes are intracellular vesicles that can be used to transport substances such as nutrients and drugs (i) into the cell, (ii) out of the cell, and (iii) between different parts of a cell.The liposome can be used as a vehicle for administration of nutrients and pharmaceutical drugs. Liposomes can be prepared by disrupting biological membranes (such as by sonication).

Among several promising new drug-delivery systems, liposomes represent an advanced technology to deliver active molecules to the site of action.

stealth liposomes

A significant step in the development of long-circulating liposomes came with inclusion of the synthetic polymer poly-(ethylene glycol) (PEG) in liposome composition. The presence of PEG on the surface of the liposomal carrier has been shown to extend blood-circulation time while reducing mononuclear phagocyte system uptake.

This technology has resulted in a large number of liposome formulations encapsulating active molecules, with high target efficiency and activity. Further, by synthetic modification of the terminal PEG molecule, stealth liposomes can be actively targeted with monoclonal antibodies or ligands.

Stealth liposome is very effective because it is the liposome which has been combined withPEG i.e.Poly ethylene glycol, an advancement technology for drug delievery system. The basic requirement that te molecule should be of low molecular weight orwecan say the only limitation

c DNA is a DNA that is complementary to a given RNA which serves as a template for synthesis of the DNA in the presence of reverse transcriptase. It can easily targeted to the nucleus because of its low molecular weight  by the liposome. For that reason it should bind or associated with the ligand that show high rate of complemetarity ith the receptor present on the target cell . So that the cDNA travelalon with the ligand to the cell and target to the nucleus because this cDNA must have NLS i.e. Nuclear localisation signal.