![1. http://nptel.ac.in/courses/102103013/23
2. http://www.pharmainfo.net/nandini/blog/introduction-liposomes
3. Karp, Gerald. (2010) Cell and molecular biology:concepts and experiments [Hoboken, N.J.] : Wiley](https://image.slidesharecdn.com/presentation1-180626074226/85/liposome-mediated-gene-delivery-17-320.jpg)
liposome mediated gene delivery
- 1. Presented by: PRATIBHA KUMARI SHARMA M.Sc BIOTECHNOLOGY Guided by: LINSHA
- 2. 1. Introduction 2. Liposomes 3. Classifications 4. Cationic liposome 5. Anionic liposome 6. Advantage and disadvantages 7. References
- 3. Liposome are fluid filled spherical vesicles made of phospholipids molecule. Produced from glycolipids, cholesterols, non-toxic surfactants and membranous proteins. Discovered in the year 1960 by British hematologist Dr. Alec D. Bangham. Manufactured and classified on the basis of size, composition, charge and speciality. These liposomes work to deliver drug by diffusion rather than by direct cell fusion.
- 5. 1. The walls of liposome consists of continous lipid bilayer organised in same manner as that of the bilayer of natural membrane. 2. Membrane proteins can be inserted into liposomes (we can study function of membrane protein in a much simpler enviornment). 3. Drugs or DNA can be linked to the wall of the liposomes or contained at high concentration within its lumen. 4. Liposomes can protect from phagocytic cells of the immune system by protective layer of synthetic polymer- polyethelene glycol. 5. The walls of the liposomes contains specific protein (hormones or antibodies) that allow the liposomes selectively to the surface of target cells.
- 6. Liposomes are classified based on their structure as: 1. Multi-laminar vesicles(MLV): made up of series of concentric bi-layer of lipid enclosing a small internal volume. 2. Oligolamelar vesicles(OLV): constitutes 2 to 10 bi layer of lipids surrounding a large internal volume 3. Unilamellar vesicle(ULV): single layer of lipids 4. Based on the size of the single layer they are further divide into the following types with in ULV as * Small unilaminar vesicle: size of 20 to 40 nm * Medium unilaminar vesicle: size of 40 to 80 nm * Large unilaminar vesicle: size of 100 to 1000 nm * Gaint unilaminar vesicle: size of more than 1000 nm
- 7. • Method of transformation first described in 1965 as a model of cellular membranes using liposomes. • Liposomes are artificial phospholipid vesicles used for the delivery. • They can be preloaded with DNA by two common methods- membranemembranefusion and endocytosis thus forming DNA- liposome complex. • This complex fuses with the cell membrane of target cell and to release the contents into the cell. • Animal cells, plant cells, bacteria, yeast protoplasts are susceptible to lipofection method.
- 9. Liposomes can be classified as either 1.Cationic liposome 2.Anionic liposome
- 10. • Positively charged liposomes which associate with the negatively charged DNA molecules by electrostatic interactions forming a stable complex. • neutral liposomes and neutral co-lipids are used as helpers. • Neutral liposomes are generally used as DNA carriers and helpers of cationic liposomes due to their non-toxic nature and high stability in serum. • Dioleoylphosphatidyl ethanolamine (DOPE) or dioleoylphosphatidyl choline (DOPC) are some commonly used neutral co-lipids. • DNA molecule interacts with the positively charged groups of the DOPE or DOPC. • The overall net positive charge allows the close association of the lipoplex with the negatively charged cell membrane followed by uptake into the cell and then into nucleus.
- 12. • Some of the DNA molecules get entrapped within the aqueous interior of these liposomes. • Divalent cations are used (e.g. Ca2+, Mg2+, Mn2+, and Ba2+) which can neutralize the mutual electrostatic repulsion. • They are termed as pH sensitive due to destabilization at low pH. • cationic liposomes get inactivated and unstable in the presence of serum and exhibit cytotoxicity • Due to reduced toxicity and interference from serum proteins, pH-sensitive liposomes are considered as potential gene delivery vehicles than the cationic liposomes.
- 14. • Study of membranes •In gene delivery •As drug deliverty carriers •Enzyme replacemnt therapy •In multi drug resistance •In tumour therapy
- 15. • Economic • Efficient delivery of nucleic acids to cells in a culture dish. • Delivery of the nucleic acids with minimal toxicity. • Protection of nucleic acids from degradation. • Easy to use, requirement of minimal steps and adaptable to high-throughput systems.
- 16. • It is not applicable to all cell types. • It fails for the transfection of some cell lines with lipids.
- 17. 1. http://nptel.ac.in/courses/102103013/23 2. http://www.pharmainfo.net/nandini/blog/introduction-liposomes 3. Karp, Gerald. (2010) Cell and molecular biology:concepts and experiments [Hoboken, N.J.] : Wiley