Liposomes: Targeted Delivery, Unmatched Precision
By Anika Gurijala
Edited by Gary Leschinsky
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WHAT ARE LIPOSOMES?
Imagine tiny bubble-like structures capable of carrying life-saving drugs straight into diseased cells. These microscopic delivery vehicles are changing the way we treat cancer and numerous other illnesses. Liposomes—small, spherical nanoparticles—are made of lipid bilayers that closely resemble cell membranes. Liposomes are remarkably versatile in drug delivery because they can encapsulate both water and fat-soluble compounds. Discovered in the 1960s by hematologist Alec Bangham, liposomes quickly gained attention for their adaptability. They can range in size from just a few nanometers to several hundred, depending on the drug’s properties and the specific illness being targeted (Nsairat, 2022).
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To understand their importance, let’s understand the bigger picture that sets the stage for these extraordinary vesicles. Drug delivery systems aim to optimize how drugs are absorbed using artificial nanoparticles, which can be made from synthetic or organic materials. These systems rely on different mechanisms—encapsulation, receptor-mediated delivery, and molecular trapping—to transport drugs effectively. For liposomes, encapsulation has proven to be the most efficient method (Nsairat, 2022).
Figure 1: Structure of a Liposome (Soni et al., 2016).
The structure of a liposome (Figure 1) closely resembles that of a cell membrane, featuring a phospholipid bilayer. This bilayer consists of a hydrophilic head which interacts with water and small ions and a hydrophobic tail which interacts with fats and other nonpolar molecules. This unique composition allows liposomes to simultaneously deliver both polar and nonpolar drugs simultaneously, making them highly versatile carriers (Allen et al., 2013).
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HOW LIPOSOMES WORK IN DRUG DELIVERY
Liposomes are excellent at carrying drugs—but how do they actually deliver them? Once inside the body, liposomes protect their cargo from degradation caused by pH variations and enzymatic breakdown. Their interaction with target cells mirrors the natural transport process of extracellular vesicles, which carry biomolecules like RNA. Then, liposomes fuse with cell membranes, releasing their contents directly into the cell (Allen et al., 2013).
Figure 2: Putative Protein Delivery by Fusogenic Liposomes (Kube et al., 2017)
As seen in Figure 2, fusogenic liposomes—designed to merge with cell membranes— encapsulate proteins or drugs for direct delivery. When fusion occurs, the lipid bilayers of both the liposome and the target cell merge, allowing the drug to enter seamlessly (Bareford et al., 2007). Liposomes can also be engineered with targeting ligands—such as antibodies or peptides—that guide them toward specific cells. This approach is particularly useful in cancer treatment. For instance, chemotherapy-loaded liposomes attach to monoclonal antibodies that recognize overexpressed growth factor receptors. This process, called receptor-mediated endocytosis, ensures that the drug affects only cancerous cells while minimizing damage to healthy tissue.
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THE FUTURE OF LIPOSOMES
Researchers continue to refine liposome technology, expanding its potential for personalized medicine. Soon, liposomes could be tailored to fit the specific needs of individual patients—offering even more precise treatments (Liu et al., 2022).
One of the most groundbreaking advancements is smart liposomes—nanoparticles programmed to respond to external triggers such as temperature or pH levels. Unlike conventional liposomes, these smart carriers release their contents only under specific conditions, improving drug efficiency and reducing side effects (Abbasi et al., 2023).
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However, challenges remain. Liposomes have a limited shelf life and require stabilizing additives to prevent degradation stability. Additionally, their high manufacturing costs make widespread accessibility difficult. Overcoming these barriers is crucial for making liposomal therapies cost-effective and available globally. Liposomes are just a small part of the vast nanotechnology landscape—but their potential is enormous. As innovation continues, they are set to revolutionize drug delivery, offering new hope for patients around the world (Leserman et al., 1981).
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WORKS CITED: Abbasi, H., Kouchak, M., Mirveis, Z., Hajipour, F., Khodarahmi, M., Rahbar, N., & Handali, S. (2023). What We Need to Know about Liposomes as Drug Nanocarriers: An Updated Review. Advanced pharmaceutical bulletin, 13, 1, 7–23. https://doi.org/10.34172/apb.2023.009 Leserman, L., Machy, P. & Barbet, J. (1981). Cell-specific drug transfer from liposomes bearing monoclonal antibodies. Nature, 293, 226–228. https://doi.org/10.1038/293226a0  Bareford, Lisa M, and Peter W Swaan. (2007). Endocytic mechanisms for targeted drug delivery. Advanced drug delivery reviews. 59, 8, 748-58. doi:10.1016/j.addr.2007.06.008 Liu, Peng et al. (2022). A Review of Liposomes as a Drug Delivery System: Current Status of Approved Products, Regulatory Environments, and Future Perspectives. Molecules (Basel, Switzerland) vol. 27, 4, 1372. doi:10.3390/molecules27041372 Allen, Theresa M., and Pieter R. Cullis. (2013). Liposomal Drug Delivery Systems: From Concept to Clinical Applications. Advanced Drug Delivery Reviews, 65, 1, 36–48. https://doi.org/10.1016/j.addr.2012.09.037  Nsairat, Hamdi, et al. (2022). Liposomes: Structure, Composition, Types, and Clinical Applications. Heliyon, 8, 5. https://doi.org/10.1016/j.heliyon.2022.e09394  Kube, Sarah et al. (2017). Fusogenic Liposomes as Nanocarriers for the Delivery of Intracellular Proteins. Langmuir:the ACS journal of surfaces and colloids. 33, 4, 1051-1059. Soni, V., Chandel, S., Jain, P., & Asati, S. (2016). Role of liposomal drug-delivery system in cosmetics. Applications of Nanobiomaterials. https://doi.org/10.1016/B978-0-323-42868-2.00005-X