Liposome
The discovery came about when Bangham and R. W. Horne were testing the institute's new electron microscope by adding negative stain to dry phospholipids.
The resemblance to the plasmalemma was obvious, and the microscopic pictures provided the first evidence that the cell membrane is a bilayer lipid structure.
The following year, Bangham, his colleague Malcolm Standish, and Gerald Weissmann, an American physician, established the integrity of this closed, bilayer structure and its ability to release its contents following detergent treatment (structure-linked latency).
[13] During a Cambridge pub discussion with Bangham, Weissmann first named the structures "liposomes" after something which laboratory had been studying, the lysosome: a simple organelle whose structure-linked latency could be disrupted by detergents and streptolysins.
[14] Liposomes are readily distinguishable from micelles and hexagonal lipid phases through negative staining transmission electron microscopy.
Later, Weissmann, then an emeritus professor at New York University School of Medicine, recalled the two of them sitting in a Cambridge pub, reflecting on the role of lipid sheets in separating the cell interior from its exterior milieu.
As Bangham had been calling his lipid structures "multilamellar smectic mesophases," or sometimes "Banghasomes," Weissmann proposed the more user-friendly term liposome.
By preparing liposomes in a solution of DNA or drugs (which would normally be unable to diffuse through the membrane) they can be (indiscriminately) delivered past the lipid bilayer.
[26] Lastly, the membrane of the liposome and the endosome fuse together, releasing the encapsulated contents onto the cytoplasm and avoiding degradation at the lysosomal level due to minimal contact time.
[27] A study provides a promising preclinical demonstration of the effectiveness and ease of preparation of Valrubicin-loaded immunoliposomes (Val-ILs) as a novel nanoparticle technology.
In the context of hematological cancers, Val-ILs have the potential to be used as a precise and effective therapy based on targeted vesicle-mediated cell death.
[31] This new application of liposomes is in part due to the low absorption and bioavailability rates of traditional oral dietary and nutritional tablets and capsules.
They typically form after supplying enough energy to a dispersion of (phospho)lipids in a polar solvent, such as water, to break down multilamellar aggregates into oligo- or unilamellar bilayer vesicles.
The original aggregates, which have many layers like an onion, thereby form progressively smaller and finally unilamellar liposomes (which are often unstable, owing to their small size and the sonication-created defects).
They were first proposed by G. Cevc and G. Blume[44] and, independently and soon thereafter, the groups of L. Huang and Vladimir Torchilin[45] and are constructed with PEG (Polyethylene Glycol) studding the outside of the membrane.
Also morphologically related to liposomes are highly deformable vesicles, designed for non-invasive transdermal material delivery, known as transfersomes.
[50] A study published in May 2018 also explored the potential use of liposomes as "nano-carriers" of fertilizing nutrients to treat malnourished or sickly plants.
Results showed that these synthetic particles "soak into plant leaves more easily than naked nutrients", further validating the utilization of nanotechnology to increase crop yields.
For example, deep learning was used to monitor a multistep bioassay containing sucrose-loaded and nucleotides-loaded liposomes interacting with a lipid membrane-perforating peptide.
