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Lecture

Vesicles: Formation and Characterization

In course

MSE-425: Soft matter

The first part of the course is devoted to the self-assembly of molecules. In the second part we discuss basic physical chemical principles of polymers in solutions, at interfaces, and in bulk. Finally, we look at colloids and emulsions. ...

Description

This lecture covers the formation and characterization of vesicles, focusing on methods such as rehydration, sonication, extrusion, electroformation, and microfluidics. It also discusses the influence of production methods on vesicle size, characterization techniques like light scattering, and the use of vesicles as delivery vehicles in drug delivery.

Instructors (2)

Esther Amstad

Esther Amstad studied material science at ETH in Zurich. She also carried out her PhD thesis at the same University under the supervision of Prof. Marcus Textor; for her thesis, she worked on the surface modification and steric stabilization of oxide nanoparticles. As a postdoctoral fellow, she joined the experimental condensed soft matter group of David A. Weitz at Harvard University where she used droplet based microfluidics to assemble different types of functional micro- and nanomaterials. In addition, she developped new microfluidic devices that enable the production of very small, airborne drops as well as devices that produce highly monodisperse emulsion drops at a very high throughput. In June 2014, Esther joined the material science department (IMX) of EPFL where she is leading the Soft Materials Laboratory (SMAL).

Harm-Anton Klok

Official source

Related concepts (21)

Dynamic light scattering

Dynamic light scattering (DLS) is a technique in physics that can be used to determine the size distribution profile of small particles in suspension or polymers in solution. In the scope of DLS, temporal fluctuations are usually analyzed using the intensity or photon auto-correlation function (also known as photon correlation spectroscopy - PCS or quasi-elastic light scattering - QELS). In the time domain analysis, the autocorrelation function (ACF) usually decays starting from zero delay time, and faster dynamics due to smaller particles lead to faster decorrelation of scattered intensity trace.

Static light scattering

Static light scattering is a technique in physical chemistry that measures the intensity of the scattered light to obtain the average molecular weight Mw of a macromolecule like a polymer or a protein in solution. Measurement of the scattering intensity at many angles allows calculation of the root mean square radius, also called the radius of gyration Rg. By measuring the scattering intensity for many samples of various concentrations, the second virial coefficient, A2, can be calculated.

Lipid bilayer

The lipid bilayer (or phospholipid bilayer) is a thin polar membrane made of two layers of lipid molecules. These membranes are flat sheets that form a continuous barrier around all cells. The cell membranes of almost all organisms and many viruses are made of a lipid bilayer, as are the nuclear membrane surrounding the cell nucleus, and membranes of the membrane-bound organelles in the cell. The lipid bilayer is the barrier that keeps ions, proteins and other molecules where they are needed and prevents them from diffusing into areas where they should not be.

Vesicle (biology and chemistry)

In cell biology, a vesicle is a structure within or outside a cell, consisting of liquid or cytoplasm enclosed by a lipid bilayer. Vesicles form naturally during the processes of secretion (exocytosis), uptake (endocytosis), and the transport of materials within the plasma membrane. Alternatively, they may be prepared artificially, in which case they are called liposomes (not to be confused with lysosomes). If there is only one phospholipid bilayer, the vesicles are called unilamellar liposomes; otherwise they are called multilamellar liposomes.

Lipid bilayer phase behavior

One property of a lipid bilayer is the relative mobility (fluidity) of the individual lipid molecules and how this mobility changes with temperature. This response is known as the phase behavior of the bilayer. Broadly, at a given temperature a lipid bilayer can exist in either a liquid or a solid phase. The solid phase is commonly referred to as a “gel” phase. All lipids have a characteristic temperature at which they undergo a transition (melt) from the gel to liquid phase.

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