Characterization of Liposomes in Solution

The Challenge: Characterization of Liposomes in Solution
A company engaged in the development of novel delivery methods for small molecule therapeutics needs accurate determinations of liposomal morphology (size distribution and shape), and assembly (lamellarity) of lipid particles. However, common methods of size determination such as Dynamic Light Scattering (DLS) are not direct measures of size, are hampered by heterogeneous samples, and provide no information regarding shape or lamellarity. Direct visualization of nanoscale liposomes by freeze fracture TEM is prone to distortion and artifacts from sample preparation and does not provide the critical structural details (i.e. lamellarity).

The Solution: Molecular Microscopy
NIS provided the direct visualization and analytical characterization (size, shape and lamellarity) of native fully hydrated liposomes at the same time. In addition, image-based sizing methods can be used to provide detailed size distribution.  Our client was able to reach crucial decision as a result of the data generated by Molecular Microscopy studies performed by NanoImaging Services greatly accelerating this project’s development and avoiding potential miscues based on indirect measurements.

Morphology and Lamellarity:

Shape and lamellarity are shown with Molecular Microscopy images of liposomes (DMPC/cholesterol) imaged at a magnification of 21,000x (left) and 52,000x (right).

Size and Shape Distribution:

Semi-automated nanoparticle contouring (left) allows quantitative characterization (right) of liposomal shape and size.

3-Dimensional Structure and Substructure:

Tomographic reconstruction of liposomal encapsulated Doxorubicin allows direct determination of particle assembly and capsulation efficiency.