How Many Passes Does it Take?
An Investigation to Determine the Optimal Number of Liposome Extrusion Cycles
Author:
Kasey Piper ’25Co-Authors:
Faculty Mentor(s):
Kenny Mineart, Chemical EngineeringFunding Source:
PURAbstract
Liposomes are lipid-based nanoparticles commonly known for their drug carrying capacity and value in membrane and nanoreactor research. One commonly used method of fabricating liposomes of particular size is membrane extrusion where liposomes are pushed through a porous membrane and form smaller liposomes. However, the details pertaining to liposome extrusion, such as the number of passes, membrane pore sizes, and pre-extrusion sample preparation, vary between labs. The goal of this project is to establish a relationship between the number of passes through a track-etched, polycarbonate membrane, and the average diameter and lamellarity of extruded liposomes. To investigate, we extrude samples to different amounts varying from 1 to 1,000 passes and measure the average hydrodynamic diameter and diameter distribution of each using dynamic light scattering (DLS). We measure lamellarity with small angle x-ray scattering (SAXS) and cryogenic transmission electron microscopy (CryoTEM). When liposome size distribution and lamellarity data start to flatten out, it is suggested that extrusion has been completed, and further extruding would not change the liposome size and lamellarity. These results provide researchers with the optimal number of passes for liposome extrusion that will allow them to form ideal distributions in the shortest amount of time.