Extruders - NanoSizer MINI

Extruders - NanoSizer MINI

detailed step-by-step guide for performing lipid extrusion with a mini extruder to create unilamellar vesicles using an 11-pass process:

Materials Needed:

  1. Lipids (e.g., phospholipids such as phosphatidylcholine)
  2. Solvent (e.g., chloroform or a suitable organic solvent)
  3. Buffer solution (for hydration)
  4. Mini extruder with appropriate membrane filters (typically with pore sizes between 50 nm and 200 nm)
  5. Vacuum pump (optional, for degassing)
  6. Sonicator (optional, for further size reduction)
  7. Glass vials or containers
  8. Syringe and needles
  9. Graduated cylinders and pipettes
  10. Dialysis tubing (if needed for purification)

Procedure:

  1. Lipid Film Formation:

    • Dissolve the lipids in a suitable organic solvent (e.g., chloroform) to create a lipid solution. The lipid concentration will depend on your specific formulation.
    • Evaporate the solvent using a rotary evaporator or by flushing with nitrogen gas to form a thin lipid film on the wall of a glass container.

  2. Hydration:

    • Add an appropriate buffer solution to hydrate the lipid film. The buffer composition can vary based on the intended application.
    • Swirl or vortex the container gently to help the lipids hydrate, forming multilamellar vesicles (MLVs).

  3. Probe Sonication (Optional):

    • If desired, perform probe sonication to further break down the MLVs into smaller liposomes. Be cautious not to overheat the sample during sonication.

  4. Extrusion Setup:

    • Assemble the mini extruder with a membrane filter of the desired pore size. Ensure that the extruder is clean and free from air bubbles.

  5. Loading the Sample:

    • Load the hydrated liposome suspension into a syringe and attach it to the extruder.

  6. Extrusion Passes:

    • Extrude the liposome suspension through the membrane filter for a total of 11 passes. For each pass, use the syringe to push the suspension through the filter.

  7. Collecting Liposomes:

    • Collect the liposome suspension in a clean container after each pass. You will notice a reduction in size and an increase in homogeneity with each pass.

  8. Quality Control:

    • Measure the size distribution and polydispersity index (PDI) of the liposomes using dynamic light scattering (DLS) or another appropriate characterization method. This will help you determine if further passes are necessary.

  9. Purification (Optional):

    • If required, purify the liposomes by dialysis against the buffer solution to remove any remaining solvent or unencapsulated materials.

  10. Storage:

    • Store the unilamellar liposomes in appropriate conditions (e.g., refrigeration or freeze-drying) and use them for your intended application.

Tips:

  • Maintain a controlled environment to prevent contamination during the process.
  • Keep the extruder and equipment clean to avoid cross-contamination between passes.
  • Avoid excessive pressure while extruding to prevent membrane filter damage.
  • If the liposomes are not of the desired size after 11 passes, you can perform additional passes as needed.

Remember that the success of the process may vary based on the specific lipid composition, membrane filter pore size, and other factors. Monitoring the liposome size and characteristics at each step will help you achieve the desired results.