Rapid single-step formation of liposomes by flow assisted stationary phase interdiffusion

Area of Science:

• Biophysical Chemistry
• Materials Science
• Nanotechnology

Background:

• Traditional laboratory preparation of unilamellar liposomes is time-consuming, often requiring several hours to achieve a monodisperse size distribution.
• Achieving reproducible liposome populations is crucial for various applications, including drug delivery.

Purpose of the Study:

• To present a novel, rapid methodology for preparing large unilamellar vesicles (LUVs) with a monodisperse size distribution.
• To demonstrate the application of the stationary phase interdiffusion (SPI) principle for efficient liposome production.

Main Methods:

• Utilized a stationary phase interdiffusion (SPI) principle involving a lipid-ethanol phase and an aqueous phase separated by a stationary interface.
• Employed a horizontal capillary with density difference-induced convective flow to create the interface.
• Investigated the influence of temperature, lipid type, lipid concentration, ethanol content, pH, and time on vesicle size.

Main Results:

• Successfully prepared monodisperse large unilamellar vesicles (LUVs) in approximately 10 minutes.
• Demonstrated that vesicle size is primarily modulated by temperature and lipid type, with minimal influence from other experimental parameters.
• Achieved LUVs in the 100-200 nm range using refined natural lipids (soy and egg lecithin), suitable for drug delivery.

Conclusions:

• The stationary phase interdiffusion (SPI) method offers a significantly faster and simpler approach to producing reproducible liposome suspensions.
• This rapid production tool is highly beneficial for researchers requiring consistent liposome characteristics, particularly for drug delivery applications.
• The methodology is easily implementable using basic laboratory equipment like capillaries and syringes.