Microfluidic assembly of mono-dispersed liposome and its surface modification for enhancing the colloidal stability

In the present study, mono-dispersed 100 nm-sized liposomes (DPPC:cholesterol = 8:2 (mol)) were produced by a novel microfluidic assembly method with optimized flow rate ratio (non-aqueous phase:aqueous phase = 60.0:6.0 (mL/h)). These liposomes were incorporated with ionic surfactants, such as anionic palmitic acid (PAL) or cationic hexadecylamine (HDA), to enhance their colloidal stability, which was confirmed through TEM and ζ-potential analysis. Moreover, to enhance their intestinal stability, the surfaces of liposomes were modified with biodegradable polymers by electrostatic attraction. Specifically, cationic chitosan was coated onto anionic PAL-incorporated liposomes, whereas anionic pectin was used for cationic HDA-incorporated liposomes. Finally, branched-chain amino acids (BCAAs) were encapsulated into the PAL-incorporated liposomes with surface modifications, showing 31.2 % of encapsulation efficiency. This study could contribute a novel approach for microfluidic assembly of the liposomes, providing deeper insight into surface modifications and enhancement of the colloidal stability.