Data to support: A novel microfluidic-based approach to formulate size-tuneable large unilamellar cationic liposomes: formulation, cellular uptake and biodistribution investigations.

This data set supports working where we demonstrate a new method to produce both small and large liposome formulations.
Figure 2. Effect of aqueous buffer concentration on liposomes formulated by microfluidics. Effect of cationic lipid choice. DOPE:DOTAP ( ), DOPE:DDA ( ) and DSPC:Chol ( ) liposomes were formulated by microfluidics in the Nanoassemblr Platform (Precision Nanosystems) at increasing concentrations of TRIS buffer pH 7.4, then dialyzed and characterized by dynamic light scattering in terms of size (A), PDI (B) and zeta-potential (C). Dynamic light scattering size distribution plots of DOPE:DOTAP (D), DOPE:DDA (E) and DSPC:Chol (F) liposomes, and representative images of formulations prepared at lowest (left) and highest (right) buffer concentration are shown. Results are represented as mean ± SD of three independent experiments.
Figure 3. Cryo-TEM micrographs of small (A, B) and large DOPE:DOTAP liposomes (D , E) formulated by microfluidics at 4 mg/mL, 1:1 FRR, 15 mL/min TFR and 10 and 1000 mM TRIS buffer pH 7.4. The dense black spheres are water crystals. Hydrodynamic size (bars) and PDI (values) (F) and size distribution plots of small and large liposomes (G) are shown. Results are represented as mean ± SD of three DLS measurements.
Figure 4. The role of cationic lipid content within the liposome formulation. Effect of molar percentage of cationic lipid on size (A), PDI (B) and zeta-potential (C). DSPC:Chol liposomes (5:5 molar ratio) were prepared at increasing molar percentages of DOTAP: 0% ( ), 5% ( ), 13%( ) and 23% ( ). All formulations were prepared at 4 mg/mL, 1:1 FRR and 15 mL/min TFR, dialyzed and characterized by DLS. Effect of buffer choice on size (D) and PDI (E). DSPC:Chol (10:10 molar ratio) and DSPC:Chol:DOTAP (10:10:1 molar ratio) liposomes were prepared at 4 mg/mL, 1:1 FRR and 15 mL/min at increasing concentrations of TRIS buffer pH 7.4 or citrate buffer pH 6.0, dialyzed and characterized by DLS. DSPC:Chol – TRIS buffer ( ), DSPC:Chol – citrate buffer ( ), DSPC:Chol:DOTAP – TRIS buffer ( ), DSPC:Chol:DOTAP – Citrate buffer ( ). Results are represented as mean ± SD of three independent experiments.
Figure 5. In vitro liposome uptake in bone marrow-derived macrophages. A) Percentage of liposome+ or Dil-C18+ cells (surface-bonded or internalized). B) Relative liposome surface area (SAr). C) Relative number of liposomes (Nr). D) Relative liposome internal volume (Vr). Small DOPE:DOTAP ( ), small DOPE:DDA ( ), large DOPE:DOTAP ( ), large DOPE:DDA ( ). E) Representative flow cytometry plots of liposome uptake at 1, 4 and 24 hours (black) with respect to control cells at time zero (shaded grey). Results are represented as mean ± SD of three independent experiments. Statistical analysis was performed by one-way ANOVA followed by Turkey test. P<0.05 (*), ns (non-significant).
Figure 6. In vivo biodistribution of small ( ) and large ( ) DOPE:DOTAP (A – C) and DOPE:DDA (D – E) cationic liposomes in CD1 mice upon intramuscular injection. The percentage of injected dose (%ID) was analysed at the injection site (A, D), popliteal lymph node (B, E) and inguinal lymph node (C, F). Results are represented as mean ± SD of 4 ± 1 mice. G) AUC for each of the sites considered.