Tecnai g2 20 fei supertwin 200 kv

The mean hydrodynamic diameter, polydispersity index (PI) and zeta potential of the resulting liposome formulations were determined at 25 °C by dynamic light scattering (DLS) using a particle size analyzer (Zetasizer S90, Malvern, UK). The suspension was diluted 100 times in either 5% dextrose solution for particle size measurements or PBS (0.15 M NaCl, phosphate 10 mM, pH 7.2) for zeta potential measurements.
Liposome morphology was evaluated via cryogenic-transmission electron microscopy (Cryo-TEM). TEM samples were prepared on a carbon film-coated grid to which 1% sodium phosphotungstate was added for negative staining before images were obtained. Cryo-TEM specimens were prepared in the controlled environment vitrification system at 25 °C and ~100% relative humidity. Vitrified samples were examined with a Tecnai G2-20—FEI SuperTwin 200 kV at the Center of Microscopy at UFMG.

pDNA nanoparticles were characterized by hydrodynamic diameter (HD), polydispersity index (PDI), and zeta potential using a Zetasizer Nano ZS machine (DLS, Malvern Panalytical). For analysis of LNP structure using cryogenic transmission electron microscopy (cryo-TEM), LNP samples were prepared in a vitrification system (25 °C, ~100% humidity). Vitrified samples were examined using Tecnai G2-20 - FEI SuperTwin 200 kV at the Microscopy Center of UFMG. pDNA concentration in LNPs for in vitro and in vivo use was quantified using a NanoDrop Spectrophotometer (ThermoFisher), and Qubit™ 1× dsDNA HS Assay Kit (ThermoFisher, no. Q33230) in Qubit equipment (ThermoFisher) according to manufacturer’s instructions.