Formation of nanostructured colloidosomes using electrostatic deposition of solid lipid nanoparticles onto an oil droplet interface

- Nanosized colloidosomes were created by electrostatic deposition.
- The saturation concentration (Csat) of solid lipid nanoparticles was 1.1-1.5%.
- DLVO theory was used to correlate the experimental Csat-values to theoretical ones.

This study describes the assembly of colloidosomes by adsorbing solid lipid nanoparticles (SLN) onto the interfaces of oil-in-water emulsion droplets via electrostatic deposition technique. Oil-in-water emulsions (10% w/w corn oil, 1% w/w whey protein isolate in water) and SLN (10% octadecane, 1% sodium dodecyl sulfate in water) were prepared using a microfluidizer. The surface saturation concentration (Csat) of negatively charged SLN adsorbed onto the positively charged oil-in-water emulsions (at oil droplet concentration of 0.5%) at pH 3 was investigated by measuring ζ-potential, and particle size, as well as assessing the microstructure by optical microscopy. Each of these methods depicted Csat between 1.1-1.5% (w/w). The results were explained by calculating theoretical Csat using molecular forces acting between the adsorbed droplets as described by the DLVO theory. We demonstrated that the surface saturation of SLN on emulsion droplets depends on the particle size population.