Self-Assembly in Lipidic Particles - Self-Assembled Supramolecular Architectures: Lyotropic Liquid Crystals - page 149

liposomes-cubosomes transition in the ME-based aqueous dispersion (Fig.
5.17b). We found that the direct L α - V 2 transition in the dispersion does not
reveal the same mechanism as that of its fully hydrated bulk system. The
obtained results suggest that the polymeric stabilizer F127 especially plays a
signifi cant role in the membrane fusion processes. It incorporates in consider-
able amount into the internal nanostructure and leads to the formation of a
highly swollen Im3m phase.

5.8 FOOD-GRADE ISA SOMES

For the formation of food-grade ISAsomes, it is important to ensure that all
components meet the requirements of the food industry. It was, therefore,
important to replace the solubilized oil (TC) by food-grade oils such as tri-
glycerides and to stabilize the aqueous dispersions by emulsifi ers acceptable
in the food industry. We were thus able to form various food-grade ISAsomes
that were stabilized by different food-grade surfactants in which TC was
replaced by triglycerides such as triolein, or an essential oil [R( + ) - limonene],

and other hydrophobic food-active materials (data not shown).

5.9 SUMMARY

This chapter has discussed ISAsomes, which are unique emulsion droplets
consisting of well-defi ned interiors with hierarchical nanostructures, and has
also focused on how these systems were infl uenced when the temperature and
the solubilizing hydrophobic component were varied and their lipid composi-
tion controlled. We have presented fi ndings proving that the formation of
these soft nanoparticulate systems was driven simply by the principles of self-
assembly. In general, the following major conclusions could be drawn from our
investigations:

1 . Formation of MLO-Based ELPs and EMEs . We showed that the for-
mation of stable ELPs (oil-free dispersions) at high temperatures as well as
EMEs (oil-loaded dispersions) at room temperature was possible by tuning
the curvature of the inner particle nanostructures. This could be done by
varying the temperature and/or altering the system's composition (Fig. 5.9).
For more information on the formation and the characterization of other
nanostructured aqueous dispersions, the interested reader is directed to two
recent reviews on this topic (Boyd et al., 2009; Yaghmur & Glatter, 2009).
2 . Dispersions with Internal Reversible Nanostructures . The confi ned
nanostructures in the emulsifi ed particles are reversible structures, that is, they
exist in thermodynamic equilibrium with the surrounding aqueous phase, and
they depend only on the actual temperature and oil content. At each investi-
gated composition and temperature, the MLO-based internal structure was