(241a) Nanoencapsulation Using the Rapid Expansion of Water-in-Supercritical Carbon Dioxide Microemulsion

A novel technique for the nanoencapsulation is investigated using the rapid expansion of water-in-supercritical CO2 microemulsion in which coating material is dissolved in the supercritical CO2 phase. Lysozyme, small enzyme extracted from egg white, is dissolved by polar nano-water domains within CO2 reverse microemulsion. The aqueous cores of reverse micellar nanodroplets filled up with lysozyme is formed and dispersed in the supercritical solutions of paraffin/CO2 to form the inverse microemulsion system. Sodium bis (2-ethylhexyl) sulfosuccinate (AOT) in the presence of 2,2,3,3,4,4,5,5-octafluoro-1-pentanol (F-pentanol) is used as a stabilizer of the microemulsion system. The rapid expansion of the supercritical microemulsion into the atmosphere is carried out for an encapsulation process. The morphology of particles is examined by the SEM observation. TEM images of particles are also taken to affirm the existence of the aqueous lysozyme solution inside the polymer shell. The size of the micelles seemed to play a significant role in mechanism of encapsulation process. The results suggest that the rapid expansion of water-in-supercritical CO2 microemulsion is a promising method for encapsulation in nanoscale but the coating material should be chosen properly.