This work presents a new process assisted by supercritical fluids (SAILA: Supercritical Assisted Injection in Liquid antisolvent) that can be used for the production of nanoparticles in stable suspensions. This process is based on direct injection of liquid foam (LE), where the compound is dissolved in a liquid anti-solvent. In particular, polycaprolactone (PCL) and β-carotene (β-C) were used as model compounds. Moreover, after the presentation of the results of preliminary feasibility tests, a first attempt of interpretation of the mechanisms involved in the formation of nanoparticles is carried out. The authors highlight that SAILA process is able to successfully produce stable suspensions of PCL and β-C nanoparticles. In particular, it has been observed that the surface tension of LE significantly influences the particles’ sizes. This tension depends on temperature: when this parameter increases, smaller particles are obtained. The reduction of surface tension of LE, then, improves mixing between solvent and non-solvent resulting in downsizing. Finally, SEM images show that particles are irregular-spherical: this suggests that the formation of nanoparticles is started by an almost instant nanomixing, followed by nucleation and growth of nanoparticles.
R. Campardelli et al., GRICU 2012 Conference, Montesilvano (PE), 16-19 September 2012, p. 37-40