Hybrid biphasic microparticles based on polyhedral oligomeric silsesquioxanes

Biphasic eggshell-like microparticles based on poly(ε-caprolactone) (PCL)/octaisobutyl polyhedral oligomeric silsesquioxanes (octa-iBuPOSS) hybrid blends were prepared by controlling the phase separation process during single spinneret electrospraying. The biphasic eggshell-like microparticles contained a PCL-rich shell and a very hydrophobic octa-iBuPOSS-rich inner phase, which cannot be achieved otherwise. The study of octa-iBuPOSS-based model system demonstrates that the electrospraying can be employed to fabricate biphasic particles through manipulating the phase separation process. The facile fabrication of the eggshell-like particles reported here provided valuable insight into not only the controlled release of very hydrophobic drugs but also the surface coating of medical devices where hydrophobic molecules are necessary but required to be encapsulated inside biocompatible materials.