Mesoporous organosilica nanoparticles with large radial pores via an assembly-reconstruction process in bi-phase.

Mesoporous organosilica nanoparticles (MONs) have attracted increasing interest for guest molecule delivery. In this work, we prepared MONs with radially oriented large pores for the first time in a water-ethanol/n-hexane biphasic reaction system. The MONs possess ethane-incorporated organosilica frameworks, large radial pores with openings of 17-78 nm, a high surface area (1219 cm2 g-1), a large pore volume (2.2 cm3 g-1), tunable diameters (124-287 nm), and excellent biocompatibility. We reveal that the formation of large pore MONs in the biphasic reaction system undergoes a surfactant-directed self-assembly following mesostructure reconstruction, providing a new mechanism for the preparation of large mesoporous nanoparticles. Also, the effects of the reaction parameters including temperature and the stirring rate on the pore size are systemically investigated. Furthermore, large pore MONs were loaded with bovine serum albumin (BSA) and small interference RNA (siRNA), which exhibit high protein loading and siRNA delivery capabilities, suggesting the potential of the MONs for biomedical applications.