Simply and effectively control the shell thickness of hollow mesoporous silica nanoparticles by polyethylene glycol for drug delivery applications

This study reports for the first time the usage of polyethylene glycol (PEG) as the capping agent to control mesoporous shell thickness of hollow mesoporous silica nanoparticles (HMSN)-a promising nanocarrier. HMSN was synthesized with hard template method and PEG with different molecular weights and concentrations would be added at the mesoporous coating. The samples dSiO(2)@MSN synthesized with and without PEG were analyzed DLS, field-emission scanning electron microscopy, Brunauer-Emmett-Teller and Barrett-Joyner-Halenda to characterize their mesoporous shells. Meanwhile transmission electron microscope, Zeta potential, energy dispersive X-ray spectroscopy, Fourier-transform infrared, loading capacity, release profile and cytotoxicity analysis was conducted to characterize HSMNs. As PEG's molecular weight or concentration increased, the mesoporous shell thickness gradually raised. Particles synthesized in the presence of 2% PEG 6000 retained the monodispersed spherical morphology with a particle diameter of 95.40 nm and a mesoporous shell thickness of 14.40 nm, which was about 7.0 nm thicker. dSiO(2)@MSN-P owned equal mesopore diameter and higher surface area compared to dSiO(2)@MSN-0. HMSN-P showed similar loading capacity but better sustained release profile than HMSN-0. Moreover, both HMSN-0 and HMSN-P performed as biocompatible materials. This study would contribute a simple and effective method to control the shell thickness of HMSN with PEG for drug delivery applications.