pH-Responsive Hollow Mesoporous Silica Nanoparticles with Fludarabine for Cancer Therapy

In this work, alkylammonium-functionalized hollow mesoporous silica as a nonocarrier of drugs was synthesized to realize enhanced cancer therapy by pH stimuli for sustained drug release. First, functionalized hollow mesoporous silica nanoparticles (Hollow MSNs) were synthesized using dodecyl dimethyl(3-sulfopropyl)ammonium hydroxide (DDAPS), sodium dodecyl sulfate (SDS), and triethanolamine as structure-directing agents, while tetraethyl orthosilicate (TEOS) and N-trimethoxysilypropyl-N,N,N-trimethylammonium chloride (TMAPS) were used as silica sources under basic condition via the sol-gel process. The structure and morphology of the alkylammonium-functionalized hollow mesoporous silica nanoparticles (Hollow MSN-N⁺CH₃) were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N₂ adsorption-desorption analysis, and Fourier transform infrared (FT-IR) spectroscopy. The functionalized hollow MSNs had a particle size of about 450 nm and a shell thickness of about 60 nm with uniform size. The nanoparticle had a surface area of 408 m²g^-1, pore volume of 0.8 cm³g^-1, and a uniform pore diameter of 45.9 Å. In the cancer cell viability test with a MCF-7 cell, fludarabine-incorporated and alkylammonium-functionalized hollow mesoporous silica nanoparticles (Flu/Hollow MSN-N⁺CH₃) showed excellent cancer cell death comparable with pure fludarabine drug with the controlled drug release by pH stimuli. It is suggested that our current materials have potential applicability as pH-responsive nanocarriers in the field of cancer therapy.