Gold-Capped Mesoporous Silica Nanoparticles as an Excellent Enzyme-Responsive Nanocarrier for Controlled Doxorubicin Delivery.

Mesoporous silica nanoparticles (MSNs) have ideal characteristics as next generation of controlled drug delivery systems. In this study, a MSN-based nanocarrier was fabricated and gold nanoparticle (GNP)-biotin conjugates were successfully grafted onto the pore outlets of the prepared MSN. This bioconjugate served as a capping agent with a peptide-cleavable linker sensitive to matrix metalloproteinases (MMPs), which are overexpressed extracellular proteolytic enzymes in cancerous tissue. The prepared nanocarriers were fully characterised by scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption/desorption, Fourier transform infra-red spectroscopy (FTIR), dynamic light scattering (DLS) and thermo gravimetric analysis (TGA). In vitro release studies showed efficient capping of MSNs with gold gate and controlled release of Doxorubicin (DOX) in the presence of matrix metalloproteinase-2 (MMP-2) and acidic pH values. High DOX-loading capacity (21%) and encapsulation efficiency (95.5%) were achieved using fluorescence technique. DOX-loaded nanocarriers showed high cytocompatibility and could efficiently induce cell death and apoptosis in the MMP-2 overexpressed cell lines. Moreover, Haemolysis, platelet activation and inflammatory responses assessment approved excellent hemocompatibility and minimal side effects by encapsulation of DOX in MSNs carrier.