A dual surfactant synthetic approach was employed for the synthesis of large-pore mesoporous silica nanoparticles (MSNs). The as-synthesized mesoporous silica exhibited not only 2D hexagonal mesostructure with an average pore size of about 7nm but also a spherical nanoparticulate morphology. A delayed co-condensation synthesis method was further employed to create site-specific core-shell bifunctional MSNs. These core-shell large-pore MSNs are biocompatible and can be efficiently taken up by cells. They are therefore promising nanocarriers for cellular delivery purposes.