Hollow Carbon Nanospheres with Tunable Hierarchical Pores for Drug, Gene, and Photothermal Synergistic Treatment.

Design and synthesis of porous and hollow carbon spheres have attracted considerable interest in the past decade due to their superior physicochemical properties and widespread applications. However, it is still a big challenge to achieve controllable synthesis of hollow carbon nanospheres with center-radial large mesopores in the shells and inner surface roughness. Herein, porous hollow carbon nanospheres (PHCNs) are successfully synthesized with tunable center-radial mesopore channels in the shells and crater-like inner surfaces by employing dendrimer-like mesoporous silica nanospheres (DMSNs) as hard templates. Compared with conventional mesoporous nanospheres, DMSN templates not only result in the formation of center-radial large mesopores in the shells, but also produce a crater-like inner surface. PHCNs can be tuned from open center-radial mesoporous shells to relatively closed microporous shells. After functionalization with polyethyleneimine (PEI) and poly(ethylene glycol) (PEG), PHCNs not only have negligible cytotoxicity, excellent photothermal property, and high coloading capacity of 482 µg of doxorubicin and 44 µg of siRNA per mg, but can also efficiently deliver these substances into cells, thus displaying enhanced cancer cell killing capacity by triple-combination therapy.