Preparation of Triple‐Responsive Porous Silica Carriers and Carbon Quantum Dots for Photodynamic‐/Chemotherapy and Multicolor Cell Imaging

Abstract Photosensitive carbon quantum dots (CQDs) provide a new route to treat cancer owing to their ability to produce singlet oxygen. In this paper, pH/redox/enzyme‐responsive porous silica‐based carriers with CQDs were constructed for photodynamic‐chemical combination therapy. The porous silica (pSiO₂) sample comprises uniform spheres with center‐radial channels, which is favorable for drug loading and delivery. CQDs with a size of 2.5 nm were synthesized and have the excellent ability to generate singlet oxygen. After loading CQDs and drug molecules, the channels of pSiO₂ carrier were blocked with hyaluronic acid (HA)/chitosan (CHI) layer. The disulfide bonds, conjugating HA to the surface of pSiO₂ carrier, would achieve redox‐responsive drug release, while breaking disulfide bonds and the HA/CHI layer could endow the pSiO₂ carrier enzyme/pH‐responsive drug release. The prepared pSiO₂ carriers display low cytotoxicity and good biocompatibility for multicolor imaging and photodynamic‐/chemotherapy.