Multifunctional Mesoporous Silica Nanoparticles with Thermal-Responsive Gatekeeper for NIR Light-Triggered Chemo/Photothermal-Therapy.

In this work, a matrix metalloproteinase (MMP)-triggered tumor targeted mesoporous silica nanoparticle (MSN) is designed to realize near-infrared (NIR) photothermal-responsive drug release and combined chemo/photothermal tumor therapy. Indocyanine green (ICG) and doxorubicin (DOX) are both loaded in the MSN modified with thermal-cleavable gatekeeper (Azo-CD), which can be decapped by ICG-generated hyperthermia under NIR illumination. A peptidic sequence containing a short PEG chain, matrix metalloproteinase (MMP) substrate (PLGVR) and tumor cell targeting motif (RGD) are further decorated on the MSN via a host-guest interaction. The PEG chain can protect the MSN during the circulation and be cleaved off in the tumor tissues with overexpressed MMP, and then the RGD motif is switched on to target tumor cells. After the tumor-triggered targeting process, the NIR irradiation guided by ICG fluorescence can trigger cytosol drug release and realize combined chemo/photothermal therapy.