NIR-responsive sandwich drug loading system for tumor targeting and multiple combined treatment
A novel drug loading system, Au@Si–NN–Si@SiO2, is constructed by a layer-by-layer assembly approach. The core Au nanorods serve as the matrix for a near-infrared light (NIR) responsive photothermal feature. Meanwhile, the assembly's middle shell is composed of azobenzene linked silica, which produces free radicals by breaking –NN– bonds at a high temperature brought about by a NIR irradiation-caused photothermal effect, which further triggers the loaded drug release. The outer shell is formed of SiO2 in order to prevent leakage of drug in the middle layer. The fully drug loaded nanocarriers, Au@Si–NN–Si@SiO2-Dox, exhibit an excellent photothermal effect (43%) at a concentration of 170 μg mL−1 under 808 nm NIR laser at 2.3 W cm−2. The antitumor performance of Au@Si–NN–Si@SiO2-Dox was investigated using human colon cancer cells (HCT116) as a model. By combining NIR-triggered drug release, free radical generation and the photothermal effect, the proposed Au@Si–NN–Si@SiO2-Dox exhibits improved antitumor efficiency. By using a dosage of 170 μg mL−1, a cell viability of 17.56% is achieved for HCT116 (5 × 103–1 × 104 cells per well) with 10 min of NIR laser irradiation (808 nm, 2.3 W cm−2). All the results demonstrate that Au@Si–NN–Si@SiO2-Dox exhibits wonderful dosage-dependent antitumor performance and has great potential as a therapeutic agent for tumors or even for use in the clinic.
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