MMP2 and glioma: To further elucidate the specificity and capabilityof NIR-I and-II photothermal tumor cell ablation by MMP-activated GNDs@gelatin,MMP-2 overexpressed C6 glioma cells and MMP-2 low expressed A549 cellswere incubated with 100 μg·mL–1 of GNDs@gelatinfor 24 h.