A graphene oxide-based sequential nanocatalyst for efficient tumor combination therapy

Graphene oxide (GO) is a versatile and promising nanomaterial, and it can mimic peroxidase-like activity to generate hydroxyl radicals to kill tumor cells. However, the low biocompatibility and catalytic efficiency limit its application in tumor treatment. Here, we constructed a sequential catalytic nanocatalyst based on GO to overcome its drawbacks and improve the therapeutic effect. GO nanosheets were coated onto periodic mesoporous organosilica (PMOs) and then glucose oxidase (GOD) was modified on the surface to create PMO@GO-GOD. The GO-wrapping of the PMOs could reduce the damage of the two-dimensional GO nanosheets in the cell membrane. The loaded GOD decomposed glucose into H2O2 to continually supply the catalytic substrate for GO and thus enhanced its catalytic performance. Meanwhile, effective photothermal therapy could be achieved by GO shells. The administration of PMO@GO-GOD resulted in a remarkable antitumor effect with no obvious systemic toxicity.