Here, the biodegradability of 2D Au nanosheets (AuNS) by enzymatic catalysis of human myeloperoxidase (hMPO) using a test-tube model and an in vitro model with MPO-secreting neutrophil-like cells (present in the blood) differentiated from human leukemia (HL-60) cells has been reported. This evidence concerns the gene MPO and leukemia.