Cytotoxicity and pro-apoptosis evaluation. Cytotoxicity of CuSO4, H-CuSO4, HKUST-1 NPs and H-HKUST-1 to (A) HEKa and (B) HDF cells. (n = 3, ***P < 0.001). C) Cytotoxicity of PPCN to HEKa and HDF cells. D) Cell apoptosis of (a) HEKa cells and (b) HDF cells after treatment with PPCN, CuSO4, H-CuSO4, HKUST-1 NPs or H-HKUST-1 with a copper concentration of 0.5 mM where applicable.