Figure 4. Cell damage was evaluated by cell proliferation assay and electron microscope observation. (A) CD34+ HSC/HPCs were treated with 10 μM SeMet for 15 h or 200 μM CoNPs for 24 h. Alternatively, CD34+ HSC/HPCs were treated with 10 μM SeMet for 15 h before additional treatment with 200 μM CoNPs for 24 h. Edu staining was performed immediately after these treatments were finished. In addition, after these treatments were finished, cells were culture in fresh medium for 24 h before Edu staining. (B) CD34+ HSC/HPCs were treated with 10 μM SeMet and 200 μM CoNPs, alone or in combination, followed by electron microscope observation. *p < 0.05, **p < 0.01, and ***p < 0.001 vs. control cells that did no subjected to any treatments.