Interaction of MnO and ZnO nanomaterials with biomedically important proteins and cells.

Zinc and manganese nanomaterials may have potential for biomedical nanotechnology. Here first generation Zn and Mn oxide nanomaterials were prepared as determined by XRD. Transmission electron microscopy confirmed their nanoscale in two dimensions and revealed a rod or belt-like morphology for MnO or ZnO respectively. Association of MnO and ZnO to three model biomedically important proteins (albumin, protamine and thrombin) has been characterized by ultra-violet and dynamic laser light spectroscopy, UVS and DLLS respectively. UVS demonstrated a concentration-dependent loss of protein from the supernatant upon sedimentation of MnO or ZnO. Shifts in the surface charge of the MnO or ZnO by DLLS confirmed the protein's adsorption to the surface. MnO and ZnO were incubated with live human cells in culture (HeLa, A375 or 1321N1). A marked difference was observed for the two nanomaterials behavior in cell culture where the MnO could be discerned associating at the cell surface whereas the ZnO caused the cells to exhibit a rounded up morphology. Trypan blue dye exclusion studies demonstrated cytotoxicity of the ZnO at high concentrations 62.5-31.5 microg/mL whereas surprisingly the MnO demonstrated no cytotoxicity at any of the concentrations tested.