Cellular Compatibility of Biomineralized ZnO Nanoparticles Based on Prokaryotic and Eukaryotic Systems

Zinc oxide nanoparticles (NPs) with the size of ∼100 nm were prepared via a facile biomineralization process in the template of silk fibroin (SF) peptide at room temperature. These ZnO NPs have shown the remarkable behavior of low toxicity to Gram-positive bacteria (Staphylococcus aureus, Staphylococcus agalactiae), Gram-negative bacteria (Escherichia coli), and eukaryotic cells (mouse L929 fibroblasts). Bacteriological testing indicated that ZnO NPs presented a 50% inhibitory effect on Streptococcus agalactiae at the concentrations of >100 mM, whereas at the same concentrations, the growth of Staphylococcus aureus and Escherichia coli were hardly inhibited. On the other hand, a remarkable proliferation of Staphylococcus aureus or Escherichia coli was observed at the concentrations of ZnO NPs