Gold Biomineralization on Bacterial Biofilms for Leaching of Au3+ Damages Eukaryotic Cells

Heavy metals not only pollute the environment but also are health and environmental hazard. Bacteria constitute inexpensive and eco-friendly material to eliminate and recycle heavy metals via biomineralization and bio-sorption. However, the effect of metal biomineralization in bacterial biofilms on the ecological balance of bacteria and infectious diseases is unclear. This study aimed to explore the interaction between a eukaryotic cell line HEK293T and mineralized Escherichia coli, using a model of gold biomineralization on E. coli biofilms (E. coli-Au). In our present model, bacterial activity was not disrupted and bacterial adhesion and invasion were enhanced. E. coli-Au invaded the cytoplasm and nuclei of HEK293T cells and damaged them via intracellular growth and multiplication. The present findings indicate that metal biomineralization in bacterial biofilms for leaching of heavy metal ions is hazardous to eukaryotic cells and even human health.