In Situ Synthesis of a Mesoporous MIL-100(Fe) Bacteria Exoskeleton

The mesoporous iron polycarboxylate MIL-100(Fe) was synthesized in the presence of Pseudomonas putida bacteria. The synthesis was performed under green conditions, i.e., pure aqueous media at 30 °C that were compatible with the preservation of the cell membrane integrity. Interestingly, the resulting biohybrid exhibited a very different microstructure than a physical mixture of the two components, as it led to the formation of a novel living material featuring an exoskeleton encapsulating individual bacteria cell. Remarkably, TEM and STEM observations on cross sections revealed that this shell was not directly in contact with the cell wall, suggesting the exopolysaccharides network promotes strong interactions with the MOF precursors, leading to high proximity between the two components.