E. coli cells as a source of biohybrid material: electron microscopy and microanalysis study

Objectives: The work relates to the research of E.coli cells formed under conditions of superproduction of the bacterioferritin protein Dps. These protein molecules are capable of forming biohybrid structures by accumulating inorganic nanoparticles of the iron-oxygen system with identical properties, including sizes within the nanometer range, in their internal cavities. Current methods of obtaining bacterioferritin Dps protein molecules rely on destroying their source: E.coli cells. A key issue for study and subsequent application is establishing whether it is possible to obtain these protein molecules without destroying E.coli cells in order to form biohybrid structures. Experimental: E.coli cells were grown under conditions of superproduction of bacterioferritin Dps protein molecules, then deposited on a molybdenum foil substrate for electron microscopy and energy-dispersive microanalysis studies. Based on the resulting data on morphology data and elemental composition, the possibility of forming protein molecules without destroying the cells was investigated in order to create biohybrid structures based on them. Conclusions: It has been established that under conditions of protein superproduction, E.coli cells produce bacterioferritin Dps molecules, with a significant amount of this protein possibly being released into the extracellular space. The morphology of E.coli cells themselves does not change under conditions of superproduction and protein emission. When Mohr’s salt was added to the culture fluid, the released protein contains a significant amount of iron atoms, which may result from bacterioferritin Dps molecules forming biohybrid structures. These results demonstrate a simple, affordable method of forming biohybrid structures containing iron-oxygen nanoparticles for use in technologies, including the targeted delivery of nanoparticles and the functionalization of accessible surfaces.