in situ SAXS study of biomimetic magnetite formation

Magnetotactic bacteria sustainably produce chains of magnetite nanoparticles with exceptional properties. Inspired by these bacteria, we developed a synthetic route emulating the bacteria’s proteins with charged polymers inducing a biomineralization-reminiscent crystal formation. Using in-situ SAXS and ex-situ cryo-XANES, we elucidated the gained control via a kinetic stabilization of a transient iron phase, also observed in the bacteria. While new evidence shows that this stabilization is based on an electrostatic polymer-precursor interaction, different polymers show deviations in the final nanoparticle morphology. We accordingly propose an in situ SAXS study to monitor the formation of magnetite nanoparticles, with a primary focus on characterizing the weakly scattering, pre-nucleation iron species. This study aims to understand the effect of different polycations on the kinetic stabilization of low-density iron, particularly considering variations in polymer molecular weight.