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Updated: Mar 28, 2026

Synthesis of Cationized Magnetoferritin for Ultra-fast Magnetization of Cells
Published on: December 13, 2016
On the mineral core of ferritin-like proteins: structural and magnetic characterization
A García-Prieto1, J Alonso2, D Muñoz3
1Dpto. de Física Aplicada I, Universidad del País Vasco - UPV/EHU, 48013 Bilbao, Spain and BCMaterials, Parque tecnológico de Zamudio, 48160 Derio, Spain. malu.gubieda@ehu.eus.
Abstract:
It is generally accepted that the mineral core synthesized by ferritin-like proteins consists of a ferric oxy-hydroxide mineral similar to ferrihydrite in the case of horse spleen ferritin (HoSF) and an oxy-hydroxide-phosphate phase in plant and prokaryotic ferritins. The structure reflects a dynamic process of deposition and dissolution, influenced by different biological, chemical and physical variables. In this work we shed light on this matter by combining a structural (High Resolution Transmission Electron Microscopy (HRTEM) and Fe K-edge X-ray Absorption Spectroscopy (XAS)) and a magnetic study of the mineral core biomineralized by horse spleen ferritin (HoSF) and three prokaryotic ferritin-like proteins: bacterial ferritin (FtnA) and bacterioferritin (Bfr) from Escherichia coli and archaeal ferritin (PfFtn) from Pyrococcus furiosus. The prokaryotic ferritin-like proteins have been studied under native conditions and inside the cells for the sake of preserving their natural attributes. They share with HoSF a nanocrystalline structure rather than an amorphous one as has been frequently reported. However, the presence of phosphorus changes drastically the short-range order and magnetic response of the prokaryotic cores with respect to HoSF. The superparamagnetism observed in HoSF is absent in the prokaryotic proteins, which show a pure atomic-like paramagnetic behaviour attributed to phosphorus breaking the Fe-Fe exchange interaction.
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