Design of magnetic akaganeite-cyanobacteria hybrid biofilms

Common Anabaena cyanobacteria are shown to form intra-cellularly akaganeite β-FeOOH nanorods of well-controlled size and unusual morphology at room temperature. High-resolution transmission electron microscopy showed that these nanorods present a complex arrangement of pores forming a spongelike structure. These hybrid akaganeite-cyanobacteria were used to form “one-pot” hybrid biofilms. The hybrid biofilm presents higher coercivity (Hc = 44.6 kA m− 1 (560 Oe)) when compared to lyophilized akaganeite-cyanobacteria powder (Hc = 0.8 kA m− 1 (10 Oe)) due to the quasi-assembly of the cells on the glass substrate compared to the lyophilized randomly akaganeite-cyanobacteria powder.