The team of Japanese researchers fabricated memory nodes made up of biochemically synthesized ferrihydrite bionanodots (Fe-BND) in protein cavities by biomimetic layer-by-layer assembly (BioLBL) using the specific binding and mineralization function of peptide aptamer minTBP-1 attached to the exterior of nanoparticle-accommodated recombinant minT1-LF.
MinT1-LF successfully aligned to form separate layers using the wet chemical process of BioLBL. The fabricated Fe-BND array was embedded into a stacked metal oxide-semiconductor (MOS) device structure as a charge storage node.
The MOS capacitor showed memory operation, and an increase of bionanodot layer number increased the charge
storage ability of the memory device.
The authors note that, in this study, they only examined Fe@minT1-LF in MOS capacitors; however, ferritin can incorporate various kinds of nanoparticles in its cavity, not only by biomineralization but also by nanoparticle-directed assembly. "By using different nanoparticles encapsulated in minT1-LF, we can fabricate heterogeneous layers of different nanoparticles with divergent electronic properties such as band gap."
This approach can be used to develop novel types of multilayered memory devices. Moreover, applications of heterogeneous nanoparticle multilayers made by the BioLB method are not restricted to memory devices but can be applied to optoelectronics, battery cells, and so on.