"PhD Defense: Ferritin-based Hybrid Nanocomposites for Enzyme-mimetic Catalytic Activity"

Who: Unai Carmona, Nanomaterials Group

Place: CFM Auditorium

Date: Wednesday, 13 September 2017, 11:00

In this thesis natural and synthetic hybrid ferritin are studied from three different perspectives:
(I) The catalytic activity of platinum nanoparticle-apoferritin nanocomposites is characterized focusing on the catalase and superoxide dismutase enzyme mimetic activities. The possibility of tuning the activities with a variety of inhibitors was studied. The interaction between the gold nanoparticles encapsulated within apoferritin with no catalase activity and mercury ions is also characterized. Owing to this interaction, the activation on catalytic activity was observed. Subsequently, a mechanism for the catalytic reaction is proposed. In addition, (II) the bioinorganic ferroxidase activity of encapsulated platinum nanoparticles specifically within a homopolymeric L-chain apoferritin is studied. The resulting hybrid nanoparticle gains ferroxidase activity and becomes able to mineralize iron in a similar way natural ferritin does. Furthermore, (III) a new intrinsic property of ferritin L-chain is identified and characterized. By separating the redox reaction of iron oxidation and reduction of Cytochrome C (Cyt-c) ferritin protein shell, it was identified that only the L-chain allows for an efficient reduction of Cyt-c and in consequence conduction of electrons. Finally, the demineralization of the ferritin mineral induced by illumination with light with various wavelengths is characterized. With iron being essential for the cellular metabolism, the demineralization effect in cell cultures once those are exposed to blue light was explained. These new findings are considered of importance for future investigation of biochemical processes happening in nature that involve ferritin.

Supervisor: Mato Knez

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