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Physical Chemistry

Hybrid nanozymes with synergetic catalytic activity as antimicrobial agents

Faizan Zarreen Simnani
EC Lyon and RMIT

Research Areas

Chemistry, Biochemistry, Nanotechnologies

Project Brief

Nanozymes are nanoparticles with catalytic properties that can mimic the behaviour of natural enzymes [Walther 2018]. Reactive oxygen species (ROS) can be generated by different nanozymes. These ROS can be used for photodynamic therapy as they can trigger the death of pathogens such as bacteria or cancer cells [Maddheshiya 2022]. The reactive surface of metal nanoparticles associated to their large specific surface area make them interesting candidates for these therapeutic applications [Liu 2021]. In addition, iron oxide nanoparticles can be also considered as nanozymes [Gao 2007], as well as hyperthermic agent. Furthermore, they can be actuated with an external magnetic field.

The objectives of the thesis will be to design new nanoparticles composed of an iron oxide core and a metal seeds shell and to use them for the capture and elimination of bacteria from complex media. We recently demonstrated that the resulting vicinity of the two nanomaterials (noble metal seeds/oxide nanoparticles) in the nanozymes give rise to new catalytic activities or synergies by mimicking the colocalization of enzymatic activities as cells do [Pablo-Sainz-Ezquerra 2023]. To capture bacteria and amplify the antimicrobial effect, peptides such as magainin, will be immobilized onto nanoparticles surface.

The PhD student will work in a first step on the chemical modification of iron oxide nanoparticles surfaces to graft noble metal nanocatalyzers. The structural and surface properties of nanoparticles will be characterized at INL by Transmission Electron Microscopy (TEM), zetammetry, infrared spectroscopy and photoelectron spectroscopy. Then, the catalytic activity of nanozymes will be evaluated through the oxidation of a coloured substrate (TMB) or a fluorescent substrate. Finally, the candidate will study the antimicrobial activity of nanozymes at RMIT Melbourne. Two non-academic partners based in France will be involved in this project. The first is Beaujon Hospital (AP-HP, Paris) and in particular the Endoscopy service. Indeed, one application that will be investigated in this project will be the design of antibacterial surfaces for endoscopes using nanozymes. The second is SON SAS, a company specialized in the conception and production of metal-modified iron oxide nanoparticles.

[Gao 2007] L. Gao et al, Nature Nanotech., 2007, 2, 577.
[Liu 2021] Q. Liu et al, Nano Micro Lett., 2021, 13, 154.
[Maddheshiya 2022] S. Maddheshiya et al, Frontiers in Bioeng. Biotechnol. 2022, 10, 880214.
[Pablo-Sainz-Ezquerra 2023] A. M. Pablo-Sainz-Ezquerra et al, ACS Appl. Nano Mater., 2023, 6, 13166.
[Walther 2018] R. Walther et al, Angew. Chem. Int. Ed. 2018, 57, 1.