Hiring Institution
Aix Marseille Université (AMU)

PhD-Awarding Institutions
Aix Marseille Université (AMU)
RMIT University (RMIT)

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Option 1

Mechanical antibiotics and anti-viral nanomaterials synthesized by laser-ablative methods

It was established only recently that smaller nanoparticles and nanostructures are increasingly deadly for bacteria (1-3 micrometers) and virus (~0.1 micrometer). However, the mechanism of the biocidal action (hence antibiotic), spanning more than one order of magnitude in size of nano-“killer” objects, needs a further refinement. We will test the existing perception/hypothesis that nano-particles could be bio-toxic and that nano-textured surfaces can perform better as biocidal agents. Nano-surfaces are perceived as surfaced-fixed nanoparticles. Validity of this statement will be scrutinised in this Project and practical guiding principles will be established for the use of nano-materials (particles and surfaces). By using nano-coatings on substrates, a controlled laser melting/ablation will be creating different chemical composition of nano-textured surfaces which will be closely matching or identical to the chemical composition of nanoparticels made by ablation in solution. Fractal aspect of nano-textures ranging 0.1 – 10 micrometers in size will be created on laser ablated surfaces with chemical composition corresponding to that of nanoparticles. Plasma deposition as well as atomic layer deposition (ALD) will be used for coatings over laser treated surfaces (accessible via collaboration in Melbourne).

This Project combines experts in nanoparticle fabrication using laser ablation in solution (Andrei Kabashin, Aix-Marseille University) and assessment of their biocidal activity and biocompatability (Elena Ivanova, RMIT).

A. Kabashin’s team (France) are specialists in the development of non-chemical laser-ablative routes for the synthesis of ultrapure colloidal nanomaterials, namely the pioneers of methods based on ultrashort laser ablation in liquid ambient. These methods are now considered as the most efficient among laser-ablative pathways to finely control size and physico-chemical characteristics of formed nanomaterials. In contrast to conventional chemical routes, laser ablation unique in providing essentially non-equilibrium conditions for nanostructure growth, which makes possible the synthesis of nanoformulation of virtually any material or the combination of seemingly unimaginable materials in one nanoformulation (e.g., plasmonic-semiconductor, plasmonic-magnetic, etc.). In addition, the synthesis can be performed in ultrapure environment (e.g., deionized water), which excludes any contamination of formed nanomaterials. This technique was advantageous for the synthesis of a variety of nanomaterials (TiN, ZrN, MoS2, WS2, Bi, B, etc.), which look extremely promising for biomedical tasks (photothermal therapy, nuclear medicine, bioimaging). Biocidal and bio-toxicity of this new class of materials will be examined by E. Ivanova, RMIT.

It was originally discovered (E. Ivanova, RMIT) that some insects, possess high aspect ratio nanoscale pillars on the waxy epicuticular layer of their wing membranes that exhibit bactericidal activity. This phenomenon was first observed on the wings of cicadas, which contain regular arrays of vertical nanopillars. The irregular pattern of longer nanopillars present on the wings of dragonflies demonstrated improved bactericidal activity against a wider array of bacterial cell morphologies, indicating such nanofeatures can be optimised for improved performance. Synthetic analogues with similar high aspect ratio nanoscale features were created, most notably titanium and black silicon (S. Joudkazis, SUT, E. Ivanova, RMIT). These nanostructured surfaces lyse bacterial cells through a mechanical rupture process. As cells come into contact with the high aspect ratio surface nanofeatures, they strongly adsorb, which causes the cell membrane to stretch between adjacent features, eventually resulting in rupture of the membrane and cell lysis. This provides a novel solution to the issue of bacterial colonization, as a biomimetic template for the design of synthetic antibacterial surfaces.

This PhD project will combine expertise of French partner in the synthesis of new functional nanomaterials and their deposition on surfaces (including nanostructured surfaces prepared by the Australian partners), and further assessment of biocidal action of such nanostructures by the Australian partners.

The project will have access to laser-ablative facilities of Aix-Marseille University and nanofabrication facilities at Swinburne Univ. Technol. and Melbourne Center of Nanofabrication (MCN) at Australian National Fabrication Facility (ANFF), and advanced electron microscopy (free of charge access), materials characterisation and PC2 facilities at RMIT. Technical expertise of S. Juodkazis (SUT) will be available for nanofabrication and optical/structural characterisation of the nanotextured surfaces and nanoparticles. Capability to produce nanoparticles by femtosecond laser ablation in solution at Swinburne is readily available and can be accessed by French team. In addition, during our first discussions, an Australian company Quoba Systems (https://quobasystems.com.au/) expressed their interest in this PhD project for a potential commercialization of results.”

Option 2

Magnetic control of biocidal properties using laser-synthesized nanomaterials

It was established only recently that smaller nanoparticles and nanostructures are increasingly deadly for bacteria (1-3 micrometers) and virus (~0.1 micrometer). However, the mechanism of the biocidal action (hence antibiotic) spanning more than one order of magnitude in size of nano-“killer” objects needs a further refinement. Magnetic field applied during laser ablation for nanoparticle generation or nanotexturing of surfaces has profound effects on morphology and composition as established by supervisor teams. When ultra-short laser pulses are used, highly energetic electrons leave the laser exposed region with ions lagging behind. Depending on the orientation of magnetic B – field, the ion and electron currents spins in opposite directions and different radius. Effects of surface morphology used for biocidal actions will be tested as well as nanoparticles produced with and without magnetic fields. Current results hint that B-field results in smaller nanoparticles as well as sharper nanotextures. This hypothesis will be tested in this Project. Trapping of magnetic nanoparticles on nanotextured surfaces (magnetic and non-magnetic) using external magnet are expected to control initial adhesion and biofouling of surfaces, which is currently not resolved issue to stop bacterial colonisation. Magnetic control of nanoparticles will be relevant across several biomedical imaging techniques. Application potential: anti-biofouling of large scale surfaces used underwater.
This Project combines expertise in the fabrication of nanomaterials, including magnetic nanostructures (Fe3O4, Fe3O4-Au core-satellites, etc.) using laser ablation in liquid ambient (Andrei Kabashin, Aix-Marseille University), fabrication of laser treated surfaces and their further coating by magnetic materials (RMIT in collaboration in Melbourne), and evaluation of their biocidal activity and biocompatibility (Elena Ivanova, RMIT). Plasma deposition as well as atomic layer deposition (ALD) will be used for coatings over laser treated surfaces (accessible via collaboration in Melbourne).

A. Kabashin’s team (France) are specialists in the development of non-chemical laser-ablative routes for the synthesis of ultrapure colloidal nanomaterials, namely the pioneers of methods based on ultrashort laser ablation in liquid ambient. These methods are now considered as the most efficient among laser-ablative pathways to finely control size and physico-chemical characteristics of formed nanomaterials. In contrast to conventional chemical routes, laser ablation unique in providing essentially non-equilibrium conditions for nanostructure growth, which makes possible the synthesis of nanoformulation of virtually any material or the combination of seemingly unimaginable materials in one nanoformulation (e.g., plasmonic-semiconductor, plasmonic-magnetic, etc.). In addition, the synthesis can be performed in ultrapure environment (e.g., deionized water), which excludes any contamination of formed nanomaterials. This technique was advantageous for the synthesis of a variety of nanomaterials, including magnetic ones (nanoparticles of Fe, Co Ni and composites such as Si-Fe, Fe-Au nanostructures). Biocidal and bio-toxicity of these new class of material will be examined by E. Ivanova, RMIT.

The project will have access to nanofabrication facilities at Swinburne Univ. Technol. and Melbourne Center of Nanofabrication (MCN) at Australian National Fabrication Facility (ANFF), advanced electron microscopy (free of charge access), materials characterisation and PC2 facilities at RMIT. Technical expertise of S. Juodkazis (Swinburne) will be available for fabrication and optical/structural characterisation of the nanotextured surfaces and nanoparticles. Capability to produce nanoparticles by femtosecond laser ablation in solution at Swinburne is readily available and can be accessed by French team. In addition, during our first discussions, an Australian company Quoba Systems (https://quobasystems.com.au/) expressed their interest in this PhD project for a potential commercialization of results.

Option 3

Chirality as tool to control biocidal nanomaterials/textures

It was established only recently that smaller nanoparticles and nanostructures are increasingly deadly for bacteria (1-3 micrometers) and virus (~0.1 micrometer). However, the mechanism of the biocidal action (hence antibiotic) spanning more than one order of magnitude in size of nano-“killer” objects needs a further refinement. Many important biomolecules could occur as enantiomers, including amino acids and sugars. We will use chirality of optical field (circular polarisation) to produce nanoparticels and nanotextures on surfaces by ablation for test of biocidal activity, Chirality control in Raman scattering/spectroscopy has become an established field revealing importance of usually overlooked effects of chirality and symmetry breaking, By use of ultra-short laser pulses, highly non-equilibrium formation of nanomaterials and nanotextures is taking place and bears signatures of energy deposition, which has strong chiral effect. Nanoparticles and nanotextured surfaces will be produced with chiral and non-chiral (linear polarisation) laser pulses and will be tested for their optical activity for chiral sensors as well as biocidal activity. This is largely unexplored domain of control in nanomaterials, which already shows strong application potential in sensors. Chirality can be engineered also by non-symmetric material deposition over non-chiral textures. This approach to produce chirally active nano-surfaces for biocidal functionality will be explored in this project.

Andreï Kabashin
Elena Ivanova

Chemistry and Physics of nanoparticles, Biocidal properties of nanomaterials