Dance to the Vibrations – Motion of Active Granular Rotors

Speaker: Dr Christian Scholz –  Friedrich-Alexander University Erlangen-Nuremberg

Venue   : Thu 8 Sept 2016 – 4pm (Murdoch University, venue tba)

The majority of animal life performs active motion, i.e. organisms store energy within internal degrees of freedom and later release it in terms of directed motion. While in biological organisms this topic itself has been studied extensively, from swimming bacteria to flocks of animals, interest grew also in physical systems of inanimate objects that perform active motion. Most noticeable artificial microswimmers, but also active granular walkers.

Many studies consider translational active motion, but it has been shown that also rotational active motion leads to interesting novel effects in many-particle systems. In simulations of actively rotating spinners, a counter-intuitive separation of particles into patches of equal sense of rotation has been observed.

We use a particle design established in to experimentally create a system of 3D-printed active rotors, driven by vertical vibrations. Our experiments confirm the numerical observation of a phase separated stationary state. The evolution of the patterns from the mixed initial state can be quantified from the size of the clusters from the Voronoi triangulation or the length of the interface between patches, by counting Delaunay bonds between particles of opposite sense of rotation. The particle motion can be mapped onto a Langevin equation, which allows a direct comparison between experiment and simulation.

Centimetre- to nanometre-scale exploration of biomineral structure

Speaker: Dr Jeremy Shaw –  CMCA@Physics, University of Western Australia

Venue   : Thu 28 April 2016 – 4pm (Murdoch University, Senate Conference Room)

The iron biomineralised teeth of marine chitons are organic/inorganic composite structures that are built using hierarchically ordered components that span multiple length scales. Understanding the mechanisms governing the highly controlled bio-fabrication of these natural structures is necessary for inspiring the design of novel advanced materials. This study utilises a range of imaging techniques to journey from the level of the whole organism down to the nanoscale structural components that underpin the material properties of these remarkable structures.

Whole tooth anatomy was explored using a combination of optical microscopy and X-ray micro-computed tomography, which provide a means to digitally examine structure/function relationships at the centimetre- to micrometre-scale. The composite organic and mineral sub-structure of the teeth was observed using a combination of SEM-based serial sectioning (3-view and focused ion beam milling) and electron tomography, which reveal micrometre- to nanometre-scale detail of hierarchical components.

The teeth are shown to be comprised of a network of organic fibres that are arranged in a comparable orientation to the final mineralised product. These fibres are also shown to persist throughout the mineralisation process, but may be displaced or fragmented by the growing mineral phase. Fibres are also shown to pass through multiple mineral phases, which may impart structural and functional properties superior to the mineral in isolation. The fibre network and mineral architecture of the tooth as a whole are arranged in a manner that matches the feeding mechanics proposed for this species of chiton.

The multi-scale data generated by these various imaging modalities has revealed insights into the growth and design of these hierarchically structured biominerals. The provision of a final blueprint of the entire fibre network that underlies chiton tooth structure will facilitate the interpretation of fibre/mineral structure across a range of lengths scales in future studies.

Sex, Sperm and Society : Bee Amazed

Speaker: Prof Boris Baer – Center for Integrated Bee Research @ University of Western Australia

Venue: Thu 21 April 2016 – 3pm (Murdoch University, ECL1.031 which is below ECL2.031)

Boris Baer is the head of CIBER, the Center for integrative Bee Research at the University of Western Australia. In this talk, he will provide information about several aspects of bee sperm production and structure, including the occurrence of a curious nanostructure.

Tissue mechanics on the meso-scale: Probing mechanical contrast with optics

Speaker : Prof David D Sampson – University of Western Australia

Venue    : Thu 19 May 2016 @ 4pm (Murdoch University, ECL2.031)

The mechanics of cells and tissues is important in a variety of ways that drives major topics of research in cell biology, biophysics and medicine. Arguably, research on the cellular and sub-cellular scale and, at the other extreme, on the whole organ scale of medical imaging, is being well served by existing imaging methods. The gap in the spatial resolution spectrum between these two extremes presents an opportunity to be filled by optics, in probing length scales from the few micrometers to perhaps 10-100 times that. Such scales are relevant to probing a cell and convey the potential to study cell mechanics in situ in real tissues. They also convey the potential to resolve heterogeneous tissue structures, such as cancer, which could aid in the more effective surgical removal of tumors. Mechanical properties are important to measure in their own right, but additionally they also represent an alternative form of contrast to that of optical properties, which provides new opportunity in imaging tissues. Probing mechanics with optics is not new, but various aspects have converged recently to make possible high-contrast, high-resolution imaging of tissue mechanics. This plenary will try to tease out this story, demonstrate progress, and highlight where the field might go in the future.

Professor David D. Sampson is at the Optical+Biomedical Engineering Laboratory, School of Electrical, Electronic & Computer Engineering and at the Centre for Microscopy, Characterisation & Analysis of the  University of Western Australia.

BIOGRAPHY:

Professor David Sampson heads the Optical+Biomedical Engineering Laboratory and is Director of the Centre for Microscopy, Characterisation & Analysis at The University of Western Australia. He directs the Western Australian nodes of the Australian Microscopy & Microanalysis Research Facility and the National Imaging Facility (Australia). He is a Fellow of the Institute of Electrical and Electronics Engineers, the OSA – The Optical Society and SPIE – The International Society for Optics and Photonics. Prof. Sampson’s research interests are in the science and applications of light in medicine and biology. His research is focused on the translation of microscopy techniques to imaging in the living body – medical microscopy. He was awarded the IEEE Photonics Society’s Distinguished Lecturer Award in 2013 for the Microscope-in-a-Needle, a deep tissue imaging platform. His other interests are in optical elastography, the microscale imaging of tissue stiffness, and parametric imaging of other tissue properties, such as optical attenuation, birefringence, and speckle dynamics to detect microvasculature, with a view to creating a suite of tools to comprehensively characterise the tissue microenvironment.

Surface Area of a Football Field in a Single Gram

Speaker : Dr Piotr Kowalczyk – Murdoch University

Venue    : Thu 2 June 2016 @ 4pm (Murdoch University, ECL1.031 – 1 floor below ECL2.031)

Disordered microporous carbonaceous materials are – mostly as activated carbons – used for a wide range of technical applications such as filters for gases, i.e. as molecular sieves for air purification, catalysts supports, adsorption heat pumps or electrodes in double layer capacitors. In different applications their open microporosity (pore size less than 2.0 nm) and huge specific surface area of micropores (up to about 1000 m²/g) are important characteristics.

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Riemannian Elastic Metric for Shape Analysis

Speaker : Assoc Prof Hamid Laga – Murdoch University

Venue    : Thu 17 Mar @ 4pm (Murdoch University, ECL2.031)
In this talk, I will present our recent work on 3D modelling and analysis using elastic metrics defined on non-linear Riemannian manifolds. I will first review the basic ideas and the mathematical concepts using 2D shapes and then show how we extended these concepts to the analysis of 3D shapes. I will particularly focus on one particular representation of 3D shapes called Square Root Normal Fields (SRNF) and demonstrate its utility in solving various shape analysis problems including (1) elastic registration, (2) geodesic computation, deformation transfer, and (4) statistical analysis of 3D shapes. I will conclude by outlining the limitations of the work and discussing potential directions for future work.

Phytomimetic 4D printing

Speaker : Dr Elisabetta Matsumoto – Harvard University

Venue    : Fri 15 Apr @ 3:30pm (Murdoch University, ECL2.031)
The nascent technique of 4D printing has the potential to revolutionize manufacturing
in elds ranging from organs-on-a-chip to architecture to soft robotics.
By expanding the pallet of 3D printable materials to include the use stimuli
responsive inks, 4D printing promises precise control over patterned shape
transformations. With the goal of creating a new manufacturing technique, we
have recently introduced a biomimetic printing platform that enables the direct
control of local anisotropy into both the elastic moduli and the swelling response
of the ink.

Foam Structure and Rheology: The shape and feel of random soap froth

Nature’s amazing mazes : minimal surface forms in biology and chemistry

Controlling Diffusion in Lipid Mesophases: Implications for Protein Crystallization, Reconstitution & Biosensors Developments

Speaker : Prof Raffaele Mezzenga – ETH Zürich

Venue    : 5 May 2016 – 4pm (Murdoch University, ECL1.031 – 1 floor below ECL2.031)

Lipid-based reversed liquid crystalline mesophases, such as bicontinuous cubic, reversed hexagonal or reversed micellar cubic phases, have attracted deep interest in the last few decades due to their potential applications in the food, cosmetic and pharmaceutical arenas. Different crystallographic structures of the lipid mesophase give access to different diffusion coefficients and distinct ensued diffusion and transport modes of both hydrophilic and hydrophobic molecules. It becomes thus crucial to engineer the space group of the mesophases in a controlled way, in order to provide a rationale design for all physical mechanisms associated with molecular transport within the lipid nanostructures. In this talk I will discuss our recent contributions to control molecular transport within lipid mesophases, by either exploiting endogenous or exogenous stimuli and I will emphasize how this has direct implications for in-meso protein crystallization, in-meso enzymatic reactions, protein reconstitution and biosensors development. A new detection strategy relying on nanoconfined enzymatic reactions coupled with molecular recognition and birefringence development in-meso for detection of biomarkers, viruses, bacteria and parasites will be introduced and discussed.

Figure 1. (a) Detection of E. Coli with cubic mesophases. (b) A simple biosensors made of lipidic cubic phases.⁵

References

1. Garti N, Somasundaran P, Mezzenga R., “Self-Assembled Supramolecular Architectures: Lyotropic Liquid Crystals”, Wiley (2012)

2. Zabara A, Negrini R, Onaca-Fischer O, Mezzenga R “Perforated bicontinuous cubic phases with pH-responsive interconnectivities”. Small, 9, 3602 (2013)

3. Vallooran JJ., Negrini R., Mezzenga R., “Controlling Anisotropic Drug Diffusion in Lipid-Fe3O4 Nanoparticle Hybrid Mesophases by Magnetic Alignment”, Langmuir, 29, 999 (2013)

4. Negrini R., Mezzenga R., “Diffusion, Molecular Separation, and Drug Delivery from Lipid Mesophases with Tunable Water Channels”, Langmuir, 28, 16455 (2012).

5. Vallooran, J. J., Handschin, S., Pillai, S.M., Vetter, B.N, Rusch, S., Beck, H.P., Mezzenga, R. (2016) Lipidic Cubic Phases as a Versatile Platform for the Rapid Detection of Biomarkers, Viruses, Bacteria, and Parasites, Adv. Funct. Mater., 26, 181-190.