Mimicking magnets with lattices of bacterial vortices
Speaker : Dr Francis Woodhouse – Cambridge University
Venue : Thu 7 Apr 2016 @ 4pm, Murdoch University, room ECL1.031 (below ECL2.031)
When alone in an unbounded fluid, a rod-shaped motile bacterium like E. coli will swim in straight lines punctuated by random turns. Pack many of them together in the same fluid, however, and they adopt collective swirling patterns akin to macroscopic turbulence. Confining the bacteria within a small circular cavity tames this turbulence and leads instead to a steadily spinning bacterial vortex. If many such vortices are then linked together in a square lattice of cavities, the rotation sense of a vortex becomes dependent on those of its neighbours. By declaring the senses to be ‘up’ and ‘down’ spins, the result is a bacterial analogue of an Ising ferromagnet. After explaining the background to these so-called ‘active matter’ systems, I will explore the challenges involved in mapping classical statistical physics models to this decidedly non-classical system – but only after revealing an entirely unexpected twist in the experiments.
Complex self-assembly morphologies of multicomponent miktoarm star copolymers
Date : 18 Feb 2016, 4:15pm (Murdoch University, ECL2.031)
The self-assembly morphologies of various complex architectured miktoarm star copolymers consisting of more than two components has been investigated using dissipative particle dynamics simulations. The star topology of such molecules allow a wealth of new structures to be controllably realized as a function of composition, interaction parameters and molecular architecture. Here a number of highlights are presented showing many novel kaleidoscopic morphologies, including 2D tiling patters and 3D networks many of which show hierarchical features, i.e. ordering on multiple length scales. Several examples are extensions of the well-known bicontinuous structures P, D and G found in many natural and synthetic two-component systems.
3D Printing of High Fidelity Tissue Engineering Scaffolds
Speaker : Prof Paul Dalton – Würzburg University / Germany
Venue : 31 March 2016 @ 15:00 (Murdoch University, Senate Conference Room)
Considering the complexity of the structure and the organization of the natural tissues, a major challenge in tissue engineering applications is to produce three-dimensional (3D) structures that are anatomically accurate. Consequently, there has been a significant effort in developing techniques to manufacture substrates with a defined organization, however resolutions remain limited. Melt electrospinning writing is an additive manufacturing process that electrostatically stabilizes a molten thread, placing it accurately onto a collector. It can generate organized 3D scaffolds with a precise and predictable layer-by-layer deposition with finely resolved fibers. This solvent-free approach provides a pathways to clinical products while addressing the need for 3D architecture requirements for a variety of tissue engineering applications.
: Paul Dalton is a Professor in Biofabrication at the University of Würzburg, Germany. He has 20 years’ of interdisciplinary experie
nce in biomedical materials, including polymer processing, surgery, nanotechnology and surface science. Originally from Perth, Australia, and trained as a materials scientist, he was part of a successful team in the 1990s taking an artificial cornea from concept to the clinic. Paul post-docced at the University of Toronto, Canada, and RWTH Aachen, Germany, working in neural tissue engineering and applying nanotechnology to life science applications. As an independent fellow at the University of Southampton, he invented melt electrospinning writing as a new 3D printing technology and performed experimental surgery to understand the neuroinflammation of hydrogels in the spinal cord. Between 2010 and 2013, he split his time between Shanghai Jiao Tong University in China and Queensland University of Technology in Australia. Paul has an H-Index of 36 from only 70 research articles published in journals including Advanced Materials, Progress in Polymer Science, Nature Communications and Nature Materials.