15 Apr 2016 : Elisabetta Matsumoto

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.

3 Nov 2016: Andrew Kraynik

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

Speaker : Dr Andrew M Kraynik – Sandia National Labs (retired)

Venue    : 3 Nov 2016 – 4pm (Murdoch University, tba)

Soap froth – the quintessential foam – is composed of polyhedral gas bubbles separated by thin liquid films. Why do foams have a shear modulus and yield stress, which we usually associate with solids? How are the bubbles shaped and how are they packed? These and other questions have been explored through simulations with the Surface Evolver, a computer program developed by Ken Brakke. We will describe foam structures ranging in complexity from perfectly ordered foams based on the Kelvin cell to random polydisperse foams with 12^3 cells in which the individual cells have a wide distribution of shapes and sizes – the former is highly idealized and the latter are very realistic. The calculations are in excellent agreement with seminal experiments by Edwin B. Matzke (1946) – a botanist – on foam structure, and shear modulus measurements by Princen and Kiss (1986). The connection between elastic-plastic rheology and foam structure involves intermittent cascades of topological transitions; this cell-neighbor switching is a fundamental mechanism of foam flow. Diffusive coarsening, a mechanism for foam aging, has also been simulated.

 

03 Mar 2016 : Gerd Schröder-Turk

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

Speaker : Dr Gerd Schröder-Turk – Murdoch University

Venue    : 3 March 2016 – 4pm (Murdoch University, SC3.39)

Triply-periodic minimal surfaces are commonly observed as the spatial nanostructure of a variety of biological systems as well as self-assembled lipid or copolymer systems. In this talk I will explain what these negatively curved surfaces are, and give a variety of examples where they occur in nature. I will focus on the occurrence of these structures in a number of green butterfly species, where the structure acts as a photonic crystal. That is, the green coloration is the result of the nanostructure, not of a green pigment.

5 May 2016 : Raffaele Mezzenga

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.

2016_05_05_RaffaeleMezzengaImage2

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.

7 Apr 2016 : Francis Woodhouse

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.

 

18 Feb 2016 : Jacob Kirkensgaard

Complex self-assembly morphologies of multicomponent miktoarm star copolymers

Speaker : Dr Jacob Kirkensgaard – University of Copenhagen
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.

31 Mar 2016: Paul Dalton

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.

Biography: Paul Dalton is a Professor in Biofabrication at the University of Würzburg, Germany. He has 20 years’ of interdisciplinary experie2016_03_31_PaulDaltonBionce 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.