Creativity, Discovery, Engagement
Learning Like No Other
Stay up-to-date on the latest research and build relationships with academics at the Materials Science & Biophysics Seminar Series, which bring experts from around the world to campus to discuss their recent findings. Everyone is welcome!
 Mustafa Culha, PhD, Professor of Chemistry
|
Hexagonal boron nitrides and their applications from nanomedicine to nanophotonicsFriday, September 6, 2024 Health Sciences Building EC 1218 2:00 - 3:00 PM Host: Dr. Trinanjan Datta (tdatta@augusta.edu) Hexagonal boron nitrides (hBNs) are 2D nanomaterials with unique physicochemical properties. They are formed by the covalent bonding of boron (B) and nitrogen (N) atoms in a hexagonal pattern similar to graphene. Thus, their properties are often compared but they have rather different properties due to the difference in the electronegativity of the B and N atoms compared to the C-C bond in graphene, where the electron cloud in the s bond is more localized on N atom. The bond p consists of an empty p orbital of B and the full orbital p of N. In this way, the electrons of N are less delocalized. Therefore, the bond is more ionic and the symmetry of the electronic state is broken. Due to this electronic structure, the band gap is rather wide (~5.9 eV), and as a result, they lose their electrical conductivity. However, this electronic structure brings other novel photonic properties including single photon emission. The hBNs have also attracted the attention of biomedical researchers in recent years due to their biocompatibility, low toxicity, and potential use in neutron capture therapy, drug delivery, and cancer therapy through their degradation products. In this talk, I will present our effort to utilize these unique nanomaterials as nanocarriers, cancer therapeutics, and single photon emitters. |
|
|
Cell softening/stiffening as a driver of morphogenesisFriday, October 4, 2024 Health Sciences Building EC 1218 2:00 - 3:00 PM Host: Dr. Abdul Malmi-Kakkada (amalmikakkada@augusta.edu) During animal development, the acquisition of three-dimensional morphology is a consequence of the interaction between cellular forces and the mechanical properties of cells. While the generation and transmission of cellular forces has been widely explored, less is known about cell material properties, which are often assumed to be uniform or constant. Recently, this view is being challenged by new work showing that cells dynamically adjust their material properties to optimize tissue development. In this talk I will illustrate this with two examples: limb bud extension, the process by which our arms and legs start to develop; and gastrulation, the process by which cells in a monolayer form a furrow and ingress to create a new tissue layer. Using a combination of experiments and computational modelling, we show that older models of limb bud formation that rely on a growth gradient or cell migration are not feasible, and propose a new model that combines convergent extension movements and a gradient of tissue softening to drive limb extension. In the next example we used line-scan Brillouin microscopy to show that gastrulating cells undergo rapid and spatially varying changes in their mechanical properties. We identify microtubules as potential effectors of cell mechanics in this system and show through computational modelling that while stiffer cells correlate with deeper furrows, better outcomes are achieved if cells are initially softer and stiffen over time, as seen in our measurements. Together our work highlights the existence and importance of evolving cell mechanical properties during morphogenesis. |
|
|
Coordinating Adhesion with Repulsion: How Cells Use Polymer Brushes to Orchestrate LifeFriday, November 1, 2024 Health Sciences Building EC 1218 2:00 - 3:00 PM Host: Dr. Abdul Malmi-Kakkada (amalmikakkada@augusta.edu) Multi-cellular organisms rely on reversible adhesions to orchestrate the motion and organization of cells. To date, the physics of tissue formation and cohesion has primarily focused on the molecular adhesions between cells and the balance of forces throughout the tissue. In this talk, I will introduce an important but neglected physical mechanism that cells may use to break or weaken cellular adhesions in a controllable, dynamic fashion. At the heart of this control is cells’ ability to rapidly extrude giant sugar polymers to form a polymer brush-like structure at cell interfaces. I will present data confirming that the repulsive forces generated by this compressed brush (glycocalyx) substantially modify the adhesive state of cells. Further, I will share how our lab has hijacked the cell’s method for tailoring its interface to generate a novel class of ultra-thick polymer brush. We employ these tunable brushes as a biomimetic system to systematically explore the forces exerted by glycocalyx on adherent cells. Experiments confirm that the polymer-generating enzyme, hyaluronan synthase, can squeeze polymers into tight confined spaces and drive dramatic cell deformation or even force cells to detach from the substrate. In light of the observed upregulation of hyaluronan glycocalyx synthesis in biological events that require adhesion modulation, ranging from embryogenesis to synaptogenesis, I argue that controlled growth and organization of large hyaluronan polymers at the cell’s interface may play a substantial role in the mechanics and dynamics of cell organization in multi-cellular systems. |
|
|
Altermagnets: A new phase of matter(?)Friday, November 15, 2024 Health Sciences Building EC 1218 2:00-3:00 PM Host: Dr. Trinanjan Datta (tdatta@augusta.edu) Electrons have intrinsic angular momenta (spin), which give rise to the familiar ferromagnets when they are ordered in a parallel fashion. While (ferro)magnets were discovered about 2500 years ago, antiferromagnets where the spins of electrons in a solid order in a staggered fashion, has a much shorter history, and was conclusively observed less than a century ago. In the last 5 years, the possibility of a novel magnetic phase, dubbed altermagnetism, was raised. This to-be-new phase is claimed to be different from both ferromagnetism and antiferromagnetism. In this talk, I am going to provide a theoretical discussion of altermagnetic materials using a combination of first principles quantum mechanical simulations (Density Functional Theory) and group theory based symmetry approaches. After providing an introduction to different types of magnetism in solids, I will derive mathematical conditions that provide a definition of an altermagnet, and then use computational simulations to provide examples of real altermagnetic materials and the connection between their microscopic and macroscopic properties. |
|
Seminar series sponsored by: Augusta University Research Institute, College of Science and Mathematics, Department of Physics and Biophysics
