Mar 2024
Abstract:
Plant synthetic biology is applied in sustainable agriculture, clean energy, and biopharmaceuticals, addressing crop improvement, pest resistance, and plant-based vaccine production by introducing exogenous genes into plants. This technique faces challenges delivering genes due to plant cell walls and intact cell membranes. Novel approaches are required to address this challenge, such as utilizing nanomaterials known for their efficiency and biocompatibility in gene delivery. The presentation will introduce metal-organic frameworks (MOFs) for gene delivery in intact plant cells by infiltration. Hence, small-sized ZIF-8 nanoparticles were synthesized and demonstrated effective DNA/RNA delivery into Nicotiana benthamiana leaves and Arabidopsis thaliana roots, presenting a promising and simplified method for gene delivery in intact plant cells. We further demonstrate that small-sized ZIF-8 nanoparticles protect RNA from RNase degradation and successfully silence an endogenous gene by delivering siRNA in N. benthamiana leaves.
Bio:
Pei is currently in her third year of PhD under the supervision of Professor Niveen M. Khashab at KAUST. She obtained her bachelor’s degree in 2018 at Yunnan Normal University and her master’s degree in 2021 at Hunan University in China. Her research focuses on engineered-nanomaterials for bio-application, especially for gene delivery and drug delivery.
Abstract:
Polybutadiene (PBD) trans-1,4 is synthesized through catalytic polymerization of 1,3-butadiene monomer using a reported chromium catalytic system. Achieving optimal properties involves carefully balancing the reaction conditions. In particular, crystallization rate over polymerization rate, solvent medium, and thermodynamic parameters, lead to the formation of single crystals polymer powder having a crystal thickness of about 7.8 nm with platelet-like morphology. This polymer has excellent dynamic properties, including excellent anti-fatigue, low rolling resistance, low heat buildup, good strength, and low abrasion loss. Besides that, trans isomer greater than 80% has semicrystalline properties with unique polymorphism, low entropy monoclinic phase (staple at room temperature) to high entropy hexagonal phase (staple at a temperature >50°C), this monoclinic shifts to higher temperatures on annealing crystals in the hexagonal phase, this shift is attributed to increase in the crystal thickness. With these extraordinary properties, PBD with a trans-isomer of 99% and molecular weight, Mw >1x106 g/mol are successfully achieved and characterized using a variety of techniques (GPC, NMR, WAXS, SAXS, TGA, DSC, ED, and SEM). It is known that such a high Mw enhances the mechanical properties of the polymer. Nonetheless, using conventional ways such as extrusion and injection molding techniques to process is rather difficult, due to the increases in the zero-shear viscosity, resulting from the entanglement. Conventionally solution/melt spinning route is feasible by dissolving 5wt.% of the polymer in a toxic solvent, but this approach is environmentally unfriendly. Alternatively, we have demonstrated a novel way to process the relevant polymer using a friendly solvent-free route, which is solids state processing. The resultant polymer with a preserved nascent powder character was hot-pressed and drawn to a tape with a maximum ratio of ~7a below the melting point without using any solvent, followed by the uniaxial deformation using a tensile test, resulting in tensile modules and strength of ~7 GPa and ~0.3 GPa, respectively. Finally, the uniaxially drawn tape was thermally stabilized until 1000 °C and 450°C by using sulfonation and organic peroxide crosslinking mechanisms.
Bio:
Nasser obtained his bachelor’s degree in chemistry, from King Saud University, KSU in Riyadh, in 2014. Since late 2014, he has been working for nearly 10 years for Saudi Basic Industries Corporation, SABIC. His role in SABIC is working as a Scientist and looking after polystyrene process technology. In 2020, he gained his master’s degree, from King Abdullah University for Science and Technology, KAUST under the supervision of Professor Nikos Hadjichristidis. The master’s thesis is titled Atom Transfers Radical Emulsion Polymerization Using Water soluble-initiators and Ligands. he is currently a third-year Ph.D. student at KAUST under the supervision of Professor Sanjay Rastogi. He is exploring a novel carbon fiber route using solid-state processed Ultra-High molecular weight trans-1,4-polybutadiene.
Abstract:
Transition-metal-mediated C(sp2)–(hetero)atom coupling reactions are among the most explored organic transformations, enabling efficient construction of molecules and facile access to molecular complexity for applications across many disciplines. Over the past five decades, a vast amount of literature has evolved around palladium, copper, nickel, and other metals. Despite the advances, many protocols still suffer from drawbacks, including air-sensitive or costly metal catalysts, complicated ligand architectures, strong bases, or higher temperatures, which result in a narrow application and substrate scope. In order to address these issues, new strategies combining transition metals with photochemistry have been developed, which provided milder conditions. However, these dual photoredox strategies utilizing blue light suffer from low penetration of the light through reaction media and unwanted side-product formation, namely hydrodehalogenation. Low-energy light offers a solution to this problem as it can avoid unwanted excitation of reaction species, leading to reduced side-products. Using red light and organic photocatalyst, we demonstrate the broad scope of (hetero)aryl bromides and various nucleophiles.
Bio:
Amir is currently in his third year of PhD under the supervision of Professor Magnus Rueping at KAUST Catalysis Center. Amir received his integrated BSc and MSc in Chemistry, specialty Inorganic Chemistry from Kazan Federal University in Kazan, Russia in 2021. His PhD research focuses on the synthesis and characterization of cyanoarene-based organic dyes for application in photochemical reactions.