Browsing by Author "Meyer, Matthew D."

Now showing 1 - 6 of 6
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    Enabling Solution Processable COFs through Suppression of Precipitation during Solvothermal Synthesis
    (American Chemical Society, 2022) Khalil, Safiya; Meyer, Matthew D.; Alazmi, Abdullah; Samani, Mohammad H. K.; Huang, Po-Chun; Barnes, Morgan; Marciel, Amanda B.; Verduzco, Rafael; Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment
    Covalent organic frameworks (COFs) are crystalline, nanoporous materials of interest for various applications, but current COF synthetic routes lead to insoluble aggregates which precludes processing for practical implementation. Here, we report a COF synthesis method that produces a stable, homogeneous suspension of crystalline COF nanoparticles that enables the preparation of COF monoliths, membranes, and films using conventional solution-processing techniques. Our approach involves the use of a polar solvent, diacid catalyst, and slow reagent mixing procedure at elevated temperatures which altogether enable access to crystalline COF nanoparticle suspension that does not aggregate or precipitate when kept at elevated temperatures. On cooling, the suspension undergoes a thermoreversible gelation transition to produce crystalline and highly porous COF materials. We further show that the modified synthesis approach is compatible with various COF chemistries, including both large- and small-pore imine COFs, hydrazone-linked COFs, and COFs with rhombic and hexagonal topologies, and in each case, we demonstrate that the final product has excellent crystallinity and porosity. The final materials contain both micro- and macropores, and the total porosity can be tuned through variation of sample annealing. Dynamic light scattering measurements reveal the presence of COF nanoparticles that grow with time at room temperature, transitioning from a homogeneous suspension to a gel. Finally, we prepare imine COF membranes and measure their rejection of polyethylene glycol (PEG) polymers and oligomers, and these measurements exhibit size-dependent rejection and adsorption of PEG solutes. This work demonstrates a versatile processing strategy to create crystalline and porous COF materials using solution-processing techniques and will greatly advance the development of COFs for various applications.
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    Filamentous virus-like particles are present in coral dinoflagellates across genera and ocean basins
    (Oxford University Press, 2023) Howe-Kerr, Lauren I.; Knochel, Anna M.; Meyer, Matthew D.; Sims, Jordan A.; Karrick, Carly E.; Grupstra, Carsten G. B.; Veglia, Alex J.; Thurber, Andrew R.; Vega Thurber, Rebecca L.; Correa, Adrienne M. S.
    Filamentous viruses are hypothesized to play a role in stony coral tissue loss disease (SCTLD) through infection of the endosymbiotic dinoflagellates (Family Symbiodiniaceae) of corals. To evaluate this hypothesis, it is critical to understand the global distribution of filamentous virus infections across the genetic diversity of Symbiodiniaceae hosts. Using transmission electron microscopy, we demonstrate that filamentous virus-like particles (VLPs) are present in over 60% of Symbiodiniaceae cells (genus Cladocopium) within Pacific corals (Acropora hyacinthus, Porites c.f. lobata); these VLPs are more prevalent in Symbiodiniaceae of in situ colonies experiencing heat stress. Symbiodiniaceae expelled from A. hyacinthus also contain filamentous VLPs, and these cells are more degraded than their in hospite counterparts. Similar to VLPs reported from SCTLD-affected Caribbean reefs, VLPs range from ~150 to 1500 nm in length and 16–37 nm in diameter and appear to constitute various stages in a replication cycle. Finally, we demonstrate that SCTLD-affected corals containing filamentous VLPs are dominated by diverse Symbiodiniaceae lineages from the genera Breviolum, Cladocopium, and Durusdinium. Although this study cannot definitively confirm or refute the role of filamentous VLPs in SCTLD, it demonstrates that filamentous VLPs are not solely observed in SCTLD-affected corals or reef regions, nor are they solely associated with corals dominated by members of a particular Symbiodiniaceae genus. We hypothesize that filamentous viruses are a widespread, common group that infects Symbiodiniaceae. Genomic characterization of these viruses and empirical tests of the impacts of filamentous virus infection on Symbiodiniaceae and coral colonies should be prioritized.
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    Immunohistochemical and ultrastructural analysis of the maturing larval zebrafish enteric nervous system reveals the formation of a neuropil pattern
    (Springer Nature, 2019) Baker, Phillip A.; Meyer, Matthew D.; Tsang, Ashley; Uribe, Rosa Anna
    The gastrointestinal tract is constructed with an intrinsic series of interconnected ganglia that span its entire length, called the enteric nervous system (ENS). The ENS exerts critical local reflex control over many essential gut functions; including peristalsis, water balance, hormone secretions and intestinal barrier homeostasis. ENS ganglia exist as a collection of neurons and glia that are arranged in a series of plexuses throughout the gut: the myenteric plexus and submucosal plexus. While it is known that enteric ganglia are derived from a stem cell population called the neural crest, mechanisms that dictate final neuropil plexus organization remain obscure. Recently, the vertebrate animal, zebrafish, has emerged as a useful model to understand ENS development, however knowledge of its developing myenteric plexus architecture was unknown. Here, we examine myenteric plexus of the maturing zebrafish larval fish histologically over time and find that it consists of a series of tight axon layers and long glial cell processes that wrap the circumference of the gut tube to completely encapsulate it, along all levels of the gut. By late larval stages, complexity of the myenteric plexus increases such that a layer of axons is juxtaposed to concentric layers of glial cells. Ultrastructurally, glial cells contain glial filaments and make intimate contacts with one another in long, thread-like projections. Conserved indicators of vesicular axon profiles are readily abundant throughout the larval plexus neuropil. Together, these data extend our understanding of myenteric plexus architecture in maturing zebrafish, thereby enabling functional studies of its formation in the future.
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    Immunohistochemical and ultrastructural analysis of the maturing larval zebrafish enteric nervous system reveals the formation of a neuropil pattern
    (Springer Nature, 2019) Baker, Phillip A.; Meyer, Matthew D.; Tsang, Ashley; Uribe, Rosa Anna
    The gastrointestinal tract is constructed with an intrinsic series of interconnected ganglia that span its entire length, called the enteric nervous system (ENS). The ENS exerts critical local reflex control over many essential gut functions; including peristalsis, water balance, hormone secretions and intestinal barrier homeostasis. ENS ganglia exist as a collection of neurons and glia that are arranged in a series of plexuses throughout the gut: the myenteric plexus and submucosal plexus. While it is known that enteric ganglia are derived from a stem cell population called the neural crest, mechanisms that dictate final neuropil plexus organization remain obscure. Recently, the vertebrate animal, zebrafish, has emerged as a useful model to understand ENS development, however knowledge of its developing myenteric plexus architecture was unknown. Here, we examine myenteric plexus of the maturing zebrafish larval fish histologically over time and find that it consists of a series of tight axon layers and long glial cell processes that wrap the circumference of the gut tube to completely encapsulate it, along all levels of the gut. By late larval stages, complexity of the myenteric plexus increases such that a layer of axons is juxtaposed to concentric layers of glial cells. Ultrastructurally, glial cells contain glial filaments and make intimate contacts with one another in long, thread-like projections. Conserved indicators of vesicular axon profiles are readily abundant throughout the larval plexus neuropil. Together, these data extend our understanding of myenteric plexus architecture in maturing zebrafish, thereby enabling functional studies of its formation in the future.
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    Self assembled, sulfonated pentablock copolymer cation exchange coatings for membrane capacitive deionization
    (Royal Society of Chemistry, 2019) Jain, Amit; Weathers, Cierra; Kim, Jun; Meyer, Matthew D.; Walker, W. Shane; Li, Qilin; Verduzco, Rafael; Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment
    Membrane capacitive deionization (MCDI) is a simple and low-cost method for brackish water desalination involving reversible electrosorption using high surface area, porous electrodes paired with ion-exchange membranes. Ion-exchange membranes improve charge efficiency and salt adsorption capacity by limiting the transport of co-ions and inhibiting faradaic reactions at the electrode surface. Effective ion-exchange membranes for MCDI should have high permselectivity and low ionic resistance, but there is typically a trade-off between these two properties. In this work, we studied partially sulfonated pentablock copolymer (sPBC) as a cation-exchange coating for MCDI electrodes. sPBC ion exchange coatings of varying ion exchange capacity (IEC, 1.0, 1.5, 2.0 meq g−1) and a range of casting solvent compositions (10–60 wt% n-propanol in toluene) were prepared. Transmission electron microscopy analysis of the membranes showed a morphological change from a micellar to lamellar and then to an inverse micellar structure with increasing polarity of the casting solvent. Water uptake and salt permeability increased with increasing IEC and casting solvent polarity over the entire range of conditions tested. MCDI device studies indicated that charge efficiency and salt adsorption capacity both increased with water uptake over a range of casting solvent compositions due to morphological changes in the sPBC film. This work demonstrates an effective solution-processible ion-exchange layer for MCDI using a self-assembling block copolymer and suggests that ideal ion-exchange coatings for MCDI should have high water uptake to minimize ionic resistance while at the same time maintaining a high charge density of fixed charged groups to achieve high permselectivity.
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    Three-dimensional printing of wood
    (AAAS, 2024) Thakur, Md Shajedul Hoque; Shi, Chen; Kearney, Logan T.; Saadi, M. A. S. R.; Meyer, Matthew D.; Naskar, Amit K.; Ajayan, Pulickel M.; Rahman, Muhammad M.
    Natural wood has served as a foundational material for buildings, furniture, and architectural structures for millennia, typically shaped through subtractive manufacturing techniques. However, this process often generates substantial wood waste, leading to material inefficiency and increased production costs. A potential opportunity arises if complex wood structures can be created through additive processes. Here, we demonstrate an additive-free, water-based ink made of lignin and cellulose, the primary building blocks of natural wood, that can be used to three-dimensional (3D) print architecturally designed wood structures via direct ink writing. The resulting printed structures, after heat treatment, closely resemble the visual, textural, olfactory, and macro-anisotropic properties, including mechanical properties, of natural wood. Our results pave the way for 3D-printed wooden construction with a sustainable pathway to upcycle/recycle natural wood.