Open Access Publications

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Open access publications by faculty, postdocs, and graduate students in the Department of Chemical and Biomolecular Engineering


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Now showing 1 - 20 of 70
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    Ionic-Liquid-Mediated Deconstruction of Polymers for Advanced Recycling and Upcycling
    (ACS Macro Letters, 2023-08-15) Christoff-Tempesta, Ty; Epps, Thomas H. III
    Ionic liquids (ILs) are a promising medium to assist in the advanced (chemical and biological) recycling of polymers, owing to their tunable catalytic activity, tailorable chemical functionality, low vapor pressures, and thermal stability. These unique physicochemical properties, combined with ILs’ capacity to solubilize plastics waste and biopolymers, offer routes to deconstruct polymers at reduced temperatures (and lower energy inputs) versus conventional bulk and solvent-based methods, while also minimizing unwanted side reactions. In this Viewpoint, we discuss the use of ILs as catalysts and mediators in advanced recycling, with an emphasis on chemical recycling, by examining the interplay between IL chemistry and deconstruction thermodynamics, deconstruction kinetics, IL recovery, and product recovery. We also consider several potential environmental benefits and concerns associated with employing ILs for advanced recycling over bulk- or solvent-mediated deconstruction techniques, such as reduced chemical escape by volatilization, decreased energy demands, toxicity, and environmental persistence. By analyzing IL-mediated polymer deconstruction across a breadth of macromolecular systems, we identify recent innovations, current challenges, and future opportunities in IL application toward circular polymer economies.
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    Fatty acid synthase as a feasible biomarker for triple negative breast cancer stem cell subpopulation cultured on electrospun scaffolds
    (Materials Today Bio, 2021-09) Rabionet, Marc; Polonio-Alcalá, Emma; Relat, Joana; Yeste, Marc; Sims-Mourtada, Jennifer; Kloxin, April M.; Planas, Marta; Feliu, Lidia; Ciurana, Joaquim; Puig, Teresa
    There is no targeted therapy for triple negative breast cancer (TNBC), which presents an aggressive profile and poor prognosis. Recent studies noticed the feasibility of breast cancer stem cells (BCSCs), a small population responsible for tumor initiation and relapse, to become a novel target for TNBC treatments. However, new cell culture supports need to be standardized since traditional two-dimensional (2D) surfaces do not maintain the stemness state of cells. Hence, three-dimensional (3D) scaffolds represent an alternative to study in vitro cell behavior without inducing cell differentiation. In this work, electrospun polycaprolactone scaffolds were used to enrich BCSC subpopulation of MDA-MB-231 and MDA-MB-468 TNBC cells, confirmed by the upregulation of several stemness markers and the existence of an epithelial-to-mesenchymal transition within 3D culture. Moreover, 3D-cultured cells displayed a shift from MAPK to PI3K/AKT/mTOR signaling pathways, accompanied by an enhanced EGFR and HER2 activation, especially at early cell culture times. Lastly, the fatty acid synthase (FASN), a lipogenic enzyme overexpressed in several carcinomas, was found to be hyperactivated in stemness-enriched samples. Its pharmacological inhibition led to stemness diminishment, overcoming the BCSC expansion achieved in 3D culture. Therefore, FASN may represent a novel target for BCSC niche in TNBC samples. Highlights • Polycaprolactone scaffolds provide a softer 3D alternative to traditional cell culture. • Scaffolds expand the triple negative breast cancer stem cell niche. • Fatty Acid Synthase (FASN) is hyperactivated in scaffold-cultured cells. • FASN inhibition overcomes the stemness expansion achieved in 3D culture. Graphical abstract available at:
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    Tuning High-Density Polyethylene Hydrocracking through Mordenite Zeolite Crystal Engineering
    (ACS Sustainable Chemistry and Engineering, 2023-06-19) Kots, Pavel A.; Doika, Panagiota A.; Vance, Brandon C.; Najmi, Sean; Vlachos, Dionisios G.
    We investigate the hydrocracking of high-density polyethylene using a bifunctional Pt/Al2O3 and modified mordenite acid catalyst. Mass transport limitations impact polymer diffusion into the mordenite pore complex. Initial reaction intermediates are formed on the zeolite’s outer surface. Intercrystallite open-end mesopores improve the diffusion of reaction intermediates deeper into the crystal. Recrystallization and desilication of mordenite lead to a higher polymer conversion and shift the product distribution maximum from pentanes to hexanes and heptanes. The nature of mesopores (occluded or open) and total Brønsted acidity significantly impact zeolite activity and selectivity.
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    Unpacking the multimodal, multi-scale data of the fast and slow lanes of the cardiac vagus through computational modelling
    (Experimental Physiology, 2023-04-30) Gee, Michelle M.; Hornung, Eden; Gupta, Suranjana; Newton, Adam J. H.; Cheng, Zixi (Jack); Lytton, William W.; Lenhoff, Abraham M.; Schwaber, James S.; Vadigepalli, Rajanikanth
    New Findings What is the topic of this review? The vagus nerve is a crucial regulator of cardiovascular homeostasis, and its activity is linked to heart health. Vagal activity originates from two brainstem nuclei: the nucleus ambiguus (fast lane) and the dorsal motor nucleus of the vagus (slow lane), nicknamed for the time scales that they require to transmit signals. What advances does it highlight? Computational models are powerful tools for organizing multi-scale, multimodal data on the fast and slow lanes in a physiologically meaningful way. A strategy is laid out for how these models can guide experiments aimed at harnessing the cardiovascular health benefits of differential activation of the fast and slow lanes. The vagus nerve is a key mediator of brain–heart signaling, and its activity is necessary for cardiovascular health. Vagal outflow stems from the nucleus ambiguus, responsible primarily for fast, beat-to-beat regulation of heart rate and rhythm, and the dorsal motor nucleus of the vagus, responsible primarily for slow regulation of ventricular contractility. Due to the high-dimensional and multimodal nature of the anatomical, molecular and physiological data on neural regulation of cardiac function, data-derived mechanistic insights have proven elusive. Elucidating insights has been complicated further by the broad distribution of the data across heart, brain and peripheral nervous system circuits. Here we lay out an integrative framework based on computational modelling for combining these disparate and multi-scale data on the two vagal control lanes of the cardiovascular system. Newly available molecular-scale data, particularly single-cell transcriptomic analyses, have augmented our understanding of the heterogeneous neuronal states underlying vagally mediated fast and slow regulation of cardiac physiology. Cellular-scale computational models built from these data sets represent building blocks that can be combined using anatomical and neural circuit connectivity, neuronal electrophysiology, and organ/organismal-scale physiology data to create multi-system, multi-scale models that enable in silico exploration of the fast versus slow lane vagal stimulation. The insights from the computational modelling and analyses will guide new experimental questions on the mechanisms regulating the fast and slow lanes of the cardiac vagus toward exploiting targeted vagal neuromodulatory activity to promote cardiovascular health.
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    Insights into solvent and surface charge effects on Volmer step kinetics on Pt (111)
    (Nature Communications, 2023-04-25) Wilson, Jon C.; Caratzoulas, Stavros; Vlachos, Dionisios G.; Yan, Yushan
    The mechanism of pH-dependent hydrogen oxidation and evolution kinetics is still a matter of significant debate. To make progress, we study the Volmer step kinetics on platinum (111) using classical molecular dynamics simulations with an embedded Anderson-Newns Hamiltonian for the redox process and constant potential electrodes. We investigate how negative electrode electrostatic potential affects Volmer step kinetics. We find that the redox solvent reorganization energy is insensitive to changes in interfacial field strength. The negatively charged surface attracts adsorbed H as well as H+, increasing hydrogen binding energy, but also trapping H+ in the double layer. While more negative electrostatic potential in the double layer accelerates the oxidation charge transfer, it becomes difficult for the proton to move to the bulk. Conversely, reduction becomes more difficult because the transition state occurs farther from equilibrium solvation polarization. Our results help to clarify how the charged surface plays a role in hydrogen electrocatalysis kinetics.
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    Anisotropy factors in small-angle scattering for dilute rigid-rod suspensions
    (Journal of Applied Crystallography, 2023-06) Rooks, J.; Gilbert, P. H.; Porcar, L.; Liu, Y.; Butler, P.
    Alignment of anisotropic particles along specific orientations influences the mechanical and rheological properties of a material. Small-angle scattering techniques are widely used to probe this alignment through analysis of anisotropic two-dimensional scattering intensity patterns. The anisotropy factor is the simplest and most common quantitative parameter for describing scattering anisotropy, especially in systems containing rod-like particles, and there are several methods for calculating this factor. However, there has been no systematic study comparing these methods while also evaluating the limitations imposed by non-idealities from instrumentation or polydisperse morphology. Three of the most common methods for calculating an anisotropy factor are examined here and their effectiveness for describing the orientation of a theoretical cylinder is evaluated. It is found that the maximum theoretical value of 1 for the anisotropy factor is only accessible at certain values of scattering vector q. The analysis details recommendations for q-range selection and data binning, as these influence the calculations. The theoretical results are supported by experimental small-angle neutron scattering data for a wormlike micelle solution undergoing shear, where different calculation methods yield distinct quantifications of anisotropy.
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    High-efficiency and multilocus targeted integration in CHO cells using CRISPR-mediated donor nicking and DNA repair inhibitors
    (Biotechnology and Bioengineering, 2023-04-11) Hamaker, Nathaniel K.; Lee, Kelvin H.
    Efforts to leverage clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) for targeted genomic modifications in mammalian cells are limited by low efficiencies and heterogeneous outcomes. To aid method optimization, we developed an all-in-one reporter system, including a novel superfolder orange fluorescent protein (sfOrange), to simultaneously quantify gene disruption, site-specific integration (SSI), and random integration (RI). SSI strategies that utilize different donor plasmid formats and Cas9 nuclease variants were evaluated for targeting accuracy and efficiency in Chinese hamster ovary cells. Double-cut and double-nick donor formats significantly improved targeting accuracy by 2.3–8.3-fold and 19–22-fold, respectively, compared to standard circular donors. Notably, Cas9-mediated donor linearization was associated with increased RI events, whereas donor nicking minimized RI without sacrificing SSI efficiency and avoided low-fidelity outcomes. A screen of 10 molecules that modulate the major mammalian DNA repair pathways identified two inhibitors that further enhance targeting accuracy and efficiency to achieve SSI in 25% of transfected cells without selection. The optimized methods integrated transgene expression cassettes with 96% efficiency at a single locus and with 53%–55% efficiency at two loci simultaneously in selected clones. The CRISPR-based tools and methods developed here could inform the use of CRISPR/Cas9 in mammalian cell lines, accelerate mammalian cell line engineering, and support advanced recombinant protein production applications.
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    Circularity in polymers: addressing performance and sustainability challenges using dynamic covalent chemistries
    (Chemical Science, 2023-05-05) Yan, Tianwei; Balzer, Alex H.; Herbert, Katie M.; Epps, Thomas H. III; Korley, LaShanda T. J.
    The circularity of current and future polymeric materials is a major focus of fundamental and applied research, as undesirable end-of-life outcomes and waste accumulation are global problems that impact our society. The recycling or repurposing of thermoplastics and thermosets is an attractive solution to these issues, yet both options are encumbered by poor property retention upon reuse, along with heterogeneities in common waste streams that limit property optimization. Dynamic covalent chemistry, when applied to polymeric materials, enables the targeted design of reversible bonds that can be tailored to specific reprocessing conditions to help address conventional recycling challenges. In this review, we highlight the key features of several dynamic covalent chemistries that can promote closed-loop recyclability and we discuss recent synthetic progress towards incorporating these chemistries into new polymers and existing commodity plastics. Next, we outline how dynamic covalent bonds and polymer network structure influence thermomechanical properties related to application and recyclability, with a focus on predictive physical models that describe network rearrangement. Finally, we examine the potential economic and environmental impacts of dynamic covalent polymeric materials in closed-loop processing using elements derived from techno-economic analysis and life-cycle assessment, including minimum selling prices and greenhouse gas emissions. Throughout each section, we discuss interdisciplinary obstacles that hinder the widespread adoption of dynamic polymers and present opportunities and new directions toward the realization of circularity in polymeric materials.
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    Techno-Economic and Life Cycle Analyses of Thermochemical Upcycling Technologies of Low-Density Polyethylene Waste
    (ACS Sustainable Chemistry and Engineering, 2023-05-08) Hernández, Borja; Kots, Pavel; Selvam, Esun; Vlachos, Dionisios G.; Ierapetritou, Marianthi G.
    In this study we compare techno-economics and life cycle assessment of thermochemical depolymerization technologies, including pyrolysis, gasification, hydrocracking, hydrothermal liquefaction, and hydrogenolysis, to generate various products from low-density polyethylene (LDPE) waste. We elucidate the effects of production scale, collection cost, and concentration of LDPE in plastic waste. Pyrolysis of LDPE to olefins followed by their conversion to lubricant oils is the most profitable technology. Hydrogenolysis, producing a small fraction of lubricant oils, becomes profitable at plant sizes above 25 kt/y and produces the lowest CO2 emissions. Hydrocracking is the second most environmentally friendly technology but becomes economically competitive at sufficiently large scales, and the supply chain for collecting plastics is optimized. Gasification of LDPE to H2 produces high emissions, and the price of H2 of ∼3 $/kg is higher than current markets and recently announced goals. Similarly, hydrothermal liquefaction also gives high emissions, making carbon capture systems imperative for both technologies. Our results demonstrate that lowering the cost of sorting LDPE from plastic waste, collecting waste near big cities, building sufficiently large plants, and achieving high selectivity to value-added products are critical to successful plastic waste management.
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    Direct Conversion of Ethane to Oxygenates, Ethylene, and Hydrogen in a Noncatalytic Biphasic Plasma Microreactor
    (ACS Sustainable Chemistry and Engineering, 2023-05-29) Cameli, Fabio; Dimitrakellis, Panagiotis; Vlachos, Dionisios G.
    We selectively upgrade ethane (C2H6) to ethanol (C2H5OH), methanol (CH3OH), and acetic acid (CH3COOH) in a catalyst-free, continuous, argon/water biphasic plasma microreactor. The water (H2O) evaporates and electron- dissociates into OH· radicals. OH· recombines with alkyl radicals, produced via electron dissociation of ethane, to generate the oxygenates that absorb into H2O. A plasma-assisted path, reminiscent of the low-temperature thermocatalytic ethane steam reforming, leads to significant H2 coproduction. The gaseous stream also comprises CO2 and C2H4. Up to 1.3 and 1 μmol min–1 of liquid C2H5OH and CH3OH are attained, respectively. Compared to CO2-assisted ethane plasma conversion, which produces many oxygenates with low selectivity, the carbon selectivity can range from >70% C2H5OH, CH3OH, and CH3COOH to 60% C2H4. The low carbon footprint, electrified, modular, intensified process using a reactive evaporation and separation plasma could pave the way for the valorization of underutilized shale gas resources in remote areas.
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    Turning Carbon Dioxide into Sustainable Food and Chemicals: How Electrosynthesized Acetate Is Paving the Way for Fermentation Innovation
    (Accounts of Chemical Research, 2023-06-20) Crandall, Bradie S.; Overa, Sean; Shin, Haeun; Jiao, Feng
    Conspectus The agricultural and chemical industries are major contributors to climate change. To address this issue, hybrid electrocatalytic–biocatalytic systems have emerged as a promising solution for reducing the environmental impact of these key sectors while providing economic onboarding for carbon capture technology. Recent advancements in the production of acetate via CO2/CO electrolysis as well as advances in precision fermentation technology have prompted electrochemical acetate to be explored as an alternative carbon source for synthetic biology. Tandem CO2 electrolysis coupled with improved reactor design has accelerated the commercial viability of electrosynthesized acetate in recent years. Simultaneously, innovations in metabolic engineering have helped leverage pathways that facilitate acetate upgrading to higher carbons for sustainable food and chemical production via precision fermentation. Current precision fermentation technology has received much criticism for reliance upon food crop-derived sugars and starches as feedstock which compete with the human food chain. A shift toward electrosynthesized acetate feedstocks could help preserve arable land for a rapidly growing population. Technoeconomic analysis shows that using electrochemical acetate instead of glucose as a fermentation feedstock reduces the production costs of food and chemicals by 16% and offers improved market price stability. Moreover, given the rapid decline in utility-scale renewable electricity prices, electro-synthesized acetate may become more affordable than conventional production methods at scale. This work provides an outlook on strategies to further advance and scale-up electrochemical acetate production. Additional perspective is offered to help ensure the successful integration of electrosynthesized acetate and precision fermentation technologies. In the electrocatalytic step, it is critical that relatively high purity acetate can be produced in low-concentration electrolyte to help ensure that minimal treatment of the electrosynthesized acetate stream is needed prior to fermentation. In the biocatalytic step, it is critical that microbes with increased tolerances to elevated acetate concentrations are engineered to help promote acetate uptake and accelerate product formation. Additionally, tighter regulation of acetate metabolism via strain engineering is essential to improving cellular efficiency. The implementation of these strategies would allow the coupling of electrosynthesized acetate with precision fermentation to offer a promising approach to sustainably produce chemicals and food. Reducing the environmental impact of the chemical and agricultural sectors is necessary to avoid climate catastrophe and preserve the habitability of the planet for future generations.
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    Deducing subnanometer cluster size and shape distributions of heterogeneous supported catalysts
    (Nature Communications, 2023-04-08) Liao, Vinson; Cohen, Maximilian; Wang, Yifan; Vlachos, Dionisios G.
    Infrared (IR) spectra of adsorbate vibrational modes are sensitive to adsorbate/metal interactions, accurate, and easily obtainable in-situ or operando. While they are the gold standards for characterizing single-crystals and large nanoparticles, analogous spectra for highly dispersed heterogeneous catalysts consisting of single-atoms and ultra-small clusters are lacking. Here, we combine data-based approaches with physics-driven surrogate models to generate synthetic IR spectra from first-principles. We bypass the vast combinatorial space of clusters by determining viable, low-energy structures using machine-learned Hamiltonians, genetic algorithm optimization, and grand canonical Monte Carlo calculations. We obtain first-principles vibrations on this tractable ensemble and generate single-cluster primary spectra analogous to pure component gas-phase IR spectra. With such spectra as standards, we predict cluster size distributions from computational and experimental data, demonstrated in the case of CO adsorption on Pd/CeO2(111) catalysts, and quantify uncertainty using Bayesian Inference. We discuss extensions for characterizing complex materials towards closing the materials gap.
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    Analytical characterization of host-cell-protein-rich aggregates in monoclonal antibody solutions
    (Biotechnology Progress, 2023-04-05) Herman, Chase E.; Min, Lie; Choe, Leila H.; Maurer, Ronald W.; Xu, Xuankuo; Ghose, Sanchayita; Lee, Kelvin H.; Lenhoff, Abraham M.
    Host-cell proteins (HCPs) and high molecular weight (HMW) species have historically been treated as independent classes of impurities in the downstream processing of monoclonal antibodies (mAbs), but recent indications suggest that they may be partially linked. We have explored this connection with a shotgun proteomic analysis of HMW impurities that were isolated from harvest cell culture fluid (HCCF) and protein A eluate using size-exclusion chromatography (SEC). As part of the proteomic analysis, a cross-digest study was performed in which samples were analyzed using both the standard and native digest techniques to enable a fair comparison between bioprocess pools. This comparison reveals that the HCP profiles of HCCF and protein A eluate overlap substantially more than previous work has suggested, because hundreds of HCPs are conserved in aggregates that may be up to ~50 nm in hydrodynamic radius and that persist through the protein A capture step. Quantitative SWATH proteomics suggests that the majority of the protein A eluate's HCP mass is found in such aggregates, and this is corroborated by ELISA measurements on SEC fractions. The SWATH data also show that intra-aggregate concentrations of individual HCPs are positively correlated between aggregates that were isolated from HCCF and protein A eluate, and species that have generally been considered difficult to remove tend to be more concentrated than their counterparts. These observations support prior hypotheses regarding aggregate-mediated HCP persistence through protein A chromatography and highlight the importance of this persistence mechanism.
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    Scalable, process-oriented beam lattices: Generation, characterization, and compensation for open cellular structures
    (Additive Manufacturing, 2021-12-01) Woodward, Ian R.; Fromen, Catherine A.
    Additively manufactured lattices are emerging as promising candidates for structural, thermal, chemical, and biological applications. However, achieving a satisfactory prototype or final part with this level of complexity requires synthesis of disparate knowledge from the distinctly digital and physical processing stages. This work proposes an integrated framework for processing self-supporting, open lattice structures that do not require supports and facilitate material removal in post-processing steps. We describe a minimal yet comprehensive design strategy for generating uniform lattice structures with conformal open lattice skins for an arbitrary unit cell configuration. Using continuous liquid interface production (CLIP™) on a Carbon M1, printability is evaluated for five unique bending-dominated lattice structures at unit cell length scales from 0.5 to 3.5 mm and strut diameters ranging from 0.11 to 1.05 mm. Using a cubic lattice as a basis, we further examine dimensional fidelity with respect to 2D lattice void dimensions and part position, finding differences between length scales and within parts, due to physical processing artifacts. Finally, we demonstrate a functional grading strategy based on process control methods to compensate for dimensional deviations. Using an iterative approach based on a naïve process model, deviation of the planar strut radius in a cubic lattice was decreased by approximately 85% after two iterations. These insights and strategies can be readily applied to other structures, characterization techniques, and additive manufacturing processes, thereby improving the exchange of information between digital and physical processing and lowering the energy barriers to producing high-quality lattice parts.
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    Anodically-Generated Alkyl Radicals Derived from Carboxylic Acids as Reactive Intermediates for Addition to Alkenes
    (ChemElectroChem, 2023-05-12) Ding, Haoran; Orazov, Marat
    Electrochemically driven C−C coupling has the potential to reduce the cost and environmental impact of some organic syntheses currently accomplished through thermochemical methods. Here, we use electrochemical oxidation of carboxylic acids as a source of reactive carbon-centered radicals that enable radical addition to alkenes in the anode boundary layer. We demonstrate an optimization of reaction conditions to suppress the thermodynamically favored, but synthetically undesirable radical self-coupling in favor of radical addition to styrene. In methanol solvent, 88 % selectivity and 72 % Faradaic efficiency for targeted functionalized benzenes are achieved. For low current densities, iridium anodes outperform platinum, gold, palladium, and glassy carbon anodes. With constant potential or constant current electrolyses, the deposition of organic by-products on the catalyst surface leads to anode passivation. We show that periodic cathodic current pulses effectively regenerate the catalyst. Lastly, we confirm the role of free radicals in the reaction mechanism with a radical trap. Graphical Abstract available at: Electrochemically driven C−C coupling: High anodic current density favors the formation of the undesirable radical self-coupling product. Low anodic current density favors the formation of the target product, but also leads to more solvent oxidation. Solvent oxidation at low current density can be suppressed by multiple methods to achieve high Faradaic efficiency of the target product at high selectivity.
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    Reductive Enzyme Cascades for Valorization of Polyethylene Terephthalate Deconstruction Products
    (ACS Catalysis, 2023-04-07) Gopal, Madan R.; Dickey, Roman M.; Butler, Neil D.; Talley, Michael R.; Nakamura, Daniel T.; Mohapatra, Ashlesha; Watson, Mary P.; Chen, Wilfred; Kunjapur, Aditya M.
    To better incentivize the collection of plastic wastes, chemical transformations must be developed that add value to plastic deconstruction products. Polyethylene terephthalate (PET) is a common plastic whose deconstruction through chemical or biological means has received much attention. However, a limited number of alternative products have been formed from PET deconstruction, and only a small share could serve as building blocks for alternative materials or therapeutics. Here, we demonstrate the production of useful monoamine and diamine building blocks from known PET deconstruction products. We achieve this by designing one-pot biocatalytic transformations that are informed by the substrate specificity of an ω-transaminase and diverse carboxylic acid reductases (CAR) toward PET deconstruction products. We first establish that an ω-transaminase from Chromobacterium violaceum (cvTA) can efficiently catalyze amine transfer to potential PET-derived aldehydes to form monoamine para-(aminomethyl)benzoic acid (pAMBA) or diamine para-xylylenediamine (pXYL). We then identified CAR orthologs that could perform the bifunctional reduction of terephthalic acid (TPA) to terephthalaldehyde or the reduction of mono-(2-hydroxyethyl) terephthalic acid (MHET) to its corresponding aldehyde. After characterizing 17 CARs in vitro, we show that the CAR from Segniliparus rotundus (srCAR) had the highest observed activity on TPA. Given these elucidated substrate specificity results, we designed modular enzyme cascades based on coupling srCAR and cvTA in one pot with enzymatic cofactor regeneration. When we supply TPA, we achieve a 69 ± 1% yield of pXYL, which is useful as a building block for polymeric materials. When we instead supply MHET and subsequently perform base-catalyzed ester hydrolysis, we achieve 70 ± 8% yield of pAMBA, which is useful for therapeutic applications and as a pharmaceutical building block. This work expands the breadth of products derived from PET deconstruction and lays the groundwork for eventual valorization of waste PET to higher-value chemicals and materials.
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    Nanoparticle pre-treatment for enhancing the survival and activation of pulmonary macrophage transplant
    (Drug Delivery and Translational Research, 2023-03-14) Jarai, Bader M.; Bomb, Kartik; Fromen, Catherine A.
    Despite recent clinical successes of chimeric antigen receptor T cell therapies in treating liquid cancers, many lingering challenges stand in the way of therapeutic translation to broader types of malignancies. Macrophages have been proposed as alternatives to T cells given macrophages’ advantages in promoting tumor infiltration, acquiring diverse antigens, and possessing the ability to continuously stimulate adaptive responses. However, the poor survival of macrophages upon transplantation in addition to transient anti-tumor phenotypical states have been major obstacles standing in the way of macrophage-based cell therapies. Given recent discoveries of nanoparticle strategies in improving macrophage survival and promoting phenotype retention, we herein report the ability to extend the survival and phenotype of macrophage transplants in murine lungs via pre-treatment with nanoparticles of varying degradation rates. Macrophages pre-treated with 100 µg/ml dose of poly(ethylene glycol) diacrylate nanoparticle formulations improve pulmonary macrophage transplant survival over untreated cells beyond 7 days, where degradable nanoparticle formulations result in over a 50% increase in retention of transplanted cell counts relative to untreated cells. Furthermore, pre-treated macrophages more efficiently retain an imposed pro-inflammatory-like polarization state following transplantation out to 7 days compared to macrophages pre-treated with a classical pro-inflammatory stimulus, interferon-gamma, where CD86 costimulatory molecule expression is greater than 150% higher in pre-treated macrophage transplants compared to untreated counterparts. These findings provide an avenue for a major improvement in the lifespan and efficacy of macrophage-based cell therapies and have broader implications to other phagocyte-based cellular therapeutics and administration routes. Graphical abstract available at:
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    A Genetic Engineering Toolbox for the Lignocellulolytic Anaerobic Gut Fungus Neocallimastix frontalis
    (ACS Synthetic Biology, 2023-04-21) Hooker, Casey, A.; Hanafy, Radwa; Hillman, Ethan T.; Muñoz Briones, Javier; Solomon, Kevin V.
    Anaerobic fungi are powerful platforms for biotechnology that remain unexploited due to a lack of genetic tools. These gut fungi encode the largest number of lignocellulolytic carbohydrate active enzymes (CAZymes) in the fungal kingdom, making them attractive for applications in renewable energy and sustainability. However, efforts to genetically modify anaerobic fungi have remained limited due to inefficient methods for DNA uptake and a lack of characterized genetic parts. We demonstrate that anaerobic fungi are naturally competent for DNA and leverage this to develop a nascent genetic toolbox informed by recently acquired genomes for transient transformation of anaerobic fungi. We validate multiple selectable markers (HygR and Neo), an anaerobic reporter protein (iRFP702), enolase and TEF1A promoters, TEF1A terminator, and a nuclear localization tag for protein compartmentalization. This work establishes novel methods to reliably transform the anaerobic fungus Neocallimastix frontalis, thereby paving the way for strain development and various synthetic biology applications.
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    Dynamic bioinspired coculture model for probing ER+ breast cancer dormancy in the bone marrow niche
    (Science Advances, 2023-03-08) Pradhan, Lina; Moore, DeVonte; Ovadia, Elisa M.; Swedzinski, Samantha L.; Cossette, Travis; Sikes, Robert A.; van Golen, Kenneth; Kloxin, April M.
    Late recurrences of breast cancer are hypothesized to arise from disseminated tumor cells (DTCs) that reactivate after dormancy and occur most frequently with estrogen receptor–positive (ER+) breast cancer cells (BCCs) in bone marrow (BM). Interactions between the BM niche and BCCs are thought to play a pivotal role in recurrence, and relevant model systems are needed for mechanistic insights and improved treatments. We examined dormant DTCs in vivo and observed DTCs near bone lining cells and exhibiting autophagy. To study underlying cell-cell interactions, we established a well-defined, bioinspired dynamic indirect coculture model of ER+ BCCs with BM niche cells, human mesenchymal stem cells (hMSCs) and fetal osteoblasts (hFOBs). hMSCs promoted BCC growth, whereas hFOBs promoted dormancy and autophagy, regulated in part by tumor necrosis factor–α and monocyte chemoattractant protein 1 receptor signaling. This dormancy was reversible by dynamically changing the microenvironment or inhibiting autophagy, presenting further opportunities for mechanistic and targeting studies to prevent late recurrence.
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    Dynamic Electrification of Dry Reforming of Methane with In Situ Catalyst Regeneration
    (ACS Energy Letters, 2023-02-10) Yu, Kewei; Wang, Cong; Zheng, Weiqing; Vlachos, Dionisios G.
    We report the design and performance of a rapid pulse Joule heating (RPH) reactor with an in situ Raman spectrometer for highly endothermic, reversible reactions. We demonstrate it for methane dry reforming over a bimetallic PtNi/SiO2 catalyst that shows better performance than its monometallic counterparts. The catalyst temperature ramp rate can reach ∼14000 °C/s, mainly owing to the low thermal mass and resistivity of the heating element. Joule heating elements afford temperatures unachievable by conventional technology to enhance performance and more than double the energy efficiency. Dynamic electrification can increase syngas productivity and rate. Extensive characterizations suggest that pulse heating creates an in situ catalyst regeneration strategy that suppresses coke formation, sintering, and phase segregation, resulting in improved catalyst stability, under many conditions. Potentially driven by renewable electricity, the RPH can provide superb process advantages for high-temperature endothermic reactions and lead to negative carbon emissions.
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