Open Access Publications - Department of Chemical and Biomolecular Engineering

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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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Aldehyde Electrophilicity and Ring Strain Govern Xylose Acetalization Pathways for Biobased Chemical Production
(Chemistry-Sustainability-Energy-Materials, 2025-12-25) John Li, Zezhong; Patel, Deep M.; Sun, Songlan; Bourmaud, Claire L.; Chen, Tso-Hsuan; Vlachos, Dionisios G.; Luterbacher, Jeremy S.
Xylose acetalization has emerged as a potent tool to extract this sugar from lignocellulosic biomass and for creating new biobased chemicals and materials. This article elucidates a generalized reaction network for xylose acetalization and reveals the role of aldehyde electrophilicity and ring strain in intermediate formation. Aldehydes with strong electrophilicity stabilize xylose as both furanose- and pyranose-monoacetals, whereas weaker aldehydes favour xylofuranose acetalization due to the high ring strain in pyranose acetals. The energetically favoured furanose diacetals dominate the product distribution over extended reaction time regardless of aldehyde types and reaction pathways. Measurements of the xylose tautomer ratio in the reaction conditions highlighted the importance of xylose isomerization in forming furanose acetals. These mechanistic insights not only explain the evolution of reaction intermediates but also aid in identifying potential products for sustainable chemical synthesis.
Peptide-Reinforced Photocrosslinkable PEG-based Hydrogels
(RSC Applied Polymers, 2026-01-05) Russell, Sam; Jang, Daseul; Thomas ,Jessica; Grysan, Patrick; Sprandl, Linus; Biesalski, Markus; Korley, LaShanda T.J.; Bruns, Nico
Hydrogels are polymer networks that swell in aqueous solvents. These materials have applications in many fields, including drug delivery, tissue engineering, and soft robotics. For example, polyethylene glycol (PEG) diacrylate is often used as a light-curable crosslinker for the synthesis of PEG-based hydrogels, e.g., in bioinks for 3D printing. However, a common limitation of PEG hydrogels is their typically poor mechanical properties, particularly when in a swollen state. The mechanical strength of natural polymeric materials, such as spider silk and collagen, arises from the formation of hierarchical secondary protein structures that unfold under mechanical load. Here, we present a bio-inspired approach to reinforcing PEG-based hydrogels that mimic these hierarchical structures by incorporating poly(β-benzyl-L-aspartate) (PBLA) blocks between cross-linking end groups and PEG chain segments. We used this peptide-containing crosslinker in combination with a small hydrophilic comonomer, 2-hydroxyethyl acrylate, to synthesise PHEA-linked by-(PBLA-b-PEG-b-PBLA) conetworks with tailored compositions, yielding improved and tailorable mechanical properties. This approach affords hydrogels with increased strength and toughness while retaining the networks’ swelling ability. This research presents a promising avenue for developing robust photocrosslinkable hydrogels with broad practical applications.
Linearly scaled-up plasma-water biphasic DBD microreactors: Application to hydrogen peroxide synthesis and water decontamination
(ACS Sustainable Chemistry & Engineering, 2025-11-24) Camelia, Fabio; Dimitrakellisa, Panagiotis; Vlachosa, Dionisios G.
We previously demonstrated that a modular biphasic liquid water/helium plasma reactor can efficiently produce hydrogen peroxide (H2O2). Here we demonstrate that by increasing the reactor length and thus the residence time or the applied plasma power, we can increase the outlet H2O2 concentration in the aqueous phase (an example of 39 mM is showcased) while using an argon plasma. By introducing spatially resolved optical emission spectroscopy (OES), we reveal an increasing water-produced ·OH radical concentration along the tubular reactor and correlate the ·OH production with the H2O2 concentration. High peroxide concentrations achieved through a straightforward linear reactor scale-up are suitable for green partial oxidation reactions and biochemical and environmental decontamination. This potential is exemplified by showcasing the complete and ultrafast continuous flow decolorization of an aqueous solution of highly concentrated (300 mg L–1) methylene blue (MB).
Tutorial: Machine-Learning-Based CREASE-2D Analysis of 2D SAXS Profiles to Characterize Anisotropic Nanostructures in Soft Materials
(ACS Measurement Science Au, 2025-11-26) Reddy Akepati, Sri Vishnuvardhan; Gupta, Nitant; Shah, Jay; Kronenberger, Stephen; Venkat, Vaibhav; Sridhar, Rohan Adhikari; Bianco, Simona; Adams, Dave J.; Jayaraman, Arthi
We present a tutorial to guide users on how to extend the Computational Reverse Engineering Analysis of Scattering Experiments-2D (CREASE-2D) framework to interpret their experimental two-dimensional small-angle scattering (SAS) data from soft materials (e.g., polymers, peptide amphiphiles, biomolecular fibrils). Unlike most traditional SAS analysis approaches, which typically rely on azimuthally averaged one-dimensional (1D) profiles, CREASE-2D utilizes the complete 2D scattering profile to reveal information about anisotropy in the structure. In past applications, CREASE has provided insights into complex structural features, including the cross-sectional shapes of assembled nanostructures and dispersity in these features, which are difficult to discern with existing analytical models. While (1D-) CREASE has been applied to SANS and SAXS data, this tutorial shares the steps for implementing CREASE-2D using an example of a dipeptide solution system, for which we have SAXS data. We present details for these steps involved in using CREASE-2D to interpret SAXS profiles: how to preprocess SAXS data, define relevant structural features, generate three-dimensional real-space structures for specific values of these features, train a machine learning (ML) surrogate model to predict scattering profiles for given structural features, and optimize these features using genetic algorithms (GA). Then, we use these steps to interpret complex 2D-SAXS data collected from dipeptide solutions that, in microscopy images, exhibit nanoscale structures that could be elliptical tubes/flat tapes/cylinders or a combination of these cross sections. Open-source codes, computational hardware, and software requirements, as well as the strengths and limitations of this protocol, are also presented. We expect researchers working with (soft) biomaterials, peptide amphiphiles, amphiphilic polymer solutions, polymer nanocomposites, and blends of particles/polymers will find this CREASE-2D method and this tutorial of use.
Metabolite-responsive scaffold RNAs for dynamic CRISPR transcriptional regulation
(Nucleic Acids Research, 2025-11-24) Stohr, Anthony M; Hansen, Helena; Richards, Blake; Park,Hayeon; Goncalves, Antonio G; Agrawal., Ayushi; Blenner, Mark; Wilfred Chen
CRISPR activation is a powerful tool to upregulate a vast array of genes in many different contexts. However, there are few dynamic CRISPR transcriptional programs, which limit its usage in the creation of living biosensors, self-regulating microbial factories, or conditional therapeutics. Here, we address this limitation by embedding a molecular switch directly into a guide RNA to create a combined sensor–actuator called a metabolite-responsive scaffold RNA (MR-scRNA). We demonstrate the regulatory potential for MR-sc RNAs by conditionally activating genes in three different kingdoms of life. We create MR-scRNAs responsive to two distinct metabolites, theophylline and tryptophan, by swapping the molecular switch used. MR-scRNAs respond quickly in a dose-dependent manner specifically to their target metabolite and enhance biochemical production when used as a dynamic regulator of pathway enzyme expression. The broad functionality and ease of design of the MR-scRNAs offer a promising tool for dynamic cellular regulation.
Reversible temperature-induced shape transition of Pt nanoparticles supported on Al2O3
(Nanoscale Advances, 2025-11-07) Pool Mazun, Ricardo; Khan, Salman A.; Liao, Vinson; Hansen, Thomas W.; Yousuf, Md Raian; Yang, Piaoping; Shrotri, Abhijit; Hoffman, Adam S.; Bare, Simon R.; Vlachos, Dionisios G.; Karim, Ayman M.
Supported platinum catalysts are widely used in industry for hydrogenation reactions. The variations of the electronic and geometric properties of Pt nanoparticles due to temperature can greatly affect their reactivity. In this work, we use in situ X-ray absorption spectroscopy and environmental transmission electron microscopy to study the effect of H2 and temperature on the shape and electronic properties of 1.8 nm average diameter Pt nanoparticles supported on Al2O3. We utilize actively trained machine learning potentials with uniform acceptance force-bias Monte Carlo (fbMC) to estimate the structural distribution of Pt15/g-Al2O3 (110) clusters at finite temperatures. Our predicted cluster geometries are consistent with experimental data showing the nanoparticles reversibly change shape from 3D hemispheres at low temperatures (35–100 °C) to 2–2.5D rafts at higher temperatures (200–400 °C). Furthermore, experiments and computations indicate that the contraction in Pt–Pt bond distances and higher electron density on Pt at higher temperatures are attributed primarily to the change in nanoparticle shape and associated increased interaction with Al2O3. Our results show the fluxional nature of supported Pt nanoparticles driven by temperature changes.
MemorySeq identifies heritable epigenetic phenotypes that initiate cell culture stress tolerance in CHO cells
(iScience, 2025-09-12) Grissom, Spencer; Dixon, Zachary; Singh, Abhyudai; Blenner, Mark
During manufacturing batches, Chinese hamster ovary (CHO) cells encounter critical levels of environmental stressors which can significantly reduce cell health and productivity. Therefore, stress tolerance must be considered during selection of a suitable host. In this study, we employ a population-based transcriptomic method, referred to as MemorySeq, and differential gene expression analysis on stress-shocked CHO cells to identify stress responsive biomarkers. These biomarkers exhibit transient and intermediate heritable memory states characteristic of epigenetic switches and transcriptional bursting. Using this workflow, 199 genes were found to exhibit transcriptional variability characteristic of two-state systems with switching that forms four network communities of co-fluctuating genes. These communities were enriched in genes related to the regulation of apoptotic processes, gene expression, and metabolic pathways. Seven genes were identified as promising biomarkers of stress-resistance. Genetic engineering methods may be employed in the future to bias clonal populations toward higher stress tolerance to manufacturing stress.
Low-Q Asymptotic Behavior of the Effective Structure Factor Yields Model-Independent Radius of Interparticle Interaction (Ri)
(ACS Measurement Science Au, 2025-11-07) Edwards, Chelsea E. R.; Leite, Wellington C.; Liu, Yun
Guinier analysis has been extensively used in academic and industrial research settings to obtain the model-independent size of a polymer, protein, or colloid in solution from small-angle scattering data. Using the Guinier model, the radius of gyration (Rg) is extracted from the form factor at low Q. Here, we develop an analogous approach for analyzing the effective structure factor data at low Q to extract a model-independent radius of interaction potential, Ri. Whereas Rg describes how spread out the scattering length density distribution of particles is from their center of mass, Ri is an effective root-mean-square distance that quantifies how far the interparticle correlation deviates from its ideal gas configuration due to interactions. We demonstrate this novel analysis method by applying it to experimental small-angle neutron scattering data on lysozyme protein solutions. We discuss its broad implications for analysis of low-Q asymptotic X-ray and neutron scattering data, where Guinier analysis is traditionally applied.
Short term hemodynamic effects of atrial fibrillation in a closed-loop human cardiac-baroreflex system
(PLoS ONE, 2025-10-29) Adeodu, Oluwasanmi; Gee,Michelle; Mahmoudi, Babak; Vadigepalli, Rajanikanth; Kothare,Mayuresh V.
Atrial fibrillation (AF) remains the leading cardiac cause of stroke and AF-related death rate in the United States has been increasing for over twenty years. While the effect of standalone AF on heart rate is well established, there is a lack of clarity on its impact on other critical hemodynamic metrics. This is ostensibly due to interaction with other common comorbidities, especially hypertension. In addition, AF has a complex relationship with the state of the baroreflex. Evidence indicates that baroreflex sensitivity (BRS), the ability of the intrinsic cardiac control system to initiate parasympathetic response, is suppressed during AF. Therefore, a proper assessment of the hemodynamic impact of AF must take the state of the baroreflex into consideration. In this paper, we present a lumped parameter model of the human cardiovascular-baroreflex system that adequately translates AF-induced electrophysiological changes to measurable hemodynamic effects. We consider the stochastic effects of the electrical disruption in the sinus node, the absence of atrial contraction and BRS suppression. Our model provides insight into the impact of standalone AF on key benchmarks: heart rate, arterial pressure and stroke volume, under varying degrees of BRS suppression. In addition, the development of a tractable mathematical model is essential for the in-silico evaluation of emerging neuromodulation therapies for AF. Our model predictions are in agreement with published clinical data and suggest that high blood pressure during standalone AF is strongly dependent on the extent of damage to the baroreflex, which may explain conflicting reports of AF-related hypertension and normotension.
Evaluation of “Difficult-to-Express” Monoclonal Antibodies in a CHO-Based Hybrid Site-Specific Integration System Under Industrially Relevant Conditions
(Biotechnology Journal, 2025-08-17) Szkodny, Alana C.; Lee, Kelvin H
Variation in the primary sequence of monoclonal antibodies (mAbs) can negatively affect their behavior in biopharmaceutical manufacturing platforms, and efforts to identify mAbs with poor “developability” characteristics lack robust methods for assessing mAb expression from an industrially relevant platform. Recent advancements in site-specific integration-based (SSI) platforms in Chinese hamster ovary (CHO) cells can mitigate the high transcriptional variation observed with random integration and the low industrial relevance of transient expression by providing a flexible platform for mAb expression from a consistent clonal background. This work applies a novel SSI-based expression system capable of generating isogenic cell pools in less than 1 month to systematically compare the expression of ten sequence variants of two therapeutically relevant mAbs from two genomic loci under industrially relevant culture conditions. Eight single amino acid mutations in trastuzumab resulted in reduced productivity compared to the wild-type mAb in batch cultures, and three mutations maintained a low-expressing phenotype in fed-batch cultures. The mutations resulted in variant-specific patterns of decreased domain stability and increased ER stress. The application of industrially relevant SSI systems in developability workflows could strengthen the understanding of the sequence determinants of mAb expression to improve mAb design, candidate selection, and process development decisions.
Small Angle X-Ray Scattering Studies on the Effects of Ultra Shear Technology on Model Animal and Plant-Based Protein Solutions
(Journal of Food Process Engineering, 2025-05-19) Janahar, Jerish Joyner; Hu, Hetian; Balasubramaniam, V. M.; Teixeira, Susana C. M.
The effects of shear, temperature, and high pressure on model solutions of bovine milk and plant proteins were investigated. Samples of bovine β-lactoglobulin (BLG), pea lectin (PL), and their mixture (MIX) were treated by high-pressure processing (HPP) and ultra-shear technology (UST). BLG and PL are known for their allergenic properties, and processing conditions can potentially be used to decrease allergenicity, as well as engineer beverage properties of interest. Small angle X-ray scattering (SAXS) and confocal laser scanning microscopy were used to measure the impact of processing on the protein solutions from the microscopic to the molecular scale. SAXS data were analyzed by various approaches to assess changes in protein size and shape, oligomerization, and aggregation. The results are consistent with the BLG sensitivity to shear, pressure, and temperature. The pressure holding time was shown to be critical and thermal effects at ambient pressure are distinct from those observed under pressure. Although some changes in shape were detected, PL showed structural and colloidal resistance to the processing conditions applied. The MIX solutions appear to show a convolution of the effects observed on the isolated protein solutions, granting further investigation to clarify potential interactions between the proteins. These findings are valuable for the development of liquid beverages based on animal and plant proteins and their blends, enhancing control over functional properties and expanding their applications in food, nutraceuticals, and biomedical fields.
Nanostructured iron and nickel oxide aerogels revolutionizing asphaltene removal in hydrocarbon processing
(Scientific Reports, 2025-04-13) Babaei, Elahe; Bazyari, Amin; Shojaei, Behzad; Thompson, Levi T.
Asphaltenes, complex molecules in crude oil, cause significant challenges in oil production and refining due to their tendency to form agglomerates and precipitate. This study investigates the effectiveness of preparation method of metal oxide-based adsorbents (NiO and Fe2O3) in removing asphaltenes. Nanostructured NiO and Fe2O3 xerogels and aerogels were produced through the Pechini-type and epoxide-derived sol − gel methods and employed for the adsorption of Ap1, a specific asphaltene extracted from Iranian crude oil. The nanomaterials were characterized by XRD, N2 adsorption-desorption, FE-SEM, EDS, and FT-IR. The influence of synthesis parameters, including citric acid to metal precursor molar ratio, type of adsorbent, textural characteristics, adsorption temperature, sol-gel protocols, calcination temperatures, and drying conditions, on the adsorbent performance was systematically studied. The NiO(X-300) xerogel synthesized by the epoxide-derived sol − gel with calcination at 300 °C exhibited the highest asphaltene adsorption capacity (q = 558 mg/g) among all xerogels tested. This capacity was 102% and 87% higher than those achieved on optimized reference NiO(P-600) (q = 276 mg/g) and Fe2O3(P-600) (q = 298 mg/g) adsorbents prepared by the Pechini-type method, respectively. The textural properties of both NiO and Fe2O3 materials were improved upon supercritical CO2 drying of the epoxide-derived gels, leading to the nanostructured NiO(A-300) (q = 699 mg/g) aerogel with significantly higher (~ 135%) asphaltene adsorption capacity than Fe2O3(P-600). For the best aerogels, NiO(A-300) and Fe2O3(A-450), the adsorption isotherms and the kinetic data were best fitted by the Jovanovic and the Elovich models, respectively. Ap1 exhibited rapid adsorption onto NiO(A-300) and NiO(X-300), achieving equilibrium within 20 min. The adsorption process was demonstrably spontaneous and exothermic.
Gas-Phase Oxidative Dehydrogenation of Ethane via NO/O2 Mixtures
(Industrial & Engineering Chemistry Research, 2025-05-13) Houck, Nicholas M.; Lobo, Raul F.
A kinetic and thermodynamic tubular reactor model for the oxidative dehydrogenation of ethane using homogeneous NO/O2 mixtures is developed to investigate the factors controlling the ethylene selectivity. Two primary mechanisms for ethane oxidative dehydrogenation are identified from the model: the reaction between NO and NO2 to form OH radicals drives ethane dehydrogenation at large NO volume fractions (≥5%), and H2O2 homolysis drives the reaction at low NO volume fractions (<5%). The reaction conditions were optimized for C2H6 conversion; a near three-fold increase in conversion was achieved with a final 53% ethane conversion and a 90% ethylene selectivity. CO, CO2, H2O, He, and N2 were explored to control the selectivity and reaction kinetics but had little impact. Under optimal conditions, most initial NO radicals were converted into NO2; replacement of NO with NO2 was investigated. NO2/O2 mixtures achieved a maximum of 38% ethane conversion at a 90% ethylene selectivity with a 5% NO2 conversion.
Catalytic Ethane Dehydrogenation Using a Porcupine Heating Element in a Joule-Heated Reactor
(Industrial & Engineering Chemistry Research, 2025-05-03) Burentugs, Enerelt; Lobo, Raul F.
A Joule-heated reactor containing a porous catalyst film deposited on a FeCrAl porcupine coil as the heating element was assembled and evaluated. The catalytic ethane dehydrogenation reaction was investigated utilizing a ZSM-5-supported MnOx catalyst. The system achieved an ethylene production rate of 31.3 mmolC2H4 gcat–1 h–1 with an ethylene selectivity exceeding 99% and 98 + % carbon balance and has a larger volumetric catalyst inventory than other Joule-heated reactor configurations reported to date. Despite ample insulation, computational fluid dynamics (CFD) simulations using ANSYS-CFX revealed axial and radial temperature gradients within the reactor, reducing the catalyst utilization effectiveness. The simulations demonstrate that adiabatic operation (perfect insulation and reflecting radiative heat back into the system) could double the ethylene production rate while improving energy efficiency. Mass and heat transfer resistances did not affect rates for catalyst layer thicknesses up to 135 μm. Analysis of the flow pattern revealed that buoyancy effects are significant at low inlet gas velocities (υin = 0.53 cm s–1 or Reinlet = 1.7), leading to reverse flows near the front and back coil terminals. These insights provide a foundation for optimizing Joule-heated reactor geometry, configuration, and performance.
Influence of Pressure Holding Time on Ovalbumin Solution Behavior via Small-Angle Neutron Scattering and Diffusing Wave Spectroscopy
(Journal of Food Process Engineering, 2025-04-14) Paul, Brian; Furst, Eric M.; Lenhoff, Abraham M.; Gilbert, Elliot P.; Wagner, Norman J.; Teixeira, Susana C. M.
Protein–protein interactions (PPIs) were characterized as a function of salt concentration and applied hydrostatic pressure for hen egg ovalbumin solutions. In situ data were collected using small-angle neutron scattering (SANS) at various concentrations of ammonium sulfate. The nondestructive nature of SANS allows for extended pressure holding times and the investigation of the reversibility of effects on PPIs. An empirical scaling developed previously is shown to capture the dependence of the reduced osmotic second virial coefficient on an effective pressure, combining osmotic and hydrostatic contributions. A comparison to small-angle X-ray scattering data for ovalbumin indicates enhanced net attraction at all conditions investigated with longer pressure holding times. Pressure effects on PPIs measured by SANS are shown not to be fully reversible in the presence of salt. Pressure-triggered aggregation was detected in the hours after depressurization at moderate salt concentrations, with slow recovery of pressure-induced attraction at high salt concentrations. Consistency is demonstrated between predicted solution viscosities and experimental observations from viscometry and in situ high-pressure diffusing wave spectroscopy. Furthermore, both the strength of ovalbumin PPIs and the relative solution viscosity display Barus-like scaling with effective pressure, exhibiting distinct pressure-viscosity coefficients from those of water.
Rheological, electrochemical, and microstructural properties of graphene oxides as flowable electrodes for energy storage applications
(RSC Advances, 2025-03-25) Pincot, André; Chin, Jeffrey; Murphy, Ryan; Burpo, F. John; Yi, Caspar; Chen, Edward; Bahaghighat, H. Daniel; Thompson, Benjamin; Yuk, Simuck F.; McKinley, Gareth H.; Nagelli, Enoch A.; Armstrong, Matthew
Interest in novel energy storage and conversion methods has prompted a broad interest in potential applications of conductive, complex materials such as graphene oxide slurries. Investigating the complex rheological, material, and chemical properties of chemically exfoliated graphene oxide suspensions is a potential means to address that interest. The morphological size and clustering, rheology, and electronic conductivity are determined to characterize the properties of graphene oxide (GO) suspensions from variable centrifugation speeds. The evolution of viscosity is then analyzed under oscillatory shear, steady shear, and transient shear characteristics. The resulting microstructure is then analyzed via neutron scattering analysis and imaged with scanning electron microscopy. Small-Angle Neutron Scattering (SANS) of a 500g centrifuged GO suspension determined that particle structure is locally flat sheet-like at lengths below 100 nm, crumpled aggregates of GO sheets with surface roughness at length scales from 200 nm to 2 μm, and a dense mass fractal of overlapping GO sheets extending up to length scales of 20 μm. Increased centrifugation force of the 1000g GO suspension corresponded with lower zero-shear viscosity, yield stress, and less pronounced thixotropic behavior. Rheo-dielectric measurements were conducted on 1000g and 500g GO suspensions to determine the ohmic resistance, electronic conductivity, and specific capacitance. The more fluid-like microstructure of 1000g with smaller monodispered thinning GO sheets in suspension had lower ohmic resistance and higher electronic conductivity compared to the 500g GO suspension with more polydispersed larger aggregates. The 1000g GO suspension had the highest specific capacitance of 4.63 mF cm−2 at the highest shear rate of 700 s−1 due to the higher frequency of particle–particle collisions during shear within the network of smaller and more intrinsically conductive GO sheets to store charge. Therefore, the results of this study have implications for future studies in flowable carbon nanomaterials in flow battery and flow capacitor technologies.
Life Cycle Assessment of Thermoelectrics: Ecological Viability in Intermittent Waste Heat Scenarios
(ACS Omega, 2025-04-01) Iyer, Rakesh Krishnamoorthy; Sabet, Morteza; Pilla, Srikanth
This study evaluates the ecological impacts of thermoelectrics (TEs) in stationary applications that periodically generate waste heat using life cycle assessment (LCA) methodology, a first of its kind. Six TE modules are analyzed for a periodic heat-emitting application: a natural gas-based power plant that meets only peak electricity demand. The analysis uses detailed inventories from an earlier study regarding the production and end-of-life stages of the TEs. The results show that while TEs are effective in conserving fossil fuels and lowering greenhouse gas emissions, they do not exhibit significant positive effects on other environmental impacts. These findings persist even when accounting for variations in TE conversion efficiency and lifetime and the implementation of a circular economy approach for recycling and repurposing TE modules. This suggests that the environmental suitability of TEs is predominantly influenced by the type of fossil energy source they replace, making current TEs unsuitable for stationary applications that periodically generate waste heat. The study also highlights the need for further research on the development of new, practical TEs that utilize nontoxic, abundant elements and are produced through less energy-intensive techniques.
Biophysical modelling of intrinsic cardiac nervous system neuronal electrophysiology based on single-cell transcriptomics
(The Journal of Physiology, 2025-03-12) Gupta, Suranjana; Gee, Michelle M.; Newton, Adam J. H.; Kuttippurathu, Lakshmi; Moss, Alison; Tompkins, John D.; Schwaber, James S.; Vadigepalli, Rajanikanth; Lytton, William W.
The intrinsic cardiac nervous system (ICNS), termed as the heart's ‘little brain’, is the final point of neural regulation of cardiac function. Studying the dynamic behaviour of these ICNS neurons via multiscale neuronal computer models has been limited by the sparsity of electrophysiological data. We developed and analysed a computational library of neuronal electrophysiological models based on single neuron transcriptomic data obtained from ICNS neurons. Each neuronal genotype was characterized by a unique combination of ion channels identified from the transcriptomic data, using a cycle threshold cutoff that ensured the electrical excitability of the neuronal models. The parameters of the ion channel models were grounded based on passive properties (resting membrane potential, input impedance and rheobase) to avoid biasing the dynamic behaviour of the model. Consistent with experimental observations, the emergent model dynamics showed phasic activity in response to the current clamp stimulus in a majority of neuronal genotypes (61%). Additionally, 24% of the ICNS neurons showed a tonic response, 11% were phasic-to-tonic with increasing current stimulation and 3% showed tonic-to-phasic behaviour. The computational approach and the library of models bridge the gap between widely available molecular-level gene expression and sparse cellular-level electrophysiology for studying the functional role of the ICNS in cardiac regulation and pathology.
Zeolite-Encapsulated Ni Catalyst for the Direct Conversion of Mono- and Polysaccharides to Ethylene Glycol
(ACS Sustainable Chemistry and Engineering, 2025-04-25) Surendhran, Roshaan; Orazov, Marat; Lobo, Raul F.
We have developed a simple, scalable, postsynthetic treatment for the encapsulation of Ni nanoparticles inside MFI zeolites as size-selective hydrogenation catalysts. We show that size-selective sieving of glucose from glycolaldehyde by the Ni-MFI-type zeolites enables an improvement in ethylene glycol yield by minimizing sorbitol and mannitol formation. This property is applied for the direct conversion of glucose to ethylene glycol, which can achieve 63% yield with less than 2% sugar alcohols in batch operation at lower reaction temperatures than previously reported (170 °C vs 230 °C). This improvement in size selectivity and yield can be extended to polysaccharides. The impacts of catalyst loadings, temperature, pH, and substrate concentration were studied, and optimal conditions for high selectivity were identified for both glucose and starch.
Reversible CO2 Hydrogenation, Neutron Crystallography, and Hydride Reactivity of a Triiridium Heptahydride Complex
(Angewandte Chemie International Edition, 2025-04-01) Cherepakhin, Valeriy; Do, Van K.; Chavez, Anthony J.; Kelber, Jacob; Klein, Ryan A.; Novak, Eric; Cheng, Yongqiang; Wang, Xiaoping; Brown, Craig M.; Williams, Travis J.
The authors report the structure, reactivity, and catalytic utility of a triiridium complex, [Ir3H6(μ3-H)(PN)3]2+ (2-H, PN = (2-pyridyl)CH2PBut2). Despite its unusual stability to unsaturated organics, electrophiles, and even CF3SO3D, they find that complex 2-H catalyzes hydrogenation of CO2 to formate (TONIr = 9600) and reverse formic acid dehydrogenation (TONIr = 54 400). The hydrogenation operates via a reactive intermediate [Ir3H4(μ-H)4(PN)3]+ (5). Neutron crystallography and DFT-supported neutron vibrational spectroscopy of 2-H reveal Ir─H bond lengths and elucidate the vibration modes within the Ir3H7 core. Stoichiometric oxidation of 2-H produces four classes of iridium complexes of varied nuclearity and hydride structure: tetra- and pentanuclear clusters [Ir3H6(μ3-AuPPh3)(PN)3]2+ (2-Au) and [Ag{Ir2H4(μ-OAc)(PN)2}2]3+ (6) are generated using AuPPh3+ and AgOAc, respectively. Further oxidation to class [Ir2H3(μ-X)2(PN)2]+ is possible with AgOAc, Hg(OAc)2, or I2. Finally, a TEMPO/HCl system completely oxidizes the hydrides and gives [Ir2Cl4(μ-Cl)2(PN)2] (11). Graphical Abstract available at: https://doi.org/10.1002/anie.202501943 A novel triiridium heptahydride cluster catalyzes reversible CO2 hydrogenation. Foundational structural and reactivity studies that combine neutron crystallography and spectroscopy, electrochemistry, synthetic studies, and kinetics uncover previously elusive metal–metal cooperative reactivity that enables a unique approach to functionalizing CO2.

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