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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Revealing and Engineering Assembly Pathways of 3D DNA Origami Crystals

Recent developments in nanomaterial self-assembly demonstrate the capability to create tailored nanostructures by engineering both the binding coordination and specificity of interactions between material subunits. DNA origami frames allow for the design and fabrication of a broad variety of ordered 3D nanoscale architectures through self-assembly, facilitated by frame-to-frame bonds with designable strength and specificity. While the bond design is critical to lattice formation, the assembly process itself is often dependent on a thermal pathway. Highly ordered nanoscale frameworks, assembled from DNA frames, are predominantly crystallized through thermal annealing pathways that typically follow a “slow” cooling approach, with experiments on the time scale of days yielding DNA origami crystals in the range of 1−10 μm. This extended assembly time scale hinders the study of crystal formation pathways, necessitating a deeper understanding of factors governing successful annealing. Lack of insight into time scale also presents a practical limitation for material fabrication. Here, we investigate key factors affecting lattice assembly pathways and demonstrate that precise engineering of assembly conditions greatly reduces assembly times by up to nearly 2 orders of magnitude. We evaluate the nucleation and growth of crystals via optical and electron microscopy, and small-angle X-ray scattering techniques, mapping the time−temperature-transformation of superlattices from the melt through single-crystal optical tracking. The results show that origami frame assembly can be described by classical nucleation and growth theory, which can, in turn, be used to prescribe the growth of the crystals. Lastly, these findings are applied to demonstrate thermal pathway-dependent assembly, forming distinct assemblies based on different thermal annealing profiles.

36 MATERIALS SCIENCE↗
DOE OSTI2025

RT-EZ: A Golden Gate Assembly Toolkit for Streamlined Genetic Engineering of Rhodotorula toruloides

For economic and sustainable biomanufacturing, the oleaginous yeast Rhodotorula toruloides has emerged as a promising platform for producing biofuels, pharmaceuticals, and other valuable chemicals. However, genetic manipulation of R. toruloides has been limited by its high GC content and the lack of a replicating plasmid, necessitating gene integration into the genome of the yeast. To address these challenges, we developed the RT-EZ (R. toruloides Efficient Zipper) toolkit, a versatile tool based on Golden Gate assembly, designed to streamline R. toruloides engineering with improved efficiency and flexibility. The RT-EZ toolkit simplifies vector construction by incorporating new features such as bidirectional promoters and 2A peptides, color-based screening using RFP, and sequences optimized for both Agrobacterium tumefaciens-mediated transformation (ATMT) and easy linearization, enabling straightforward selection and transformation. Notably, the RT-EZ kit can be used to construct an expression cassette with four different genes in one assembly reaction, significantly improving vector construction speed and efficiency. The utility of the RT-EZ toolkit was demonstrated through the successful synthesis of arachidonic acid in R. toruloides by coexpressing fatty acid elongases and desaturases. Furthermore, this result underscores the potential of the RT-EZ toolkit to advance synthetic biology in R. toruloides, providing a streamlined method for addressing genetic engineering challenges in the yeast.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Rational Modulation of Plant Root Development Using Engineered Cytokinin Regulators

Achieving precise control over quantitative developmental phenotypes is a key objective in plant biology. Recent advances in synthetic biology have enabled tools to reprogram entire developmental pathways; however, the complexity of designing synthetic genetic programs and the inherent interactions between various signaling processes remains a critical challenge. Here, we leverage Type-B response regulators to modulate the expression of genes involved in cytokinin-dependent growth and development processes. We rationally engineered these regulators to modulate their transcriptional activity (i.e., repression or activation) and potency while reducing their sensitivity to cytokinin. By localizing the expression of these engineered transcription factors using tissue-specific promoters, we can predictably tune cytokinin-regulated traits. As a proof of principle, we deployed this synthetic system in Arabidopsis thaliana to either decrease or increase the number of lateral roots. The simplicity and modularity of our approach makes it an ideal system for controlling other developmental phenotypes of agronomic interest in plants.

Cell signaling↗
DOE OSTI2025

Engineered Membrane Vesicle Production via oprF or oprI Deletion Has Distinct Phenotypic Effects in Pseudomonas putida

Membrane vesicle (MV) production is a natural phenomenon in Gram-negative bacteria and represents an emerging synthetic biology tool for the secretion of biomolecules or bioproducts. Manipulation of membrane components has proven successful in enhancing MV production. However, the impact of membrane disruptions on strain fitness and protein composition warrants further investigation for the use of MVs in industrial bioprocesses. Here, we identify and characterize two genetic engineering strategies for inducing hypervesiculation-deletion of genes for the outer membrane porin OprF or the lipoprotein OprI-in the commonly used platform Pseudomonas putida KT2440. Deletion of oprI generated up to a 1.5-fold increase in MVs, larger MVs with a greater proportion of outer membrane proteins, and no significant impact on strain fitness compared to wild type. In contrast, deletion of oprF, relative to wild type, generated up to a 4-fold increase in MVs but diminished growth, permeabilized membranes, and increased cytosolic protein packaging. Both hypervesiculation phenotypes increased nontargeted and MV-targeted mNeonGreen extracellular signal by up to 6-fold, demonstrating vesiculation as a mechanism for protein secretion. Despite increased blebbing of MVs from gene deletions, proteins involved in membrane biosynthesis were not elevated relative to wild type. Overexpression of gpsA, which initiates glycerophospholipid biosynthesis, in the ΔoprF background improved the membrane integrity by 37% and maintained MV formation, highlighting the importance of membrane biosynthesis in restoring the membrane in hypervesiculating strains. Together, this study provides genetic engineering strategies with corresponding phenotypic outcomes toward providing a synthetic biology toolset for MV deployment in P. putida.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2026

Engineering Escherichia coli for Urease-Driven Synthesis of Metal Oxide Nanomaterials

The development of functional nanomaterials with controlled morphologies is essential for advancements in medicine, electronics and computing, energy, catalysis, and environmental applications. However, conventional synthesis methods often demand high energy input and pose significant environmental challenges. Urease-based biomineralization presents an efficient, eco-friendly alternative for nanomaterial production under mild conditions. In this study, we engineered Escherichia coli ( E. coli ) to express a urease gene cluster from Sporosarcina pasteurii using CRAGE-Duet technology. The engineered strain successfully synthesized calcium carbonate and calcium phosphate crystals. Expanding the approach, we synthesized metal oxide nanoparticles, including hematite (Fe 2 O 3 ), and nanocrystalline anatase titanium dioxide (TiO 2 ). These nanomaterials were characterized by electron microscopy, demonstrating the potential of E. coli as a sustainable and versatile platform for green nanomaterial synthesis.

bacteria↗
DOE OSTI2025

Regioisomeric Engineering for Multicharge and Spin Stabilization in Two-Electron Organic Catholytes

Developing multicharge and spin stabilization strategies is fundamental to enhancing the lifetime of functional organic materials, particularly for long-term energy storage in multiredox organic redox flow batteries. Current approaches are limited to the incorporation of electronic substituents to increase or decrease the overall electron density or bulky substituents to sterically shield reactive sites. With the aim to further expand the molecular toolbox for charge and spin stabilization, we introduce regioisomerism as a scaffold-diversifying design element that considers the collective and cumulative electronic and steric contributions from all of the substituents based on their relative regioisomeric arrangements. Through a systematic study of regioisomers of near-planar aromatic cyclic triindoles and nonplanar nonaromatic cyclic tetraindoles, we demonstrate that this regioisomeric engineering strategy significantly enhances the H-cell cycling stability in the above two new classes of 2e – catholytes, even when current strategies failed to stabilize the multicharged species. Density functional theory calculations reveal that the strategy operates by redistributing the charge and spin densities while highlighting the role of aromaticity in charge stabilization. The most stable 2e – catholyte candidate was paired with a viologen derivative anolyte to achieve a proof-of-concept all-organic flow battery with 1.26–1.49 V, 98% capacity retention, and only 0.0117% fade/h and 0.00563% fade/cycle over 400 cycles (192 h), which is the highest capacity retention ever reported over 400 cycles in a multielectron all-organic flow battery setup. We anticipate regioisomeric engineering to be a promising strategy complementary to conventional electronic and steric approaches for multicharge and spin stabilization in other functional organic materials.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Engineering Enantiocomplementary Protoglobins for Stereoconvergent Construction of N -Alkylated α-Aminoketones

The synthesis of enantiopure compounds from a mixture of E/Z alkenes represents a notable challenge in synthetic chemistry. While enzymes excel in achieving unparalleled selectivity, their inherent specificity often confines activity to a single stereoisomeric substrate, consequently restricting the overall efficiency of such transformations. Here, we demonstrate that protoglobin-derived hemoproteins can catalyze stereoconvergent intermolecular amination using simple N-alkyl hydroxylamines as nitrene precursors, a transformation which remains elusive in synthetic chemistry. These engineered enzymes process E/Z mixtures of silyl enol ethers, enabling the precise incorporation of N-alkyl amino moieties (−NHAlkyl) into diverse molecular structures (up to 79% yield and 95% ee). Two complementary protoglobin variants were engineered using directed evolution to enable enantiodivergent synthesis of both enantiomers of α-aminoketones. This enzymatic platform achieves stereoconvergent and enantiodivergent transformations, facilitating the conversion of simple chemicals into an array of valuable pharmaceutical compounds featuring aminoketone functionalities.

Alcohols↗
DOE OSTI2026

Node Distortions as a Means of Defect Engineering in Zr-Based MOFs

Defect engineering in Zr-based metal–organic frameworks (Zr-MOFs) has focused primarily on missing-linker defects. However, recent studies suggest that node dehydroxylation–which creates distortions and coordinatively unsaturated Zr sites (Zr cus )–may have a more significant impact on properties. The present work uses pair distribution function (PDF) and thermogravimetric analysis coupled with systematic defect manipulation to study the effect of node dehydroxylation and missing-linker defects in UiO-66. By employing rapid heat treatment (RHT) under humid flow, we tracked the transition from high-symmetry [Zr 6 O 4 (OH) 4 ] 12+ to distorted [Zr 6 O 6 ] 12+ nodes. This structural evolution significantly improves As(V) uptake, whereas increasing the number of missing linkers–via chemical treatment or RHT of mixed-ligand frameworks–fails to enhance performance. Crucially, our detection of distorted nodes in as-synthesized UiO-66 also raises the possibility that these defects were silently present in many earlier studies that span various applications, where their role in governing performance may have been inadvertently overlooked. The present study challenges the prevailing “missing-linker” paradigm and establishes cluster dehydroxylation as a defect-engineering strategy to enhance Lewis-acidic performance in Zr-MOFs.

Adsorption↗
DOE OSTI2024

Isotope engineering for spin defects in van der Waals materials

Abstract Spin defects in van der Waals materials offer a promising platform for advancing quantum technologies. Here, we propose and demonstrate a powerful technique based on isotope engineering of host materials to significantly enhance the coherence properties of embedded spin defects. Focusing on the recently-discovered negatively charged boron vacancy center ($${{{{{{{{\rm{V}}}}}}}}}_{{{{{{{{\rm{B}}}}}}}}}^{-}$$ V B − ) in hexagonal boron nitride (hBN), we grow isotopically purified h 10 B 15 N crystals. Compared to$${{{{{{{{\rm{V}}}}}}}}}_{{{{{{{{\rm{B}}}}}}}}}^{-}$$ V B − in hBN with the natural distribution of isotopes, we observe substantially narrower and less crowded$${{{{{{{{\rm{V}}}}}}}}}_{{{{{{{{\rm{B}}}}}}}}}^{-}$$ V B − spin transitions as well as extended coherence timeT 2 and relaxation timeT 1 . For quantum sensing,$${{{{{{{{\rm{V}}}}}}}}}_{{{{{{{{\rm{B}}}}}}}}}^{-}$$ V B − centers in our h 10 B 15 N samples exhibit a factor of 4 (2) enhancement in DC (AC) magnetic field sensitivity. For additional quantum resources, the individual addressability of the$${{{{{{{{\rm{V}}}}}}}}}_{{{{{{{{\rm{B}}}}}}}}}^{-}$$ V B − hyperfine levels enables the dynamical polarization and coherent control of the three nearest-neighbor 15 N nuclear spins. Our results demonstrate the power of isotope engineering for enhancing the properties of quantum spin defects in hBN, and can be readily extended to improving spin qubits in a broad family of van der Waals materials.

Science & Technology - Other Topics↗
DOE OSTI2024

Development of a micro-combined heat and power powered by an opposed-piston engine in building applications

Residential homes and light commercial buildings usually require substantial heat and electricity simultaneously. A combined heat and power system enables more efficient and environmentally friendly energy usage than that achieved when heat and electricity are produced in separate processes. However, due to financial and space constraints, residential and light commercial buildings often limit the use of traditional large-scale industrial equipment. Here we develop a micro–combined heat and power system powered by an opposed-piston engine to simultaneously generate electricity and provide heat to residential homes or light commercial buildings. The developed prototype attains the maximum AC electrical efficiency of 35.2%. The electrical efficiency breaks the typical upper boundary of 30% for micro–combined heat and power systems using small internal combustion engines (i.e., <10 kW). Moreover, the developed prototype enables maximum combined electrical and thermal efficiencies greater than 93%. The prototype is optimally designed for natural gas but can also run renewable biogas and hydrogen, supporting the transition from current conventional fossil fuels to zero carbon emissions in the future. The analysis of the unit’s decarbonization and cost-saving potential indicate that, except for specific locations, the developed prototype might excel in achieving decarbonization and cost savings primarily in US northern and middle climate zones.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2025

Optical neural engine for solving scientific partial differential equations

Abstract Solving partial differential equations (PDEs) is the cornerstone of scientific research and development. Data-driven machine learning (ML) approaches are emerging to accelerate time-consuming and computation-intensive numerical simulations of PDEs. Although optical systems offer high-throughput and energy-efficient ML hardware, their demonstration for solving PDEs is limited. Here, we present an optical neural engine (ONE) architecture combining diffractive optical neural networks for Fourier space processing and optical crossbar structures for real space processing to solve time-dependent and time-independent PDEs in diverse disciplines, including Darcy flow equation, the magnetostatic Poisson’s equation in demagnetization, the Navier-Stokes equation in incompressible fluid, Maxwell’s equations in nanophotonic metasurfaces, and coupled PDEs in a multiphysics system. We numerically and experimentally demonstrate the capability of the ONE architecture, which not only leverages the advantages of high-performance dual-space processing for outperforming traditional PDE solvers and being comparable with state-of-the-art ML models but also can be implemented using optical computing hardware with unique features of low-energy and highly parallel constant-time processing irrespective of model scales and real-time reconfigurability for tackling multiple tasks with the same architecture. The demonstrated architecture offers a versatile and powerful platform for large-scale scientific and engineering computations.

Tang, Yingheng (ORCID:0009000153622546)↗
DOE OSTI2025

Quantum simulation of charge and exciton transfer in multi-mode models using engineered reservoirs

Quantum simulation enables studies of open-system dynamics in non-perturbative regimes by programming electronic, vibrational, and environmental interactions on comparable energy scales. Trapped ions offer this capability, combining spins, phonons, and tunable dissipation on one platform. We demonstrate an open-system quantum simulation of charge and exciton transfer in a multi-mode linear vibronic coupling model. Using tailored spin-phonon interactions with reservoir engineering, we emulate a system with two dissipative vibrational modes coupled to donor and acceptor sites and track its non-equilibrium dynamics. We continuously tune the system from the charge transfer regime to the vibrationally assisted exciton transfer regime and find that degenerate modes enhance transfer rates at large energy gaps, while non-degenerate modes activate pathways that reduce the energy-gap dependence. Thus, the presence of one additional vibration introduces interfering pathways and reshapes non-perturbative excitation transfer. Our results establish a scalable, hardware-efficient route to simulate vibronic processes with engineered environments.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2025

Unlocking expanded flagellin perception through rational receptor engineering

Abstract The surface-localized receptor kinase FLS2 detects the flg22 epitope from bacterial flagella. FLS2 is conserved across land plants, but bacterial pathogens exhibit polymorphic flg22 epitopes. Most FLS2 homologues possess narrow perception ranges, but four with expanded perception have been identified. Using diversity analyses, AlphaFold modelling and amino acid properties, key residues enabling expanded recognition were mapped to FLS2’s concave surface, interacting with the co-receptor and polymorphic flg22 residues. Synthetic biology enabled engineering of expanded recognition from QvFLS2 (Quercus variabilis) into a homologue with canonical perception. A similar approach enabled transfer ofAgrobacteriumperception from FLS2 XL (Vitis riparia) into VrFLS2. Evolutionary analyses across three plant orders showed residues under positive selection aligning with those binding the co-receptor and flg22’s C terminus, suggesting more alleles with expanded perception exist. Our experimental data enabled the identification of specific receptor amino acid properties and AlphaFold3 metrics that facilitate predicting FLS2–flg22 recognition. This study provides a framework for rational receptor engineering to enhance pathogen restriction.

Plant Sciences↗
DOE OSTI2025

Feature engineering descriptors, transforms, and machine learning for grain boundaries and variable-sized atom clusters

Abstract Obtaining microscopic structure-property relationships for grain boundaries is challenging due to their complex atomic structures. Recent efforts use machine learning to derive these relationships, but the way the atomic grain boundary structure is represented can have a significant impact on the predictions. Key steps for property prediction common to grain boundaries and other variable-sized atom clustered structures include: (1) describing the atomic structure as a feature matrix, (2) transforming the variable-sized feature matrix to a fixed length common to all structures, and (3) applying a machine learning algorithm to predict properties from the transformed matrices. We examine how these steps and different combinations of engineered features impact the accuracy of grain boundary energy predictions using a database of over 7000 grain boundaries. Additionally, we assess how different engineered features support interpretability, offering insights into the physics of the structure-property relationships.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Engineered enzymatic cascade converts diols to amino alcohols

Aliphatic amino alcohols such as 6-amino-1-hexanol are potential platform chemicals for a variety of advanced materials, but applications are currently limited by reagent costs. Aliphatic amino alcohols can currently be synthesized from biomass-derived diols at elevated temperatures and pressures using Ru-based catalysts that produce a mixture of amino-alcohol, diamine, and cyclic amine products. Replacing chemical amination with an enzymatic cascade would reduce resource needs and enable reactions under milder conditions. In this work, we characterized a two-enzyme cascade that selectively converts C4–C7 diols to the corresponding amino alcohols under aqueous conditions at room temperature and pressure. By engineering the rate-limiting enzyme and optimizing reaction conditions, we increased amino alcohol production nearly 30-fold, achieving a selectivity of 99%. The same enzyme cascade could also be used to convert amino alcohols into cyclic amines through reduction of the corresponding cyclic imine. This engineered cascade provides a green opportunity to sustainably synthesize asymmetric bifunctional platform chemicals.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Surface engineering of Pt nanocatalysts with transition metal oleates for selective catalysis: a case study on the hydrogenation of α,β-unsaturated aldehydes

Selective and active catalysts enable effective use of feedstocks, reduced energy consumption and waste generation. Tuning the electronic structure of heterogeneous metal nanocatalysts via their surface modifications is a promising strategy to design highly selective and active catalysts for the synthesis of harder to make and more cost-efficient products. Here, we introduce transition metal oleates as a new class of ligands to engineer the catalytically active and very selective surface in organic solvents. Using citral hydrogenation and 5 nm Pt NPs as a model reaction and model catalytic system, respectively, we show that surface engineering of Pt nanocatalysts with metal oleates allows synthesis of desired partially hydrogenated product (geraniol) with ∼90% conversion with selectivity over 93%. We demonstrate that the selective synthesis of the unsaturated alcohols catalyzed by Pt NPs modified by adsorption of the transition metal salts cannot be explained by the widely accepted mechanism of preferred coordination of C$=$O groups by Lewis acids (e.g. partially oxidized transition surface metals). Our results indicate that C$=$O groups prefer to bind to negatively charged surfaces. We propose the explanation on how the adsorption of transition metal oleates can result in the increased electron density at the surface of Pt nanoparticles. Our study not only provides reliable solutions to selective hydrogenation but opens a new possibility of using metal oleates for the electronic ligand effect.

Kwon, Soon Gu [Argonne National Laboratory (ANL), ↗
DOE OSTI2025

Unveiling the support effect in Pt-based catalysts for the selective catalytic oxidation of NH 3 under realistic diesel engine conditions

Pt catalysts have been widely used for the selective catalytic oxidation of NH 3 (NH 3 -SCO) in practical applications due to their high activity at low temperatures. However, more stringent regulations require further enhancement of low-temperature NH 3 -SCO activity. In this study, we investigated the influence of different supports, including aluminum oxide (Al 2 O 3 ), silica (SiO 2 ), and chabazite (CHA), on the NH 3 -SCO performance of Pt catalysts. Furthermore, our findings demonstrate that the Pt/CHA catalyst exhibited superior NH 3 -SCO performance under realistic diesel engine conditions, characterized by high space velocity and the presence of water vapor. Notably, the Pt/CHA catalyst achieved a significantly lower T 50 (temperature at which 50% NH 3 conversion is achieved) of 218 °C under conditions with both CO 2 and H 2 O, with a 56 °C reduction compared to the state-of-the-art Pt/Al 2 O 3 catalyst. The exceptional NH 3 -SCO performance is attributed to the high abundance of metallic Pt 0 species and the presence of rich and stable acid sites that facilitate NH 3 adsorption and activation. Furthermore, these results highlight CHA as a promising support for the Pt catalyst in NH 3 -SCO applications for diesel engine emission control.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Evaluating the efficiency of touch-spun scaffolds in producing dense cell cultures for tissue engineering applications

Developing efficient scaffolds for long-term cell cultivation remains a challenge in tissue engineering. Biomimetic approaches aim to create a three-dimensional (3D) extracellular matrix (ECM)-like fiber network with a tunable hierarchical structure to promote sufficient cell attachment, differentiation, and overall viability. Among the fiber fabrication methods documented in the literature, mechanical fiber drawing techniques, such as touch-spinning, have garnered significant research interest. This is due to the simplicity of the equipment, the ability to control fiber diameter and interfiber spacing at the nanoscale without the need for external fields, and the absence of specific requirements for material dielectric properties. Despite the advantages of mechanically drawn scaffolds in biomedical research, the methodologies for cell culturing and analysis for these materials have not been adequately addressed. In this study, we assess the potential of touch-spun scaffolds in promoting NIH/3T3-GFP fibroblast cell growth for tissue engineering applications. Polycaprolactone/polyethylene oxide (PCL/PEO)-based fiber arrays with a controlled interfiber spacing of 91.9 ± 25.0 μm (N = 50) were fabricated using a modified touch-spinning apparatus and then assembled into 2D and 3D scaffolds through additive manufacturing technology. A comparative cell analysis conducted for single- and multi-layered structures showed that the 3D touch-spun scaffolds support healthy growth of up to 6.5 million fibroblast cells within 21 days and offer enhanced cell viability compared to conventional 2D fiber scaffolds, as confirmed by the Presto Blue assay. Furthermore, the metabolic activity of fibroblasts on 3D scaffolds assessed by the MTT test is approximately four times higher than that of the positive control, making the 3D touch-spun materials ideal for long-term cell culture applications.

Peranidze, Kristina [University of Georgia, Athens↗