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Results for “co-assembly”

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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28 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Interfacial Assembly and Jamming of Soft Nanoparticle Surfactants into Colloidosomes and Structured Liquids

Nanoparticle surfactant (NPS) offers a powerful strategy to generate all-liquid constructs that integrate the inherent properties of the NPs into 3D architectures. In this report using the co-assembly of fluorescent polymeric nanoparticles and amine-functionalized polyhedral oligomeric silsesquioxane, the assembly and jamming behavior of a new type of NPS at the oil-water interface is uncovered. Unlike "solid" inorganic nanoparticles, "soft" polymeric nanoparticles can reorganize when jammed, leading to a relaxation and deformation of the interfacial assemblies, for example, the 3D printed sugar-coated haw stick-like liquid tubules. With NPS serving as emulsifiers, stable Pickering emulsions are prepared that can be converted into robust colloidosomes with pH responsiveness, showing numerous potential applications for encapsulation and controlled release.

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

Confinement-Driven Segregation Enables Glassy Polymer Hybrid Materials Featuring Disordered Hyperuniformity and Integrated Self-Healing

The blending of glassy copolymer-brush modified colloids with a viscoelastic linear copolymer featuring intrinsic self-healing enabled disordered hyperuniform hybrid materials that combined mechanical robustness with structural color, processability, environmental stability, and the ability to recover structure and properties after incurring physical damage via ‘integrated self-healing’. Symmetric linear n-butyl acrylate/methyl methacrylate (BA/MMA) were co-assembled with asymmetric glassy BA/MMA statistical copolymer brush (silica) particles. ‘Confinement-driven segregation’ resulted in a microphase-separated morphology in which the linear copolymer resided within the interstitial regions of a rigid (∼1 GPa) copolymer brush particle template with disordered hyperuniform microstructure. Diffusion of the self-healing copolymer additive into damage regions drove the recovery after damage, along with the restoration of structural color due to the materials hyperuniform microstructure. The synergistic action of intrinsic and extrinsic healing mechanisms could provide a versatile platform for the bottom-up fabrication of multifunctional hybrid materials with increased damage resistance and functional longevity.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Symmetry-Breaking and Self-Sorting in Block Copolymer-Based Multicomponent Nanocomposites

Co-assembly of inorganic nanoparticles (NPs) and nanostructured polymer matrix represents an intricate interplay of enthalpic or entropic forces. Particle size largely affects the phase behavior of the nanocomposite. Theoretical studies indicate that new morphologies would emerge when the particles become comparable to the soft matrix's size, but this has rarely been supported experimentally. By designing a multicomponent blend composed of NPs, block copolymer-based supramolecules, and small molecules, a 3-D ordered lattice beyond the native BCP's morphology was recently reported when the particle is larger than the microdomain of BCP. The blend can accommodate various formulation variables. In this work, when the particle size equals the microdomain size, a symmetry-broken phase appears in a narrow range of particle sizes and compositions, which we named the "train track" structure. In this phase, the NPs aligned into a 3-D hexagonal lattice and packed asymmetrically along the c axis, making the projection of the ac and the bc plane resemble train tracks. Computational studies show that the broken symmetry reduces the polymer chain deformation and stabilizes the metastable hexagonally perforated lamellar morphology. Given the mobility of the multicomponent blend, the system shows a self-sorting behavior: segregating into two macroscopic phases with different nanostructures based on only a few nanometers NP size differences. Smaller NPs form "train track" morphology, while larger NPs form a "simple hexagon" structure, where the NPs take a symmetric hexagonal arrangement. Detailed structural evolution and simulation studies confirm the systematic-wide cooperativity across different components, indicating the strong self-regulation of the multicomponent system.

"train track" morphology↗
DOE OSTI2025

A blueprint for biomolecular condensation driven by bacterial microcompartment encapsulation peptides

Bacterial microcompartments are protein organelles with diverse metabolic capabilities. Their functional diversity is determined by an enzymatic core that is sequestered within a structurally conserved protein shell architecture. Segregation of protein cargo into the bacterial microcompartment is enabled by encapsulation peptides, which are short helical domains fused to core proteins through a disordered linker. Here, we investigate how encapsulation peptides drive multicomponent cargo assembly into biomolecular condensates. In vitro experiments supported by molecular dynamics simulations demonstrate the importance of both conserved hydrophobic packing and electrostatic interactions in stabilizing trimeric encapsulation peptide bundles. Topological rearrangements of encapsulation peptide domains can drive programmable liquid- or gel-like partitioning in vitro and in vivo. This partitioning is found to be encapsulation peptide-specific, modular, and can co-assemble at least three fluorescent reporters. In summary, we describe the molecular features necessary to drive biomolecular condensation using a widespread peptide tag. This work can serve as a blueprint for implementing encapsulation peptide biotechnology across diverse applications.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2026

Vicennial metagenomic time series unveils evolutionary dynamics of giant viruses in a freshwater ecosystem

Giant viruses play crucial ecological roles in aquatic ecosystems, yet their evolutionary dynamics in response to environmental changes, particularly in freshwater environments, are not well understood. We analyzed a 20-year time series (2000-2019) of 471 co-assembled metagenomes from Lake Mendota (USA) to reconstruct 1512 giant virus metagenome-assembled genomes, providing insights into viral genome evolution. Viruses in the order Imitervirales dominate the virome, remaining consistent across seasons and years. Our findings reveal gene duplication (23% of genes) and horizontal gene transfer (29% of genes) as key drivers of genomic innovation. A co-occurrence network analysis indicates increased virus-host interactions following the introduction of an invasive predatory zooplankton in 2009, highlighting potential hosts in Bigyra, Perkinsea, and Euglenozoa. While single nucleotide polymorphism analysis shows predominantly purifying selection in viral genes, there is a significant increase in positively selected genes post-invasion, particularly those related to infection. Comparative evolutionary analyses reveal that giant viruses exhibit genome-wide substitution rates similar to co-occurring bacteria but significantly slower than smaller dsDNA phages, suggesting both stability and adaptability. Our study demonstrates that freshwater giant viruses employ various evolutionary strategies to respond to environmental change. These results underscore their significant yet often underappreciated role in freshwater ecosystem dynamics.

Vasquez, Yumary M↗
DOE OSTI2024

Biomimetic mineralization of positively charged silica nanoparticles templated by thermoresponsive protein micelles: applications to electrostatic assembly of hierarchical and composite superstructures

High information content building blocks offer a path toward the construction of precision materials by supporting the organization and reconfiguration of organic and inorganic components through engineered functions. Here, we combine thermoresponsiveness with biomimetic mineralization by fusing the Car9 silica-binding dodecapeptide to the C-terminus of the (VPGVG) 54 elastin-like polypeptide (ELP). Using small angle X-ray scattering, we show that the short Car9 cationic block is sufficient to promote the conversion of disordered unimers into 30 nm micelles comprising about 150 proteins, 5 °C above the transition temperature of the ELP. While both species catalyze self-limiting silica precipitation, micelles template the mineralization of highly monodisperse (62 nm) nanoparticles, while unimers yield larger polydisperse species. Strikingly, and unlike traditional synthetic silica, these particles exhibit a positive surface charge, likely due to cationic Car9 sidechains projecting from their surface. Capitalizing on the high monodispersity and positive charge of the micelle-templated products, we use smaller silica and gold particles bearing a native negative charge to create a variety of superstructures via electrostatic co-assembly. Furthermore, this simple biomimetic route to positively charged silica eliminates the need for multiple precursors or surface modifications and enables the rapid creation of single-material and composite architectures in which components of different sizes or compositions are well dispersed and integrated.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

KBase Narrative - Metabolic_reconstruction_ETDI_mangrove

Mangroves are complex and dynamic coastal ecosystems under frequent fluctuations in physicochemical conditions related to the tidal regime. The frequent variation in organic matter concentration, nutrients, and oxygen availability, among other factors, drives the microbial community composition, favoring syntrophic populations harboring a rich and diverse, stress-driven metabolism. Mangroves are known for their carbon sequestration capability, and their complex and integrated metabolic activity is essential to global biogeochemical cycling. Here, we present a metabolic reconstruction based on the genomic functional capability and flux profile between sympatric MAGs co-assembled from a tropical restored mangrove.

Laux, Marcele↗
DOE OSTI2026

From Reads to Function Workshop - Milano 2026

The Bicocca Sampling Days (BSDs) model offers a reproducible “citizen science” framework integrating research, education, and public engagement through large-scale microbiome sampling, followed by a workshop of data analysis on select samples. We identified 9 bacterial and archaeal metagenome-assembled genomes from six soil samples across three separate sampling days in two approaches with indidivual sample and replicate co-assembly spanning three unique classes, providing genomic insights into microbial nutrient cycling in these systems.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Supported Pt Nanoparticles on Mesoporous Titania for Selective Hydrogenation of Phenylacetylene

Semi-hydrogenation of alkynes to alkenes is one of the most important industrial reactions. However, it remains technically challenging to obtain high alkene selectivity especially at a high alkyne conversion because of kinetically favorable over hydrogenation. In this contribution, we show that supported ultrasmall Pt nanoparticles (2.5 nm) on mesoporous TiO2 (Pt@mTiO2) remarkably improve catalytic performance toward semi-hydrogenation of phenylacetylene. Pt@mTiO2 is prepared by co-assembly of Pt and Ti precursors with silica colloidal templates via an evaporation-induced self-assembly process, followed by further calcination for thermal decomposition of Pt precursors and crystallization of mTiO2 simultaneously. As-resultant Pt@mTiO2 discloses a high hydrogenation activity of phenylacetylene, which is 2.5 times higher than that of commercial Pt/C. More interestingly, styrene selectivity over Pt@mTiO2 remains 100% in a wide phenylacetylene conversion window (20–75%). The styrene selectivity is >80% even at 100% phenylacetylene conversion while that of the commercial Pt/C is 0%. The remarkable styrene selectivity of the Pt@mTiO2 is derived from the weakened styrene adsorption strength on the atop Pt sites as observed by diffuse reflectance infrared Fourier transform spectroscopy with CO as a probe molecule (CO-DRIFTS). Our strategy provides a new avenue for promoting alkyne to alkene transformation in the kinetically unfavorable region through novel catalyst preparation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

A standardized quantitative analysis strategy for stable isotope probing metagenomics

ABSTRACT Stable isotope probing (SIP) facilitates culture-independent identification of active microbial populations within complex ecosystems through isotopic enrichment of nucleic acids. Many DNA-SIP studies rely on 16S rRNA gene sequences to identify active taxa, but connecting these sequences to specific bacterial genomes is often challenging. Here, we describe a standardized laboratory and analysis framework to quantify isotopic enrichment on a per-genome basis using shotgun metagenomics instead of 16S rRNA gene sequencing. To develop this framework, we explored various sample processing and analysis approaches using a designed microbiome where the identity of labeled genomes and their level of isotopic enrichment were experimentally controlled. With this ground truth dataset, we empirically assessed the accuracy of different analytical models for identifying active taxa and examined how sequencing depth impacts the detection of isotopically labeled genomes. We also demonstrate that using synthetic DNA internal standards to measure absolute genome abundances in SIP density fractions improves estimates of isotopic enrichment. In addition, our study illustrates the utility of internal standards to reveal anomalies in sample handling that could negatively impact SIP metagenomic analyses if left undetected. Finally, we present SIPmg , an R package to facilitate the estimation of absolute abundances and perform statistical analyses for identifying labeled genomes within SIP metagenomic data. This experimentally validated analysis framework strengthens the foundation of DNA-SIP metagenomics as a tool for accurately measuring the in situ activity of environmental microbial populations and assessing their genomic potential. IMPORTANCE Answering the questions, “who is eating what?” and “who is active?” within complex microbial communities is paramount for our ability to model, predict, and modulate microbiomes for improved human and planetary health. These questions can be pursued using stable isotope probing to track the incorporation of labeled compounds into cellular DNA during microbial growth. However, with traditional stable isotope methods, it is challenging to establish links between an active microorganism’s taxonomic identity and genome composition while providing quantitative estimates of the microorganism’s isotope incorporation rate. Here, we report an experimental and analytical workflow that lays the foundation for improved detection of metabolically active microorganisms and better quantitative estimates of genome-resolved isotope incorporation, which can be used to further refine ecosystem-scale models for carbon and nutrient fluxes within microbiomes.

54 ENVIRONMENTAL SCIENCES↗