More Like this

1. A Generalized Machine-Learning Framework for Developing Alchemical Many-Body Interaction Models for Polymer-Grafted Nanoparticles

   https://doi.org/10.1021/acs.jctc.5c00901  

   Zhang, Melody Yiyuan; Lee, Shih-Kuang Alex; Glotzer, Sharon C; Lindsey, Rebecca K (October 2025, Journal of Chemical Theory and Computation)

   Polymer-grafted nanoparticles (PGNs) serve as highly customizable building blocks for technologically relevant self-assembled nanomaterials. Physics informed Inverse design strategies are crucial for expediting exploration of the massive associated design space by identifying optimal PGN attributes such as polymer length and grafting density to meet a target self-assembled structure. However, their success hinges on accurate description of how PGN interactions vary as a function of both particle positions and physical attributes. We introduce a framework to meet this need. Specifically, we develop an “alchemical” ML-IAM that describes how PGN interactions vary as a function of both inter-PGN distances and tunable PGN attributes, simultaneously. This model is an extension of the physics-informed and explicitly many-bodied ChIMES model. The resulting extended ChIMES (X-ChIMES) model is trained on PMF data for PGNs with varied polymer ligand length. We enable efficient training data generation by combining the forward-reverse steered molecular dynamics enhanced sampling approach with a grid-sampling scheme in the HOOMD-blue software package. We demonstrate the efficacy of ChIMES for generating CG models for PGNs with fixed design attributes, the development of the X-ChIMES model, and the application of the X-ChIMES model that enhances digital alchemy inverse-design simulations using HOOMD-blue and the ChIMES Calculator. This is the first application of ChIMES in modeling CG systems and coupling with an inverse design method to target nanomaterial self-assembly. 

   more » « less
2. Process-dependent hypersonic phonon dispersion of brush particle metamaterials

   https://doi.org/10.1039/D5NR04782J  

   Li, Qiqi; Ramdane, Iyad; Tarnsangpradit, Jirameth; Rembert, Pascal; Sainidou, Rebecca; Cang, Yu; Matyjaszewski, Krzysztof; Bockstaller, Michael R; Graczykowski, Bartłomiej; Fytas, George (April 2026, Nanoscale)

   The complex dynamical processes render PGN assembly structures susceptible for the arrest of metastable states, characterized by more pronounced phononic stop-band behavior. 

   more » « less
3. Effects of bentonite on physical, mechanical and barrier properties of cellulose nanofibril hybrid films for packaging applications.

   Zheng, M. (September 2019, Cellulose)

   There is an increasing attention to cellulose nanofibrils (CNFs) for food packaging applications due to their abundance, biodegradability, and low gas permeability. In this work, oxygen and water barrier performance is studied for bio-nanocomposite films formed by incorporation of two types of bentonite (PGN and PGV) at different loads (15, 30 and 45 wt%) into continuous CNF matrix. The resulting hybrid films were analyzed for their morphology, surface energy, mechanical strengths as well as water/oxygen barrier qualities. Both types of bentonite lowered the CNF degradation temperature and strength to some degree for reasons not so clear but perhaps due to partial disruption of the CNF H-bond network. It was revealed from microscopic study that clay particles form a layer within cellulose chains, resulting in alteration of composite structure. The contact angle analysis by polar and nonpolar liquids, suggested the PGN-containing samples were more hydrophilic; clay induced polar functionalities to the composite. While 15% PGN load reduced the water vapor transmission rate from 425 to 375 g/ m2 day, higher proportions of bentonite negatively affected this trend. Also, analysis of oxygen transmission rate showed the PGN effectively restricted the oxygen passage in dry state and to a lower extent at higher relative humidity. In WVTR analysis, PGN showed a superior performance over PGV attributable to its crystalline structure as evident in XRD patterns. The proposed hybrid CNF-BNT films in this study can present an eco-friendly alternative in packaging materials, especially where penetration of water vapor and oxygen is to be avoided. 

   more » « less
4. Characterizing the shear response of polymer-grafted nanoparticles

   https://doi.org/10.1063/5.0188494  

   Moussavi, Arman; Pal, Subhadeep; Wu, Zhenghao; Keten, Sinan (April 2024, The Journal of Chemical Physics)

   Grafting polymer chains to the surface of nanoparticles overcomes the challenge of nanoparticle dispersion within nanocomposites and establishes high-volume fractions that are found to enable enhanced material mechanical properties. This study utilizes coarse-grained molecular dynamics simulations to quantify how the shear modulus of polymer-grafted nanoparticle (PGN) systems in their glassy state depends on parameters such as strain rate, nanoparticle size, grafting density, and chain length. The results are interpreted through further analysis of the dynamics of chain conformations and volume fraction arguments. The volume fraction of nanoparticles is found to be the most influential variable in deciding the shear modulus of PGN systems. A simple rule of mixture is utilized to express the monotonic dependence of shear modulus on the volume fraction of nanoparticles. Due to the reinforcing effect of nanoparticles, shortening the grafted chains results in a higher shear modulus in PGNs, which is not seen in linear systems. These results offer timely insight into calibrating molecular design parameters for achieving the desired mechanical properties in PGNs. 

   more » « less
5. Plasma microbiome in COVID-19 subjects: an indicator of gut barrier defects and dysbiosis

   https://doi.org/https://doi.org/10.1101/2021.04.06.438634  

   22. Prasad, R; Patton, M. J; Floyd, J. L; Vieira, C. P; Fortmann, S; DuPont, M; Harbour, A; Jeremy, C. S; Wright, J; Lamendella, R; et al (January 2021, bioRxiv)

   The gut is a well-established route of infection and target for viral damage by SARSCoV-2. This is supported by the clinical observation that about half of COVID-19 patients exhibit gastrointestinal (GI) symptoms. We asked whether the analysis of plasma could provide insight into gut barrier dysfunction in patients with COVID-19 infection. Plasma samples of COVID-19 patients (n=30) and healthy control (n=16) were collected during hospitalization. Plasma microbiome was analyzed using 16S rRNA sequencing, metatranscriptomic analysis, and gut permeability markers including FABP-2, PGN and LPS in both patient cohorts. Almost 65% (9 out 14) COVID-19 patients showed abnormal presence of gut microbes in their bloodstream. Plasma samples contained predominately Proteobacteria, Firmicutes, and Actinobacteria. The abundance of gram-negative bacteria (Acinetobacter, Nitrospirillum, Cupriavidus, Pseudomonas, Aquabacterium, Burkholderia, Caballeronia, Parabhurkholderia, Bravibacterium, and Sphingomonas) was higher than the gram-positive bacteria (Staphylococcus and Lactobacillus) in COVID-19 subjects. The levels of plasma gut permeability markers FABP2 (1282±199.6 vs 838.1±91.33; p=0.0757), PGN (34.64±3.178 vs 17.53±2.12; p<0.0001), and LPS (405.5±48.37 vs 249.6±17.06; p=0.0049) were higher in COVID-19 patients compared to healthy subjects. These findings support that the intestine may represent a source for bacteremia and may contribute to worsening COVID-19 outcomes. Therapies targeting the gut and prevention of gut barrier defects may represent a strategy to improve outcomes in COVID19 patients. 

   more » « less