Angela Brown, ChBE Research Puiblication

Epigallocatechin gallate alters leukotoxin secretion and Aggregatibacter actinomycetemcomitans virulence (04 February 2021)

Angela Brown, En Hyung Chang

We and others have previously shown that epigallocatechin gallate (EGCg) inhibits the activity of an important virulence factor, leukotoxin (LtxA), produced by the oral bacterium Aggregatibacter actinomycetemcomitans, suggesting the potential use of this molecule as an anti-virulence strategy to treat periodontal infections. Here, we sought to better understand the effects of EGCg on toxin secretion and A. actinomycetemcomitans pathogenicity in a co-culture model.

Anand Jagota

Length of mucin-like domains enhances cell-Ebola virus adhesion by increasing binding probability (2 March 2021)

Xinyu Cui, Nicole Lapinski, Xiaohui (Frank) Zhang, Anand Jagota

Ebola and other viruses often stick to cells in the first stage of infection through spike-like protrusions.  Here, for the Ebola virus, we develop coarse-grained molecular models to study how the properties of the  protrusions affect adhesion.  This work will help identify potential therapies.

Kelly M. Schultz

Human mesenchymal stem cell-engineered length scale dependent rheology of the pericellular region measured with bi-disperse multiple particle tracking microrheology (February 2021)

John A. McGlynn, Kilian J. Druggan, Kiera J. Croland, Kelly M. Schultz

Human mesenchymal stem cell (hMSC) remodeling is a complex process across many length scales: single cross-links break on the nanometer scale, cellular extensions pull material and degrade paths through the scaffold to enable motility on the micrometer scale and bulk scaffold degradation occurs on macroscopic scales. We measure length scale dependent material properties during cell-mediated remodeling of the pericellular region using techniques developed in our laboratory, namely bi-disperse multiple particle tracking microrheology (MPT) and MPT. By characterizing evolving length scale dependent material properties, new materials can be designed which better mimic native tissue and instruct cell behavior.

Jonas Baltrusaitis, ChBE Research Puiblication

Surface chemistry of hydroxyapatite for sustainable n-butanol production from bio-ethanol (16 September 2021)

Jonas Baltrusaitis, Daniyal Kiani

Understanding the catalyst surface chemistry is of paramount importance for the accelerated development of structure-activity/selectivity relationships that form the basis for the rational design and optimization of catalysts at large. Here, we highlight the state-of-the-art understanding regarding the surface chemistry of hydroxyapatite (HAp)—a catalyst that enables the production of value-added alcohols from bio-ethanol.

Molecular Design of Supported MoOx Catalysts with Surface TaOx Promotion for Olefin Metathesis (23 February 2022)

Bin Zhang, Shuting Xiang, Anatoly I. Frenkel, Israel E. Wachs

Surface modification of Al2O3 by tantalum oxide shifted the anchoring sites of MoOx on Al2O3. These changes in anchoring sites of MoOx resulted in an increasing number of active sites with higher specific activity (TOF).

 

Single-pot Fabrication of Cellulose-Reinforced Solid Polymer Lithium-Ion Conductors (23 February 2022)

Helen Wong, Nian Liu, Elsa Reichmanis

Polymer electrolytes present a promising alternative to conventional liquid electrolytes for flexible power needed for portable electronic systems due to higher mechanical integrity and lower risk of leaking solvent. Here, we demonstrate a ‘single-pot’ synthetic approach using a non-toxic cellulose additive that affords a flexible, free-standing solid polymer electrolyte. The results providea path towards sustainable, polymer electrolytes with performance metrics suitable for applications having lower energy demand.Polymer electrolytes present a promising alternative to conventional liquid electrolytes for flexible power needed for portable electronic systems due to higher mechanical integrity and lower risk of leaking solvent. Here, we demonstrate a ‘single-pot’ synthetic approach using a non-toxic cellulose additive that affords a flexible, free-standing solid polymer electrolyte. The results provide a path towards sustainable, polymer electrolytes with performance metrics suitable for applications having lower energy demand. 


 
Miguel Gonzalez, Krysten Minnici, Bailey Risteen, Lei Wang, Lisa M. Housel, Genesis D. Renderos, Kenneth J. Takeuchi, Esther S. Takeuchi, Amy C. Marschilok, Tomas F. Fuller, Elsa Reichmanis

Rational design of battery systems with specific performance characteristics are needed to meet the growing, diverse needs of energy storage as batteries penetrate a diverse range of sectors from automobiles to consumer electronics, among others. Here, magnetite nanoparticles were surface modified with molecular entities containing different electronic and ionic conductivities to investigate how the local surface environment affected key battery characteristics. The results contribute to the growing toolset of chemical techniques to modify active materials to create battery systems with specific performance characteristics.  

Number of surface sites and turnover frequencies for oxide catalysts (January 2022)

Israel E. Wachs

 

Mark A. Snyder, Christopher J. Kiely, and Steven McIntosh

Tailored Coupling of Biomineralized CdS Quantum Dots to rGO to Realize Ambient Aqueous Synthesis of a High-Performance Hydrogen Evolution Photocatalyst (31 August 2020)

John Sakizadeh, Joseph P. Cline, Mark A. Snyder, Christopher J. Kiely, Steven McIntosh

We establish a green, biomineralization route for the efficient synthesis of nanostructured CdS-rGO photocatalysts. These materials can be utilized to directly generate hydrogen fuel from water using sunlight.

Israel Wachs and Jonas Baltrusaitis

New Mechanistic and Reaction Pathway Insights for Oxidative Coupling of Methane (OCM) over Supported Na2WO4/SiO2 Catalysts (2 August 2021)

Sagar Sourav, Yixiao Wang, Daniyal Kiani, Jonas Baltrusaitis, Rebecca R. Fushimi, Israel E. Wachs

Oxidative coupling of methane is a catalytic chemistry whereby methane from shale gas can be converted into valuable products such as ethylene and Ethane. By carefully controlling the synthesis of a promising catalyst, viz. Na2WO4/SiO2, and by using sophisticated spectroscopic techniques, we gained new insights into how the catalyst functions (i.e. the active site and reaction mechanism). Our results provide directions on how to discover new and improved catalysts.

Mark Snyder

Scalable Biomineralization of CdS Quantum Dots by Immobilized Cystathionine γ-Lyase (17 September 2021)

Nur Koncuy Ozdemir, Joseph P. Cline, Christopher J. Kiely, Steven McIntoshMark A. Snyder

Facile enzyme immobilization on inexpensive supports enables sustainable, green nanomanufacturing of remarkably consistent CdS quantum dots by regenerable enzymatic biomineralization.
 
Bin Zhang, Israel E. Wachs   
 
The specific oxide support was found to control the number of activated sites (Al2O3 ≫ ZrO2 > CeO2 > TiO2 > SiO2) and propylene metathesis activity (Al2O3 ≫ ZrO2 ≫ TiO2 ∼ CeO2 ∼ SiO2), revealing that the oxide support cation is a potent ligand for the surface ReOx sites. This new fundamental insight allows for tuning the catalytic activity of supported ReOx sites for olefin metathesis.
 
Jun-Kun Lai, Nicholas R. Jaegers, Bar Mosevitzky Lis, Mingyu Guo, Michael E. Ford, Eric Walter, Yong Wang, Jian Zhi Hu, Israel E. Wachs
 
Blurb: The catalyst structural and chemical changes occurring during activation and aging of supported VOx-WOx/TiO2 catalysts for selective catalytic reduction (SCR) of NOx with NH3 were investigated. The surface and bulk changes during activation and aging were monitored with a suite of in situ catalyst characterization studies. It was found that surface structural changes that enhance the concentration of surface NH4+* species, primarily associated with the surface VOx sites, are related to the efficient performance of supported VOx-WOx/TiO2 catalysts for the SCR reaction.

Induced activation of the commercial Cu/ZnO/Al203 catalyst for the steam reforming of methanol (20 January 2022)

Didi Li, Fang Xu, Xuan Tang, Sheng Dai, Tiancheng Pu, Xianglin Liu, Pengfei Tian, Fuzhen Xuan, Zhi Xu, Israel E. Wachs, Minghui Zhu 

An induced activation strategy was developed to manipulate the catalyst surface reconstruction process for the supported Cu/ZnO/Al2O3 catalyst for methanol steam reforming by controlling the composition of reducing agents during catalyst activation. This treatment resulted in increasing the long-term catalyst stability by threefold and catalytic activity enhanced by twofold.                                                                                  

Anisotropic Responsive Microgels Based on the Cholesteric Phase of Chitin Nanocrystals (23 December 2021)

Sujin Lee, Elsa Reichmanis, Mohan Srinivasarao

Anisotropic stimuli-responsive microgels based upon the cholesteric phase of chitin nanocrystals and N-isopropylacrylamide were designed and synthesized. As designed, the imprinted cholesteric phase induced an asymmetric response to temperature, leading to a change in shape and optical properties. Access to synthetic structures derived from cholesterics embedded within a polymer matrix will provide guidelines for designing biopolymer composites with programmable motion.

James F. Gilchrist

Chemical vs. mechanical microstructure evolution in drying colloid and polymer coatings (24 June 2020)

Thitiporn Kaewpetch, James F. Gilchrist

This study watches the structural rearrangement of particles within a drying film using 3D high speed confocal laser scanning microscopy.  The structural evolution is tied to the particle interactions and the drying conditions and has applications from industrial and automotive coatings to development of thin films for pharmaceutical drug delivery.

The Solution is the Solution: Data-Driven Elucidation of Solution-to-Device Feature Transfer for π-Conjugated Polymer Semiconductors (16 January 2022)

Connor P. Callaway, Aaron L. Liu, Rahul Venkatesh, Yulong Zheng, Myeongyeon Lee, Carson Meredith, Martha Grover, Chad Risko, Elsa Reichmanis

Data analytics techniques coupled with materials informatics provides opportunities to accelerate the discovery and development of organic semiconductors for electronic devices. This Perspective outlines steps required to incorporate a comprehensive informatics methodology into experimental development of polymer-based organic semiconductor technologies, where data-driven approaches offer predictive capabilities previously unattainable via traditional experimental means.

 
Kedar Joshia, James F. Gilchrist

This work investigates colloidal self-assembly and crystallization in convective deposition in the presence of surfactant.  We show that added SDS alters the flow patterns inside the thin film through Marangoni-driven surface stress, which then alters the time for the assembly. The added surfactant can permit more reliable conditions for monolayer coatings.

 
Chong Shen, Zhiyu Jiang, Lanfang Li, James F. Gilchrist, H. Daniel Ou-Yang 
 
This paper describes the use of electric and magnetic fields to control the direction and speed of induced-charge electrophoresis (ICEP) driven metallic Janus microrobots. A direct current (DC) magnetic field applied in the direction perpendicular to the electric field maintains the linear movement of particles in a 2D plane. Phoretic force spectroscopy (PFS), a phase-sensitive detection method to detect the motions of phoretic particles, is used to characterize the frequency-dependent phoretic mobility and drag coefficient of the phoretic force.
Srinivas Rangarajan, ChBE Research Puiblication

Computing a Global Degree of Rate Control for Catalytic Systems (5 November 2020)

Srinivas Rangarajan, Huijie Tian

In this paper, we discuss the concept and properties of variance-based global sensitivity analysis, as an expansion of local sensitivity metrics (such as the degree of rate control), for modeling and design of catalytic reaction systems.

Elsa Reichmanis

Data Science Guided Experiments Identify Conjugated Polymer Solution Concentration as a Key Parameter in Device Performance (11 August 2021)

Rahul Venkatesh, Yulong Zheng, Campbell Viersen, Aaron Liu, Carlos Silva, Martha Grover, Elsa Reichmanis

A data science approach identified polymer solution concentration as a key parameter that helps to define the electronic performance of semiconducting polymers. The results will accelerate the design and development of sustainable materials and processes for flexible devices in applications ranging from energy storage and conversion to ubiquitous sensors for the IoT (Internet of Things).

Experimental design of a “Snap-on” and standalone single-bed oxygen concentrator for medical applications (13 February 2021)

Rama Rao Vemula, Matthew D. Urich, Mayuresh V. Kothare

Recent demand for medical oxygen has grown exponentially due to the recent COVID-19 pandemic. To this end, a novel single-bed, “Snap-on” and standalone, medical oxygen concentrator design based on a rapid pressure swing adsorption process was investigated for continuous oxygen supply.

 
Huijie Tian, Srinivas Rangarajan
 
Mean field microkinetic models are commonly employed to model catalytic reaction systems; such models often make the incorrect approximation that the adsorbates on a catalyst surface are uniformly distributed (hence the “mean field” nature of the model). The alternative method, called the kinetic Monte Carlo (kMC) simulations, are more accurate in this aspect but are more computationally intensive. In this work, we show that, at the limit of fast diffusion of adsorbates, lattice Monte Carlo simulations can be combined with machine learning to build a new type of model, viz. “neural network modified microkinetic model (NN-MK)” that are more accurate than the mean field models but not as computationally intensive as kMC. This new approach can be used to build more reliable models of catalytic systems.

 

 
Christopher Rzepa, Daniel W. Siderius, Harold W. Hatch, Vincent K. Shen, Srinivas Rangarajan, Jeetain Mittal
 
It has been previously shown that alkanes adsorb in microporous siliceous and aluminum-containing zeolites in such a way that their entropy (upon adsorption) is reduced by a constant fraction of their free (gas phase) value. Such linear relations are valuable in computationally discovering the ideal zeolite for gas adsorption, separation, and catalysis. Using Monte Carlo simulations, in this work, we showed that such relations extend to several other classes of molecules such as olefins, cyclic hydrocarbons, biomass oxygenates, and other heteroatom containing molecules like thiols. This points to the existence of a universal relation that can relate the adsorbate structure and zeolite topology with thermochemical properties.
Towards a chemistry-informed paradigm for designing molecules (March 2022)

Christopher Rzepa, Srinivas Rangarajan

This invited opinion article describes the importance of including chemistry information and constraints in molecule design and discusses approaches and specific applications for chemistry-cognizant molecule discovery.
Characterizing Nonuniform Hydrogel Elastic Moduli Using Autofluorescence (16 May 2022)
John A. McGlynn, Kelly M. Schultz
 
Hydrogel biomaterials show promise as implantable cell delivery vehicles that enhance tissue regeneration and the natural healing process. The design of these materials requires that they mimic the natural environment to retain native cell function.
Gelation phase diagrams of colloidal rod systems measured over a large composition space (27 April 2022)
Shiqin He, Marco Caggioni, Seth Lindberg, Kelly M. Schultz
 
Rheological modifiers tune product rheology with a small amount of material. This work builds gelation phase diagrams of two colloidal rod rheological modifiers using bulk rheology and microrheology measurements. These phase diagrams will provide a guide to determine the composition needed for desired rheological properties and eliminate trial-and-error experiments during product formulation.
Measuring the Effects of Cytokines on the Modification of Pericellular Rheology by Human Mesenchymal Stem Cells (9 November 2021)
Maryam Daviran, John A. McGlynn, Jenna A. Catalano, Hannah E. Knudsen, Kilian J. Druggan, Kiera J. Croland, Amanda Stratton, Kelly M. Schultz
 
Implantable hydrogels are designed to treat wounds by providing structure and delivering additional cells to damaged tissue. In this work, we encapsulate human mesenchymal stem cells in a polymer–peptide hydrogel and incubate the scaffolds in media with cytokines, a chemically cue in the wound environment. The results of this study will enable material design that anticipates changes in remodeling after implantation, improving control over hMSC delivery and healing.
Correlation of Bulk Degradation and Molecular Release from Enzymatically Degradable Polymeric Hydrogels (13 September 2021)
 
In this work, we establish a quantitative correlation between molecular release and material degradation. We characterize a radical-initiated photopolymerized hydrogel and base-initiated Michael addition-polymerized hydrogel, which form gels through distinct crosslinking reactions. Both scaffolds use the same degradable peptide crosslinker, which enables them to be degraded through the same enzymatic degradation reaction.
Rheological properties of phase transitions in polydisperse and monodisperse colloidal rod systems (August 2021)
Shiqin He, Dominic R. Pascucci, Marco Caggioni, Seth Lindberg, Kelly M. Schultz
Rheological modifiers are added to formulations to tune rheology, enable function and drive phase changes requiring an understanding of material structure and properties. Many of these materials are used by consumers during phase transitions. We characterize a colloidal rod system during phase transitions that is used as a rheological modifier to determine how composition changes the dynamic structure and properties during end use.