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1. One-pot synthesis of enzyme@metal–organic material (MOM) biocomposites for enzyme biocatalysis

   https://doi.org/DOI https://doi.org/10.1039/D1GC00775K  

   Pan, Y. ; Li, H. ; Lenertz, M. ; Han, Y. ; Ugrinov, A. ; Kilin, D. ; Chen, B. ; Yang, Z. ( March 2021 , Green chemistry)

   null (Ed.)

   Metal–organic frameworks/materials (MOFs/MOMs) are advanced enzyme immobilization platforms that improve biocatalysis, materials science, and protein biophysics. A unique way to immobilize enzymes is co-crystallization/co-precipitation, which removes the limitation on enzyme/substrate size. Thus far, most enzyme@MOF composites rely on the use of non-sustainable chemicals and, in certain cases, heavy metals, which not only creates concerns regarding environmental conservation but also limits their applications in nutrition and biomedicine. Here, we show that a dimeric compound derived from lignin, 5,5′-dehydrodivanillate (DDVA), co-precipitates with enzymes and low-toxicity metals, Ca2+ and Zn2+, and forms stable enzyme@Ca/Zn–MOM composites. We demonstrated this strategy on four enzymes with different isoelectric points (IEPs), molecular weights, and substrate sizes. Furthermore, we found that all enzymes displayed slightly different but reasonable catalytic efficiencies upon immobilization in the Ca–DDVA and Zn–DDVA MOMs, as well as reasonable reusability in both composites. We then probed the structural basis of such differences using a representative enzyme and found enhanced restriction of enzymes in Zn–DDVA than in Ca–DDVA, which might have caused the activity difference. To the best of our knowledge, this is the first aqueous-phase, one-pot synthesis of a lignin-derived “green” enzyme@MOF/MOM platform that can host enzymes without any limitations on enzyme IEP, molecular weight, and substrate size. The different morphologies and crystallinities of the composites formed by Ca–DDVA and Zn–DDVA MOMs broaden their applications depending on the problem of interest. Our approach of enzyme immobilization not only improves the sustainability/reusability of almost all enzymes but also reduces/eliminates the use of non-sustainable resources. This synthesis method has a negligible environmental impact while the products are non-toxic to living things and the environment. The biocompatibility also makes it possible to carry out enzyme delivery/release for nutritional or biomedical applications via our “green” biocomposites. 

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2. Tetrapyrrolic Surface Coatings for Applications in Photoelectrosynthetic Fuel Production

   Moore, Gary ; Beiler, Anna ; Khusnutdinova, Diana ; Wadsworth, Brian ( January 2018 , ECS Meeting Abstracts)

   Hybrid materials capable of linking light capture and conversion technologies with the ability to drive reductive chemical transformations are attractive as components in photoelectrosynthetic cells. [1] We have recently reported methods of applying molecular surface coatings composed of metalloporphyrin redox catalysts onto solid-state substrates that are either conductive or semi-conductive. [2-5] The metalloporphyrin catalysts used in this work are capable of activating electrochemical transformations including the conversion of protons to hydrogen and carbon dioxide to carbon monoxide. In one approach, metalloporphyrin precursors are prepared via a novel synthetic strategy to yield a macrocycle with a pendent 4-vinylphenyl surface attachment group at the beta-position of the porphyrin ring structure. [2] This modification allows use of a photo-induced immobilization chemistry to attach intact metalloporphyrins to a range of (semi)conducting surfaces. In addition, we have shown that initial application of thin-film polymer surface coatings can provide a molecular interface for assembling metalloporphyrin catalysts in a subsequent wet chemical treatment step. [3] In this presentation, spectroscopic characterization of these materials coupled with electrochemical analysis will be presented. These findings offer an improved understanding of the structure and function relationships governing this class of materials. 1. A. M. Beiler, D. Khusnutdinova, S. I. Jacob, G. F. Moore, Ind. & Eng. Chem. Research, 55, 5306-5314 (2016); DOI: 10.1021/acs.iecr.6b00478 2. D. Khusnutdinova, A. M. Beiler, B. L. Wadsworth, S. I. Jacob, G. F. Moore, Chem. Sci., 8, 253-259 (2017); DOI: 10.1039/c6sc02664h 3. A. M. Beiler, D. Khusnutdinova, B. L. Wadsworth, G. F. Moore, Inorg. Chem., 56, 12178 (2017); DOI: 10.1021/acs.inorgchem.7b01509 4. A. M. Beiler, D. Khusnutdinova, S. I. Jacob, G. F. Moore, ACS Appl. Mater. Interfaces, 8, 10038-10043 (2016); DOI: 10.1021/acsami.6b01557 5. B. L. Wadsworth, A. M. Beiler, D. Khusnutdinova, S. I. Jacob, G. F. Moore, ACS Catal. 6, 8048-8057 (2016); DOI: 10.1021/acscatal.6b02194 

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3. Cascade/Parallel Biocatalysis via Multi-enzyme Encapsulation on Metal–Organic Materials for Rapid and Sustainable Biomass Degradation

   https://doi.org/https://doi.org/10.1021/acsami.1c12209  

   Li, Q. ; Pan, Y. ; Li, H. ; Lenertz, M. ; Reed, K. ; Jordahl, D. ; Bjerke, T. ; Ugrinov, A. ; Chen, B. ; Yang, Z. ( September 2021 , ACS applied materials interfaces)

   null (Ed.)

   Multiple-enzyme cooperation simultaneously is an effective approach to biomass conversion and biodegradation. The challenge, however, lies in the interference of the involved enzymes with each other, especially when a protease is needed, and thus, the difficulty in reusing the enzymes; while extracting/synthesizing new enzymes costs energy and negative impact on the environment. Here, we present a unique approach to immobilize multiple enzymes, including a protease, on a metal–organic material (MOM) via co-precipitation in order to enhance the reusability and sustainability. We prove our strategy on the degradation of starch-containing polysaccharides (require two enzymes to degrade) and food proteins (require a protease to digest) before the quantification of total dietary fiber. As compared to the widely adopted “official” method, which requires the sequential addition of three enzymes under different conditions (pH/temperature), the three enzymes can be simultaneously immobilized on the surface of our MOM crystals to allow for contact with the large substrates (starch), while MOMs offer sufficient protection to the enzymes so that the reusability and long-term storage are improved. Furthermore, the same biodegradation can be carried out without adjusting the reaction condition, further reducing the reaction time. Remarkably, the simultaneous presence of all enzymes enhances the reaction efficiency by a factor of ∼3 as compared to the official method. To our best knowledge, this is the first experimental demonstration of using aqueous-phase co-precipitation to immobilize multiple enzymes for large-substrate biocatalysis. The significantly enhanced efficiency can potentially impact the food industry by reducing the labor requirement and enhancing enzyme cost efficiency, leading to reduced food cost. The reduced energy cost of extracting enzymes and adjusting reaction conditions minimize the negative impact on the environment. The strategy to prevent protease damage in a multi-enzyme system can be adapted to other biocatalytic reactions involving proteases. 

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4. Degradation behaviors and cytocompatibility of Mg/β‐tricalcium phosphate composites produced by spark plasma sintering

   https://doi.org/10.1002/jbm.b.34316  

   Narita, Kai ; Tian, Qiaomu ; Johnson, Ian ; Zhang, Chaoxing ; Kobayashi, Equo ; Liu, Huinan ( February 2019 , Journal of Biomedical Materials Research Part B: Applied Biomaterials)

   Magnesium (Mg)‐based materials have shown great potentials for bioresorbable implant applications. Previous studies showed that Mg with 10 and 20 vol % β‐tricalcium phosphate (β‐TCP) composites produced by spark plasma sintering, improved mechanical properties when compared with pure Mg. The objectives of this study were to evaluate the degradation behaviors of Mg/10% β‐TCP and Mg/20% β‐TCP composites in revised stimulated body fluid (rSBF), and to determine their cytocompatibility with bone marrow derived mesenchymal stem cells (BMSCs) using the direct culture method. During the 11 days of immersion in rSBF, Mg/β‐TCP composites showed different degradation behaviors at different immersion periods, that is, the initial stage (0–1 hr), the mid‐term stage (1 hr to 2 days), and the long‐term stage (2−11 days). The counter effects of mass loss due to microgalvanic corrosion and mass gain due to deposition of Ca‐P containing layers resulted in slower Mg²⁺ion release for Mg/20% β‐TCP than Mg/10% β‐TCP in the mid‐term, but eventually 16% mass loss for Mg/20% β‐TCP and 10% mass loss for Mg/10% β‐TCP after 11 days of immersion. The in vitro studies with BMSCs showed the highest cell adhesion density (i.e., 68% of seeding density) on the plate surrounding the Mg/10% β‐TCP sample, that is, under the indirect contact condition of direct culture. The β‐TCP showed a positive effect on direct adhesion of BMSCs on the surface of Mg/β‐TCP composites. This study elucidated the degradation behaviors and the cytocompatibility of Mg/β‐TCP composites in vitro; and, further studies on Mg/ceramic composites are needed to determine their potential for clinical applications. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2238–2253, 2019.

    

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5. Data-Driven Imputation of Miscibility of Aqueous Solutions via Graph-Regularized Logistic Matrix Factorization

   https://doi.org/10.1021/acs.jpcb.3c03789  

   Behnoudfar, Diba ; Simon, Cory M. ; Schrier, Joshua ( September 2023 , The Journal of Physical Chemistry B)

   Aqueous, two-phase systems (ATPSs) may form upon mixing two solutions of independently water-soluble compounds. Many separation, purification, and extraction processes rely on ATPSs. Predicting the miscibility of solutions can accelerate and reduce the cost of the discovery of new ATPSs for these applications. Whereas previous machine learning approaches to ATPS prediction used physicochemical properties of each solute as a descriptor, in this work, we show how to impute missing miscibility outcomes directly from an incomplete collection of pairwise miscibility experiments. We use graph-regularized logistic matrix factorization (GR-LMF) to learn a latent vector of each solution from (i) the observed entries in the pairwise miscibility matrix and (ii) a graph where each node is a solution and edges are relationships indicating the general category of the solute (i.e., polymer, surfactant, salt, protein). For an experimental data set of the pairwise miscibility of 68 solutions from Peacock et al. [ACS Appl. Mater. Interfaces 2021, 13, 11449–11460], we find that GR-LMF more accurately predicts missing (im)miscibility outcomes of pairs of solutions than ordinary logistic matrix factorization and random forest classifiers that use physicochemical features of the solutes. GR-LMF obviates the need for features of the solutions and solutions to impute missing miscibility outcomes, but it cannot predict the miscibility of a new solution without some observations of its miscibility with other solutions in the training data set. 

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