595 results match your criteria commercial monomers

Engineering Microbes to Bio-Upcycle Polyethylene Terephthalate.

Front Bioeng Biotechnol 2021 28;9:656465. Epub 2021 May 28.

School of Biological Sciences, Southern Illinois University, Carbondale, IL, United States.

Polyethylene terephthalate (PET) is globally the largest produced aromatic polyester with an annual production exceeding 50 million metric tons. PET can be mechanically and chemically recycled; however, the extra costs in chemical recycling are not justified when converting PET back to the original polymer, which leads to less than 30% of PET produced annually to be recycled. Hence, waste PET massively contributes to plastic pollution and damaging the terrestrial and aquatic ecosystems. Read More

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Methacrylate peak determination and selection recommendations using ATR-FTIR to investigate polymerisation of dental methacrylate mixtures.

PLoS One 2021 9;16(6):e0252999. Epub 2021 Jun 9.

Division of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, London, United Kingdom.

Investigation of polymerisation kinetics using ATR-FTIR systems is common in many dental studies. However, peak selection methods to calculate monomer-polymer conversion can vary, consequently affecting final results. Thus, the aim of this study is to experimentally confirm which method is less prone to systematic errors. Read More

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Bio-Based Hydrogels With Ion Exchange Properties Applied to Remove Cu(II), Cr(VI), and As(V) Ions From Water.

Front Bioeng Biotechnol 2021 20;9:656472. Epub 2021 May 20.

Research Group of Wood and Paper Chemistry, Laboratory of Natural Materials Technology, Åbo Akademi University, Turku, Finland.

Hydrogels with ion exchange properties were synthesized from compounds derived from wood biopolymer hemicellulose and from commercial vinyl monomers to be tested as active materials for the removal of Cu(II), Cr(VI), and As(V) ions. The hemicellulose -acetyl galactoglucomannan (GGM) was used as the precursor material, and through a transesterification reaction, GGM was converted into a macromonomer GGM-glycidyl methacrylate (GGM-GMA). Subsequently, the GGM-GMA macromonomer, containing more than one methacrylate group, was used as a crosslinking agent in the synthesis of hydrogels through free-radical polymerization reactions in combination with a 2-acrylamido-2-methyl-1-propanesulfonic acid monomer to produce a cation exchange hydrogel. Read More

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Cationic Polyporphyrins as siRNA Delivery Vectors for Photodynamic and Gene Synergistic Anticancer Therapy.

ACS Appl Mater Interfaces 2021 Jun 4;13(23):27513-27521. Epub 2021 Jun 4.

State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, P. R. China.

Successful gene therapy is highly dependent on the efficiency of gene delivery, which is mostly achieved by the carrier. Current gene carriers are generally nontherapeutic and take over most of the proportion in the delivery systems. Therefore, a library of polymerized and cationic photosensitive drugs (polyphotosensitizers, pPSs) with HIF-1α siRNA delivery capability is constructed to realize using "drug" to deliver "gene". Read More

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Liquid crystal display screens as a source for indoor volatile organic compounds.

Proc Natl Acad Sci U S A 2021 Jun;118(23)

Department of Chemistry, University of Toronto, Toronto, ON M5S 3H6, Canada

Liquid crystal displays (LCDs) have profoundly shaped the lifestyle of humans. However, despite extensive use, their impacts on indoor air quality are unknown. Here, we perform flow cell experiments on three different LCDs, including a new computer monitor, a used laptop, and a new television, to investigate whether their screens can emit air constituents. Read More

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Recent Developments in Lactone Monomers and Polymer Synthesis and Application.

Materials (Basel) 2021 May 27;14(11). Epub 2021 May 27.

Faculty of Chemistry, Silesian University of Technology, Krzywoustego 4, 44-100 Gliwice, Poland.

Lactones are a group of compounds that have been known for several decades. The commercial importance of lactones results from the possibility of manufacturing of a broad scope of derivatives and polymers with a wide spectrum of applications. In this work the synthesis and characterization of simple lactones are described, which due to the easy methods of the synthesis are of high importance for the industry. Read More

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Effect of Accelerated Aging on Some Mechanical Properties and Wear of Different Commercial Dental Resin Composites.

Materials (Basel) 2021 May 23;14(11). Epub 2021 May 23.

Department of Biomaterials Science and Turku Clinical Biomaterial Center-TCBC, Institute of Dentistry, University of Turku, 20500 Turku, Finland.

The aim of current in vitro research was to determine the effect of hydrothermal accelerated aging on the mechanical properties and wear of different commercial dental resin composites (RCs). In addition, the effect of expiration date of the composite prior its use was also evaluated. Five commercially available RCs were studied: Conventional RCs (Filtek Supreme XTE, G-aenial Posterior, Denfil, and >3y expired Supreme XTE), bulk-fill RC (Filtek Bulk Fill), and short fiber-reinforced RC (everX Posterior). Read More

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Extensins: Self-Assembly, Crosslinking, and the Role of Peroxidases.

Front Plant Sci 2021 14;12:664738. Epub 2021 May 14.

Department of Chemistry and Biochemistry, Ohio University, Athens, OH, United States.

The extensin (EXT) network is elaborated by the covalent intermolecular crosslinking of EXT glycoprotein monomers, and its proper assembly is important for numerous aspects of basic wall architecture and cellular defense. In this review, we discuss new advances in the secretion of EXT monomers and the molecular drivers of EXT network self-assembly. Many of the functions of EXTs are conferred through covalent crosslinking into the wall, so we also discuss the different types of known intermolecular crosslinks, the enzymes that are involved, as well as the potential for additional crosslinks that are yet to be identified. Read More

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Development of di-methacrylate quaternary ammonium monomers with antibacterial activity.

Acta Biomater 2021 May 20. Epub 2021 May 20.

University of Trieste, Department of Medical Sciences; Institute for Maternal and Child Health Burlo Garofolo, Via dell'Istria, 65, 34137, Trieste, Italy. Electronic address:

Nine antibacterial di-methacrylate monomers based on bis-quaternary ammonium salts (bis-QAMs) were synthesized and structurally characterized. The biological activity of the bis-QAMs was tested in terms of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) on different bacterial strains achieving promising results and, in most cases, a complete bactericidal effect using a bis-QAM concentration lower than 1 mg/mL. Two of the structures showed comparable and superior activity against S. Read More

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Live Imaging of Calciprotein Particle Clearance and Receptor Mediated Uptake: Role of Calciprotein Monomers.

Front Cell Dev Biol 2021 29;9:633925. Epub 2021 Apr 29.

Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany.

Background: The liver-derived plasma protein fetuin A is a systemic inhibitor of ectopic calcification. Fetuin-A stabilizes calcium phosphate mineral initially as ion clusters to form calciprotein monomers (CPM), and then as larger multimeric consolidations containing amorphous calcium phosphate (primary CPP, CPP 1) or more crystalline phases (secondary CPP, CPP 2). CPM and CPP mediate excess mineral stabilization, transport and clearance from circulation. Read More

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Structure-based engineering of substrate specificity for pinoresinol-lariciresinol reductases.

Nat Commun 2021 05 14;12(1):2828. Epub 2021 May 14.

Research and Development Center of Chinese Medicine Resources and Biotechnology, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, China.

Pinoresinol-lariciresinol reductases (PLRs) are enzymes involved in the lignan biosynthesis after the initial dimerization of two monolignols, and this represents the entry point for the synthesis of 8-8' lignans and contributes greatly to their structural diversity. Of particular interest has been the determination of how differing substrate specificities are achieved with these enzymes. Here, we present crystal structures of IiPLR1 from Isatis indigotica and pinoresinol reductases (PrRs) AtPrR1 and AtPrR2 from Arabidopsis thaliana, in the apo, substrate-bound and product-bound states. Read More

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Photocuring Three-Dimensional Printing of Thermoplastic Polymers Enabled by Hydrogen Bonds.

ACS Appl Mater Interfaces 2021 May 7;13(19):22946-22954. Epub 2021 May 7.

College of Transportation and Civil Engineering, Fujian Agriculture and Forestry University, Fuzhou 350108, P. R. China.

The advent of 3D printing has led to a new era of highly customized products. Printing reprocessable thermoplastic polymers is limited to slow printing techniques such as fused deposition modeling. Photocuring 3D printing is a high-speed 3D printing technique suitable for photocurable thermosetting resins because the cross-linked 3D network could achieve rapid solid-liquid separation during printing. Read More

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Recent Developments in Ring-Opening Copolymerization of Epoxides With CO and Cyclic Anhydrides for Biomedical Applications.

Front Chem 2021 20;9:647245. Epub 2021 Apr 20.

School of Materials Science and Engineering, Tongji University, Shanghai, China.

The biomedical applications of polyesters and polycarbonates are of interest due to their potential biocompatibility and biodegradability. Confined by the narrow scope of monomers and the lack of controlled polymerization routes, the biomedical-related applications of polyesters and polycarbonates remain challenging. To address this challenge, ring-opening copolymerization (ROCOP) has been exploited to prepare new alternating polyesters and polycarbonates, which would be hard to synthesize using other controlled polymerization methods. Read More

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Initiated Chemical Vapor Deposition Kinetics of Poly(4-aminostyrene).

Front Bioeng Biotechnol 2021 16;9:670541. Epub 2021 Apr 16.

Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, United States.

Chemical Vapor Deposition (iCVD) is a free-radical polymerization technique used to synthesize functional polymer thin films. In the context of drug delivery, the conformality of iCVD coatings and the variety of functional chemical moieties make them excellent materials for encapsulating pharmaceutics. Poly(4-aminostyrene) (PAS) belongs to a class of functionalizable materials, whose primary amine allows decoration of the delivery vehicles with biomolecules that enable targeted delivery or biocompatibility. Read More

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The Wdr1-LIMK-Cofilin Axis Controls B Cell Antigen Receptor-Induced Actin Remodeling and Signaling at the Immune Synapse.

Front Cell Dev Biol 2021 13;9:649433. Epub 2021 Apr 13.

Department of Microbiology & Immunology and Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada.

When B cells encounter membrane-bound antigens, the formation and coalescence of B cell antigen receptor (BCR) microclusters amplifies BCR signaling. The ability of B cells to probe the surface of antigen-presenting cells (APCs) and respond to APC-bound antigens requires remodeling of the actin cytoskeleton. Initial BCR signaling stimulates actin-related protein (Arp) 2/3 complex-dependent actin polymerization, which drives B cell spreading as well as the centripetal movement and coalescence of BCR microclusters at the B cell-APC synapse. Read More

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Use of Ionic Liquids and Co-Solvents for Synthesis of Thin-Film Composite Membranes.

Membranes (Basel) 2021 Apr 20;11(4). Epub 2021 Apr 20.

Membrane Technology Group (MTG)-Division cMACS-Faculty of Bioscience Engineering KU Leuven, Celestijnenlaan 200F, Box 2454, 3001 Leuven, Belgium.

Polyamide (PA) thin-film composite (TFC) membranes are commonly applied in reversed osmosis (RO) and nanofiltration (NF) applications due to their thin, dense top-layer, and high selectivity. Recently, the conventional organic phase (i.e. Read More

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Plastics and the microbiome: impacts and solutions.

Environ Microbiome 2021 Jan 20;16(1). Epub 2021 Jan 20.

Institute of Environmental Science and Research, 27 Creyke Rd, Ilam, Christchurch, 8041, New Zealand.

Global plastic production has increased exponentially since manufacturing commenced in the 1950's, including polymer types infused with diverse additives and fillers. While the negative impacts of plastics are widely reported, particularly on marine vertebrates, impacts on microbial life remain poorly understood. Plastics impact microbiomes directly, exerting toxic effects, providing supplemental carbon sources and acting as rafts for microbial colonisation and dispersal. Read More

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January 2021

Polymeric metal-containing ionic liquid sorbent coating for the determination of amines using headspace solid-phase microextraction.

J Sep Sci 2021 Apr 23. Epub 2021 Apr 23.

Department of Chemistry, Iowa State University, Ames, Iowa, USA.

This study describes the design, synthesis, and application of polymeric ionic liquid sorbent coatings featuring nickel metal centers for the determination of volatile and semivolatile amines from water samples using headspace solid-phase microextraction. The examined polymeric ionic liquid (PIL) sorbent coatings were composed of two ionic liquid monomers (tetra(3-vinylimidazolium)nickel bis[(trifluoromethyl)sulfonyl]imide [Ni (VIM) ] 2[NTf ] and 1-vinyl-3-hexylimidazolium [HVIM ][NTf ]), and an ionic liquid cross-linker (1,12-di(3-vinylimidazolium)dodecane  [(VIM) C ] 2[NTf ]). With these ionic liquid monomers and cross-linkers, three different types of coatings were prepared: PIL 1 based on the neat [Ni (VIM) ] 2[NTf ] monomer, PIL 2 consisting of the [Ni (VIM) ] 2[NTf ] monomer with addition of cross-linker, and PIL 3 composed of the [HVIM ][NTf ] monomer and cross-linker. Read More

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Pectin Induced Colony Expansion of Soil-Derived Strains.

Front Microbiol 2021 6;12:651891. Epub 2021 Apr 6.

Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel.

The genus is characterized by the capacity to metabolize complex organic compounds and a unique gliding motility mechanism. Flavobacteria are often abundant in root microbiomes of various plants, but the factors contributing to this high abundance are currently unknown. In this study, we evaluated the effect of various plant-associated poly- and mono-saccharides on colony expansion of two strains. Read More

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BCG Moreau N-Terminal Loss Leads to a Less Stable Dodecin With Lower Flavin Binding Capacity.

Front Cell Infect Microbiol 2021 31;11:658888. Epub 2021 Mar 31.

Laboratório de Genômica Funcional e Bioinformática, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil.

Tuberculosis still remains a concerning health problem worldwide. Its etiologic agent, , continues to be the focus of research to unravel new prophylactic and therapeutic strategies against this disease. The only vaccine in use against tuberculosis is based on the attenuated strain, BCG. Read More

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Density Functional Theory Studies on the Synthesis of Poly(α-Amino Acid)s Via the Amine-Mediated Ring Opening Polymerizations of -Carboxyanhydrides and -Thiocarboxyanhydrides.

Front Chem 2021 29;9:645949. Epub 2021 Mar 29.

MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, China.

To synthesize well-defined poly (α-amino acid)s (PAAs), ring opening polymerizations (ROP) of cyclic monomers of α-amino acid -carboxyanhydrides (NCAs) and -thiocarboxyanhydrides (NTAs) are most widely used. In this mini-review, we summarize the mechanism details of the monomer preparation and ROP. The present study used density functional theory calculations to reveal the mechanisms together with experimental phenomena in the past decades. Read More

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Tailoring the Surface Chemistry of Anion Exchange Membranes with Zwitterions: Toward Antifouling RED Membranes.

ACS Appl Mater Interfaces 2021 Apr 7;13(15):18348-18357. Epub 2021 Apr 7.

Membrane Materials and Processes, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.

Fouling is a pressing issue for harvesting salinity gradient energy with reverse electrodialysis (RED). In this work, antifouling membranes were fabricated by surface modification of a commercial anion exchange membrane with zwitterionic layers. Either zwitterionic monomers or zwitterionic brushes were applied on the surface. Read More

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Preparation, Thermal, and Thermo-Mechanical Characterization of Polymeric Blends Based on Di(meth)acrylate Monomers.

Polymers (Basel) 2021 Mar 12;13(6). Epub 2021 Mar 12.

Department of Polymer Chemistry, Institute of Chemical Sciences, Faculty of Chemistry, Maria Curie-Skłodowska University, M. Curie-Skłodowska Sq.3., 20-031 Lublin, Poland.

This study presents the preparation and the thermo-mechanical characteristics of polymeric blends based on di(meth)acrylates monomers. Bisphenol A glycerolate diacrylate (BPA.GDA) or ethylene glycol dimethacrylate (EGDMA) were used as crosslinking monomers. Read More

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The Balance of MU-Opioid, Dopamine D2 and Adenosine A2A Heteroreceptor Complexes in the Ventral Striatal-Pallidal GABA Antireward Neurons May Have a Significant Role in Morphine and Cocaine Use Disorders.

Front Pharmacol 2021 15;12:627032. Epub 2021 Mar 15.

Department of Neuroscience, Karolinska Institutet, Biomedicum, Stockholm, Sweden.

The widespread distribution of heteroreceptor complexes with allosteric receptor-receptor interactions in the CNS represents a novel integrative molecular mechanism in the plasma membrane of neurons and glial cells. It was proposed that they form the molecular basis for learning and short-and long-term memories. This is also true for drug memories formed during the development of substance use disorders like morphine and cocaine use disorders. Read More

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Re-routing of Sugar Catabolism Provides a Better Insight Into Fungal Flexibility in Using Plant Biomass-Derived Monomers as Substrates.

Front Bioeng Biotechnol 2021 8;9:644216. Epub 2021 Mar 8.

Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Utrecht, Netherlands.

The filamentous ascomycete has received increasing interest as a cell factory, being able to efficiently degrade plant cell wall polysaccharides as well as having an extensive metabolism to convert the released monosaccharides into value added compounds. The pentoses D-xylose and L-arabinose are the most abundant monosaccharides in plant biomass after the hexose D-glucose, being major constituents of xylan, pectin and xyloglucan. In this study, the influence of selected pentose catabolic pathway (PCP) deletion strains on growth on plant biomass and re-routing of sugar catabolism was addressed to gain a better understanding of the flexibility of this fungus in using plant biomass-derived monomers. Read More

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Radical Coupling Reactions of Hydroxystilbene Glucosides and Coniferyl Alcohol: A Density Functional Theory Study.

Front Plant Sci 2021 2;12:642848. Epub 2021 Mar 2.

Department of Energy Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, University of Wisconsin, Madison, WI, United States.

The monolignols, -coumaryl, coniferyl, and sinapyl alcohol, arise from the general phenylpropanoid biosynthetic pathway. Increasingly, however, authentic lignin monomers derived from outside this process are being identified and found to be fully incorporated into the lignin polymer. Among them, hydroxystilbene glucosides, which are produced through a hybrid process that combines the phenylpropanoid and acetate/malonate pathways, have been experimentally detected in the bark lignin of Norway spruce (). Read More

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Optimizing a Fed-Batch High-Density Fermentation Process for Medium Chain-Length Poly(3-Hydroxyalkanoates) in .

Front Bioeng Biotechnol 2021 26;9:618259. Epub 2021 Feb 26.

Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY, United States.

Production of medium chain-length poly(3-hydroxyalkanoates) [PHA] polymers with tightly defined compositions is an important area of research to expand the application and improve the properties of these promising biobased and biodegradable materials. PHA polymers with homopolymeric or defined compositions exhibit attractive material properties such as increased flexibility and elasticity relative to poly(3-hydroxybutyrate) [PHB]; however, these polymers are difficult to biosynthesize in native PHA-producing organisms, and there is a paucity of research toward developing high-density cultivation methods while retaining compositional control. In this study, we developed and optimized a fed-batch fermentation process in a stirred tank reactor, beginning with the biosynthesis of poly(3-hydroxydecanoate) [PHD] from decanoic acid by β-oxidation deficient recombinant LSBJ using glucose as a co-substrate solely for growth. Read More

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February 2021

Traditional Chinese Medicine Monomers: Novel Strategy for Endogenous Neural Stem Cells Activation After Stroke.

Front Cell Neurosci 2021 26;15:628115. Epub 2021 Feb 26.

Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital, Third Military Medical University (Army Military Medical University), Chongqing, China.

Stem cell therapy, which has become a potential regenerative medical treatment and a promising approach for treating brain injuries induced by different types of cerebrovascular disease, has various application methods. Activation of endogenous neural stem cells (NSCs) can enable infarcted neuron replacement and promote neural networks' regeneration without the technical and ethical issues associated with the transplantation of exogenous stem cells. Thus, NSC activation can be a feasible strategy to treat central nervous system (CNS) injury. Read More

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February 2021

Albumin Alters the Conformational Ensemble of Amyloid-β by Promiscuous Interactions: Implications for Amyloid Inhibition.

Huisi Xie Cong Guo

Front Mol Biosci 2020 23;7:629520. Epub 2021 Feb 23.

Department of Physics and International Centre for Quantum and Molecular Structures, College of Sciences, Shanghai University, Shanghai, China.

Human serum albumin (HSA) is a key endogenous inhibitor of amyloid-β (Αβ) aggregation. In vitro HSA inhibits Aβ fibrillization and targets multiple species along the aggregation pathway including monomers, oligomers, and protofibrils. Amyloid inhibition by HSA has both pathological implications and therapeutic potential, but the underlying molecular mechanism remains elusive. Read More

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February 2021

Innovative 2'--Imino-2-propanoate-Protecting Group for Effective Solid-Phase Synthesis and 2'--Deprotection of RNA Sequences.

J Org Chem 2021 Apr 11;86(7):4944-4956. Epub 2021 Mar 11.

Laboratory of Biological Chemistry, Division of Biotechnology Review and Research IV, Center for Drug Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, Maryland 20993, United States.

The implementation of protecting groups for the 2'-hydroxyl function of ribonucleosides is still challenging, particularly when RNA sequences must be of the highest purity for therapeutic applications as nucleic acid-based drugs. A 2'-hydroxyl-protecting group should optimally (i) be easy to install; (ii) allow rapid and efficient incorporation of the 2'--protected ribonucleosides into RNA sequences to minimize, to the greatest extent possible, the formation of process-related impurities (, shorter than full-length sequences) during solid-phase synthesis; and (iii) be completely cleaved from RNA sequences without the production of alkylating side products and/or formation of mutagenic nucleobase adducts. The reaction of 2'--aminoribonucleosides with ethyl pyruvate results in the formation of stable 2'--imino-2-methyl propanoic acid ethyl esters and, subsequently, of the fully protected ribonucleoside phosphoramidite monomers, which are required for the solid-phase synthesis of two chimeric RNA sequences (20-mers) containing the four canonical ribonucleosides. Read More

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