jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Karthik Ananth Mani | Noga Yaakov | Yafit Itzhaik Alkotzer | Evgeni Zelikman | Guy Mechrez
Source: Preprints.org (preprint, 2018-07-09)
Field: Materials Science — Materials Chemistry

A Robust Fabrication Method for Amphiphilic Janus Particles via Immobilization on Polycarbonate Microspheres Immobilizing particles on beads, fibers or filaments, when only one side is exposed to the reaction medium and therefore can be selectively functionalized, is a scalable and easy to control strategy for the fabrication of amphiphilic Janus particles. Here we describe a new, robust method for the fabrication of amphiphilic Janus particles based on immobilization of polymethylsilsesquioxane (PMSQ) particles on polycarbonate (PC), a high impact-resistance polymer with superior mechanical properties. The immobilization of the particles on the PC microspores is preformed via inverse solvent displacement method. PMSQ particles are added to a PC solution in tetrahydrofuran (THF), a good solvent for PC. The solution is then precipitated by the introduction of aqueous surfactant solution (anti solvent for PC) under an ultrasonic field. It is important to note that THF and water are miscible and do not form emulsion. During precipitation, PMSQ particles are assembled onto the surface of the PC spherical precipitates/microspheres. The exposed hemispheres of the PMSQ particles are then selectively silanized by (3-Aminopropyl)triethoxysilane (APTES) to introduce amine groups on their surface. To increase the polarity of the functionalized hemispheres, the amine groups are further modified to introduce carboxyl groups. SEM characterization confirms the fine embedment of PMSQ particles onto the PC microspheres. Covalent attachment of silica nanoparticles (NPs) to the functionalized hemispheres of the resulting particles along with fluorescent confocal microscopy conclusively proof the successful fabrication of amphiphilic Janus particles. The immobilization of particles onto highly rigid polymeric microspheres such as PC may pave the way to the development of a robust fabrication procedure with high resistance to temperature fluctuations and harsh mixing conditions that can arise during preparation. This method can be implemented toward a large variety of other synthetic commercial polymers such as polyamide, polyether sulfones, Polyether ether ketone or similar. Janus particles ; Amphiphile ; Chemical engineering ; Polycarbonate ; Materials science ; Fabrication ; Polymer chemistry ; Polymer ; Emulsion ; Solvent ; Nanoparticle ; Dispersity ; Chemistry ; Nanotechnology ; Copolymer ; Janus ; Organic chemistry ; Composite material Pickering emulsions and particle stabilization ; Polymer Surface Interaction Studies ; Advanced Polymer Synthesis and Characterization
Authors: Erik N. Carrión
Source: Seton Hall University eRepository (Seton Hall University) (article, 2018-01-01)
Field: Materials Science — Materials Chemistry

Tumor-Targeting Fluorinated Phthalocyanines for Theranostic Applications Hydrocarbon-based therapeutics and imaging agents are prone to chemical oxidation and degradation resulting in loss of activity and limited functional utility. Thus, more material is required to achieve long-lasting therapeutic effects. Phthalocyanines (Pcs) and their metal complexes (PcMs) can be utilized as prodrugs requiring only renewable energy resources namely, air and light, for cancer therapy and diagnostic (theranostic) applications related to photodynamic therapy (PDT). Replacement of labile C-H bonds in the Pc scaffold with a combination of fluoro and perfluoroisopropyl groups has resulted in a stable yet reactive oxidation catalyst of biological significance and importance. For example, F64PcZn, lacks tumor-cell specificity and may attach non-covalently to a tumor-targeting biovector via van der Waals interactions or via the metal-center. However, the former may leach and the latter may alter the Pc’s photo-physical and photo-chemical properties. Thus, the need for functionalized Pcs is desirable for covalent conjugation while retaining its function and reactivity. We report the bioconjugation of F48H7COOHPcZn to a peptidic ligand, Pep42, with oncoprotein recognition towards Gluocse Regulated Protein of 78 kDa (GRP78) in order to generate a small library of tumor-targeting fluorinated phthalocyanine bioconjugates (Scheme 1). F48H7COOHPcCu is also reported and capable of generating singlet oxygen (1O2). F48H7CONHPcZn-AHX-Pep42, like the unconjugated PcZn, still performed 1O2-mediated substrate oxidation and showed fluorescence after peptide attachment. Pc labeling did not affect the cargo delivery capabilities of Pep42 towards Hep2 cells. F48H7CONHPcZn-AHX-Pep42-R9 and F48H7CONHPcZn-PEG6-Pep42-R9 were biocompatible towards Hep2 cells under dark and light conditions while F48H7CONHPcZn-AHX-Pep42 showed moderate cytotoxicity in both cases unrelated to 1O2 production. The work herein highlights the development of catalytic, fluorine- based anti-cancer drugs that may be useful as potential theranostic agents. Nanotechnology ; Computer science ; Chemistry ; Materials science Porphyrin and Phthalocyanine Chemistry ; Photodynamic Therapy Research Studies ; Cancer, Hypoxia, and Metabolism
Authors: Péter Veres
Source: University of Debrecen Electronic Archive (University of Debrecen) (article, 2018-03-05)
Field: Chemistry — Spectroscopy

Synthesis of silica-gelatin hybrid aerogels and their application as drug delivery systems Doktori munkám során kidolgoztunk egy új szintézisutat különböző zselatintartalmú szilika-zselatin hibrid aerogélek előállítására. Két eltérő funkcionalizálási technika felhasználásával módosítottuk a gélváz felszínét. Különböző vizsgálati módszerekkel meghatároztuk az aerogélek összetételét és a felületi módosítás hatását a kialakuló aerogélek szerkezetére. Három, vízben rosszul oldódó hatóanyag szuperkritikus szén-dioxidból történő adszorpciójával demonstráltuk, hogy a szilika-zselatin hibrid aerogélek alkalmasak lehetnek gyógyszerhordozóként történő felhasználásra. Az előzetes batch kioldódás vizsgálatok bizonyították, hogy hidrofil, illetve hidrofób mátrix alkalmazásával rendre azonnali, illetve lassú hatóanyag-leadás érhető el. A gyors hatóanyag-leadás vizsgálata érdekében kifejlesztettünk egy új, gyors, on-line kioldódás vizsgáló módszert. Bizonyítottuk, hogy a módszer alkalmas kis mintamennyiség esetén is olyan görbék reprodukálható regisztrálására, amelyeken nagyhatékonyságú görbealak analízis végezhető. Nem konvencionális NMR módszerekkel vizsgáltuk a hibrid gélváz viselkedését különböző folyadékokban. A kapott szerkezetvizsgálati és hatóanyag-leadási eredményeket összegezve javaslatot tettünk a kioldódás mechanizmusára. Megmutattuk, hogy kis zselatin tartalmú aerogélek esetén a hatóanyag-leadást a mátrix degradációja, valamint hidratációja vezérli. A hibrid gélvázról a víz az erős hidratáció miatt leszorítja az adszorbeálódott hatóanyagot, amely a normál szilika aerogélek esetén tapasztaltnál tízszer gyorsabb leadáshoz vezet. A zselatintartalom növelésével az aerogél váz vízben egyre inkább hidrogélként viselkedik, így magasabb zselatintartalom esetén a kioldódást a hatóanyag molekulák hidrogélen keresztül történő gátolt diffúziója irányítja. Gelatin ; Drug delivery ; Drug ; Nanotechnology ; Materials science ; Chemical engineering ; Chemistry ; Organic chemistry ; Pharmacology ; Medicine ; Engineering Aerogels and thermal insulation ; Silicone and Siloxane Chemistry ; Mesoporous Materials and Catalysis
Authors: Shuai Yuan
Source: OakTrust (Texas A&M University Libraries) (article, 2018-07-27)
Field: Chemistry — Inorganic Chemistry

Developing a Synthetic Toolkit for Multi-Component Metal–Organic Frameworks Metal–organic frameworks (MOFs) are an emerging class of porous materials constructed from metal-containing nodes and organic linkers. Due to their structural and functional tunability as well as their ever-expanding application scope, MOFs have become one of the most fascinating class of materials for both scientists and engineers. MOFs provide ideal platforms to arrange various functional groups at atomic precision within the periodic lattice, leading to emergent synergistic effects in catalysis and gas adsorption. This requires the construction of MOFs from multiple metal nodes and/or organic linkers. However, the structural and compositional compilation of multi-component MOFs have posed a challenge for their synthesis. The complexity of MOFs is ultimately limited by the conventional “one-pot” synthetic method, which lacks control over the assembly of each framework component. By judicious kinetic control, we have developed stepwise synthetic strategies to build multi-component MOFs by “layer-on” molecular elaborations to preformed frameworks. A series of synthetic strategies have been developed which together form a synthetic toolkit through which a target multi-component MOF can be retro-synthetically designed and synthesized. \n\nThe first section briefly summarized the development of MOFs to provide an overview on their structural design, synthesis and potential applications. \n\nIn the second section, we focused on the synthesis of heterometallic MOFs using preformed heterometallic clusters to avoid undesired by products formed by other metal clusters. \n\nIn the third section, the mixed-linker MOFs with crystallographically ordered structures were constructed using sequential linker installation.\nIn the fourth section, we enriched the MOF synthetic toolkit by introducing linker labilization, in which selective linkers were exchanged, cleaved, and removed to create controlled defects in MOFs. The defective MOFs act as versatile platforms to create hierarchical structures and incorporate other coordinative assemblies. \n\nIn the fifth section, we realized the “retrosynthesis” multi-component MOFs by sequentially applying the above mentioned synthetic methods under kinetic considerations. \n\nIn summary, a series of synthetic methods were developed to construct multi-component MOFs with unprecedented complexity. These methods allow the rational design and synthesis of MOFs for specific applications including gas storage and separation, chemical sensing, energy harvesting and storage, catalysis, and biomedicine. Component (thermodynamics) ; Metal-organic framework ; Computer science ; Process management ; Business ; Chemistry ; Organic chemistry Metal-Organic Frameworks: Synthesis and Applications ; X-ray Diffraction in Crystallography ; Machine Learning in Materials Science
Authors: Elvis Robles‐Marín | Alexander Mondragón | Marcos Flores‐Álamo | Iván Castillo
Source: Journal of the Brazilian Chemical Society (article, 2018-01-01)
Field: Chemistry — Organic Chemistry

Silver Complex of an N-Heterocyclic Carbene Ligand with Bulky Thiocarbamate Groups The synthesis of a new N-heterocyclic carbene with bulky S-arylthiocarbamate substituents was devised from the condensation between 2-chloromethyl-4-methy-l,6-[3,5-bis(trifluoromethyl)phenyl]-S-phenyl-N,N-dimethylthiocarbamate and imidazole, resulting in the proligand -carb) 2 NHC]I. This newly synthesized proligand was crystallographically characterized, thus confirming its identity; its stability was established in several solvents, resulting in air oxidation in methanolic solution, giving rise to the decomposition product N,N'-bis[(2-S-(N'',N''-dimethyl thiocarbamoyl)-5-methyl)phenylmethyl]-4,5-dimethoxyimidazolyl-2-one. Reaction of the proligand with silver oxide afforded the corresponding complex [(S-carb) 2 NHC]AgI, which was fully characterized by spectroscopic techniques. Thiocarbamate ; Carbene ; Ligand (biochemistry) ; Chemistry ; Medicinal chemistry ; Combinatorial chemistry ; Organic chemistry ; Catalysis N-Heterocyclic Carbenes in Organic and Inorganic Chemistry ; Catalytic Cross-Coupling Reactions ; Carbon dioxide utilization in catalysis
Authors: Andrea Alù | Lincoln J. Lauhon | Xiaoqin Li | Chih‐Kang Shih | Natalie Stingelin
Source: MRS Bulletin (article, 2018-12-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Perspectives on frontiers in electronic and photonic materials Photonics ; Nanotechnology ; Engineering physics ; Materials science ; Electronic materials ; Optoelectronics ; Engineering Metamaterials and Metasurfaces Applications ; 2D Materials and Applications ; Photonic Crystals and Applications
Authors: Luca Valentini | Silvia Bittolo Bon | Nicola M. Pugno
Source: Preprints.org (preprint, 2018-07-11)
Field: Materials Science — Biomaterials

Combining Living Microorganisms with Regenerated Silk Provides Nanofibril-Based Thin Films with Heat-Responsive Wrinkled States for Smart Food Packaging Regenerated silk (RS) is a protein-based &amp;ldquo;biopolymer&amp;rdquo; that enables the design of new materials; here, we called &amp;ldquo;bionic&amp;rdquo; the process of regenerated silk production by a fermentation-assisted method. Based on yeast&amp;rsquo;s fermentation, here we produced a living hybrid composite made of regenerated silk nanofibrils and a single-cell fungi, the Saccharomyces cerevisiae yeast extract, by fermentation of such microorganisms at room temperature in a dissolution bath of silkworm silk fibers. The fermentation-based processing enhances the beta-sheet content of the RS, corresponding to a reduction in water permeability and CO2 diffusion through RS/yeast thin films enabling the fabrication of a mechanically robust film that enhances food storage durability. Finally, a transfer print method, which consists of transferring RS and RS/yeast film layers onto a self-adherent paraffin substrate, was used for the realization of heat-responsive wrinkles by exploiting the high thermal expansion of the paraffin substrate that regulates the applied strain, resulting in a switchable coating morphology from the wrinkle-free state to a wrinkled state if the food temperature overcomes a designed threshold. We envision that such efficient and smart coatings can be applied for the realization of smart packaging that, through such a temperature-sensing mechanism, can be used to control food storage conditions. SILK ; Biopolymer ; Materials science ; Yeast ; Food packaging ; Fermentation ; Substrate (aquarium) ; Coating ; Nanotechnology ; Composite material ; Food science ; Chemistry ; Polymer ; Biology Silk-based biomaterials and applications ; Insect and Arachnid Ecology and Behavior ; Advanced Materials and Mechanics
Authors: Matthew R. Hauwiller | Justin C. Ondry | A. Paul Alivisatos
Source: Journal of Visualized Experiments (article, 2018-05-17)
Field: Materials Science — Materials Chemistry

Using Graphene Liquid Cell Transmission Electron Microscopy to Study &lt;em&gt;in Situ&lt;/em&gt; Nanocrystal Etching Graphene liquid cell electron microscopy provides the ability to observe nanoscale chemical transformations and dynamics as the reactions are occurring in liquid environments. This manuscript describes the process for making graphene liquid cells through the example of graphene liquid cell transmission electron microscopy (TEM) experiments of gold nanocrystal etching. The protocol for making graphene liquid cells involves coating gold, holey-carbon TEM grids with chemical vapor deposition graphene and then using those graphene-coated grids to encapsulate liquid between two graphene surfaces. These pockets of liquid, with the nanomaterial of interest, are imaged in the electron microscope to see the dynamics of the nanoscale process, in this case the oxidative etching of gold nanorods. By controlling the electron beam dose rate, which modulates the etching species in the liquid cell, the underlying mechanisms of how atoms are removed from nanocrystals to form different facets and shapes can be better understood. Graphene liquid cell TEM has the advantages of high spatial resolution, compatibility with traditional TEM holders, and low start-up costs for research groups. Current limitations include delicate sample preparation, lack of flow capability, and reliance on electron beam-generated radiolysis products to induce reactions. With further development and control, graphene liquid cell may become a ubiquitous technique in nanomaterials and biology, and is already being used to study mechanisms governing growth, etching, and self-assembly processes of nanomaterials in liquid on the single particle level. Graphene ; Nanotechnology ; Materials science ; Nanomaterials ; Transmission electron microscopy ; Etching (microfabrication) ; Nanocrystal Quantum Dots Synthesis And Properties ; Electrohydrodynamics and Fluid Dynamics
Authors: Alexander C. Forse | Phillip J. Milner | Jung‐Hoon Lee | Halle N. Redfearn | Julia Oktawiec | Rebecca L. Siegelman | Jeffrey D. Martell | Bhavish Dinakar | Leo B. Porter-Zasada | Miguel I. Gonzalez | Jeffrey B. Neaton | Jeffrey R. Long | Jeffrey A. Reimer
Source: ChemRxiv (preprint, 2018-09-20)
Field: Chemistry — Inorganic Chemistry

Elucidating CO2 Chemisorption in Diamine-Appended Metal–Organic Frameworks The widespread deployment of carbon capture and sequestration as a climate change mitigation strategy could be facilitated by the development of more energy-efficient adsorbents. Diamine-appended metal–organic frameworks of the type diamine–M2(dobpdc) (M = Mg, Mn, Fe, Co, Ni, Zn; dobpdc4− = 4,4′-dioxidobiphenyl-3,3′-dicarboxylate) have shown promise for carbon capture applications, although questions remain regarding the molecular mechanisms of CO2 uptake in these materials. Here, we leverage the crystallinity and tunability of this class of frameworks to perform a comprehensive study of CO2 chemisorption. Using multinuclear nuclear magnetic resonance (NMR) spectroscopy experiments and van der Waals-corrected density functional theory (DFT) calculations for thirteen diamine–M2(dobpdc) variants, we demonstrate that the canonical CO2 chemisorption products—ammonium carbamate chains and carbamic acid pairs—can be readily distinguished, and that ammonium carbamate chain formation dominates for diamine–Mg2(dobpdc) materials. In addition, we elucidate a new chemisorption mechanism in the material dmpn Mg2(dobpdc) (dmpn = 2,2-dimethyl-1,3-diaminopropane), which involves formation of a 1:1 mixture of ammonium carbamate and carbamic acid and accounts for the unusual adsorption properties of this material. Finally, we show that the presence of water plays an important role in directing the mechanisms for CO2 uptake in diamine–M2(dobpdc) materials. Overall, our combined NMR and DFT approach enables a thorough depiction and understanding of CO2 adsorption within diamine–M2(dobpdc) compounds, which may aid similar studies in other amine-functionalized adsorbents in the future. Carbamic acid ; Diamine ; Chemisorption ; Physisorption ; Adsorption ; Chemistry ; Ethylenediamine ; Metal-organic framework ; Crystallinity ; van der Waals force ; Inorganic chemistry ; Organic chemistry ; Molecule ; Polymer chemistry ; Crystallography Metal-Organic Frameworks: Synthesis and Applications ; Carbon Dioxide Capture Technologies ; Covalent Organic Framework Applications
Authors: Matteo Di Giosia | Francesco Valle | Andrea Cantelli | Andréa Bottoni | Francesco Zerbetto | Matteo Calvaresi
Source: Preprints.org (preprint, 2018-04-28)
Field: Chemistry — Organic Chemistry

C&lt;sub&gt;60&lt;/sub&gt; Bioconjugation with Proteins: Towards a Palette of Carriers for All pH Ranges The high hydrophobicity of fullerenes and the resulting formation of aggregates in aqueous solutions hamper the possibility of their exploitation in many technological applications. Noncovalent bioconjugation of fullerenes with proteins is an emerging approach for their dispersion in aqueous media. Contrary to covalent functionalization, bioconjugation preserves the physicochemical properties of the carbon nanostructure. The unique photophysical and photochemical properties of fullerenes are then fully accessible for applications in nanomedicine, sensoristic, biocatalysis and materials science fields. However, proteins are not universal carriers. Their stability depends on the biological conditions for which they have evolved. Here we present two model systems based on pepsin and trypsin. These proteins have opposite net charge at physiological pH. They recognize and disperse C60 in water. UV-Vis spectroscopy, zeta-potential and atomic force microscopy analysis demonstrates that the hybrids are well dispersed and stable in a wide range of pH&amp;rsquo;s and ionic strengths. A previously validated modelling approach identifies the protein-binding pocket involved in the interaction with C60. Computational predictions, combined with experimental investigations, provide powerful tools to design tailor-made C60@proteins bioconjugates for specific applications. Bioconjugation ; Fullerene ; Chemistry ; Nanomedicine ; Nanotechnology ; Aqueous solution ; Non-covalent interactions ; Ionic bonding ; Zeta potential ; Nanoparticle ; Materials science ; Combinatorial chemistry ; Organic chemistry ; Hydrogen bond ; Molecule Fullerene Chemistry and Applications ; Molecular Junctions and Nanostructures ; Diamond and Carbon-based Materials Research
Authors: Edgar Andrés Chavarriaga Miranda | Alex Lopera | Juan Fernando Montoya Carvajal | Stiven Villada Gil | Óscar Jaime Restrepo Baena
Source: Scientia et technica (article, 2018-12-30)
Field: Chemistry — Inorganic Chemistry

Síntesis y caracterización de pigmentos inorgánicos azules CoAl1.95Cr0.05O4 y Zn0,8Co0,2Al2O4 por combustión en solución Los pigmentos inorgánicos azules con estructura espinela CoAl1.95Cr0.05O4 y Zn0,8Co0,2Al2O4 se sintetizaron por el método de síntesis de combustión en solución usando glicina como combustible. La estructura cristalina de los polvos sintetizados fue determinada por el método de difracción de rayos X (DRX), el cual mostró la formación de la estructura espinela. La microscopía electrónica de barrido de emisión de campo (MEBEC) permitió observar que los polvos presentaron porosidad con partículas aglomeradas. La espectroscopía de reflectancia difusa visible mostró bandas de absorción asociadas al Co2+ en coordinación tetraédrica. Finalmente, se concluye que la síntesis de combustión en solución permite obtener pigmentos inorgánicos que pueden ser usados en la fabricación de pinturas arquitectónicas. Humanities ; Physics ; Chemistry ; Art Pigment Synthesis and Properties ; Cultural Heritage Materials Analysis