Core/Shell Nanoparticles: Classes, Properties, Synthesis Mechanisms, Characterization, and Applications

Roger Sheldon (1942) received a PhD in organic chemistry from the University of Leicester (UK) in 1967. This was followed by post-doctoral studies with Prof. Jay Kochi in the U.S. From 1969 to 1980 he was with Shell Research in Amsterdam and from 1980 to 1990 he was R&D Director of DSM Andeno. In 1991 he moved to his present position as Professor of organic chemistry and catalysis at the Delft University of Technology (The Netherlands). His primary research interests are in the application of catalytic methodologies—homogeneous, heterogeneous and enzymatic—in organic synthesis, particularly in relation to fine chemicals production. He developed the concepts of E factors and atom utilization for assessing the environmental impact of chemical processes.

Biocatalysis in ionic liquids

Environmental fate and toxicity of ionic liquids: a review.

Ionic liquids are remarkable chemical compounds, which find applications in many areas of modern science. Because of their highly tunable nature and exceptional properties, ionic liquids have become essential players in the fields of synthesis and catalysis, extraction, electrochemistry, analytics, biotechnology, etc. Apart from physical and chemical features of ionic liquids, their high biological activity has been attracting significant attention from biochemists, ecologists, and medical scientists. This Review is dedicated to biological activities of ionic liquids, with a special emphasis on their potential employment in pharmaceutics and medicine. The accumulated data on the biological activity of ionic liquids, including their antimicrobial and cytotoxic properties, are discussed in view of possible applications in drug synthesis and drug delivery systems. Dedicated attention is given to a novel active pharmaceutical ingredient-ionic liquid (API-IL) concept, which suggests using traditional drugs in ...

Biological Activity of Ionic Liquids and Their Application in Pharmaceutics and Medicine.

Finally, we have addressed some relevant findings on the importance of having well-defined synthetic strategies developed for the generation of MNPs, with a focus on particle formation mechanism and recent modifications made on the preparation of monodisperse samples of relatively large quantities not only with similar physical features, but also with similar crystallochemical characteristics. Then, different methodologies for the functionalization of the prepared MNPs together with the characterization techniques are explained. Theorical views on the magnetism of nanoparticles are considered.

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Magnetic nanoparticles: preparation, physical properties, and applications in biomedicine

Uniformly sized silica-coated magnetic nanoparticles (magnetite@silica) are synthesized in a simple one-pot process using reverse micelles as nanoreactors. The core diameter of the magnetic nanoparticles is easily controlled by adjusting the w value ([polar solvent]/[surfactant]) in the reverse-micelle solution, and the thickness of the silica shell is easily controlled by varying the amount of tetraethyl orthosilicate added after the synthesis of the magnetite cores. Several grams of monodisperse magnetite@silica nanoparticles can be synthesized without going through any size-selection process. When crosslinked enzyme molecules form clusters on the surfaces of the magnetite@silica nanoparticles, the resulting hybrid composites are magnetically separable, highly active, and stable under harsh shaking conditions for more than 15 days. Conversely, covalently attached enzymes on the surface of the magnetite@silica nanoparticles are deactivated under the same conditions.

Simple Synthesis of Functionalized Superparamagnetic Magnetite/Silica Core/Shell Nanoparticles and their Application as Magnetically Separable High‐Performance Biocatalysts

Purification of l(+)-lactic acid from fermentation broth with paper sludge as a cellulosic feedstock using weak anion exchanger Amberlite IRA-92

Ionic liquids are compounds that composed only of ions and are liquid at room temperature. Thus, it is normally named room temperature ionic liquid (RTIL). In this study, the application of RTILs to the extractive fermentation of biomaterials was investigated as a substitute of organic solvents. The relative toxicity of the RTILs on the growth ofE. coli was tested. The inhibition of cell growth in the presence of various ionic liquids was measured using solid and liquid culture, and EC50 of each RTILs was calculated. The number of viable and total cells was measured by the number of colonies and optical density, respectively. Effective concentrations of toxicity (EC50) in these tested systems were similar with conventional solvents, such as acetone, acetonitrile, and ethanol. The viability ofE. coli was affected by the polarity and ionic properties of ionic liquids. The resistance of the microorganisms against ionic liquids was different with the cations and anions composing ionic liquids. No general influence of the anionic compound of the ionic liquids was found on toxicity comparing with distinctive influence of cationic moiety.

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Influence of ionic liquids on the growth ofEscherichia coli

Ionic liquids have been suggested as potential “green solvents” due to their unique properties such as non-volatility, nonflammability, and a wide temperature range for liquid phase. This review describes recent advances of biocatalyst reactions in ionic liquids. Enzyme-catalyzed reactions in ionic liquids-transesterification, synthesis, conversion, ammoniolysis, hydrolysis, epoxidation, resolution, and oxidation are presented. The use of ionic liquids for protein folding/refolding and the toxicity of ionic liquids are also discussed.

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Enzyme-catalyzed reactions in ionic liquids

β-Glucosidase (βG) can relieve the product inhibition of cellobiose in the cellulosic ethanol production by converting cellobiose into glucose. For the potential recycled uses, βG was immobilized and stabilized in the form of enzyme coating on polymer nanofibers. The βG coating (EC-βG) was fabricated by crosslinking additional βG molecules onto covalently attached βG molecules (CA-βG) via glutaraldehyde treatment. The initial activity of EC-βG was 36 times higher than that of CA-βG. After 20 days of incubation under shaking, CA-βG and EC-βG retained 33 and 91% of each initial activity, respectively. Magnetic nanofibers were also used for easy recovery and recycled uses of βG coating. It is anticipated that the recycled uses of highly active and stable βG coating can improve the economics of cellulosic ethanol production so long as economical materials are employed as a host of enzyme immobilization.

Sang-Mok Lee

Papers

Simple Synthesis of Functionalized Superparamagnetic Magnetite/Silica Core/Shell Nanoparticles and their Application as Magnetically Separable High‐Performance Biocatalysts

Purification of l(+)-lactic acid from fermentation broth with paper sludge as a cellulosic feedstock using weak anion exchanger Amberlite IRA-92

Influence of ionic liquids on the growth ofEscherichia coli

Enzyme-catalyzed reactions in ionic liquids

β-Glucosidase coating on polymer nanofibers for improved cellulosic ethanol production