Nanoparticles in Biological Systems Stark, Wendelin J
Angewandte Chemie (International ed.),
February 7, 2011, Letnik:
50, Številka:
6
Journal Article
Recenzirano
Understanding the behavior of nanoparticles in biological systems opens up new directions for medical treatments and is essential for the development of safe nanotechnology. This Review discusses ...molecules and nanoparticles when in contact with cells or whole organisms, with a focus on inorganic materials. The interaction of particles with biology unravels a series of new mechanisms not found for molecules: altered biodistribution, chemically reactive interfaces, and the combination of solid-state properties and mobility. Externally guided movement of medicaments by using functional nanomagnets brings mechanics into drug design. In subsequent sections, the role of inertness and bioaccumulation is discussed in regard to the long-term safety of nanoparticles.
Nanoparticles can serve as semi‐heterogeneous supports since they readily disperse in common solvents and combine high surface area with excellent accessibility. Reversible agglomeration through ...solvent changes and magnetic separation provide technically attractive alternatives to classical catalyst filtration. This account places emphasis on recent developments in this emerging area.
High surface area, excellent accessibility, and the ability to readily disperse in common solvents facilitate the use of nanoparticles as semi‐heterogeneous supports. Reversible agglomeration through solvent changes and magnetic separation provide technically attractive alternatives to classical catalyst filtration.
Information, such as text printed on paper or images projected onto microfilm, can survive for over 500 years. However, the storage of digital information for time frames exceeding 50 years is ...challenging. Here we show that digital information can be stored on DNA and recovered without errors for considerably longer time frames. To allow for the perfect recovery of the information, we encapsulate the DNA in an inorganic matrix, and employ error‐correcting codes to correct storage‐related errors. Specifically, we translated 83 kB of information to 4991 DNA segments, each 158 nucleotides long, which were encapsulated in silica. Accelerated aging experiments were performed to measure DNA decay kinetics, which show that data can be archived on DNA for millennia under a wide range of conditions. The original information could be recovered error free, even after treating the DNA in silica at 70 °C for one week. This is thermally equivalent to storing information on DNA in central Europe for 2000 years.
Committing to memory: Digital information can endure thousands of years of storage when translated into ACGT nucleotide coding and encapsulated as DNA in silica glass spheres. This method was demonstrated with the digitalized Archimedes Palimpsest.
Due to its longevity and enormous information density, DNA is an attractive medium for archival storage. The current hamstring of DNA data storage systems-both in cost and speed-is synthesis. The key ...idea for breaking this bottleneck pursued in this work is to move beyond the low-error and expensive synthesis employed almost exclusively in today's systems, towards cheaper, potentially faster, but high-error synthesis technologies. Here, we demonstrate a DNA storage system that relies on massively parallel light-directed synthesis, which is considerably cheaper than conventional solid-phase synthesis. However, this technology has a high sequence error rate when optimized for speed. We demonstrate that even in this high-error regime, reliable storage of information is possible, by developing a pipeline of algorithms for encoding and reconstruction of the information. In our experiments, we store a file containing sheet music of Mozart, and show perfect data recovery from low synthesis fidelity DNA.
Carbon is anything but a new material, yet ubiquitously applicable for many catalytic transformations in modern organic chemistry. It is highly versatile, as it occurs as modifications abundantly ...available as 1–3D carbonaceous materials due to technical progress. In addition, materials such as activated charcoal, ordered mesoporous carbon (OMC), graphite and graphene (oxide), carbon nanotubes (CNTs), nanospheres (nano-onions, fullerenes), and many others are no “innocent” supports, as demonstrated by many recent publications within the revitalized field of “carbocatalysis”. By nature, carbon scaffolds offer a perfect link between nanoscaled matter and organic molecules, which makes them an ideal cornerstone for molecular catalysts. Apart from this inherent chemical significance, the physical properties (e.g., different conductivity) are equally important for the performance of heterogeneous or immobilized homogeneous catalysts. Careful selection of the carbon scaffold enables control of reactivity by tuning the electronic interactions of active sites with the support or among each other. Moreover, separation and recycling of “heterogenized” catalysts can be further improved by rendering carbon “magnetic”, that is, by incorporation of magnetic particles or by coating metal nanomagnets with graphene-like shells. Altogether, tuning the properties of carbon supports might lead to catalysts tailored not only in matters of reactivity (electron shuttle), but also to down-to-earth problems such as purification (magnetic separation and recycling). This critical review will highlight how far such concepts have already been implemented in the design of “heterogenized” catalysts and is meant to widen the perspectives where certain concepts have yet to be realized.
DNA storage offers substantial information density
and exceptional half-life
. We devised a 'DNA-of-things' (DoT) storage architecture to produce materials with immutable memory. In a DoT framework, ...DNA molecules record the data, and these molecules are then encapsulated in nanometer silica beads
, which are fused into various materials that are used to print or cast objects in any shape. First, we applied DoT to three-dimensionally print a Stanford Bunny
that contained a 45 kB digital DNA blueprint for its synthesis. We synthesized five generations of the bunny, each from the memory of the previous generation without additional DNA synthesis or degradation of information. To test the scalability of DoT, we stored a 1.4 MB video in DNA in plexiglass spectacle lenses and retrieved it by excising a tiny piece of the plexiglass and sequencing the embedded DNA. DoT could be applied to store electronic health records in medical implants, to hide data in everyday objects (steganography) and to manufacture objects containing their own blueprint. It may also facilitate the development of self-replicating machines.
Boomerang catalysis: A catalyst catch–release system is established by the noncovalent attachment of a Pd N‐heterocyclic carbene complex to graphene‐coated magnetic Co nanoparticles. The ...immobilization by pyrene tags (see scheme; blue) is reversible at elevated temperatures, releasing the homogeneous catalyst. The hydroxycarbonylation of aryl halides is performed in 16 iterative reactions with this highly active catalyst.
Synthesis in a day! Carbon‐coated metal nanoparticles can be covalently functionalized by diazonium chemistry. These colloidal reagents can now serve as a basis to magnetically functionalize ...molecules during synthesis, enabling their recovery within seconds.
The functionalization of magnetic nanoparticles has been an important field in the last decade due to the versatile applications in catalysis and biomedicine. Generally, a high degree of ...functionalities on the surface of the nanoparticles is desired. In this study, covalent functionalization of various aromatic sulfonic acids on carbon‐coated cobalt nanoparticles are investigated on surface functionalization yield and stability. The nanoparticles are prepared via covalent linkage of an in situ generated diazonium on the graphene‐like surface. Adsorption and wash experiments were performed to confirm a covalent bonding of the naphthalene derivatives on the nanoparticle surface. With an increased number of sulfonic acid groups on the aromatic compound a significantly lower loading is observed on the corresponding functionalized nanoparticles. This can be counteracted by a change of nitrite species. With this method, nanoparticles with a high number of sulfonic acid groups can be produced.
Sulfonated magnetic nanoparticles may be used as catalysts or potentially as anticoagulants in blood. To achieve high activities, a high loading of sulfonate groups is desired. In this article we investigated the maximization of covalent functionalized sulfonate groups on the surface of carbon‐coated cobalt nanoparticles, assessed their stability and investigated the activity towards ring opening polymerization of glycidol.
Abstract
Palladium promotion and deposition on
monoclinic
zirconia are effective strategies to boost the performance of bulk In
2
O
3
in CO
2
-to-methanol and could unlock superior reactivity if well ...integrated into a single catalytic system. However, harnessing synergic effects of the individual components is crucial and very challenging as it requires precise control over their assembly. Herein, we present ternary Pd-In
2
O
3
-ZrO
2
catalysts prepared by flame spray pyrolysis (FSP) with remarkable methanol productivity and improved metal utilization, surpassing their binary counterparts. Unlike established impregnation and co-precipitation methods, FSP produces materials combining low-nuclearity palladium species associated with In
2
O
3
monolayers highly dispersed on the ZrO
2
carrier, whose surface partially transforms from a
tetragonal
into a
monoclinic-
like structure upon reaction. A pioneering protocol developed to quantify oxygen vacancies using in situ electron paramagnetic resonance spectroscopy reveals their enhanced generation because of this unique catalyst architecture, thereby rationalizing its high and sustained methanol productivity.
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