In den Warenkorb. Sicher bezahlen. Folgen Sie uns. Das Passwort muss mind. Darin sollte mind. Recht Steuern Wirtschaft. Startseite Technik Technik Allgemein Nanotechnologie. Erschienen: Starov Nanoscience Colloidal and Interfacial Aspects lieferbar, ca. Produktbeschreibung The common perception is that nanoscience is something entirely new, that it sprung forth whole and fully formed like some mythological deity. But the truth is that like all things scientific, nanoscience is the natural result of the long evolution of scientific inquiry.
Following a historical trail back to the middle of the 19th century, nanoscience is the inborn property of colloid and interface science. It should also be appreciated that over the past decades, a number of novel nanostructures have been developed, but whatever we call them, we cannot forget that their properties and behavior are still in the realm of colloid and interface science. However one views it, the interest and funding in nano-science is a tremendous opportunity to advance critical research in colloid chemistry.
Nanoscience: Colloidal and Interfacial Aspects brings together a prominent roster of 42 leading investigators and their teams, who detail the wide range of. Request PDF on ResearchGate | Nanoscience: Colloidal and interfacial aspects | The common perception is that nanoscience is something entirely new, that it.
Nanoscience: Colloidal and Interfacial Aspects brings together a prominent roster of 42 leading investigators and their teams, who detail the wide range of theoretical and experimental knowledge that can be successfully applied for investigating nanosystems, many of which are actually well-known colloidal systems. This international grouping of pioneering investigators from academia and industry use these pages to provide researchers of today and tomorrow with a full examination of nano-disperse colloids, homogeneous and heterogeneous nano-structured materials and their properties , and shelf-organization at the nano-scale.
This course was taught by Pete Johnson, who introduced me to retrosynthetic analysis, and in the process showed me how I could achieve the connectivity I had doodled when younger. This classroom work was followed up soon thereafter by practical training at the hands of Phil Garner. Phil was an old school 'guts and glory' synthetic type, and I learned from him everything I needed to about the practical side of synthetic organic.
This work culminated in the first paper I co-authored  , where I learned painful lessons with the Fieser triangle at the twilight of the pen and ink era.
With my belly full of synthetic fire, I sought out a place to pursue my trade. In the mids Yale University was hotbed for synthesis, and picking out an advisor was a difficult choice. I ultimately chose Harry Wasserman, based on the freedom he gave his group in choosing and attacking synthetic and physical challenges. During this period I developed and finished a variety of syntheses. My break came, however, when looking in the back pages of the journal Heterocycles in the "New Natural Products" section. I noticed a rather interesting new molecule known as rapamycin that had the vicinal tricarbonyl motif in vogue in the Wasserman group.
When I suggested we go after this molecule, Harry demurred, pointing out its complexity and that "nobody would be interested". I kept my eye on the literature, however, and when Dave Williams published the "Central America" fragment of the related macrolide FK, I urged Harry to see if he could get some intermediate that I could use to demonstrate our methodology for tricarbonyl synthesis. With hands shaking, I cracked the vial and started on the synthesis. This synthesis generated some buzz, catching the eye of folks like Sam Danishefsky and facilitating my next move.
The customers would like to overcome health problems such as cardiovascular problems and obesity through consuming foods rather than drugs. In the case of the colloid, the volume fraction of particles or particle density may be so low that a significant amount of fluid may need to be removed initially for the gel-like properties to be recognized. Pure and Applied Chemistry. A chemical surfactant surrounds the particle during formation and regulates its growth. Reversible assembly of metal nanoparticles induced by penicillamine.
Sorting out what I wanted to do after grad school was a bit of a challenge. In those days I knew I wanted to be an academic, but what I wanted to do scientifically was an open question. I started thinking about proposals for postdoctoral fellowships, but the synthetic ideas I generated didn't fire me up like I thought they should.
I really enjoyed the power of organic synthesis, but I wanted to do something with the molecules that I laboriously fashioned. Once again my love of connectivity kicked in, this time with supramolecular chemistry. I started thinking of molecules instead of atoms as building blocks. I looked around for professors with a like mind, and applied to Julius Rebek at Pittsburgh. While in the Rebek group I used my synthetic abilities while gaining the insight into physical organic chemistry that has informed the rest of my career.
I started out working on self-replicating systems  , developing new systems that had novel capabilities, including external regulation . I also took on a brutal project, focused on the synthesis of water-soluble analogs of Kemp's triacid.
This project was a massive effort, with a huge number of reactions required to optimize the initial steps. We did, however, obtain the desired receptors and observe some interesting binding processes in water . During this part of my time in the group, Julius offered that if I stayed an additional year I could work on projects of my own.
During this time I discovered my inner mentor.
Much to the annoyance of my labmates, I built a veritable army of undergraduates, pursuing supramolecular chemistry, along with a project in fullerenes [6,7]. After finishing my postdoctoral work, I moved to the University of Massachusetts. I chose UMass based on its quality and longstanding reputation for collaborative research. Upon arrival, I collected a fired up group of graduate students and went to it.
I maintained my fullerenes project  , and initiated a set of three other supramolecular projects. Of these projects, our work on flavoenzyme models was the one that really took off. We also used integrated experimental and computational techniques to actually establish what hydrogen bonding does to the electrons in hydrogen-bonded complexes . Finally, we put this all together to generate molecular switches and devices .
This work has continued through our long productive collaboration with Graeme Cooke, now at University of Glasgow, moving from redox-active systems [14,15] to photovoltaics along with Ifor Samuel at St. Figure 1: Flavoenzyme model system for determining the role of aromatic stacking in flavin redox processes. Reprinted with permission from .
Copyright American Chemical Society. After four or so years of work on redox-modulated recognition two things happened. First, I realized that we could predict what would happen with the systems before we made them. This took much of the fun out of the work. Simultaneously, I received tenure, and tried to sort out what I wanted to do for my next career phase.
Our next move was into polymers, where we started the conceptual journey we are still taking. The key question we asked is "we know what happens when you have one host—guest dyad, but what happens when you have 10, 50, on a polymer? We also showed that we could self-assemble a polymer around an electroactive guest, effectively encapsulating and isolating it .
Figure 2: Recognition element-functionalized polymers for 'plug and play' modification and self-assembly. The research really became interesting when we started mixing multivalent complementary polymers together.
When we mixed together diaminopyridine and uracil polymers together in chloroform we generated a turbid solution. Under the microscope we found that the turbidity surprisingly arose from vesicular structures . Through quite a bit of experimentation we determined that the unprecedented self-assembly process was driven by self-sorting of the polymer chains to provide vesicle walls with denser recognition elements in the middle than at the outside . While we were working with polymers, we were just starting to move into nanoparticles.
As with the polymers, we started off studying the interactions of recognition element-functionalized nanoparticles with monovalent guests — in this case our old friend flavin where we showed modulation of the flavin redox potentials . Taking this research one step further, we created a nanoparticle with a mixed monolayer consisting of hydrogen bonding and aromatic staking sidechains. When we incubated this NP with flavin we observed an increase in binding over time, i. We have since demonstrated this templation with peptides  and are still! As I mentioned above, I am an incessant tinkerer, a trait that has rubbed off on the group.
This "bricks and mortar" assembly process provides a modular system where structure and stoichiometry of the components drives structure formation. These assemblies set us on a path of generating nanocomposite materials, including regular structures using diblock copolymers [25,26] and nanoparticle—protein [27,28] and nanoparticle—nucleic acid composites .
Figure 3: Recognition-mediated assembly of nanoparticle—polymer constructs.
Reproduced from . Concurrently with our 3D self-assembly, we pursued the use of nanoparticles for surface modification. This research has focused on the use of these particles to efficiently impart functional properties to surfaces . When combined with nanoimprint lithography  this process gives us access to nano-textured nanopatterned surfaces [33,34]. We have recently employed this strategy to control cell growth on surfaces  , including using the surface properties of the nanoparticle to dictate cell selectivity .
Our move into nanocomposites coincided with our efforts to interface materials and biology — the current core focus of the lab. We started off looking at nucleic acids, where we showed that cationic nanoparticles could bind to anionic DNA and inhibit transcription . We also developed a number of strategies for delivery of small molecules, including glutathione-mediated release of covalently attached thiols  , as the effective release of drugs adsorbed into the cationic monolayers of nanoparticles  , and even photoactivatable drug  and DNA release . When we started looking at how particles interact with proteins, however, very little was known about how these materials would play together.
We found out pretty quickly that the answer was "not very well". Binding of the nanoparticle induced protein denaturation, with loss of bioactivity .
We hypothesized that this denaturation arose from interaction of the protein with the hydrophobic elements of the simple ligands we were using. This hypothesis led us to create what we call the "tabula rasa" ligand  , namely a ligand that features a hydrophobic interior for self-assembly, and a short tetra ethylene glycol layer to block interactions of the hydrophobic interiors with proteins . Once we appended simple anionic and cationic recognition elements to the surface these system bound proteins with high affinity  and some degree of selectivity .
What was surprising is that not only did the particle—protein binding process not denature the proteins, it actually stabilizes them ! This result stills surprises researchers who follow the dogma that proteins must denature at interfaces.