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Dendrimer - Wikipedia, the free encyclopedia In the synthesis of dendrimers, monomers lead to a monodisperse polymer, tree-like, or generational structure. The properties of dendrimers are dominated by the functional groups on the molecular surface. It is theoretically possible to design a water-soluble dendrimer with internal hydrophobicity, which would allow it to carry a hydrophobic drug in its interior. en.wikipedia.org /wiki/Dendrimer   (381 words)

mmackay-dendrimer A dendrimer is a highly branched polymer, as shown in the schematic below, and consists of a core where a monomer unit is attached. This is a G4 dendrimer with an -OH core. Dendrimers show some unique properties, one is the intrinsic viscosity going through a maximum at the fourth generation (see e.g. www.egr.msu.edu /~mackay/mmackay-dendrimer.htm   (978 words)

What is a dendrimer? Dendrimer synthesis is a relatively new field of polymer chemistry defined by regular, highly branched monomers leading to a monodisperse, tree-like or generational structure. There are two defined methods of dendrimer synthesis, divergent2 and convergent.3 In the divergent method the molecule is assembled from the core to the periphery; while in the convergent method, the dendrimer is synthesized beginning from the outside and terminating at the core. Dendrimers have two major chemical environments, the surface chemistry due to the functional groups on the termination generation,which is the surface of the dendritic sphere, and the sphere's interior which is largely shielded from exterior environments due to the spherical shape of the dendrimer structure. kyky.essortment.com /whatisdendrime_rsnz.htm   (589 words)

Poly(amidoamine) (PAMAM) Dendritic Nanostructures for Controlled Site-specific Delivery of Acidic Anti-inflammatory ... Dendrimers are one of the emerging delivery systems with the capability to present such hydrophobic agents in a formulation with better prospective. PAMAM dendrimer of generation 4 amine-terminated (4.0 G-NH) was used in concentration of 0.1%, 0.2%, 0.3%, and 0.4% wt/vol with drug FB in various formulations DF, and DF (DF represents drug-dendrimer complex), respectively, for in vitro characterization. This might be owing to the fully ionized state achieved by the dendrimers at pH 7.0 as compared with acidic or basic states and hence higher degree of association of FB with dendrimer, which further enhanced its solubility in the aqueous phase. www.aapspharmscitech.org /view.asp?art=pt060367   (3942 words)

dendrimer - a definition from Whatis.com   (Site not responding. Last check: 2007-11-05) A dendrimer (from Greek dendra for tree) is an artificially manufactured or synthesized molecule built up from branched units called monomers. Dendrimers are of interest to researchers in medical technology, where they might help carry and deliver drugs in the body, or serve as replacements for plasma components. Dendrimers might also prove useful in the manufacture of nanoscale batteries and lubricants, catalysts, and herbicides. whatis.techtarget.com /definition/0,,sid9_gci515363,00.html?track=NL-34&ad=491809   (222 words)

Patent 6,410,680 The dendrimer construct has a generally globular shape, and the branched chains nearer the surface are sufficiently densely packed to restrict the movement of larger biomolecules into the dendritic construct toward the metal active sites. The dendrimer construct may have all structurally similar arms, and each arm may contain similar repeat internal branch units (except for one or more branch units with which the ion binding site is associated); or each arm may contain dissimilar internal branch units. The dendrimer construct will not be a substrate for enzymatic degradation Moieties in the outermost tiers, on the surface of the dendritic construct, can be modified to facilitate affinity of the complex to cell surfaces or tissues, and particular modifications can be used to provide affinity for selected types of cells or tissues. www.pharmcast.com /Patents/Yr2002/June2002/062502/6410680_Dendrimer062502.htm   (1404 words)

NanoCure Corporation   (Site not responding. Last check: 2007-11-05) Because differences in dendrimer surface charge were thought to be of paramount importance in the biological function of this scaffold, changes in the terminal groups of the dendrimer were examined first. In addition, it appeared that all of the folic acid molecules on the dendrimer surface were accessible for binding with cellular receptors in the acetamide molecule, while approximately two-thirds of the targeting moieties in the hydroxyl molecule were available for binding. Dendrimer based scaffolds with the three modified surfaces were synthesized and substituted with identical numbers of folic acid and FITC moieties. www.avidimer.com /drug.html   (5196 words)

MVS Solutions - Novel Dendrimer Compound, A Biochop Using the Same and a Fabricating Method Thereof A bio chip comprising substrate, the dendrimer molecular layer of Chemical Formula 1 according to Claim 1, which is multiple covalently bonded to the substrate surface, and probe compound, which is bound to amine on the termini of the dendrimer molecular layer. Furthermore, the dendrimer's amine tip is shielded by a protection group, which enables monolayer arrangement of dendrimers on the substrate surface, and was designed to be easily removable. The dendrimer can also become an important element in surface research (in which molecules are fixed to the substrate surface and their properties are investigated) as a surface substrate. www.mvssolutions.com /PBC_05-016869.html   (9431 words)

RedOrbit - Science - Dendritic Nanotechnologies Announces Initial Roll-Out of New Priostar Dendrimer Family Initially, Priostar dendrimers could be used as high-performance additives to address polymer manufacturers' need for new technologies that can reduce curing times, enable them to process additives into a new formulations, or improve strength and durability. The size and shape of a dendrimer are determined by shells (known as generations) grown around a core structure, while the reactivity of the dendrimer is determined by its surface chemical functionality, together with size and shape. Dendrimers are nanostructures with specific, precise and predictable physical properties that make them especially useful for pharmaceuticals, medical imaging, electronics, materials, and the mass commercial markets. www.redorbit.com /news/science/542571/dendritic_nanotechnologies_announces_initial_rollout_of_new_priostar_dendrimer_family/?source=r_science   (846 words)

Genisphere - Architecture of 3DNA Dendrimer As a class, dendrimers are complex, branched molecules built from interconnected natural or synthetic monomeric subunits. The molecules that determine the target and labeling specificity of the dendrimer are attached either as oligonucleotides or as oligonucleotide conjugates. The architecture of the 3DNA dendrimer imposes no restrictions on the type of specificity or label used, so the dendrimer may be configured to meet a wide variety of detection needs. www.genisphere.com /about_3dna.html   (700 words)

Dendrimers: The Chemist's Snowflake The polarity of the dendrimer is dictated by the polarity of the side groups exposed at the periphery of the molecule. In divergent synthesis, the assembly of the dendrimer occurs from the core and radiates outward. In convergent synthesis, the assembly of the dendrimer occurs from the periphery of the molecule toward the core (Hawker and Frechet, 1990). www.sas.upenn.edu /~zurbano/mce/dendrimers.html   (1993 words)

Triazine based Dendrimers Dendrimer is a compound word, composed of the Greek "dendron", meaning tree and the word "polymer", that itself is a fusion of the Greek "poly" (many) and "meros" (part). Dendrimers can be divided in three zones: The region of the initiator core, the region of the inner branching units and the outer level, carrying the endgroups. We examined the incorporation of the obtained Dendrimers in Lipids with DSC and Langmuir-technique, what is reported elsewhere [14]. pages.unibas.ch /mdpi/ecsoc-4/a0098/a0098.htm   (1916 words)

Dendritic Polymers and Their Potential Applications The name dendrimer is derived from Greek words dendron meaning "tree" and meros meaning "part." A major difference between linear polymers and dendrimers is that a linear polymer consists of long chains of molecules, like coils, crisscrossing each other. Once the dendrimer reaches its target, the bond between the drug and the dendrimer is cleaved (enzymatically or photochemically). Dendrimers can be functionalized at the periphery or at the core with variety of functional groups for catalysis actions. www.eng.buffalo.edu /Courses/ce435/Dendrimers/Dendrimers.html   (2247 words)

Using Ethidium Bromide To Probe the Interactions between DNA and Dendrimers Starburst dendrimers (SBDs) are a relatively new class of polymers possessing radially branched amidoamine units emanating from a central core, whose structure is created by the stepwise attachment of layers, termed generations. This might be due to the stronger ionic interactions between DNA and dendrimers and/or to the DNA conformation being not as constrained for dendrimer binding as it is for histone binding. This indicates that the binding between DNA and dendrimer is weaker at higher ionic strength, which is in agreement with electrostatic contributions to the binding. pubs.acs.org /cgi-bin/jtextd?langd5/16/i01/html/la981429v   (3776 words)

US/Australia Dendrimer Nanotechnology Venture to Be Established Dendrimers are a novel class of precisely defined nano-scale (1 billionth to 100 billionths of a meter) synthetic compounds with structures that can be precisely designed for a wide range of applications. Dr. Tomalia's US research team leads the world in producing novel dendrimer structures and Starpharma is at the forefront of pharmaceutical applications of dendrimers. Dr. Tomalia is both the pioneer in dendrimer technology and a recognised leader in nanotechnology in the USA. www.prnewswire.com /cgi-bin/stories.pl?ACCT=104&STORY=/www/story/08-06-2001/0001548804&EDATE   (903 words)

Evaluations of Unformulated and Formulated Dendrimer-Based Microbicide Candidates in Mouse and Guinea Pig Models of ... The lysine dendrimer generations are built out from a central core (boldface), through a series of layers or generations. dendrimer or placebo in a volume of 15 µl. Dendrimers, a new class of candidate topical microbicides with activity against herpes simplex virus infection. aac.asm.org /cgi/content/full/47/12/3784   (2905 words)

Dendrimer Dendrimer, polymeric molecule about the size of an average protein that has a branching shape. Depending on the dendrimer core (central part), the dendrimer can start with 3 to 8 (or more) branches, with 3 and 4 being the most common numbers observed. The name 'dendrimer' is derived from the ancient Greek word 'dendron' (tree), and the suffix 'mer' (segment). nanoatlas.ifs.hr /dendrimer.html   (156 words)

ANS Dendrimer review: Background   (Site not responding. Last check: 2007-11-05) At high generations, steric crowding of the branches at the surface of a dendritic molecule causes the adoption of a globular conformation.[17,20] The branch ends may lie either on the surface of the molecule, or throughout the entire structure, possibly determined by factors such as the solvent and the dendrimer constitution. The behaviour of dendrimers as hosts is essential if they are to find success as solubilising agents,[24] catalysts, and drug delivery[25] and slow release agents for perfumes, herbicides and drugs. The depiction of dendrimers can be a somewhat more pressing problem, as many dendritic structures simply cannot be portrayed in more conventional ways. www.ninger.com /dendrimer/one.htm   (692 words)

Thermal Decomposition of Generation-4 Polyamidoamine Dendrimer Films: Decomposition Catalyzed by Dendrimer-Encapsulated ... Dendrimer decomposition was also investigated by thermogravimetric analysis (TGA) in both air and argon atmospheres. C during the TPD experiment induced the desorption of large dendrimer fragments at 55, 72, 84, 97, 127, 146, and 261 amu. However, the Pt particles also catalyze bond scission within the dendrimer fragments so that decomposition of the dendrimer to gaseous hydrogen is the dominant reaction pathway compared to desorption of the larger dendrimer fragments observed in the absence of Pt particles. pubs.acs.org /cgi-bin/abstract.cgi/langd5/2005/21/i09/abs/la047242n.html   (429 words)

IBM Research | Almaden Research Center | Science and Technology | Polymer Science | Dendrimer Chemistry   (Site not responding. Last check: 2007-11-05) It is anticipated that the structural control afforded by these approaches will permit the use of dendrimers as the active component, or in the manufacture of advanced microelectronics and magnetic storage devices. Dendritic macromolecules, or dendrimers, are synthetic 3-dimensional macromolecules that are prepared in a step-wise fashion from simple branched monomer units, the nature and functionality of which can be easily controlled and varied. As a consequence, dendrimers are now considered to be one of the prime nanometer-scale building blocks for the construction of nanoscale objects, molecular devices and molecular 'machines', advanced drug-delivery systems, etc. www.almaden.ibm.com /st/chemistry/ps/dendrimers/index.shtml   (201 words)

Structural characterization of an amine-terminated hybrid dendrimer: molecular dynamics studies Polyamidoamine (PAMAM) dendrimers have been successfully used as gene transfection vectors due to the primary amines on their surface and interior tertiary amines. This molecular dynamics study characterized the biological functionality of dendrimers depending on the location of primary amines in amine-terminated dendrimers as a function of protonation. Dendrimers with fully protonated amines presented a narrower distribution of primary amines than those without, showing fully stretched structures. www.foresight.org /Conferences/MNT8/Abstracts/Baker   (494 words)

Gene Therapy: Encyclopedia of Medicine Scientists are also investigating the introduction of raw recombinant DNA by injecting it into the bloodstream or placing it on microscopic beads of gold shot into the skin with a "genegun." Another possible vector under development is based on dendrimer molecules. A class of polymers (naturally occurring or artificial substances that have a high molecular weight and formed by smaller molecules of the same or similar substances), is "constructed" in the laboratory by combining these smaller molecules. In the laboratory, dendrimers have shown the ability to transport genetic material into human cells. health.enotes.com /medicine-encyclopedia/gene-therapy   (4479 words)

Nano News - Dendrimer Nanoparticle Overcomes Drug Resistance in Tumor Cells The researchers also found that this potentially beneficial effect is not seen with all dendrimer nanoparticles. In one formulation, the investigators used a dendrimer that had free carboxylic acid groups at the multiple ends of the branched dendrimer polymer. The researchers called this conjugate A. The second formulation, named conjugate B, comprised a dendrimer with free amino groups at the ends of the polymer. nano.cancer.gov /news_center/nanotech_news_2006-04-03b.asp   (311 words)

Enhanced delivery of antisense oligonucleotides with fluorophore-conjugated PAMAM dendrimers -- Yoo and Juliano 28 ... Conjugated dendrimer alone or dendrimer–oligonucleotide (OD) complexes were applied to cells with and without serum. The ratio of Oregon green 488 to each generation 5 dendrimer is 4:1 (open bar), 1.75:1 (filled bar), 0.8:1 (hatched bar) and unconjugated generation 5 dendrimer (shaded bar). The complexes of oligonucleotide and fluorophore-conjugated dendrimer were formed at constant ratio (0.5 µM for oligonucleotide and 20 µg/ml for G5-Org). nar.oxfordjournals.org /cgi/content/full/28/21/4225   (3320 words)

A novel, sensitive detection system for high-density microarrays using dendrimer technology -- STEARS et al. 3 (2): 93 ... DNA dendrimers were prepared as previously described (4). Probes were synthesized with 30, 20, 10, and 5 µg for the direct incorporation method (A) and 20, 10, 5, and 1 µg of total RNA for the dendrimer detection (B). Of the 1,700 genes that were spotted on the microarrays, a set of 116 expressed genes were arbitrarily chosen for a more in-depth analysis of the signal, background, and specific signal generated. physiolgenomics.physiology.org /cgi/content/full/3/2/93   (3790 words)

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