Exploiting dense shell/packing principles to invoke stereoselectivity in a reaction accelerated by a chiral dendrimer

As dendrimers approach their dense shell or dense packed limit, a certain amount of conformational organization exists. Any substrate binding within the dendrimer’s external layerwill experience the same organizational effects. This paper describes how these effects can be exploited towards stereocontrol with respect to binding and reactivity

Controlling microenvironments and modifying anion binding selectivities using core functionalised hyperbranched polymers

An isophthalamide anion binding site has been incorporated into hyperbranched polymers resulting in a change in the selectivity of the receptor from chloride to bromide

Graphene Oxide-Gallic Acid Nanodelivery System for Cancer Therapy

Despite the technological advancement in the biomedical science, cancer remains a life-threatening disease. In this study, we designed an anticancer nanodelivery system using graphene oxide (GO) as nanocarrier for an active anticancer agent gallic acid (GA). The successful formation nanocomposite (GOGA) was characterized using XRD, FTIR, HRTEM, Raman, and UV/Vis spectroscopy. The release study shows that the release of GA from the designed anticancer nanocomposite (GOGA) occurs in a sustained manner in phosphate-buffered saline (PBS) solution at pH 7.4. In in vitro biological studies, normal fibroblast (3T3) and liver cancer cells (HepG2) were treated with different concentrations of GO, GOGA, and GA for 72 h. The GOGA nanocomposite showed the inhibitory effect to cancer cell growth without affecting normal cell growth. The results of this research are highly encouraging to go further for in vivo studies

Investigation of Gamma-aminobutyric acid (GABA) A receptors genes and migraine susceptibility

Background Migraine is a neurological disorder characterized by recurrent attacks of severe headache, affecting around 12% of Caucasian populations. It is well known that migraine has a strong genetic component, although the number and type of genes involved is still unclear. Prior linkage studies have reported mapping of a migraine gene to chromosome Xq 24–28, a region containing a cluster of genes for GABA A receptors (GABRE, GABRA3, GABRQ), which are potential candidate genes for migraine. The GABA neurotransmitter has been implicated in migraine pathophysiology previously; however its exact role has not yet been established, although GABA receptors agonists have been the target of therapeutic developments. The aim of the present research is to investigate the role of the potential candidate genes reported on chromosome Xq 24–28 region in migraine susceptibility. In this study, we have focused on the subunit GABA A receptors type ε (GABRE) and type θ (GABRQ) genes and their involvement in migraine. Methods We have performed an association analysis in a large population of case-controls (275 unrelated Caucasian migraineurs versus 275 controls) examining a set of 3 single nucleotide polymorphisms (SNPs) in the coding region (exons 3, 5 and 9) of the GABRE gene and also the I478F coding variant of the GABRQ gene. Results Our study did not show any association between the examined SNPs in our test population (P > 0.05). Conclusion Although these particular GABA receptor genes did not show positive association, further studies are necessary to consider the role of other GABA receptor genes in migraine susceptibility

A short synthesis of the β-amyloid (Aβ) aggregation inhibitor 3-p-toluoyl-2-[4′-(3-diethylaminopropoxy)-phenyl]-benzofuran.

A short and convenient synthesis of 3-p-toluoyl-2-[4′-(3-diethylaminopropoxy)-phenyl]-benzofuran, an inhibitor of the aggregation of β-amyloid, which is thought to be the underlying cause of Alzheimer's disease, is described. A short and convenient synthesis of 3-p-toluoyl-2-[4′-(3-diethylaminopropoxy)-phenyl]-benzofuran, an inhibitor of the aggregation of β-amyloid protein is described

Synthesis of Fluorinated Amphiphilic Polymers and the Morphological Dependence on Their Oxygen Binding Capacity

Water-soluble materials that can bind, sense, and deliver oxygen are important for several applications. These include catalysis, environmental sensors, smart packaging, agriculture, and medicine. Herein we report the synthesis of two related fluorinated amphiphilic polymers that can self-assemble into small micelles (20–30 nm) or larger vesicles (>300 nm). We found that the oxygen binding capacity of these polymers was dependent on the morphology of their self-assembled structures. At a constant fluorine concentration of 1.5 mg/mL, the oxygen solubility within the vesicle solution was 55% higher than that measured in pure water and 25% higher than the corresponding micelle solution. The increased concentration of oxygen in the vesicle solution indicated a significantly higher level of oxygen binding, which was attributed to additional oxygen trapped within the vesicle’s aqueous interior

Effect of Terminal-Group Functionality on the Ability of Dendrimers to Bind Proteins

It is known that dendrimers can bind proteins with good selectively. This selectivity comes about from an optimization based on matching the size of the dendrimer with the size of the protein’s interfacial binding area. In this paper, we report how this selectivity can be moderated by the functionality on the surface of the dendrimer. Specifically, we describe the synthesis of amino acid functionalized dendrimers and the effect of functionality on the dendrimer’s ability to bind and inhibit the enzymatic protein, chymotrypsin. The results show how dendrimer binding can be increased or decreased depending on the terminal functionality. These results will allow new ligands to be designed and synthesized, possessing increased and selective protein-binding abilities

Probing Dense Packed Limits of a Hyperbranched Polymer through Ligand Binding and Size Selective Catalysis

In the area of dendritic chemistry (hyperbranched polymers and dendrimers) it is often generalized that dendrimers are the molecule of choice for smart, selective, or technical applications involving encapsulation or controlled/selective environments. This is despite the fact that hyperbranched polymers (HBP)­s are generally easier and cheaper to synthesize, making them more amenable to large-scale applications. Dendrimers have been successful in these applications by virtue of a dense packed or dense shell limit. This paper describes the synthesis of a series of narrowly dispersed HBPs possessing binding and catalytic cores with a high and uniform loading. Subsequent binding experiments clearly demonstrated the existence of a dense packed limit with respect to polymer molecular weight and ligand size. A series of catalytic experiments were also performed in an attempt to exploit these molecules and their dense packed limit to the area of shape/size selective catalysisan area where dendrimers have previously been used with celebrated success. However, although we were able to show the existence of a dense packed limit, we were initially unable to demonstrate any selectivity based on substrate size or shape. Nevertheless, further studies into core branching motif and multiplicity eventually enabled us to obtain a series of HBPs capable of perturbing the shape/size selectivity of a simple oxidation reaction involving two alkenes. Specifically, we were able to demonstrate a 3.5-fold shift in chemoselectivity toward a smaller alkene of lower reactivity. These results compare favorably with those obtained using dendrimers and allow us to conclude that, with careful thought regarding core design, HBPs are indeed capable of being applied to technical/smart applications involving controlled and selective environments

The Synthesis of Chiral Dendritic Molecules Based on the Repeat Unit L-Glutamic Acid

The convenient synthesis of a glutamate based dendrimeric molecule is reported. This chiral unsymmetrical dendrimer, contains 15 chiral centres an with identical configurations (L)