At Sixes and Sevens Molecular synthesis macroscopic aggregation have often been regarded as entirely separate processes. From the researcher's standpoint, once reagents mixed, is largely passive, whereas processes such crystallization can be more actively manipulated. Carnall et al. (p. 1502 ) characterized an unusual system in which formation of aggregated cyclic macromolecules (macrocycles) from small peptide-based building blocks was governed by intimately interdependent factors ranging...

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTThe Structure of DNA−Liposome ComplexesDanilo D. Lasic, Helmut Strey, Mark C. A. Stuart, Rudolf Podgornik, and Peter M. FrederikView Author Information MegaBios Corporation, Burlingame, California Division Computer Research Technology Laboratory for Structural Biology National Institutes Health, Bethesda, Maryland Department Pathology, Electron Microscopy Unit Limburg University, Maastricht, The Netherlands Cite this: J. Am. Chem. Soc. 1997,...

Niosomes are used in studies for drug delivery or gene transfer. However, their physical properties and features relative to liposomes not well documented. To characterize more rationally optimize niosome formulations, the of these vesicle systems compared those composed phosphatidylcholine phosphatidylethanolamine lipids plus cholesterol. highly stable only slightly leaky than as assayed by calcein leakage; permeability ions (KCl) is higher that liposomes. Contrary liposomes, size niosomes...

Polydopamine is a biomimetic self-adherent polymer, which can be easily deposited on wide variety of materials. Despite the rapidly increasing interest in polydopamine-based coatings, polymerization mechanism and key intermediate species formed during deposition process are still controversial. Herein, we report systematic investigation polydopamine formation halloysite nanotubes; negative charge high surface area nanotubes favour capture intermediates that involved decelerate kinetics...

We verified that antibody-binding substances in serum interfere two-site immunoassays involving murine antibodies are heterophilic antibodies. Incubation of containing and a monoclonal antibody to human choriogonadotropin (hCG) leads formation series soluble immune complexes. investigated the recognition hCG by reagent presence found this be diminished. Consequently, about 30% samples falsely appear contain increased concentrations hCG. The effect on analyte probably results from steric...

Liposomes can be loaded with weak acids and bases, which exist in solutions equilibrium membrane permeable uncharged form, using various gradients across their membranes. Because some cases the estimated drug concentration liposomes exceeds aqueous solubility we investigated physical state of liposome encapsulated anticancer Doxorubicin. X‐Ray diffraction, electron microscopy test tube experiments have shown that upon encapsulation molecules form a gel‐like phase

Cationic lipids are widely used for gene delivery, and inclusion of dioleoylphosphatidylethanolamine (DOPE) as a helper lipid in cationic lipid-DNA formulations often promotes transfection efficacy. To investigate the significance DOPE's preference to adopt hexagonal phase mechanism transfection, properties efficiencies SAINT-2/DOPE lipoplexes were compared those containing lamellar-phase-forming dipalmitoylphosphatidylethanolamine (DPPE). After interaction with anionic vesicles, simulate...

In 1985 we isolated a new vascular anticoagulant protein VAC alpha, now called annexin V, with high binding affinity (Kd less than 10(-10) M) for phospholipids. Its effect was attributed to displacement of coagulation factors from the phospholipid membrane. The present study demonstrates that inhibition prothrombinase activity by V strongly depends on curvature membrane surface and calcium concentration. Half-maximal small vesicles, composed 20% phosphatidylserine 80% phosphatidylcholine,...

Abstract Ternary systems of surfactants, water and organic solvents were studied by monitoring the steady‐state fluorescence versatile solvatochromic probe Nile Red. We found not only that Red can be used throughout whole isotropic regions in phase diagram, but also subtle changes aggregation state surfactant monitored. The formation inverted micelles n ‐hexane could followed upon addition small amounts water, to normal water–organic solvent mixtures. In aqueous C 12 EO 4 solutions...

Abstract Using a modified "two-site" immunoradiometric assay, termed an "interference assay," we have demonstrated the occurrence of non-analyte antibody-binding substances in approximately 40% serum samples. These multivalently bind antibodies from any several species at site other than antigen-binding site. two-site assay for human choriogonadotropin, investigated their effect on analyte quantification. In this system these mimic presence analyte; when is actually present, they can also...

The structure of the lipoplex formed from DNA and sugar-based cationic gemini surfactant 1, which exhibits excellent transfection efficiency, has been investigated in pH range 8.8-3.0 utilizing small-angle X-ray scattering (SAXS) cryo-electron microscopy (cryo-TEM). Uniquely, three well-defined morphologies were observed upon gradual acidification: a lamellar phase, condensed an inverted hexagonal (H(II)) columnar phase. Using molecular modeling, we link physical behavior to specific...

The concurrent self-assembly of new 1,3,5-trisamide-cyclohexane-based low molecular weight hydrogelators and various surfactants in water leads to the formation self-assembled fibrillar networks with encapsulated micelles. This prototype system presents an example orthogonal self-assembly, that is, independent two different supramolecular structures, each their own characteristics coexist within a single system.

Social networking: A variety of novel multicompartment nanostructures has been easily formed by combining the supramolecular aggregative properties surfactants with low-molecular-weight hydrogelators that are based on 1,3,5-cyclohexyltricarboxamide (see picture, AA=amino acid). The resulting structures include self-assembled interpenetrating networks.

A pH sensitive carrier is obtained by coating a cyclodextrin vesicle with an adamantane-terminated octapeptide through the formation of inclusion complex. Upon lowering from 7.4 to 5.0, peptide beta-sheets on surface induces transition bilayer sphere fiber. This fully reversible and repeatable. The vesicles release their cargo upon fiber formation.

Breaking bilayers: Incorporation of dynamic covalent bonds in vesicle-forming surfactants leads to the formation responsive vesicles, which can be switched back and forth between bilayer state isotropic solution using either dilution or a change pH value as external stimuli.

Stacks of macrocycles, assembled using reversible disulfide-bond formation, are covalently captured by photoinitiated exchange disulfide bonds, inducing the formation hydrogels (see picture). This strategy allows access to structures beyond thermodynamic minima traditionally targeted dynamic combinatorial chemistry.

A family of self-replicating macrocycles was developed using dynamic combinatorial chemistry. Replication is driven by self-assembly the replicators into fibrils and relies critically on mechanically induced fibril fragmentation. Analysis separate libraries made from one six peptide-functionalized building blocks different hydrophobicity revealed two selection criteria that govern emergence these systems. First, need to have a critical macrocycle size endows them with sufficient multivalency...

The direct conversion of ethanol to higher value 1-butanol is a catalytic transformation great interest in light the expected wide availability bioethanol originating from fermentation renewable resources. In this contribution we describe several novel compositions porous metal oxides (PMO) as highly active and selective catalysts for Guerbet coupling temperature range 180–320 °C. PMO that do not contain any noble metals are obtained by calcination series hydrotalcite precursors synthesized...

The novel concept of amphiphilic molecular motors that self-assemble into responsive supramolecular nanotubes in water is presented. dynamic function the motor units inside assemblies was studied using UV-vis absorption spectroscopy and cryo-transmission electron microscopy (cryo-TEM) microscopy. Reorganization between distinct, well-defined vesicles can be reversibly induced by light, going through rotation cycle motor, i.e. driven alternate photochemical thermal isomerization steps system....