Interface Engineering by Molecular Layer Deposition on Polymer Membrane for Selective Ion Transport.

Molecular layer deposition (MLD) of ethylene glycol-alucone (EG-alucone) on the Nafion cation exchange membrane is investigated to understand its impact on the morphology of the composite and consequent enhancement of ion transport selectivity. X-ray photoelectron spectroscopy, scanning electron microscopy, Density functional theory, and Doppler broadening positron annihilation spectroscopy are comprehensively employed to examine the morphology of the composite, particularly the engineered interface between EG-alucone and Nafion. These studies reveal the diffusion and subsequent reaction of the Lewis-acidic trimethyl aluminum precursor with the polymer substrate during MLD.

Structure and properties of mixed valent CeFeAl.

Temperature dependent magnetic, electrical transport and thermal properties of polycrystalline orthorhombic CeFeAlintermetallic compound have been studied along with its isostructural La counterpart, LaFeAl. For the cerium compound, low fieldmagnetization exhibits an antiferromagnetic like ordering () ∼ 4 K. The main feature of the magnetic susceptibility plot is a broad hump spanning a large temperature range, indicating mixed valence of Ce in the compound, in good agreement with reported literature.

A highly efficient redox stabilization strategy for Am-Cm separation using AgBiO.

AgBiO is reported for the exclusive oxidation of Am → AmO at near-neutral pH conditions. Literature methods of AmO generation are generally two-step processes; , Am → AmO oxidation followed by AmO → AmO reduction. These methods for Am → AmO oxidation use high temperatures (80-100 °C) and/or several reagents, causing the presence of the AmO-complex rather than the AmO ions.

LiAlO:Gd-Based Versatile and Ultrasensitive Detector for Gamma and Neutrons by Thermal and Optical Stimulation.

Considering the low-level dose detection requirement for neutron and γ radiation in cancer therapy, synthesis and exploratory studies have been performed on a newly developed phosphor LiAlO:Gd. Our results reveal that the presence of both Li and Gd makes it sensitive to both gamma and thermal neutrons. The applicability of LiAlO:Gd for beta, gamma, and neutrons in both thermally stimulated and optically stimulated modes has been verified by extensive experiments followed by kinetic parametric evaluation with theoretical calculations.

A High-Affinity "Synthavidin" Receptor for Squaraine Dyes.

Strong-binding host-guest pairings in aqueous media have potential as "supramolecular glues" in biomedical techniques, complementing the widely-used (strept)avidin-biotin combination. We have previously found that squaraine dyes are bound very strongly by tetralactam macrocycles possessing anthracenyl units as cavity walls. Here we show that replacing the anthracenes with pentacyclic 5,7,12,14-tetrahydro-5,7,12,14-tetraoxapentacene (TOP) units generates receptors which bind squaraines with increased affinities (around K =10  m ) and improved selectivities.

Biomedical Applications of Metal Organic Polygons and Polyhedra (MOPs).

Since the discovery and structural characterization of metal organic polygons and polyhedra (), scientists have explored their potential in various applications like catalysis, separation, storage, and sensing. In recent years, scientists have explored the potential of supramolecular in biomedical application. Pioneering works by Ehrlich, Rosenberg, Lippard, Stang and others have demonstrated that have great potential as a novel class of metallo-therapeutics that can deliver cargoes (drugs and dyes) selectively.

Selective glucose sensing in complex media using a biomimetic receptor.

Glucose is a key biomedical analyte, especially relevant to the management of diabetes. Current methods for glucose determination rely on the enzyme glucose oxidase, requiring specialist instrumentation and suffering from redox-active interferents. In a new approach, a powerful and highly selective achiral glucose receptor is mixed with a sample, l-glucose is added, and the induced CD spectrum is measured.

A synthetic transcription factor pair mimic for precise recruitment of an epigenetic modifier to the targeted DNA locus.

We developed an epigenetically active, cooperative DNA binding transcription factor platform assisted by cucurbit[7]uril (CB7) host-guest modules. This new type of molecule termed ePIP-HoGu not only mimics the operation of transcription factors as a pair but also recruits the epigenetic modifier to a particular DNA locus.

Metal Organic Polyhedra: A Click-and-Clack Approach Toward Targeted Delivery.

Mixed self-assembly of ligands and , PXDA (), and Pd(NO) afforded metal organic polyhedra ( - ) which bear 24 covalently attached CB[7] and cyclooctyne moieties. Post assembly modification (PAM) of by covalent strain promoted alkyne azide click reaction provided bearing covalently attached functionality (PEG, sulfonate, biotin, c-RGD, fluorescein and cyanine). Orthogonal CB[7] guest mediated non-covalent PAM of with afforded and .

Hybrid Molecular Container Based on Glycoluril and Triptycene: Synthesis, Binding Properties, and Triggered Release.

We designed and synthesized a "hybrid" molecular container 1, which is structurally related to both cucurbit[n]uril (CB[n]) and pillar[n]arene type receptors. Receptor 1 was fully characterized by H NMR, C NMR, IR, MS and X-ray single crystal diffraction. The self-association behavior, host-guest recognition properties of 1, and the [salt] dependence of K were investigated in detail by H NMR and isothermal titration calorimetry (ITC).

Blurring the Lines between Host and Guest: A Chimeric Receptor Derived from Cucurbituril and Triptycene.

We report the synthesis and X-ray crystal structure of a cucurbituril-triptycene chimeric receptor (1). Host 1 binds to guests typical of CB[6]-CB[8], but also binds to larger guests such as blue box (20) and the Fujita square (22). Intriguingly, the geometries of the 1⋅20 and 1⋅22 complexes blur the lines between host and guest in that both components fulfill both roles within each complex.

Cucurbit[7]uril Enables Multi-Stimuli-Responsive Release from the Self-Assembled Hydrophobic Phase of a Metal Organic Polyhedron.

Mixed self-assembly of ligands 1, 2, 1,6-hexanediamine (HDA), and Pd(NO) afforded Fujita-type metal organic polyhedron MOP1 (diameter ≈ 8.2 nm), which is covalently functionalized with an average of 18 cucurbit[7]uril (CB[7]) units, as evidenced by H NMR, diffusion-ordered spectroscopy NMR, and transmission electron microscopy measurements. By virtue of the host-guest properties of CB[7], the inner cavity of MOP can be rendered hydrophobic by using octadecyl HDA (3) as guest during the self-assembly process.

Self-assembly of cucurbit[7]uril based triangular [4]molecular necklaces and their fluorescence properties.

Self-assembly of rigid-rod dipyridine ligand 1 with M(en)(NO) (M = Pd, Pt) affords triangular (3, 5) and square (4, 6) supramolecular coordination complexes (SCCs). The binding affinity of 1 toward CB[n]-type containers results in the formation of triangular [4]molecular necklaces ([4]MNs, 7-10) by either one-pot or post complexation approaches as evidenced by H NMR, diffusion ordered spectroscopy, and ESI-MS.

Synthetic mimics of biotin/(strept)avidin.

Biotin/(strept)avidin self-assembly is a powerful platform for nanoscale fabrication and capture with many different applications in science, medicine, and nanotechnology. However, biotin/(strept)avidin self-assembly has several well-recognized drawbacks that limit performance in certain technical areas and there is a need for synthetic mimics that can either become superior replacements or operational partners with bio-orthogonal recognition properties. The goal of this tutorial review is to describe the recent progress in making high affinity synthetic association partners that operate in water or biological media.

Conformational Slippage Determines Rotational Frequency in Five-Component Nanorotors.

Several five-component nanorotors ROT-3 that rotate at different rates were prepared by adding phenanthrolines of distinct lateral size as brake blocks to the four-component nanorotor ROT-2. The brake blocks interfere with the 180° rotor causing the rotational frequency to drop from 97 kHz to 5 kHz. The effect of the rotating brake blocks on the rotational frequency in ROT-3 is accurately predicted by a nanomechanical model called "conformational slippage".

Acyclic Cucurbit[n]uril-Type Molecular Container Enables Systemic Delivery of Effective Doses of Albendazole for Treatment of SK-OV-3 Xenograft Tumors.

Approximately, 40-70% of active pharmaceutical ingredients (API) are severely limited by their extremely poor aqueous solubility, and consequently, there is a high demand for excipients that can be used to formulate clinically relevant doses of these drug candidates. Here, proof-of-concept studies demonstrate the potential of our recently discovered acyclic cucurbit[n]uril-type molecular container Motor1 (M1) as a solubilizing agent for insoluble drugs. M1 did not induce significant rates of mutations in various Salmonella typhimurium test strains during the Ames test, suggesting low genotoxicity.

Fast Response and High Sensitivity of ZnO Nanowires-Cobalt Phthalocyanine Heterojunction Based H2S Sensor.

The room temperature chemiresistive response of n-type ZnO nanowire (ZnO NWs) films modified with different thicknesses of p-type cobalt phthalocyanine (CoPc) has been studied. With increasing thickness of CoPc (>15 nm), heterojunction films exhibit a transition from n- to p-type conduction due to uniform coating of CoPc on ZnO. The heterojunction films prepared with a 25 nm thick CoPc layer exhibit the highest response (268% at 10 ppm of H2S) and the fastest response (26 s) among all samples.

Ultrasensitive and selective detection of dopamine using cobalt-phthalocyanine nanopillar-based surface acoustic wave sensor.

A highly selective and sensitive surface acoustic wave (SAW) sensor of dopamine (DA) was developed by depositing cobalt phthalocyanine (CoPc) nanopillars on gold-coated sensing platform of SAW sensor. The developed biosensor presents a sensitivity of 1.6°/nM, has a low limit of detection (LOD) on the order of 0.

In situ diazonium-modified flexible ITO-coated PEN substrates for the deposition of adherent silver-polypyrrole nanocomposite films.

In this paper, we report a simple and versatile process of electrografting the aryl multilayers onto indium tin oxide (ITO)-coated flexible poly(ethylene naphthalate) (PEN) substrates using a diazonium salt (4-pyrrolylphenyldiazonium) solution, which was generated in situ from a reaction between the 4-(1H-pyrrol-1-yl)aniline precursor and sodium nitrite in an acidic medium. The first aryl layer bonds with the ITO surface through In-O-C and Sn-O-C bonds which facilitate the formation of a uniform aryl multilayer that is ∼8 nm thick. The presence of the aryl multilayer has been confirmed by impedance spectroscopy as well as by electron-transfer blocking measurements.

Reversible cargo shipping between orthogonal stations of a nanoscaffold upon redox input.

The sterically shielded terpyridine was prepared, both as a new ligand and as part of the four-station nanoscaffold . Mixing of terpyridine , the parent phenanthroline and the shielded phenanthroline in the presence of Zn(2+) (1 : 1 : 1 : 1) furnished quantitatively the inverse HETTAP complex [Zn()()](2+) by self-sorting, while in the presence of Cu(+) the HETPHEN complex [Cu()()](+) was preferred (89%). Due to the akin coordination preferences of Cu(2+) and Zn(2+), the above self-sorting was implemented for Cu(+)/Cu(2+) on nanoscaffold , the latter equipped with the binding motifs of (PhenAr2) and (TerpyAr2).

A five-component nanorotor with speed regulation.

A five-component supramolecular nanorotor with reversibly acting brakes has been prepared from a four-component nanorotor by adding the photo- and heat-responsive 2,2'-diazastilbene as a signal transducer. The rotational speed was reversibly switched between 86 and 38 kHz.