Nano-sized Channels Research Articles

Globular structure of the hypermineralized tissue in human femoral neck

Bone becomes more fragile with ageing. Among many structural changes, a thin layer of highly mineralized and brittle tissue covers part of the external surface of the thin femoral neck cortex in older people and has been proposed to increase hip fragility. However, there have been very limited reports on this hypermineralized tissue in the femoral neck, especially on its ultrastructure. Such information is critical to understanding both the mineralization process and its contributions to hip fracture. Here, we use multiple advanced techniques to characterize the ultrastructure of the hypermineralized tissue in the neck across various length scales. Synchrotron radiation micro-CT found larger but less densely distributed cellular lacunae in hypermineralized tissue than in lamellar bone. When examined under FIB-SEM, the hypermineralized tissue was mainly composed of mineral globules with sizes varying from submicron to a few microns. Nano-sized channels were present within the mineral globules and oriented with the surrounding organic matrix. Transmission electron microscopy showed the apatite inside globules were poorly crystalline, while those at the boundaries between the globules had well-defined lattice structure with crystallinity similar to the apatite mineral in lamellar bone. No preferred mineral orientation was observed both inside each globule and at the boundaries. Collectively, we conclude based on these new observations that the hypermineralized tissue is non-lamellar and has less organized mineral, which may contribute to the high brittleness of the tissue.

Color-specific porosity in double pigmented natural 3d-nanoarchitectures of blue crab shell

3D-engineered nano-architectures with various functionalities are still difficult to obtain and translate for real-world applications. However, such nanomaterials are naturally abundant and yet wasted, but could trigger huge interest for blue bioeconomy, provided that our understanding of their ultrastructure-function is achieved. To date, the Bouligand pattern in crustaceans shell structure is believed to be unique. Here we demonstrated that in blue crab Callinectes sapidus, the 3D-nanoarchitecture is color-specific, while the blue and red-orange pigments interplay in different nano-sized channels and pores. Thinnest pores of about 20 nm are found in blue shell. Additionally, the blue pigment co-existence in specific Bouligand structure is proved for the green crab Carcinus aestuarii, although the crab does not appear blue. The pigments interplay, simultaneously detected by Raman spectroscopy in color-specific native cuticles, overturns our understanding in crustaceans coloration and may trigger the selective use of particular colored natural nanoarchitectures for broaden area of applications.

Efficient extraction of slowly-released Cr(vi) from nano-sized ion channels in Cr(vi)–ettringite from reduced chromite ore processing residue

Complete extraction of Cr(vi) from rCOPR which involved ion exchange in ion channels of Cr(vi)–ettringite, formation and growth of nano-CaCO3.

A new heterometallic MOF with 1D nano-sized channels for cyanosilylation reaction and prevention effect against arrhythmia by reducing the sympathetic excitability

In this work, by appealing to a heterometallic cluster approach, a new highly porous metal-organic framework (MOF) formulated as {(Me2NH2)[Ni3K2(TZIA)3(H2O)3]·(DMF)4}n (1) has been fabricated by a solvothermal reaction of a bifunctional organic ligand 5-(1 H-tetrazol-5-yl)isophthalic acid (H3TZIA) with the Ni(II) and K(I) salts in water and DMF mixed solvents. The resulting activated 1a has been explored in detail for BET analysis to probe its porosity. The removal of water molecule at the aim of generating 1a makes K+ ion become a heterogeneous catalyst of size-selective with high efficiency for solvent-free cyanosilylation of acetaldehyde under mild conditions. Furthermore, the prevention effect of the compound on the arrhythmia occurrences after anesthesia during operation was evaluated. The arrhythmia incidence and abnormal blood pressure was calculated and measured for the detection of compound prevention ability. Besides, the Norepinephrine (NE) and Adrenaline (A) released by the cardiomyocytes were measured by the ELISA kit.

A highly ruffled distorted nickel-imidazolylporphyrin framework with 1D open nano-sized channels

A novel 3D porphyrin-based metal-organic framework (MOF) {(Me2NH2)3[Ni6(TImP)3(BTC)]}·xG (1, G = guest) has been successfully synthesized and characterized. Complex 1 consists of 1D nano-sized channels, which were formed by the interconnection of highly ruffled meso‑tetra(4‑imidazolyl)porphyrin (TImP) and auxiliary BTC3− (1,3,5‑benzenetricarboxylate) linker. The structural analysis indicated that highly ruffled deformation of porphyrin in complex 1 formed as a result of the coordination environment of the substituted imidazole group and the metal centers. It is worth noting that highly distorted porphyrin is very rare in 2D or 3D porphyrin-based structures. The adsorption and catalytic properties for complex 1have also been investigated. The negligible adsorption capacity and moderate catalytic property is due to the Me2NH2+ blocking the porous channels, which prevented the penetration of the gas molecules and the substrate to reach the active Ni(II) sites.

Observation of dynamic charge stripes in Tm0.19Yb0.81B12 at the metal–insulator transition

Accurate low temperature charge transport measurements in combination with high-precision x-ray diffraction experiments have allowed detection of the symmetry lowering in the single domain Tm0.19Yb0.81B12 crystals that belong to the family of dodecaborides with metal–insulator transition. Based on the fine structure analysis we discover the formation of dynamic charge stripes within the semiconducting matrix of Tm0.19Yb0.81B12. The charge dynamics in these conducting nano-size channels is characterized by broad-band optical spectroscopy that allowed estimating the frequency (~2.4 × 1011 Hz) of quantum motion of the charge carriers. It is suggested that cooperative Jahn–Teller effect in the boron sublattice is a cause of the large-amplitude rattling modes of the Tm and Yb ions responsible for the ‘modulation’ of the conduction band along one of the directions through the variation of 5d-2p hybridization of electron states.

RETRACTED ARTICLE: A Low Cytotoxic Metal–Organic Framework Carrier: pH-Responsive 5-Fluorouracil Delivery and Anti-Cervical Cancer Activity Evaluation

A new porous metal–organic framework (MOF) [Zn2(ad)2(fmdb)(H2O)](DMF)3 (1, DMF = N,N-dimethylformamide) based on zinc(II) ions, biomolecular adenine (Had) and 4,4′-(fluoromethylene)dibenzoic acid (H2fmdb) has been successfully obtained via a one-pot solvothermal reaction. The structural analysis via the single crystal X-ray diffraction reveals that compound 1 locates in the monoclinic space group C2/c and demonstrates a three-dimensional channel-type neutral framework. The as-prepared complex 1 exhibits low toxicity by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium (MTT) assay, revealing its potential application in human health care. In light of its nano-sized channel space and good stability in biological buffers solution, the activated compound 1 (1a) has been applied as a carrier for loading the anticancer drug 5-Fu (5-Fluorouracil) though a simple adsorption process. The successful loading of 5-Fu was confirmed by the gas sorption measurement and the loading capacity was determined by UV–Vis spectroscopy, which reveals a drug loading capacity of 44.6 wt%. The drug delivery in the simulated cancerous tissues (pH = 5.0) exhibited a more complete release in comparison with that in the normal tissues (pH = 7.4), demonstrating the compound 1a could be potentially used as a pH-controlled drug delivery carrier. In connection to these, in vitro anticancer activity of 5-Fu loaded 1a was also evaluated using MTT assays against two human cervical cancer cells HeLa and SiHa.

Alternative Technology for Creating Nanostructures Using Dip Pen Nanolithography

For modern microelectronics, at the present time, the technologies of consciousness smart structures play an important role, which can provide accuracy, stability and high quality of the structures. Submicron lithography methods are quite expensive and have natural size limitations, not allowing the production of structures with an extremely small lateral limitation. Therefore, an intensive search was conducted for alternative methods for creating submicron resolution structures. Especially attractive one is the possibility of self-organization effects utilization, where the nanostructure of a certain size is formed under the influence of internal forces. The dip pen nanolithography method based on a scanning probe microscope uses a directwrite technology and allows one to carry out a playback of small size structures with high accuracy. In the experiment, a substrate coated with Au (15 nm) using a DPN technique is applied to the polymer to form a desired pattern nano-sized channel. The experiment was conducted using a pointed probe SiN, coated MHA-Acetonitrile, on the Si(111)/Fe3Si/Au structure.

RETRACTED: Application of a water stable porous metal-organic framework for 5-Fu delivery and inhibiting human spinal cord tumor cells

Abstract A water-stable porous Zn-based metal-organic framework with the chemical formula of {[Zn(bptc)(H2O)]·(DMA)4}n (1, DMA = N,N-dimethylacetamide) has been synthesized and structurally characterized using the biphenyl-3,3′,5,5′-tetracarboxylic acid (H4bptc). The single X-ray study reveals that complex 1 belongs to the chiral tetragonal space group I4122, and features chiral four-fold helical metal chains as SBUs. Furthermore, complex 1 exhibits 1D nano-sized channels with a pore diameter of 12.1 × 12.1 A2 along the c axis and a high pore volume of 50.9%. In particular, the desolvated 1 could adsorb around 51.2 wt% 5-fluorouracil (5-Fu) and the cumulative release value of 5-Fu at 72 h was about 84.9% in PBS (pH 7.4) at 37 °C. In addition, in vitro anticancer activity of compounds 1 and 5-Fu loaded 1a on four human spinal cord tumor cells (U266, MM1S, RPMI-8226 and KM-3) was further determined.

Synthesis and anti-myocarditis activity in a multifunctional lanthanide microporous metal-organic framework with 1D helical chain building units.

A new microporous lanthanide metal-organic framework, {[Yb(BTB)(H2O) (DEF)2}n (1, DEF=N,N-Diethylformamide), with 1D nano-sized channels has been constructed by bridging helical chain secondary building units with 1,3,5-benzenetrisbenzoic acid (H3BTB) ligand. Structural characterization suggests that this complex crystallizes in the hexagonal space group P6122 and possesses 1D triangular channels with coordinated water molecules pointing to the channel center. In addition, anti-myocarditis properties of compound 1 were evaluated in vivo. The results showed that compound 1 can improve hemodynamic parameters of, and it may be a good therapeutic option for heart failure in the future.

Alternative technology for creating nanostructures using Dip Pen Nanolithography

AbstractFor modern microelectronics, at the present time, the technologies of consciousness smart structures play an important role, which can provide accuracy, stability and high quality of the structures. Submicron lithography methods are quite expensive and have natural size limitations, not allowing the production of structures with an extremely small lateral limitation. Therefore, an intensive search was conducted for alternative methods for creating submicron resolution structures. Especially attractive one is the possibility of self-organization effects utilization, where the nanostructure of a certain size is formed under the influence of internal forces. The dip pen nanolithography method based on a scanning probe microscope uses a directwrite technology and allows one to carry out a playback of small size structures with high accuracy. In the experiment, a substrate coated with Au (15 nm) using a DPN technique is applied to the polymer to form a desired pattern nano-sized channel. The experiment was conducted using a pointed probe SiN, coated MHA-Acetonitrile, on the Si(111)/Fe_3Si/Au structure.

A robust microporous ytterbium metal-organic framework with open metal sites for highly selective adsorption of CO2 over CH4

A rare three-dimensional (3D) microporous lanthanide metal–organic framework, {[Yb(BTB)(H2O)](MeOH)2(H2O)}n (1), with 1D nano-sized channels has been constructed by bridging helical chain secondary building units with 1,3,5-Benzenetrisbenzoic acid (H3BTB) ligand. The highly rigid and stable framework contains a 1D triangular channel-type structure with highly polar pore surfaces decorated with abundant open metal sites. The desolvated framework {[Yb(BTB)]}n is found to exhibit permanent porosity with high CO2 storage capacities and significant selective sorption of CO2 over CH4 around room temperature.

A Chiral Metal-Organic Material that Enables Enantiomeric Identification and Purification

Summary We show that CMOM-3S, a previously unreported porous crystalline metal-organic material that exhibits intrinsic homochirality, serves as a general-purpose chiral crystalline sponge (CCS) and a chiral stationary phase (CSP) for gas chromatography (GC). The properties of CMOM-3S are enabled by nano-sized channels connected to adaptable molecular recognition sites that mimic enzyme-binding sites. Further, CMOM-3S is composed of inexpensive components, facile to prepare, and requires only trace amounts of analyte. When coupled with the thermal and hydrolytic stability of CMOM-3S, these features mean that a coated fused silica capillary column in which CMOM-3S serves as a CSP is both more versatile and more robust than three benchmark commercial columns. That the enantiomer with the longer GC retention time is consistently captured in CCS experiments enables CMOM-3S to serve as a powerful tool to enable both chiral purification and enantiomer identification.

Aligned electrospun nanofibers as proton conductive channels through thickness of sulfonated poly (phthalazinone ether sulfone ketone) proton exchange membranes

Abstract A novel approach is proposed to fabricate sulfonated poly (phthalazinone ether sulfone ketone) (SPPESK) proton exchange membranes with ordered through-plane electrospinning nanofibers, which provide nano-scale through-plane proton conductive channels along the thickness direction of the membranes, aiming to satisfy the challenging requirement of high through-plane proton conductivity in fuel cell operations. Induced by electrostatic attraction of strong electric field, the negatively charged sulfonic acid groups tend to aggregate towards surface of the electrospun fibers, which is evidenced by TEM and SAXS and further induces aggregation of the sulfonic acid groups in the SPPESK inferfiber voids filler along the surface of the nanofibers. The aligned electrospun nanofibers carries long-range ionic clusters along the thickness direction of the membrane and results in much higher total through-plane conductivity in the thickness aligned electrospun membranes, nearly twice as much as that of the cast SPPESK membrane. With smooth treatment, the thickness aligned electrospun SPPESK membranes exhibit higher single cell power density and tensile strength as compared with Nafion 115 (around 1.2 and 1.5 folds, respectively). Such a design of thickness aligned nano-size proton conductive channels provide feasibility for high performance non-fluorinated PEMs in fuel cell applications.

A Molecular Propeller with Three Nanohoop Blades: Synthesis, Characterization, and Solid-State Packing.

Nanoscale carbon-rich molecular architectures are not only aesthetically appealing but also of practical importance for energy and biomedical technologies. Herein, we report the synthesis of cyclic-oligophenylene-based nanopropeller 1 by using an efficient synthon strategy involving sequential intramolecular bisboronate homocoupling and reductive aromatization by H2 SnCl4 . The nanopropeller molecules pack into a layered hexagonal lattice featuring long-ranged nano-sized channels and a total guest-accessible volume of 48 %, as revealed by X-ray diffraction studies. We suggest that such a solid-state arrangement is determined by the interplay between the propeller architecture and the intermolecular van der Waals interactions.

Highly Water-Stable Novel Lanthanide Wheel Cluster Organic Frameworks Featuring Coexistence of Hydrophilic Cagelike Chambers and Hydrophobic Nanosized Channels.

In attempts to investigate the potential luminescent sensing materials for sensitive detection of environmental pollutants, a new family of lanthanide wheel cluster organic frameworks (Ln-WCOFs) UJN-Ln4 has been constructed by employing one of the cycloalkane dicarboxylic acid derivatives. Adopting different conformations, the ligand links Ln4 second building units (SBUs) and Ln24 tertiary building units (TBUs) to form a unique wheel cluster layer-pillared 3D framework featuring the coexistence of hydrophobic nanosized channels and trigonal antiprism arrays with hydrophilic cagelike chambers. Apart from charming structures, isostructural UJN-Ln4 displays interesting porous, water-stable features. Systematic luminescence studies demonstrate that solvent water molecules can enhance the emission intensity of solid-state UJN-Eu4. Acting as a recyclable luminescent probe, water-stable luminescent UJN-Eu4 exhibits superior "turn-off" detection for Fe3+ and Cu2+ ions in aqueous solutions. Due to the nanosized hydrophobic channels, UJN-Eu4 also shows highly sensitive sensing of sodium dodecyl benzenesulfonate (SDBS) via luminescence "turn-on" respondence, representing the first example of quantitatively detecting SDBS in aqueous solutions by employing luminescent lanthanide frameworks as fluorescent sensors. The results also open up the exploration of novel luminescent Ln-WCOFs exhibiting unique applications in sensitive detecting of harmful pollutants in aquatic environments.

Two 3D cupric metal–organic frameworks based on the biphenyl-2,3,3′,5′-tetracarboxylate ligand and possessing 1D nanosized channels

From the same starting materials, two novel metal–organic frameworks, namely {(cation)[Cu4(bptca)2(OH)(H2O)2]·x(solvent)}n (1) and {(cation)[Cu3(bptca)2(H2O)3]·y(solvent)}n (2) (H4bptca=biphenyl-2,3,3′,5′-tetracarboxylic acid), have been synthesized through the linkage of Cu2(COO)4 paddle-wheel clusters. The complex 1 possesses both dinuclear [Cu2O2] subunits encapsulated into cage-like units and tetranuclear [Cu4(μ3-OH)2] clusters, which exhibits an unusual 3D 4-nodal (4,4,4,8)-connected network with {412.812.104}{43.83}4{46}{86} topology. Reducing the metal-to-ligand ratio, the other 3D (4,4)-connected framework 2 with {42.84} PtS-type topology was constructed under the intervention of mononuclear Cu(bptca)2 and single Cu2(COO)4 paddle-wheel supporting layers. Notably, both of the frameworks 1 and 2 accommodate infinite open 1D nanosized quadrate channels.

A novel nanochannel fabrication for nanofluidic applications using synchrotron radiation via a micro patterned X-ray mask

Extremely long nano-sized channels were fabricated based on a novel X-ray mask fabrication method. Using the fabricated nanochannels, the generation of ion concentration polarization, a novel transport phenomenon in nanofluidics, was investigated.

PH-Dependent ionic-current-rectification in nanopipettes modified with glutaraldehyde cross-linked protein membranes

In this study, we investigated for the first time the influence of an artificial membrane on the ionic current rectification of nanopipettes at various pH levels. The nanopipettes were fabricated and then modified with bovine serum albumin–glutaraldehyde (BSA–GA) artificial membranes. We determined the degree of ionic current rectification of these nanopipettes and compared them with those of bare nanopipettes. In contrast to the bare nanopipettes, the BSA–GA-modified nanopipettes demonstrated pH-dependent ionic current rectification. We also examined the tunability of the degree of rectification using streptavidin (STV) whose isoelectric point differs from that of BSA. The results showed that the ionic current rectification of nanopipettes can be tuned as the addition of STV into the BSA–GA artificial membrane increases the degree of rectification. Using the proposed approach, nanoscale spearhead pH sensors could be fabricated for highly localized extracellular or intracellular pH measurement. Moreover, it is possible to realize the applications of nano-sized channels in relatively larger channels using the present method.

Structure and band gap determination of irradiation-induced amorphous nano-channels in LiNbO3

The irradiation of lithium niobate with swift heavy ions results in the creation of amorphous nano-sized channels along the incident ion path. These nano-channels are on the order of a hundred microns in length and could be useful for photonic applications. However, there are two major challenges in these nano-channels characterization: (i) it is difficult to investigate the structural characteristics of these nano-channels due to their very long length and (ii) the analytical electron microscopic analysis of individual ion track is complicated due to electron beam sensitive nature of lithium niobate. Here, we report the first high resolution microscopic characterization of these amorphous nano-channels, widely known as ion-tracks, by direct imaging them at different depths in the material, and subsequently correlating the key characteristics with electronic energy loss of ions. Energetic Kr ions (84Kr22 with 1.98 GeV energy) are used to irradiate single crystal lithium niobate with a fluence of 2 × 1010 ions/cm2, which results in the formation of individual ion tracks with a penetration depth of ∼180 μm. Along the ion path, electron energy loss of the ions, which is responsible for creating the ion tracks, increases with depth under these conditions in LiNbO3, resulting in increases in track diameter of a factor of ∼2 with depth. This diameter increase with electronic energy loss is consistent with predictions of the inelastic thermal spike model. We also show a new method to measure the band gap in individual ion track by using electron energy-loss spectroscopy.