Nanoneedle Arrays Research Articles

Efficient removal of arsenic from groundwater using iron oxide nanoneedle array-decorated biochar fibers with high Fe utilization and fast adsorption kinetics

Although Fe-based biochar adsorbents are attractive for removing arsenic from water due to their advantages of costing little and being producible at a large scale, the practical applications of these granular adsorbents are mainly limited by low Fe utilization and slow adsorption kinetics. In this study, iron oxide nanoneedle array-decorated biochar fibers (Fe-NN/BFs) adsorbents have been prepared through a simple hydrothermal reaction. The vertical growth of iron oxide nanoneedle arrays on the surface of biochar fibers maximizes Fe utilization and shortens As diffusion distance, thereby increasing As removal kinetics and capacity. Batch experiments show that the adsorption capacities of Fe-NN/BFs for As(V) and As(III) reach to 93.94 and 70.22 mg/g-Fe at pH 7.0, respectively. As(V) levels (275 μg/L) in groundwater are rapidly reduced (less than 5 min) to below 10 μg/L using Fe-NN/BFs (1 g/L) at pH 6.7. Similar As(III) levels can be reduced to below 10 μg/L within 30 min by Fe-NN/BFs (1.5 g/L). In fixed-bed experiments, the treatment volumes of As(V) and As(III) spiked groundwater reach to 2900 BV (26.2 L) and 2500 BV (22.6 L), respectively, using two columns packed with Fe-NN/BFs in tandem (C0 = 275 μg/L, 2 g of adsorbents in each column). When the As concentration in the influent is reduced to 50 μg/L (As(V): 25 μg/L + As(III): 25 μg/L), the treatment volume using one column reaches up to 11000 BV. The Fe-NN/BFs packed column can be easily regenerated and reused many times. After four regenerations, the treatment volume of As(V) and As(III) were reduced by 10.4% and 22.8%, respectively.

Photothermal forces enhanced by nanoneedle array for nanoparticle manipulation

Plasmonic nanostructures provide strong electromagnetic fields enhancement and confinement for nanoparticle trapping. Here, we study the thermal and optical nanoparticle trapping effects using plasmonic nanoneedles array. Results show that the photo-thermal force outside the nanostructure can affect movements of nanoparticles in the far field as a result of heat transfer. The thermal force is decreased about one order of magnitude for nanoparticle at about 6μm away from the nanostructure where the optical force is no longer effective. Plasmonic nanoneedles with high aspect ratio provides more trapping positions in three dimensions. The thermal force together with the near field optical force make plasmonic nanoneedles array a flexible and wide working range manipulation strategy for nanoparticles.

Binary tungsten-molybdenum oxides nanoneedle arrays as an advanced negative electrode material for high performance asymmetric supercapacitor

Herein, the novel binary tungsten-molybdenum oxides (W0.4Mo0.6O3) nanoneedle arrays have been prepared by a facile one-step hydrothermal method without adding any surfactant. The as-prepared W0.4Mo0.6O3 nanoneedle arrays can provide abundant exposed reaction active sites and utilize expedite transport channel to facilitate the diffusion of electrolyte ion. Thus, as an electrode for supercapacitor, it exhibits a high specific capacity of 115.7 mAh g−1 at the current density of 1 A g−1 and good rate performance. To achieve the high energy density of supercapacitor, an asymmetric supercapacitor is fabricated by using the W0.4Mo0.6O3 nanoneedle arrays as the negative electrode and the polygni multiflori caulis-based honeycomb-like carbon (PMCHC) as the positive electrode, which possesses a high output voltage of 1.5 V and an energy density of 20.2 Wh kg−1 at a high power density of 750.6 W kg−1, as well as good cycling stability. Such facile synthesis strategy and outstanding electrochemical behaviors imply that the binary metal oxides nanoneedle arrays is a promising electrode material for energy-storage system.

Cellulose acetate nanoneedle array covered with phosphorylcholine moiety as a biocompatible and sustainable antifouling material

Extensive efforts have been devoted toward developing antibiofilm materials that can efficiently suppress bacterial attachment and subsequent biofilm formation. However, many of the previous approaches are based on non-biocompatible, non-degradable, and environmentally harmful synthetic materials. Herein, we report an efficient and sustainable biofilm-resistant material that is made of a biocompatible, biodegradable, and naturally abundant cellulose derivate biopolymer. The biofilm-resistant material is made of cellulose acetate (CA) and possesses precisely defined nanoscale needle-like architectures on its surface. The CA nanoneedle array is further coated with a cell-membrane mimicking monomer of 2-methacryloryloxyethyl phosphorylcholine (MPC). Based on the synergetic integration of the bio- and environment-friendly polymers of CA and MPC into nanoscale topography, the nanostructured CA not only effectively prevents bacterial attachment but also simultaneously exhibits strong bactericidal effects against both gram-positive and gram-negative bacteria. This natural cellulose derivative-based nanostructured material has strong potential as a biocompatible, and eco-friendly antibiofilm material for versatile uses in biomedical and industrial applications.

Fe doped skutterudite-type CoP3 nanoneedles as efficient electrocatalysts for hydrogen and oxygen evolution in alkaline media

Non-noble-metal catalysts are the key point for the development of water splitting to produce hydrogen, a process which can be used to overcome the energy crisis. In this paper, we investigated water splitting in alkaline environments using skutterudite-type cobalt phosphide (CoP3) nanoneedle arrays fabricated on carbon cloth. A moderate amount of iron is doped into pristine CoP3, and the resulting Co1−xFexP3 shows a significant enhancement for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) compared with the pristine CoP3. Co0.7Fe0.3P3 displays the best HER performance, with an overpotential of 167 mV vs. reversible hydrogen electrode (RHE) to reach a current density of 10 mA cm−2 (η10) and a Tafel slope of 65.1 mV dec−1. Co0.7Fe0.3P3 also shows the best OER catalytic performance, reaching a current density of 50 mA cm−2 (η50) at an overpotential of 330 mV vs. RHE. Our results indicate that simple second metal element doping is an effective way to improve the HER and OER performance of skutterudite-type electrocatalysts in alkaline media.

Scalable growth of SiC quasi-aligned nanoneedle arrays and their electron emission behaviors under high temperatures

Scalable growth of SiC quasi-aligned nanoarrays on SiC wafer substrate was reported through the pyrolysis of polymer precursor by using Au as the catalysts. Differently to the conventional one-dimensional nanostructures often with cylindrical shape, the as-grown SiC nanowires possessed tapered configurations with sharp tips, enabling their desired formation with typical nanoneedle morphology. Their turn-on fields manifested a decline from 3.4 to 1.4 V/μm, when the temperatures were adjusted from room temperature to 400 °C, evidencing their excellent field emission performance. Furthermore, they behaved a high stability with no obvious current emission degradation when subjected to high temperature of 200 °C over 10 h, representing their promising applications in vacuum electronics with robust stability under high-temperature harsh conditions.

Zn Doped FeCo Layered Double Hydroxide Nanoneedle Arrays with Partial Amorphous Phase for Efficient Oxygen Evolution Reaction

Exploiting earth-abundant electrocatalysts with comparable high performance and stability to the benchmarking noble metal-based catalysts for oxygen evolution reaction (OER) is of fundamental impor...

Energy Focus: Ceramic nanoneedle arrays increase sunlight absorptance in concentrated solar power plants

Energy Focus: Ceramic nanoneedle arrays increase sunlight absorptance in concentrated solar power plants

Direct growth of hierarchical nanoneedle arrays with branched nanotubes from titanium foil with excellent anti-corrosion and superhydrophilicity

We report a facile solution method to directly form dendritic titanium oxide (TiO2) nanostructures from titanium (Ti) substrates for realizing high specific surface areas with excellent crystallinity. We first form spiky nanoneedles on Ti substrates by using chemical solution etching, which are utilized as trunks. In addition, we employ a chemical exfoliation and rolling method to realize branched nanotubes over the spiky nanoneedles. Subsequent heat treatment leads to form TiO2 rutile crystal structures. The fabricated platform shows ∼140 times higher specific surface areas than the planar surface, while exhibiting excellent anti-corrosive properties. As one of the potential applications, we demonstrate that the dendritic TiO2 surfaces have excellent surface wickability to exhibit significantly enhanced heat transfer characteristics in boiling process.

Hierarchically porous nickel–cobalt phosphide nanoneedle arrays loaded micro-carbon spheres as an advanced electrocatalyst for overall water splitting application

Due to the easy recyclability and pollution-free nature of hydrogen fuel, its highly purified production through electrochemical water splitting process has been attracting increasing attention. In this work, a hybrid of hierarchical porous nickel–cobalt phosphide nanoneedle arrays supported micro-carbon spheres was successfully synthesized and employed as robust bifunctional electrocatalyst for overall water splitting. The optimized Ni1Co3–P@CSs displayed catalytic activity with a low overpotential (η) of 57 mV at 10 mA cm−2 for hydrogen evolution and a η of 330 mV at 20 mA cm−2 for oxygen evolution, along with good stability after testing for 30 h. The water splitting cell of the Ni1Co3–P@CSs delivered smaller cell voltage at a current density of 50 mA cm−2 and much better durability than a similar device based on RuO2/C and Pt/C. The enhanced performance was assumed to the unique hierarchical three-dimensional urchin nanostructure of bimetallic phosphide nanoneedles, which resulted in the synergetic effects to modulate electronic properties and electroactive surface area. These improved the reactant's intermediates adsorption energy, number of exposed active sites, and various shortened channels for charge transfer and reactant/electrolyte diffusion. Our finding offers an attractive electrocatalyst with low cost and high catalytic activity for efficient water electrolysis.

Facile synthesis of N-doped activated carbon derived from cotton and CuCo2O4 nanoneedle arrays electrodes for all-solid-state asymmetric supercapacitor

Nitrogen-doped activated carbon (NAC) with a high specific surface area was successfully fabricated through graphitization derived from cotton and ammonia doping. The obtained NAC exhibits an enhanced specific capacitance of 156.4 F g−1 at 0.5 A g−1 and good cycling stability with capacitance retention of 95% after 5000 cycles. Hydrothermal route was used to synthesize CuCo2O4 nanoneedles with diameter of 20 to 50 nm. CuCo2O4 electrode showed good electrochemical performance with specific capacitance of 390 F g−1 at 0.5 A g−1 and high stability. Based on the two electrodes, an all-solid-state asymmetric supercapacitor (ASC) was assembled, which can achieve specific capacitance of 26.2 F g−1 at 1 A g−1, energy density of 8.2 Wh kg−1 at a power density of 750 W kg−1 and still retains 5.6 Wh kg−1 at power density of 7500 W kg−1. Two ASCs in series successfully illuminated 52 LEDs connected in parallel, indicating the practical application of the device.

A 3D self-supported coralline-like CuCo2S4@NiCo2S4 core–shell nanostructure composite for high-performance solid-state asymmetrical supercapacitors

Rational construction of three dimensional (3D) composite structure is an important method to flexible supercapacitor electrodes and has been extensively developed. In this work, a 3D self-supported CuCo2S4@NiCo2S4 core–shell nanostructure grown on Nickel (Ni) foam, constructed by a hydrothermal method, was used as a novel supercapacitor electrode material. The unique structure possesses a large, specific surface area, rapid diffusion of electrolyte ions by numerous channels and avoids the use of additives and adhesives. The high electrical conductivity of the CuCo2S4 nanoneedle arrays can speed up electronic transmission. At a current density of 1 A g−1, the electrode material exhibits a high specific capacity of 539.2 C g−1 and cycling stability with 100% capacity retention after 5000 cycles in 3 M KOH. Furthermore, when the obtained CuCo2S4@NiCo2S4 was used as the positive electrode and an activated carbon was used as the negative electrode, a solid-state asymmetric supercapacitor was assembled. More importantly, the obtained solid-state asymmetric supercapacitor demonstrated excellent electrochemical performance. When the power density was 400 W kg−1, it delivered a high density of 23.4 W h kg−1 with a high voltage window of 1.6 V, thus demonstrating that the material has the potential for use as an efficient electrode for electrochemical capacitors. Due to its comprehensive electrochemical performance, the CuCo2S4@NiCo2S4 solid-state asymmetric supercapacitor effectively operated a red LED.

Cobalt‐Vanadium Hydroxide Nanoneedles with a Free‐Standing Structure as High‐Performance Oxygen Evolution Reaction Electrocatalysts

AbstractIt is a great challenge to develop electrocatalysts with high efficiency and low cost toward oxygen evolution reaction (OER) for the electrolysis of water. Herein, novel CoV‐hydroxide nanoneedle arrays with freestanding structure is successfully fabricated as new electrocatalysts for OER. Remarkably, the incorporation of V into Co hydroxide can significantly modulate the nanoneedle morphology, which results in the increase of active surface area, and augment the intrinsic activity by tuning the electronic structure. Particularly, we find that the freestanding Co hydroxide nanoneedles with 25 % Co substituted by V (Co0.75V0.25‐HNNs) show the optimum OER catalytic activity and have a low overpotential (268 mV at 10 mA cm−2), a small Tafel slope (80 mV dec−1) and long‐term stability, which are comparable to the other Co‐based and V‐based electrocatalysts for OER reported in literature.

Direct Delivery of Cas9-sgRNA Ribonucleoproteins into Cells Using a Nanoneedle Array

The clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system is a powerful and widely used tool for genome editing. Recently, it was reported that direct delivery of Cas9-sgRNA ribonucleoproteins (RNPs) reduced off-target effects. Therefore, non-invasive, high-throughput methods are needed for direct delivery of RNPs into cells. Here, we report a novel method for direct delivery of RNPs into cells using a nanostructure with a high-aspect-ratio and uniform nanoneedles. This nanostructure is composed of tens of thousands of nanoneedles laid across a 2D array. Through insertion of the nanoneedle array previously adsorbed with Cas9-sgRNA, it was possible to deliver RNPs directly into mammalian cells for genome editing.

Morphology-controllable synthesis of CuCo2O4 arrays on Ni foam as advanced electrodes for supercapacitors

The rational design of novel electrode materials with controllable morphologies plays a vital role in fabricating high-performance supercapacitors. In this work, a variety of CuCo2O4 arrays with different components (nanoneedle, nanosheet and nanorod) on nickel foam have been synthesized through facile hydrothermal routes. The key roles of NH4F and the alkali sources in the formation of different CuCo2O4 arrays have been discussed. As a three-electrode cell, the Ni supported CuCo2O4 nanoneedle arrays exhibit a specific capacitance of 1227.8 F g−1 at 5 mA cm−2 and capacitance retention of 95.4% after 1000 cycles, suggesting the potential application for supercapacitors. Furthermore, an asymmetric supercapacitor is fabricated with CuCo2O4 nanoneedle arrays (the anode) and activated carbon (AC) electrode (the cathode), which achieves a high energy density (31.2 W h kg−1) and excellent cycling stability (102% after 4000 cycles). Such remarkable performance is ascribed to the favorable porous structure of CuCo2O4 nanoneedle arrays which can offer abundant channels for ion diffusion and numerous active spots for reversible redox reactions. It is hoped that our work could provide inspirations for the morphology-controllable fabrications of electrode materials.

Nanoneedle-Mediated Stimulation of Cell Mechanotransduction Machinery.

Biomaterial substrates can be engineered to present topographical signals to cells which, through interactions between the material and active components of the cell membrane, regulate key cellular processes and guide cell fate decisions. However, targeting mechanoresponsive elements that reside within the intracellular domain is a concept that has only recently emerged. Here, we show that mesoporous silicon nanoneedle arrays interact simultaneously with the cell membrane, cytoskeleton, and nucleus of primary human cells, generating distinct responses at each of these cellular compartments. Specifically, nanoneedles inhibit focal adhesion maturation at the membrane, reduce tension in the cytoskeleton, and lead to remodeling of the nuclear envelope at sites of impingement. The combined changes in actin cytoskeleton assembly, expression and segregation of the nuclear lamina, and localization of Yes-associated protein (YAP) correlate differently from what is canonically observed upon stimulation at the cell membrane, revealing that biophysical cues directed to the intracellular space can generate heretofore unobserved mechanosensory responses. These findings highlight the ability of nanoneedles to study and direct the phenotype of large cell populations simultaneously, through biophysical interactions with multiple mechanoresponsive components.

Three dimensional bimetallic phosphides nanoneedle arrays as electrode materials for symmetric all-solid-state supercapacitor

Because of the rapid development of wearable electronic devices, energy storage devices with thin, lightweight and flexible have attracted much attention. Hybrid materials consisting of bimetallic phosphides nanoneedle arrays supporting on carbon cloth are successfully synthesized by a single-mode microwave and thermal annealing treatment followed by a low temperature phosphorization. For evaluating as electrode materials of supercapacitor, electrochemical performances of all samples are manipulated by a three-electrode system in 1 mol KOH solution. The results indicate that appropriate amount of Ni substitution could improve the electrochemical performance of NixCo1-xPy nanoneedle arrays as electrode of supercapacitor. Cyclic voltammetry, Galvanostatic charge/discharge curve, specific capacitance and electrochemical impedance spectroscopy display that NiCo2Py nanoneedle arrays as electrode materials of supercapacitor exhibits excellent electrochemical performance. A symmetric all-solid-state supercapacitor is assembled via using NiCo2Py nanoneedle arrays supported on carbon cloth as electrodes. The as-assembled symmetric all-solid-state supercapacitors exhibit an excellent electrochemical performance with a specific capacitance of 236.2 F/g at a scan rate of 10 mV/s. Good cycling stability of NiCo2Py has been demonstrated and 87.13% of the initial capacitance can be remained after 15000 cycles under a scan rate 3 V/s. This result indicates that NiCo2Py nanoneedle arrays/Carbon cloth hybrids are a good potential candidate as electrode materials for all-solid-state supercapacitor.

British Society for Gene and Cell Therapy Autumn Conference Friday 23 November 2018 Regent's University Conference Centre, London, UK www.bsgct.org

British Society for Gene and Cell Therapy Autumn Conference Friday 23 November 2018 Regent's University Conference Centre, London, UK www.bsgct.org

Highly performing free standing cathodic electrocatalysts for Li-O2 batteries: CoNiO2 nanoneedle arrays supported on N-doped carbon nanonet

Lithium-oxygen (Li-O2) batteries are considered as promising candidates for future energy storage systems due to their super-high theoretical energy densities. However, the poor cyclic stability and low efficiency still hinder their commercialization, which is mainly attributed to the sluggish oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) processes.In the present work, we fabricated a three-dimensional (3D) air cathode composed of CoNiO2 nanoneedles decorated N-doped porous carbon nanonet (CoNiO2/SCC-N), using silkworm cocoons as the raw materials and following the carbonization-hydrothermal route.The as fabricated batteries, with CoNiO2/SCC-N air cathode, are exhibited a very good discharge capacity of 1654 mAh g−1cathode at a current density of 0.05 mA cm-2, presenting a stability of over 147 cycles. The observed electrochemical performance is attributed to the synergistic effect of the enhanced ORR/OER activity after the introduction of CoNiO2 and the efficient mass transport characteristics of SCC-N.

Porous Silicon Nanoneedles Modulate Endocytosis to Deliver Biological Payloads.

Owing to their ability to efficiently deliver biological cargo and sense the intracellular milieu, vertical arrays of high aspect ratio nanostructures, known as nanoneedles, are being developed as minimally invasive tools for cell manipulation. However, little is known of the mechanisms of cargo transfer across the cell membrane-nanoneedle interface. In particular, the contributions of membrane piercing, modulation of membrane permeability and endocytosis to cargo transfer remain largely unexplored. Here, combining state-of-the-art electron and scanning ion conductance microscopy with molecular biology techniques, it is shown that porous silicon nanoneedle arrays concurrently stimulate independent endocytic pathways which contribute to enhanced biomolecule delivery into human mesenchymal stem cells. Electron microscopy of the cell membrane at nanoneedle sites shows an intact lipid bilayer, accompanied by an accumulation of clathrin-coated pits and caveolae. Nanoneedles enhance the internalization of biomolecular markers of endocytosis, highlighting the concurrent activation of caveolae- and clathrin-mediated endocytosis, alongside macropinocytosis. These events contribute to the nanoneedle-mediated delivery (nanoinjection) of nucleic acids into human stem cells, which distribute across the cytosol and the endolysosomal system. This data extends the understanding of how nanoneedles modulate biological processes to mediate interaction with the intracellular space, providing indications for the rational design of improved cell-manipulation technologies.