Nanobuilding Units Research Articles

Multifunctional DNA Nanogels for Aptamer-Based Targeted Delivery and Stimuli-Triggered Release of Cancer Therapeutics.

Targeted, stimulus-responsive DNA nanogels hold considerable promise for cancer therapeutics. To expand their functionality including thermoresponsiveness, here, multifunctional DNA nanogels are developed for potential application toward cancer-targeted delivery and stimuli-responsive release of cancer therapeutics. Three types of functionalized DNA nanobuilding units are formed into DNA nanogels of ≈200nm via sequence-dependent self-assembly. The sequence-dependent assembly of nanobuilding units is precisely designed for controlled assembly and thermal disassembly at physiological temperatures. The supramolecular structure exhibits multifunctionalities including temperature-induced disassembly, aptamer-mediated cancer cell targeting, and light-triggered temperature increase. The nanogels support co-loading of cancer therapeutics including anti-sense oligonucleotides and doxorubicin along with stimuli-responsive release of loaded drugs through temperature-responsive structural disassembly and pH-responsive deintercalation. The nanogels exhibit efficient aptamer-mediated cancer-specific intracellular delivery and combinational anticancer effects upon light triggering. The developed DNA nanogels, thus, constitute potential noncationic nanovectors for targeted delivery of combinational cancer therapeutics.

Controlled synthesis of three dimensional hierarchical graphene nanostructures from metal complexes as an anode material for lithium-ion batteries

Three dimensional hierarchical graphene nanostructures with refined secondary structures and primary nanobuilding units are realized here via a metal complex strategy.

Organic-Inorganic Hybrid Materials: Multi-Functional Solids for Multi-Step Reaction Processes.

The design of new hybrid materials with tailored properties at the nano-, meso-, and macro-scale, with the use of structural functional nanobuilding units, is carried out to obtain specific multi-functional materials. Organization into controlled 1D, 2D, and 3D architectures with selected functionalities is key for developing advanced catalysts, but this is hardly accomplished using conventional synthesis procedures. The use of pre-formed nanostructures, derived either from known materials or made with specific innovative synthetic methodologies, has enormous potential in the generation of multi-site catalytic materials for one-pot processes. The present concept article introduces a new archetype wherein self-assembled nanostructured builder units are the base for the design of multifunctional catalysts, which combine catalytic efficiency with fast reactant and product diffusion. The article addresses a new generation of versatile hybrid organic-inorganic multi-site catalytic materials for their use in the production of (chiral) high-added-value products within the scope of chemicals and fine chemicals production. The use of those multi-reactive solids for more nanotechnological applications, such as sensors, due to the inclusion of electron donor-acceptor structural arrays is also considered, together with the adsorption-desorption capacities due to the combination of hydrophobic and hydrophilic sub-domains. The innovative structured hybrid materials for multipurpose processes here considered, can allow the development of multi-stage one-pot reactions with industrial applications, using the materials as one nanoreactor systems, favoring more sustainable production pathways with economic, environmental and energetic advantages.

Effect of Cu Salt Molarity on the Nanostructure of CuO Prolate Spheroid

Copper sulfate pentahydrate was used as a source of Cu ion with five different molarities (0.02, 0.05, 0.1, 0.15, 2 and 0.25[Formula: see text]M). XRD, FE-SEM and TEM techniques all showed that CuO samples have polycrystalline monoclinic structure. CuO prolate spheroid is assembled from nanoparticles as building units. It was demonstrated that the purity, morphology, size range of prolate spheroid and density of nano building units are significantly influenced by Cu precursor’s molarity. The pure phase of CuO prolate spheroid was produced via molarity of 0.2[Formula: see text]M with crystallite size of 15.1565[Formula: see text]nm while the particle size of building units ranges from 16[Formula: see text]nm to 21[Formula: see text]nm. The stability of CuO nanosuspension or nanofluid was evaluated by zeta potential analysis. The obtained properties of specific structure with large surface area of CuO prolate spheroid make it a promising candidate for wide range of potential applications as in nanofluids for cooling purposes.

Hybrid, Tunable-Diameter, Metal Oxide Nanotubes for Trapping of Organic Molecules

New developments in nanosciences and nanotechnologies are strongly dependent on our ability to synthesize well-controlled nanobuilding units, with specific properties. We report in this paper the first synthesis of hybrid single-walled imogolite nanotubes (OH)3Al2O3SixGe1–xCH3 with diameter-controlled hydrophobic nanopores varying from 1.8 to 2.4 nm. Methylation and nanotube dimensions are studied by combining infrared spectroscopy, cryo-TEM observations, and X-ray scattering measurements. We show that, in solution, the water density inside methylated nanotubes is decreased by a factor of 3 compared to the bulk value. Spontaneous confinement of bromopropanol molecules inside the nanotubes, when added to the solution, is demonstrated. These newly synthesized nanotubes may open up possibilities for water filtration or water decontamination.

Nano-building block based-hybrid organic–inorganic copolymers with self-healing properties

New dynamic materials, that can repair themselves after strong damage, have been designed by hybridization of polymers with structurally well-defined nanobuilding units.

Controllable synthesis of Co3O4 nanostructures with good cycling performance and rate capacity in lithium-ion batteries

The structure modification of Co3O4 nano-parachute (i.e., nanosheets with part of nanowires as backbones) grown directly on conducting Ni foam substrates was successfully realized via a facile solution route followed by calcinations. By adjusting [OH−] value, two kinds of (Co(CO3)0.5(OH)0.11H2O) nanostructures (nanoarray and parachute-like) were obtained. Compared with other Co3O4 nanosheets, such nano-parachute not only inherits the advantages of nanosheet but also shows enormous net space between nanobuilding units. A possible formation mechanism for the two structures has been proposed. As anode materials for lithium-ion batteries, this sheet-like morphology on Ni foam exhibited enhanced lithium storage capacity.

Ti8O8(OOCR)16, a New Family of Titanium–Oxo Clusters: Potential NBUs for Reticular Chemistry

AbstractThe reactions of titanium alkoxides with a large excess of different carboxylic acids under nonhydrolytic conditions leads to the reproducible formation of well‐defined nano‐building units (NBUs) with the formula [Ti8O8(OOCR)16] [R = C6H5, C(CH3)3, CH3]. The structures of these titanium–oxo–carboxylate clusters have been determined by crossingdifferent characterization techniques and methodologies (single‐crystal X‐ray diffraction, 13C and 1H NMR spectroscopy, and FTIR spectroscopy). These NBUs are obtained in high yields and, since all the alkoxo ligands have been removed by using solvothermal‐synthesis conditions, they present better stability upon hydrolysis than the often reported alkoxo–carboxylate–titanium–oxo clusters [TinO2n–x/2–y/2(OR′)x(OOCR)y] (n ≥ 2; x ≥ 1; y ≥ 1). In addition, the solubility and transferability of these clusters in common solvents can be tuned by selecting the nature of the organic ligand. Moreover, we also report for the first time, a robust post‐modification of the carboxylate ligands by transesterification reactions on the titanium–oxo clusters. These reactions keep the integrity of the octameric titanium–oxo core intact, while completely exchanging the organic shell of the cluster. This family of [Ti8O8(OOCR)16] clusters, which present 16 points of extension, a symmetric shape, and the ability to be post‐modified with conservation of the core structure, can therefore be considered as interesting NBUs to form new metal–organic frameworks.

High capacity and excellent cycling stability of branched cobalt oxide nanowires as Li-insertion materials

In this paper, the authors report the high-performance lithium storage properties of branched cobalt oxide nanowires synthesized through a topotactic conversion route. Compared with other nanosized materials, such branched nanostructures not only inherit the advantages of high surface-to-volume ratio and good dispersion but also show better electronic contact and conduction between nanobuilding units. Both features facilitate charge transport and insertion/extraction of Li ions and lead to higher capacity and better cycling stability compared with other transition metal oxide nanomaterials. Under the condition of high current density of 100 mA/g, the reversible capacity after 50 cycles is up to 1043 mAhg−1 with an average fading rate of 0.15% per cycle.

Self-Assembled Hollow Spheres of β-Ni(OH)2 and Their Derived Nanomaterials

This paper describes a novel solution-based chemical process to architect hollow spheres of β-Ni(OH)2 with controllable sizes in submicrometer and micrometer regimes. In the synthesis, starting nickel salt (nitrate) is first converted to 6-coordinated nickel ion complex [Ni(EDA)3]2+ (bidentate ligand EDA = C2H4(NH2)2) to avoid rapid solid formation. Hollow and core−shell β-Ni(OH)2 spheres can be obtained with this template-free approach under one-pot conditions. The β-Ni(OH)2 spheres are constructed from petal-like nanobuilding units which in turn are formed from even smaller nanocrystallites. The obtained porous β-Ni(OH)2 spheres have a large specific surface area and show a unimodal pore-size distribution. Several preparative parameters have been examined and optimized. In particular, the concentration of divalent nickel in the starting solutions plays an important role in controlling thickness of the petal-like β-Ni(OH)2 flakes and diameter of spheres. The β-Ni(OH)2 flakes self-assemble into final sphe...

Super-microporous organosilicas synthesized from well-defined nanobuilding units

Super-microporous organosilica with bridging ethylene and pendant vinyl groups has been synthesized by assembling predefined nanobuilding block polyhedral oligomeric silsesquioxanes (POSS) with nonionic surfactant Brij-76 as the template. The material shows wormhole-like super-micropores with uniform size of 1.9 nm, high BET surface area of 872 m2 g–1 and pore volume of 0.52 cm3 g–1. IR and NMR results show that the bridging ethylene, the pendant vinyl groups and the double-4-membered ring structure were successfully transferred from the building blocks to the super-microporous organosilica material. The material shows high hydrothermal stability and can further react with Br2. The advantage of the present approach lies in that the relative contents and proximity of the different organic functionalities in the final material can be well controlled through the starting nanobuilding blocks.

Hollow ZnO Microspheres with Complex Nanobuilding Units

A three-tiered organization of ZnO nanobuilding blocks into hollow spherical conformations has been developed. This self-assembly approach demonstrates new capacities of template-assisted synthesis in the architecture of hollow structures as well as in the construction of structurally complex nanomaterials.

Preparation of Nanocomposites of Metals, Metal Oxides, and Carbon Nanotubes via Self-Assembly

Carbon nanotubes (CNTs)-based composites have attracted significant research interest in recent years, owing to their important applications in various technological fields. In this investigation, we describe a general approach to make CNTs-based nanocomposites via self-assembly. The method allows one to prepare binary composites as well as complex systems such as ternary or even quaternary composites where nanoparticles of active phases (e.g., metals and metal oxides) are used as primary building blocks. Six different kinds of binary, ternary, and quaternary nanocomposites, TiO2/CNTs, Co3O4/CNTs, Au/CNTs, Au/TiO2/CNTs, TiO2/Co3O4/CNTs, and Co/CoO/Co3O4/CNTs, have been reported herein in order to draw common features for various assembly schemes. To understand the interconnectivity between the active phases and CNTs, we have devised a range of experiments and examined the resultant samples with many instrumental techniques. On the basis of this work, we demonstrate that highly complex inorganic-organic nanohybrids with good controls in particle shape, size, and distribution can be fabricated from presynthesized nanobuilding units. Concerning their workability, we further show that self-assembled TiO2/CNTs are sufficiently robust and the electrochemical performance of TiO2 is significantly enhanced when it is used as a cathode material in Li-battery application.

Microsphere Organization of Nanorods Directed by PEG Linear Polymer

We demonstrate the sphere organization of ZnO, Bi2S3, MnO2, and La(OH)3 nanorods directed by PEG linear polymer. Our study shows that zinc, bismuth, manganese, or lanthanum species added to PEG solutions, in which PEG molecules are well dissolved in a coil state, convert the polymer coils to aggregate structures, which further aggregate into micrometer-sized M(n+)-PEG globules. The concentration of metallic species is higher in the globules than in bulk solutions. The surfaces of the globules act as soft templates for the initial nucleation and thereafter the growth of the nanorods. Finally, echinus-type assemblies of single-crystalline nanorods form by the metallic species hydrolyzing or reacting with deposition agents. This approach opens the possibility of using polymers as soft templates to control the organization of nano building units into designed structures.

Synthetic architecture of interior space for inorganic nanostructures

One of the major technological challenges in nanoscience and nanotechnology is the self-assembly of tiny nano-building units (e.g., nanokits and nanoparts) into larger (i.e., mesoscale or microscale) organized conformations and geometrical architectures for device applications. To meet the requirements of new applications, an interior space for the nanostructures may be further required. When coupled with chemical functionality of boundary materials, the interior “nanospace” of the nanostructures possesses both aesthetic beauty and scientific attraction. For example, in addition to well studied core–shell nanostructures, there has been increasing research interest in the fabrication of hollow inorganic nanostructures owing to their potential applications in optical, electronic, magnetic, catalytic and sensing devices ranging from photonic crystals to drug-delivery carriers and nanoreactors. In this feature article, we report our recent research progress in this emerging field; our research is concentrated on the exploration of various novel organizing schemes through which interior spaces with architectural design can be created for inorganic nanostructures. These template-free “one-pot” synthetic methods include “oriented attachment”, Ostwald ripening and Kirkendall effect etc. for direct solid evacuation under mild reaction conditions. Future research directions will also be addressed in this article.