Nano

In this paper, three-dimensional (3D) Co₃O₄ flower-like microspheres have been successfully synthesized via a facile ethylene glycol (EG)-mediated solvothermal method followed by calcination. The as-prepared flower-like precursors microspheres are formed from the assembly of 2D nanosheets in the presence of hexadecyltrimethylammonium bromide (CTAB). The flower-like architectures of the prepared precursors could be tailored by changing the amount of CTAB. Furthermore, when evaluated as a gas sensor, the obtained Co₃O₄ flower-like microspheres exhibit a good response and sensitivity toward ethanol gas, suggesting their promising potential for gas sensors application.

The free vibration equations of circular monolayer graphene are analytically derived based on nonlocal elasticity theory. The natural frequency and mode shape for the axisymmetric and asymmetric circular monolayer graphenes are analyzed using the equations. The results show that the natural frequency of the asymmetric graphene is larger than that of the axisymmetric one. The natural frequency decreases with increasing nonlocal parameter for the axisymmetric and asymmetric graphenes. In addition, the diametrical nodal lines and nodal circles for the flexural vibration of the circular monolayer graphene are investigated. To avoid vibration failure of the sensors, they can be placed at the diametrical nodal lines and nodal circles.

This research is aimed to develop a novel kind of biomarker based on water-soluble quantum dots (QDs) conjugated with estrogen receptor (ER) for the detection of breast cancer (BC). To achieve the purpose, hydrophobic octadecylamine-coated QDs were encapsulated with amphiphilic biocompatible centipede-like polymer p(aspartate)-Na-graft-p(ethylene glycol)-dodecylamine (PASP-Na-g-PEG-DDA), and then modified with ER monoclonal antibodies, which is one of the most popular biomarkers for the detection and management of breast cancer worldwide. The targeted QDs kept the original optical property of QDs. The cytotoxicity in vitro experiments showed that QDs-ER probes had no obvious toxic side effects. Remarkably, confocal laser scanning microscopy (CLSM) revealed that the localized fluorescence appeared around the nucleus of human breast cancer cell MCF7 (ER positive) compared with that of human breast cancer cell MBA-MD-231 (ER negative). According to the above analysis, this new kind of probe has great potential in the diagnosis of breast tumor in vitro in future clinical application.

Immunoglobulin A nephropathy (IgAN) has been recognized as the most prevalent form of glomerulonephritis with various histologic and clinical phenotypes in the world. The Gal-deficient IgA1 with terminally exposed GalNAc residue(s) plays a key role in the pathogenesis of the disease. In this study, a novel colorimetric biosensor based on Helix aspersa agglutinin (HAA) absorbed on polydiacetylene (PCDA) nanovesicles for N-acetylgalactosamine (GalNAC) molecular as core framework of Gal-deficient IgA1 recognition was investigated using the high affinity between lectin HAA and GalNAC. The PCDA nanovesicles were prepared via UV crosslinking. The size, morphology and elastic property of the nanovesicles were tested. The optimal concentration of HAA for the recognition of GalNAC via naked eyes observation was 3 mM and the critical concentration of GalNAC for the sensitive color transition was 2 μg/mL. This novel method has many advantages such as low prices, intuitive, real-time and easy to carry out and great potential in Gal-deficient IgA1 detection.

Chitosan (CS) is an excellent natural biodegradable and biocompatible polymer for biomedical applications, however, its poor solubility in water or organic solvents limits its applications in drug delivery. In order to resolve this problem, chitosan was modified with acrylonitrile (AN) and arginine (Arg), the modified chitosan (AN–CS–Arg) was characterized by ¹H NMR and Fourier transform infrared (FTIR). The AN–CS–Arg was self-assembled into nanoparticles to encapsulate anticancer drug doxorubicin (DOX). The size and morphology of the blank and drug-loaded AN–CS–Arg (AN–CS–Arg/DOX) nanoparticles were measured by dynamic light scattering (DLS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The mean size of both blank and AN–CS–Arg/DOX nanoparticles were around 50 nm and 170 nm, respectively. The drug-loading content was about 12%. The release profile of AN–CS–Arg/DOX nanoparticles was investigated in vitro, 80% encapsulated DOX could be released within 80 h. The AN–CS–Arg nanoparticles were nontoxic to both NIH 3T3 fibroblasts and HepG2 cancer cells. The cellular uptake of the AN–CS–Arg nanoparticles was trafficked via Confocal Laser Scanning Microscopy and Flow Cytometry, both results showed that the AN–CS–Arg nanoparticles could be internalized in HepG2 cells efficiently. The IC₅₀ of AN–CS–Arg/DOX nanoparticles to HepG2 cancer cells was 10.0 μg/mL. The AN–CS–Arg nanoparticles are potential carriers for anticancer drug delivery.

Self-assembly of nanoparticles has attracted more attention in the last decade due to their potential applications in many fields, such as sensors, surface-enhanced Raman scattering (SERS) substrate and optical/plasmonic components. Wrinkles, as one kind of common natural surface, are used to be a template/substrate in microfluidic sieves and solar cells. In this work, a wrinkled template with depth of about 200 nm and period of 1.64 μm is used for modulating the self-assembly process of gold nanorods (GNRs) to obtain patterned self-assemblies for potential application. In order to fully reflect the role of the wrinkled template in the self-assembly, the templates are placed uprightly in the GNRs solution to intensify the interplay between the wrinkled surface and nanorods. The self-assembly process is carried out in a climate chamber, where the temperature and humidity can be controlled programmingly to modulate the self-assembly conditions. The experimental results show that for the fixed wrinkled template, an obvious effect on the self-assembly is at the temperature range from 30°C to 50°C. Nematic, curved (mostly are end-to-end) and transition mode can be obtained. According to humidity, GNRs tend to form the nematic fashion in humidity lower than 60%, and the curved fashion in a higher humidity.

Various manganese oxides nano/micro-crystals, including Mn₃O₄ octahedrons, hierarchical flower-like K-δ-MnO₂ microspheres, multi-branch and strip-shaped γ-MnOOH, have been prepared by a lignosulfanate (LSN)-mediated hydrothermal process. The effect of LSN on the structure and morphology has been thoroughly investigated by X-ray powder diffraction and scanning electron microscopy (SEM). The results indicated that stepwise reduction and Ostwald's ripening occurred simultaneously in this hydrothermal process, and LSN could serve as both reducing agent and growth modifier. The appropriate reducing capacity and selective absorption ability of LSN played an important role for the formation of various manganese oxides nano/micro-crystals. The catalytic performance of the products for the oxidation of o-xylene has been also investigated. The result showed that the MnO₂ crystals prepared with LSN exhibited the highest catalytic activity.

Magnesium borate (Mg₂B₂O₅) nanorods were synthesized by a two-step process, including solution-chemical technology and a ternary-flux method, using concentrated seawater and H₃BO₃ as raw materials. X-ray diffraction (XRD) showed that the sample had triclinic structure. Scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HR-TEM) indicated that it consisted of rod-like particles with an average diameter of 100–150 nm and length over 5 μm. Differential thermal analysis (DTA) confirmed that the melting point of the ternary-flux and the formation temperature of Mg₂B₂O₅ were lower than single-flux process. The formation of Mg₂B₂O₅ nanorods was more efficient by ternary-flux than single-flux. Mechanical property of Mg₂B₂O₅ nanorods reinforced Nylon-6 composites showed that KH550 was the optimal coupling agent and made the strength of the composites to be improved to different degrees.

Sunken hollow carbon spheres (SHCs) are prepared by using glucose as carbon source and polystyrene spheres (PSs) as templates. Pt particles are then loaded on the SHCs as electrocatalyst and used for catalyzing both methanol oxidation and oxygen reduction reaction (ORR) in acidic media. Physical measurements show that the SHCs are formed due to sinking of hollow carbon spheres. It can be imagined that the SHCs have the similar specific surface area as hollow carbon spheres with reduced volume. Moreover, the SHCs have high surface area (786.3 m² ⋅ g^-1) with hollow and sunken structure are beneficial for the uniform dispersion of the noble metal particles and efficiently improve the mass transfer in catalytic reactions. The cyclic voltammogram measurements show that the current densities on Pt/SHC electrocatalyst are 2.1 times ) that on commercial Pt/C for methanol oxidation and 1.5 times () that on Pt/C for ORR at the same Pt loadings, being promising candidate for fuel cell electrocatalyst.

We present, for the first time, a rational and general method to construct pearl-like chains of platinum (Pt) clusters with cytochrome c (cyt c) as building blocks, demonstrating the great potential of cyt c for the construction of nanoscale devices. We investigate the conditions which should be fulfilled to grow pearl-like chains of Pt clusters on cyt c according to a selectively heterogeneous, template-controlled mechanism. Various mechanistic aspects of the single steps composing the metallization protocol has been addressed and discussed. The results indicate that pH and the degree of reduction reaction can be considered as the key parameters for a "fine-tuning" of the metallization procedure. The formation mechanism has been extensively studied which is extremely important for future elaboration for the preparation of better-controlled structures.

Mesostructured chitosan-coated Fe₃O₄ nanoparticles (CS-coated Fe₃O₄ NPs) were synthesized by a facile one-step solvothermal method via using chitosan as a surface-modification agent. Subsequently, the surfaces of CS-coated Fe₃O₄ NPs were successfully conjugated with folic acid (FA) molecules to obtain FA–CS-coated Fe₃O₄ NPs for improving targeted drug delivery. The morphology, chemical component and magnetic property of as-prepared composite nanoparticles were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), dynamic light scattering (DLS), scanning transmission electron microscopy (SEM), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA) and vibrating sample magnetometer (VSM). Furthermore, doxorubicin hydrochloride (DOX) as a model drug was encapsulated for investigating drug release pattern in vitro. The results show that the magnetization saturation value of FA–CS-coated Fe₃O₄ NPs was about 28.5 emu/g, exhibiting superparamagnetic properties and mesostructure. DOX could be loaded to FA–CS-coated Fe₃O₄ NPs with high capacity about 27.9%, and the release rate of DOX could be adjusted by the pH value. This work demonstrates that the prepared magnetic nanoparticles have potential applications in the treatment of cancer as targeting drug delivery carriers.

Hexagonal phase LaF₃:Tb³⁺ nano/microcrystals were successfully synthesized via ultrasonic-assisted ionic liquid (IL) method. The field emission scanning electron microscope (FESEM) images revealed that the morphologies of the as-prepared LaF₃:Tb³⁺ samples were gradually converted from nanoplates to microcylinders with increasing the concentration of Tb³⁺ ions. The photoluminescent (PL) spectrum shows that all the as-prepared La_1-xTb_xF₃ samples show the characteristic emissions of Tb³⁺⁵D₄ → ⁷F_J (J = 6-3, with ⁵D₄ → ⁷F₅ green emission at 542 nm as the strongest one) transitions. The optimal Tb³⁺-doped concentration is 20 mol.% in the LaF₃ host. The photoluminescence intensity of the La_0.80Tb_0.20F₃ microcylinders prepared by ultrasonic irradiation was largely improved as compared with that of the product prepared by stirring.

Carbon nanotubes (CNTs) have been widely applied in various fields due to excellent physical and chemical properties. As production and applications of nanotubes expand, public concern about their potential risks to human health has also risen. In the present study, the effects of CNTs on rat liver and brain by single intratracheal instillation were detected. CNTs [either single-walled carbon nanotubes (SWCNTs) or multi-walled carbon nanotubes (MWCNTs)] could be seen in the lung and liver indicating the transfer of CNTs by blood stream. CNTs could induce oxidative stress in liver with elevated Malondialdehyde (MDA) level and degressive GSH level, superoxide dismutase (SOD) and CAT activity. To brain, maybe due to the blood brain barrier and the increased SOD and CAT activity, serious oxidative stress of brain did not occur.

Three-dimensional (3D) γ-MnOOH networks are successfully prepared by one-pot solvothermal method without using any catalyst. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). It is found that the amounts of urea and H₂O₂ added, reaction temperature and time have important influences on the samples. It is interesting that the 3D networks are formed from the oriented attachment (OA) of Mn₃O₄ octahedrons; and that the phase transformation from Mn₃O₄ to γ-MnOOH occurs via the protonation of Mn₃O₄. This study is expected to offer a facile approach to the syntheses of new, intricate nanostructures.