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Zinc Oxide Nanorods Prepared in Mixed Solvents  [PDF]
Mohammad Ashraf Shah, Fahad M. Al-Marzouki
Materials Sciences and Applications (MSA) , 2010, DOI: 10.4236/msa.2010.12014
Abstract: In this paper, we demonstrate a novel and direct synthesis of hexagonal-shaped zinc oxide (ZnO) nanorods at very low temperature of ~ 80oC simply by using metallic zinc foil and de-ionized (DI) water with few drops of ethanol. The formation of ZnO structures by the reaction of metals with DI water is suggested to occur due to the oxidation of metallic zinc in presence of water. The synthesized ZnO products were characterized in terms of their structural and optical properties. By the morphological investigations using FESEM, it was observed that the grown products are hexagonal-shaped ZnO nanorods with the diameters in the range of 50-60 nm and length with ~ 1 micrometer. The EDS and XRD pattern confirmed the composition and crystallinity of the grown nanorods and revealed that the grown products are pure ZnO with the wurtzite hexagonal phase.
Incorporating β-Cyclodextrin with ZnO Nanorods: A Potentiometric Strategy for Selectivity and Detection of Dopamine  [PDF]
Sami Elhag,Zafar Hussain Ibupoto,Omer Nur,Magnus Willander
Sensors , 2014, DOI: 10.3390/s140101654
Abstract: We describe a chemical sensor based on a simple synthesis of zinc oxide nanorods (ZNRs) for the detection of dopamine molecules by a potentiometric approach. The polar nature of dopamine leads to a change of surface charges on the ZNR surface via metal ligand bond formation which results in a measurable electrical signal. ZNRs were grown on a gold-coated glass substrate by a low temperature aqueous chemical growth (ACG) method. Polymeric membranes incorporating β-cyclodextrin (β-CD) and potassium tetrakis (4-chlorophenyl) borate was immobilized on the ZNR surface. The fabricated electrodes were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The grown ZNRs were well aligned and exhibited good crystal quality. The present sensor system displays a stable potential response for the detection of dopamine in 10 ?2 mol·L ?1 acetic acid/sodium acetate buffer solution at pH 5.45 within a wide concentration range of 1 × 10 ?6 M –1 × 10 ?1 M, with sensitivity of 49 mV/decade. The electrode shows a good response time (less than 10 s) and excellent repeatability. This finding can contribute to routine analysis in laboratories studying the neuropharmacology of catecholamines. Moreover, the metal-ligand bonds can be further exploited to detect DA receptors, and for bio-imaging applications.
Intracellular ZnO Nanorods Conjugated with Protoporphyrin for Local Mediated Photochemistry and Efficient Treatment of Single Cancer Cell
Kishwar S,Asif MH,Nur O,Willander M
Nanoscale Research Letters , 2010,
Abstract: ZnO nanorods (NRs) with high surface area to volume ratio and biocompatibility is used as an efficient photosensitizer carrier system and at the same time providing intrinsic white light needed to achieve cancer cell necrosis. In this letter, ZnO nanorods used for the treatment of breast cancer cell (T47D) are presented. To adjust the sample for intracellular experiments, we have grown the ZnO nanorods on the tip of borosilicate glass capillaries (0.5 μm diameter) by aqueous chemical growth technique. The grown ZnO nanorods were conjugated using protoporphyrin dimethyl ester (PPDME), which absorbs the light emitted by the ZnO nanorods. Mechanism of cytotoxicity appears to involve the generation of singlet oxygen inside the cell. The novel findings of cell-localized toxicity indicate a potential application of PPDME-conjugated ZnO NRs in the necrosis of breast cancer cell within few minutes.
Development of Galactose Biosensor Based on Functionalized ZnO Nanorods with Galactose Oxidase
K. Khun,Z. H. Ibupoto,O. Nur,M. Willander
Journal of Sensors , 2012, DOI: 10.1155/2012/696247
Abstract: The fabrication of galactose biosensor based on functionalised ZnO nanorods is described. The galactose biosensor was developed by immobilizing galactose oxidase on ZnO nanorods in conjunction with glutaraldehyde as a cross-linker molecule. The IRAS study provided evidence for the interaction of galactose oxidase with the surface of ZnO nanorods. The electromotive force (EMF) response of the galactose biosensor was measured by potentiometric method. We observed that the proposed biosensor has a linear detection range over a concentration range from 10 mM to 200 mM with good sensitivity of 89.10±1.23 mV/decade. In addition, the proposed biosensor has shown fast time response of less than 10 s and a good selectivity towards galactose in the presence of common interferents such as ascorbic acid, uric acid, glucose, and magnesium ions. The galactose biosensor based on galactose oxidase immobilized ZnO nanorods has a shelf life more than four weeks.
Electrochemical L-Lactic Acid Sensor Based on Immobilized ZnO Nanorods with Lactate Oxidase  [PDF]
Zafar Hussain Ibupoto,Syed Muhammad Usman Ali Shah,Kimleang Khun,Magnus Willander
Sensors , 2012, DOI: 10.3390/s120302456
Abstract: In this work, fabrication of gold coated glass substrate, growth of ZnO nanorods and potentiometric response of lactic acid are explained. The biosensor was developed by immobilizing the lactate oxidase on the ZnO nanorods in combination with glutaraldehyde as a cross linker for lactate oxidase enzyme. The potentiometric technique was applied for the measuring the output (EMF) response of L-lactic acid biosensor. We noticed that the present biosensor has wide linear detection range of concentration from 1 × 10?4–1 × 100 mM with acceptable sensitivity about 41.33 ± 1.58 mV/decade. In addition, the proposed biosensor showed fast response time less than 10 s, a good selectivity towards L-lactic acid in presence of common interfering substances such as ascorbic acid, urea, glucose, galactose, magnesium ions and calcium ions. The present biosensor based on immobilized ZnO nanorods with lactate oxidase sustained its stability for more than three weeks.
Fast Formation of Surface Oxidized Zn Nanorods and Urchin-Like Microclusters  [PDF]
R. López,T. Díaz,G. García,E. Rosendo,R. Galeazzi,A. Coyopol,H. Juárez,M. Pacio,F. Morales,A. I. Oliva
Advances in Materials Science and Engineering , 2014, DOI: 10.1155/2014/257494
Abstract: Entangled Zn-ZnO nanorods and urchin-like microstructures were synthesized by the hot filament chemical vapor deposition technique at 825 and 1015°C, respectively. X-ray diffraction results showed a mixture of ZnO and Zn phases in both nanorods and urchin-like structures. The presence of Zn confirms the chemical dissociation of the ZnO solid source. The Z-ZnO nanorods with diameter of about 100?nm showed dispersed-like morphology. The urchin-like structures with micrometer diameters exhibited porous and rough morphology with epitaxial formation of nanorods. 1. Introduction Several techniques have been employed in obtaining nanostructured materials due to their potential applications in electronics, optoelectronics, and chemical gas sensing [1–4]. Recently, micro- and nanoscale composite materials with core-shell structure have stimulated a lot of attention due to their interesting properties such as large surface area and quantum confinement effects. Zn-ZnO core-shell structures are of special interest since heterojunctions can be formed at the interface. These structures offer great promise for fabrication of devices as nanotransducers [5], in solar energy conversion [6], and field emission [7], among others. Nowadays several methods are commonly applied to prepare Zn-ZnO core-shell structures such as urchin-like [6], nanoparticles [8], and nanorods [9]. Chemical vapor deposition (CVD) and its different experimental configurations such as metal organic CVD, plasma enhanced CVD, laser enhanced CVD, low pressure CVD, and HFCVD have shown versatility and reliability in obtaining a large variety of films, coatings, and recently nanostructures. The HFCVD method requires only a filament and a current source to decompose hydrogen molecules into atomic hydrogen . These radicals assist the fast decomposition of several types of gas phase and solid raw materials. In the present work is reported the formation of Zn-ZnO nanorods and urchin-like microclusters by the HFCVD technique, using catalytic produced hydrogen atoms as reducing agent. 2. Materials and Methods Zn-ZnO nanorods and urchin-like microclusters were fabricated by the HFCVD technique by using ZnO powders as reactant material. Although the main characteristic of the HFCVD system is that it uses a metallic filament, it is known that by contact with SiH4 or H2 it yields hydrogen atoms when it is heated at 1600°C and above [10, 11]. The aim of using hydrogen atoms was to produce Zn and OH gases from a ZnO solid source in a short period of time in relation to other methods. Actually, the amount of
Assembled nanostructures of ZnO nanorods prepared by seed growth method

ZHANG Yao-jun
, WAN Gang-qiang, YAN Lei, MA Qing-chang, LI Dong-xiang, ZHAO Ji-kuan

- , 2016, DOI: 10.6040/j.issn.1671-9352.0.2015.079
Abstract: 摘要: 采用微波加热方法以Zn-Al类水滑石纳米颗粒为种子、以醋酸锌为前驱物制备了多种形貌的ZnO纳米棒组装结构,使用SEM和XRD进行了表征。研究发现,当种子液用量较低时,容易制备出ZnO纳米棒的花簇结构,其中ZnO纳米棒的长度在几百纳米到2 μm之间,直径在100~300 nm之间。当种子液用量较大时,容易得到类水滑石的大片晶两面附生ZnO纳米棒或纳米管的多重结构。
Abstract: Herein, various assembled nanostructures of ZnO nanorods were prepared by microwave synthesis from zinc acetate precursor in presence of Zn-Al hydrotalcite seeds and characterized by SEM and XRD. It was found that the flower-like nanostructures of ZnO nanorods were prepared at a relative low seed usage, in which ZnO nanorods had a length of several hundred nanometer to two micrometer and a diameter of 100-300 nanometer. Whereas, the hierarchical nanostructures of large Zn-Al hydrotalcite plates with “two-side” attached ZnO nanorods or nanotubules were easily obtained as adding a large amount of seed solution
ZnO Nanorods Based Enzymatic Biosensor for Selective Determination of Penicillin  [PDF]
Zafar Hussain Ibupoto,Syed Muhammad Usman Ali,Kimleang Khun,Chan Oeurn Chey,Omer Nur,Magnus Willander
Biosensors , 2011, DOI: 10.3390/bios1040153
Abstract: In this study, we have successfully demonstrated the fabrication of a biosensor based on well aligned single-crystal zinc oxide (ZnO) nanorods which were grown on gold coated glass substrate using a low temperature aqueous chemical growth (ACG) method. The ZnO nanorods were immobilized with penicillinase enzyme using the physical adsorption approach in combination with N-5-azido-2-nitrobenzoyloxysuccinimide (ANB-NOS) as cross linking molecules. The potentiometric response of the sensor configuration revealed good linearity over a large logarithmic concentration range from 100 μM to 100 mM. During the investigations, the proposed sensor showed a good stability with high sensitivity of ~121 mV/decade for sensing of penicillin. A quick electrochemical response of less than 5 s with a good selectivity, repeatability, reproducibility and a negligible response to common interferents such as Na 1+, K 1+, d-glucose, l-glucose, ascorbic acid, uric acid, urea, sucrose, lactose, glycine, penicilloic acid and cephalosporins, was observed.
Selective Thallium (I) Ion Sensor Based on Functionalised ZnO Nanorods  [PDF]
Z. H. Ibupoto,Syed M. Usman Ali,K. Khun,Magnus Willander
Journal of Nanotechnology , 2012, DOI: 10.1155/2012/619062
Abstract: Well controlled in length and highly aligned ZnO nanorods were grown on the gold-coated glass substrate by hydrothermal growth method. ZnO nanorods were functionalised with selective thallium (I) ion ionophore dibenzyldiaza-18-crown-6 (DBzDA18C6). The thallium ion sensor showed wide linear potentiometric response to thallium (I) ion concentrations ( ?M to ?M) with high sensitivity of 36.87 ± 1.49?mV/decade. Moreover, thallium (I) ion demonstrated fast response time of less than 5?s, high selectivity, reproducibility, storage stability, and negligible response to common interferents. The proposed thallium (I) ion-sensor electrode was also used as an indicator electrode in the potentiometric titration, and it has shown good stoichiometric response for the determination of thallium (I) ion. 1. Introduction When zinc, cadmium, and lead metals are produced by the burning of coal, during this thallium (Tl+1) a poisonous metal ion penetrates into the atmosphere as a major waste product [1]. Thallium are dangerous to all people when they come in contact for very short time with the environment where amount of thallium ions is too much, and due to this they can suffer from the gastrointestinal aggravation as well as nerve problems [2]. The compounds of thallium in which two atoms of thallium (I) are present are very toxic such as thallium sulphate (Tl2SO4), even the compounds containing single atom of thallium as thallium acetate (CH3COOTl) and thallium carbonate (Tl2CO3). Furthermore, thallium (I) ion has the ability to replace K+1 in energizing the few vital enzymes such as ATPase and pyruvate kinase [3]. Thallium (I) is atoxic, when its concentration is very low as about 0.5?mg/100?g of tissue [4]. If thallium (I) ion concentration in the human body is present in excess for long time, this in result brings a change in the blood composition, harms liver, kidney, intestinal, testicular tissue, and causes hair loss [5]. Because of the poisonous effects of thallium (I) ion and its different chemical compounds, it is highly needed to measure the concentration of thallium (I) ion in real biological and environmental samples. There are many methods which have been used for the determination of thallium (I) ion such as spectrophotometric measurement, graphite-furnace atomic absorption spectrometric, flame atomic absorption spectrometric (FAAS) afterwards the extraction [6, 7], respectively, inductive-coupled plasma mass spectrometric (ICP-MS), voltammetry, and potentiometric methods. There are many advantageous of potentiometric technique such as cheap, simple,
Iron (III) Ion Sensor Based on the Seedless Grown ZnO Nanorods in 3 Dimensions Using Nickel Foam Substrate  [PDF]
Mazhar Ali Abbasi,Zafar Hussain Ibupoto,Yaqoob Khan,Azam Khan,Omer Nur,Magnus Willander
Journal of Sensors , 2013, DOI: 10.1155/2013/382726
Abstract: In the present work, the seedless, highly aligned and vertical ZnO nanorods in 3 dimensions (3D) were grown on the nickel foam substrate. The seedless grown ZnO nanorods were characterised by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD) techniques. The characterised seedless ZnO nanorods in 3D on nickel foam were highly dense, perpendicular to substrate, grown along the (002) crystal plane, and also composed of single crystal. In addition to this, these seedless ZnO nanorods were functionalized with trans-dinitro-dibenzo-18-6 crown ether, a selective iron (III) ion ionophore, along with other components of membrane composition such as polyvinyl chloride (PVC), 2-nitopentylphenyl ether as plasticizer (NPPE), and tetrabutyl ammonium tetraphenylborate (TBATPB) as conductivity increaser. The sensor electrode has shown high linearity with a wide range of detection of iron (III) ion concentrations from 0.005?mM to 100?mM. The low limit of detection of the proposed ion selective electrode was found to be 0.001?mM. The proposed sensor also described high storage stability, selectivity, reproducibility, and repeatability and a quick response time of less than 10?s. 1. Introduction Iron has remained important for the different biosystems such as haemoglobin, myoglobin, and hem enzymes and also plays role as cofactor in enzyme activities as well as in oxygen transport and electron transport. It has also harmful effects on the various biological systems either in form of being alone or combined state. Due to deficiency of iron anaemia is usually diagnosed, and excess of iron can also be a cause of many health problems. Diseases like cancer, heart problems, and other illnesses such as hemochromatosis are also linked to high level of iron in the body [1–3]. The presence of trace quantity of iron in different substances may result in decay. Several techniques have been used for the detection of iron ion from clinical, medicinal, environmental, and different industrial samples [4–7]. Therefore, it is highly demanded to develop new simple, cheap, fast, and sensitive analytical device for the detection of iron from pharmaceuticals, soil and biological samples. The methods used for the detection of iron are spectrophotometric based on bathophenanthroline, 1, 10-phenanthroline, TPTZ, and ferrozine chemical agents [8–14]. There were few sensors used for the sensing of iron [8, 9] based on the direct potentiometric technique, and it has more advantages than the previously described
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