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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.
Optical Properties of Silver Nanoparticles for Surface Plasmon Resonance (SPR)-Based Biosensor Applications  [PDF]
Lufsyi Mahmudin, Edi Suharyadi, Agung Bambang Setio Utomo, Kamsul Abraha
Journal of Modern Physics (JMP) , 2015, DOI: 10.4236/jmp.2015.68111
Abstract: It has been successfully carried out the synthesis of silver nanoparticles by chemical reduction method. Silver nitrate (AgNO3) is used as the metal precursor and trisodium citrate as the reducing agent as well as the use of polyvinyl alcohol (PVA) as a stabilizer. The formation of silver nanoparticles was observed visually with discoloration (yellow). To excite surface plasmons, attenuated total reflection (ATR) method is used with Krestchmann configuration of the prism coupling. The maximum absorption band in the UV-Vis spectrometer shows a red shift of 429.43 nm wavelength for a colloidal solution of silver nanoparticles without PVA and 429.01 nm with PVA. The addition of PVA sharpened absorption spectrum curve and produce a broad absorption band which is indicative of a smaller particle size. TEM images showed that the morphology (crystallites) silver nanoparticles have nearly spherical geometry with dispersive particle distribution. Dispersibility of nanoparticles such as this could potentially be used as an active ingredient of SPR biosensor. The observation of the SPR phenomenon shows the SPR angle shift of 0.1° when a thin layer of silver as an active ingredient a biosensor coated with silver nanoparticles and 0.2° when silver nanoparticles with PVA. SPR angle shift and increase the reflectance values caused by changes in surface Plasmon, which can be a reference that the SPR phenomenon with the sensing surface modification using an additional layer of silver nanoparticles can increase sensitivity.
Fluorescence from metallic silver and iron nanoparticles prepared by exploding wire technique  [PDF]
Abdullah Alqudami,S. Annapoorni
Physics , 2006,
Abstract: The observation of intense visible fluorescence from silver and iron nanoparticles in different solution phases and surface capping is reported here. Metallic silver and iron nanoparticles were obtained by exploding pure silver and iron wires in pure water. Bovine serum albumin protein adsorption on the silver nanoparticles showed an enhanced fluorescence. The presence of poly-vinyl pyrrolidone polymer in the exploding medium resulted in a stabilized growth of iron nanoparticles with enhanced fluorescence intensity. The fluorescence was found to be surface /interface dependant. The fluorescence is attributed to electronic transitions among characteristic interface energy bands. The magnetic nature of iron nanoparticles was confirmed from the hysteresis measurements.
Mueller matrix polarimetry of plasmon resonant silver nano-rods: biomedical prospects  [PDF]
Sayantan Ghosh,Jalpa Soni,Sudipta K. Bera,Ayan Banerjee,Nirmalya Ghosh
Physics , 2012, DOI: 10.1117/12.2016830
Abstract: Fundamental understanding of the light-matter interaction in the context of nano-particles is immensely bene- fited by the study of geometry dependent tunable Localized Surface Plasmon Resonance (LSPR) and has been demonstrated to have potential applications in various areas of science. The polarization characteristics of LSPR in addition to spectroscopic tuning can be suitably exploited in such systems as contrast enhancement mech- anisms and control parameters. Such polarization characteristics like diattenuation and retardance have been studied here using a novel combination of Muller-matrix polarimetry with the T-matrix matrix approach for silver nano-rods to show unprecedented control and sensitivity to local refractive index variations. The study carried out over various aspect ratios for a constant equal volume sphere radius shows the presence of longitu- dinal (dipolar and quadrupolar) and transverse (dipolar) resonances; arising due to differential contribution of polarizabilities in two directions. The overlap regions of these resonances and the resonances themselves exhibit enhanced retardance and diattenuation respectively. The spectral and amplitude tunability of these polarimetric parameters through the aspect ratios to span from the minimum to maximum ([0, 1] in the case of diattenuation and [0, {\pi}] in the case of retardance) presents a novel result that could be used to tailor systems for study of biological media. On the other hand, the high sensitivity of diattenuation dip (caused by equal contribution of polarizabilities) could be possibly used for medium characterization and bio-sensing or bio-imaging studies.
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.
Amperometric Hydrogen Peroxide Biosensor Based on Horseradish Peroxidase Entrapped in Titania Sol-Gel Film on Screen-Printed Electrode  [PDF]
Reza E. Sabzi, Fereshteh Rasouli, Farshad Kheiri
American Journal of Analytical Chemistry (AJAC) , 2013, DOI: 10.4236/ajac.2013.411072
Abstract: We report the fabrication of disposable and flexible Screen-Printed Electrodes (SPEs). This new type of screen-printed electrochemical platform consists of Ag nanoparticles (AgNPs) and graphite composite. For this purpose, silver nanoparticles were first synthesized by a chemical reduction method. The morphology and structure of the AgNPs were analyzed using a Scanning Electron Microscope (SEM) and UV-Visible spectroscopy. Graphite was chosen as the working electrode material for the fabrication of a thick-film. The fabrication of a screen-printed hydrogen peroxide biosensor consisting of three electrodes on a polyethylene terephthalate (PET) substrate was performed with a spraying approach (working, counter and reference: enzyme electrode, graphite, pseudo reference: Ag/AgCl). This biosensor was fabricated by immobilizing the peroxidase enzyme (HRP) in a Titania sol-gel membrane which was obtained through a vapor deposition method. The biosensor had electrocatalytic activity in the reduction of H2O2 with linear dependence on H2O2 concentration in the range of 10-5 to 10-3 M; the detection limit was 4.5 × 10-6 M.

Counting Method for Wire Bars and Rods Based on Digital Image Processing

HAN Qing-d,XIN Ying,

中国图象图形学报 , 2007,
Abstract: The automatic counting of wire bars and rods is an unsolved problem. To solve this problem, an image recognition approach which is based on the distance transform technique is presented in this paper. The profile images of wire bars and rods are captured by CCD cameras. In the image preprocessing the binary transform, erosion, dilation and open are conducted. The method of searching the seed spots in the distance transformed image is put forward, by which the numbers of wire bars and rods can be counted. The technique is verified by experiment that image are acquired in the factories. The counting results are not affected by the varieties and the profile shapes of wire bars and rods. This methodology is suitable for the image of wire bars and rods that are disorder and the pack are not trimness, so it is worthy of popularizing and applying.
A label-free biosensor based on silver nanoparticles array for clinical detection of serum p53 in head and neck squamous cell carcinoma
Wei Zhou, Yingyi Ma, Huan Yang, et al
International Journal of Nanomedicine , 2011, DOI: http://dx.doi.org/10.2147/IJN.S13249
Abstract: label-free biosensor based on silver nanoparticles array for clinical detection of serum p53 in head and neck squamous cell carcinoma Case report (5099) Total Article Views Authors: Wei Zhou, Yingyi Ma, Huan Yang, et al Published Date March 2011 Volume 2011:6 Pages 381 - 386 DOI: http://dx.doi.org/10.2147/IJN.S13249 Wei Zhou1, Yingyi Ma1, Huan Yang3, Yi Ding1,2, Xiangang Luo3 1State Key Laboratory of Oral Diseases (Sichuan University), 2West China College of Stromatology, Sichuan University, Chengdu, China; 3State Key Lab of Optical Technologies for Microfabrication, Institute of Optics and Electronics, Chinese Academy of Science, Chengdu, China Abstract: By using triangular silver (Ag) nanoparticle array, a localized surface plasmon resonance (LSPR) nanosensor was fabricated and shown to sense serum p53 protein in vitro, which is involved in head and neck squamous cell carcinoma (HNSCC). The nanosensor consists of a triangular Ag nanoparticles array with single particle dimension of 120 nm in-plane width and 45 nm out-of-plane height. When examined using LSPR nanobiosensor, the results indicated significant difference in LSPR shifts (Δλmax) between HNSCC patient and control. Although there is need for precise quantification and large-scale prospective, this report shows that the LSPR nanobiosensor provides a promising platform with attractive advantages for serological diagnosis or molecular diagnosis in tumor, such as HNSCC. This is the first clinical application of the LSPR nanosensor in HNSCC.
Room temperature ferromagnetism in chemically synthesized ZnO rods  [PDF]
Shalendra Kumar,Y. J. Kim,B. H. Koo,S. Gautam,K. H. Chae,Ravi Kumar,C. G. Lee
Physics , 2009, DOI: 10.1016/j.matlet.2008.09.057
Abstract: We report structural and magnetic properties of pure ZnO rods using X-ray diffraction (XRD), magnetization hysteresis (M-H) loop and near edge x-ray fine structure spectroscopy (NEXAFS) study at O K edge. Sample of ZnO was prepared by co-precipitation method. XRD and selective area electron diffraction measurements infer that ZnO rods exhibit a single phase polycrystalline nature with wurtzite lattice. Field emission transmission electron microscopy, field emission scanning electron microscopy micrographs infers that ZnO have rod type microstructures with dimension 200 nm in diameter and 550 nm in length. M-H loop studies performed at room temperature display room temperature ferromagnetism in ZnO rods. NEXAFS study reflects absence of the oxygen vacancies in pure ZnO rods.
Amperometric Hydrogen Peroxide Biosensor Based on Immobilization of Hemoglobin on a Glassy Carbon Electrode Modified with Fe3O4/Chitosan Core-Shell Microspheres  [PDF]
Xue-Cai Tan,Jin-Lei Zhang,Sheng-Wei Tan,Dan-Dan Zhao,Zen-Wei Huang,Yan Mi,Zai-Yin Huang
Sensors , 2009, DOI: 10.3390/s90806185
Abstract: Novel magnetic Fe3O4/chitosan (CS) microspheres were prepared using magnetic Fe3O4 nanoparticles and the natural macromolecule chitosan. Then, using an easy and effective hemoglobin (Hb) immobilization method, an innovative biosensor with a Fe3O4/CS-Hb-Fe3O4/CS “sandwich” configuration was constructed. This biosensor had a fast (less than 10 s) response to H2O2 and excellent linear relationships were obtained in the concentration range of 5.0 × 10-5 to 1.8 × 10-3 M and 1.8 × 10-3 to 6.8 × 10-3 M with a detection limit of 4.0 × 10-6 M (s/n = 3) under the optimum conditions. The apparent Michaelis-Menten constant Km was 0.29 mM and it showed the excellent biological activity of the fixed Hb. Moreover, the biosensor had long-time stability and good reproducibility. The method was used to determine H2O2 concentration in real samples.
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