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1.
Ezat Hamidi-Asl Jahan Bakhsh Raoof Abdolraoof Samadi Meibodi Zahra Haghnavaz Bazgir 《中国科学:化学(英文版)》2016,59(1):128-134
Celestine blue(CB)was introduced as a new electroactive indicator in DNA biosensors.The interaction of CB with DNA was investigated by electrochemical and spectroscopic methods.The effect of buffer kind and p H on the electrochemical behavior of CB was studied.The peak currents of CB were linearly related to DNA concentration in the range of 5.0×10~(-9) to 1.0×10~(-7)mol/L.The detection limit of this approach was 4.76×10~(-10) mol/L.Based on spectrometry data a hypochromic effect was observed in UV-Vis spectra of CB with increasing DNA concentration.The results illustrate the possible interaction mode between CB and DNA is electrostatic binding. 相似文献
2.
A novel temperature responsive water-soluble glycopolymer was synthesised via copper wire-catalysed click-polymerisation. Di-hydroxyl terminated poly(ethylene glycol) was quantitatively alkyne end-capped to yield di-alkyne terminated poly(ethylene glycol) (DAT-PEG). 2,3,4,2′,3′,4′-hexa-O-acetyl-6,6′-diazido-6,6′-dideoxy-α,α-D-trehalose (HADADT) was prepared from the di hydrated α,α-D-Trehalose by tosylation/acetylation followed by azidation. Click-polymerisation reaction between DAT-PEG and HADADT was successfully carried out to produce an alternating glycopolymer with triazole rings as linkers in high yield. All the intermediates as well as the glycopolymer were fully characterised by NMR, MS, IR, SEC, TGA and DSC. The cloud point of the aqueous solution of glycopolymer was investigated by optical microscopy and UV–vis spectroscopy. The LCST was found to be within physiological range of about 39 °C, known as fever temperature. 相似文献
3.
Francesca Bettazzi Ezat Hamid-Asl Carla Lucia Esposito Cristina Quintavalle Nello Formisano Serena Laschi Silvia Catuogno Margherita Iaboni Giovanna Marrazza Marco Mascini Laura Cerchia Vittorio De Franciscis Gerolama Condorelli Ilaria Palchetti 《Analytical and bioanalytical chemistry》2013,405(2-3):1025-1034
MicroRNAs (miRNAs, miRs) are naturally occurring small RNAs (approximately 22 nucleotides in length) that have critical functions in a variety of biological processes, including tumorigenesis. They are an important target for detection technology for future medical diagnostics. In this paper we report an electrochemical method for miRNA detection based on paramagnetic beads and enzyme amplification. In particular, miR 222 was chosen as model sequence, because of its involvement in brain, lung, and liver cancers. The proposed bioassay is based on biotinylated DNA capture probes immobilized on streptavidin-coated paramagnetic beads. Total RNA was extracted from the cell sample, enriched for small RNA, biotinylated, and then hybridized with the capture probe on the beads. The beads were then incubated with streptavidin–alkaline phosphatase and exposed to the appropriate enzymatic substrate. The product of the enzymatic reaction was electrochemically monitored. The assay was finally tested with a compact microfluidic device which enables multiplexed analysis of eight different samples with a detection limit of 7 pmol L?1 and RSD?=?15 %. RNA samples from non-small-cell lung cancer and glioblastoma cell lines were also analyzed. 相似文献
4.
Direct bioconjugation onto hair fibers, monitored by confocal laser scanning microscopy and differential scanning calorimetry, has been performed using NHS alpha-functional fluorescently tagged polymers synthesised by living radical polymerisation. 相似文献
5.
Four, individually addressable 30 microm diameter, e-beam deposited, gold microelectrodes recessed by 6 microm were suitably spaced on a single substrate to avoid diffusional overlap between each microelectrode. The single substrate device was functionalised with thiolated alpha-, beta-, and gamma-cyclodextrin nanocavities without spacer groups to ensure close proximity of the cavities to the electrode surface. The microelectrodes were assessed in two stages. The e-beam deposited micron sized electrodes were characterized using models for recessed and inlaid microdisk electrodes. Subsequently, each individually addressable, atomically flat, micro-patterned gold electrode with thiolated CD ensembles was treated as a nanoporous electrode assembly. Theoretical and experimental results were compared using cyclic voltammetry. Atomic force microscopy was also used to characterise the modified microelectrodes. Comparisons were made with thiolated CDs deposited on macroelectrodes. This is the first report of the behaviour of immobilized CD nanocavities ensembles on atomically flat gold microelectrodes. 相似文献
6.
Gholamabbas Chehardoli Mohammad Ali Zolfigol Ezat Ghaemi Elaheh Madrakian Khodabakhsh Niknam Shadpour Mallakpour 《Journal of heterocyclic chemistry》2012,49(3):596-599
3‐Chloropropylsilica was reacted with Kriptofix 21 or 22 in the presence of triethylamine to form N‐propylsilica Kryptofix 21 and Kriptofix 22. Then N2O4 was added to each of these polymers to chemisorb onto cavity of aza‐crown ethers. These functionalized polymers were applied for the fast and simple oxidation of urazoles and 1,4‐dihydropyridines, respectively. 相似文献
7.
Michael A. Tallon Yulia Rogan Bilal Marie Raymond Clark Osama M. Musa Ezat Khosravi 《Journal of polymer science. Part A, Polymer chemistry》2014,52(17):2477-2501
The physiochemical properties, comonomer sequencing, and regiospecificity of the linkages between monomeric units within homo/copolymers based on 5,6‐di‐substituted norbornene and 7‐oxanorbornene type monomers by ring‐opening metathesis polymerization are reported and correlated to their primary and secondary structural elements. In general, first‐generation Grubbs‐ I1 ruthenium catalyst generates polymers with high trans content that exhibits an extended secondary structure with exo,exo substituents, whereas second‐generation Grubbs‐ I2 catalyst produces polymers with high cis content that forms tight turns, resulting in a compact structure. Furthermore, I2 ‐produced polymers exhibit a high level of alternating cis–trans double bonds along their polymeric backbone. In stark contrast, both first‐ and second‐generation Grubbs catalysts display complete reversal in cis/trans selectivity when an oxygen atom is in position‐7 of the norbornene‐ring along with mono‐endo‐substitution in position‐5 or 6, and hence highlighting the importance of stereoelectronic complexation by the catalyst with the next incoming monomer for cis/trans selectivity. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2477–2501 相似文献
8.
David P. Cole Ezat Khosravi Osama M. Musa 《Journal of polymer science. Part A, Polymer chemistry》2016,54(3):335-344
We describe here the first example of the synthesis of 4‐arm star poly(acrylic acid) for use as a water‐soluble drag reducing agent, by applying Cu(0)‐mediated polymerization technique. High molecular weight 4‐arm star poly(tert‐butyl acrylate) (Mn = 3.0–9.0 × 105 g mol?1) was first synthesized using 4,4′‐oxybis(3,3‐bis(2‐bromopropionate)butane as an initiator and a simple Cu(0)/TREN catalyst system. Then, 4‐arm star poly(tert‐butyl acrylate) were subjected to hydrolysis using trifluoroacetic acid resulting in water‐soluble 4‐arm star poly(acrylic acid). Drag reduction test rig analysis showed 4‐arm star poly(acrylic acid) to be effective as a drag reducing agent with drag reduction of 24.3%. Moreover, 4‐arm star poly(acrylic acid) exhibited superior mechanical stability when compared with a linear poly(acrylic acid) and commercially available drag reducing polymers; Praestol and poly(ethylene oxide). The linear poly(acrylic acid), Praestol, and poly(ethylene oxide) all showed a large decrease in drag reduction of 8–12% when cycled 30 times through the drag reduction test rig while, in contrast, 4‐arm star poly(acrylic acid) demonstrated much higher mechanical stability. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 335–344 相似文献
9.
Label‐Free Electrochemical Aptasensor for Determination of Chloramphenicol Based on Gold Nanocubes‐Modified Screen‐Printed Gold Electrode 下载免费PDF全文
Ayemeh Bagheri Hashkavayi Jahan Bakhsh Raoof Reza Ojani Ezat Hamidi Asl 《Electroanalysis》2015,27(6):1449-1456
An ultrasensitive label‐free electrochemical aptasensor was developed for selective detection of chloramphenicol (CAP). The aptasensor was made using screen‐printed gold electrode modified with synthesized gold nanocube/cysteine. The interactions of CAP with aptamer were studied by cyclic voltammetry, square wave voltammetry (SWV) and electrochemical impedance spectroscopy. Under optimized conditions, two linear calibration curves were obtained for CAP determination using SWV technique, from 0.03 to 0.10 µM and 0.25–6.0 µM with a detection limit of 4.0 nM. The aptasensor has the advantages of good selectivity and stability and applied to the determination of CAP in human blood serum sample. 相似文献
10.
A Genosensor for Point Mutation Detection of P53 Gene PCR Product Using Magnetic Particles 下载免费PDF全文
Ezat Hamidi‐Asl Jahan Bakhsh Raoof Mohammad Saeid Hejazi Simin Sharifi Seyed Mahdi Golabi Ilaria Palchetti Marco Mascini 《Electroanalysis》2015,27(6):1378-1386
The development of an electrochemical genosensor involving DNA biotinylated capture probe immobilized on streptavidin coated paramagnetic beads and microfluidic based platform for the detection of P53 gene PCR product is reported. The novelty of this work is the combination of a sensitive electrochemical platform and a proper microfluidic system with a simple and effective enzyme signal amplification technology, ELISA, for detection of target DNA sequence and single nucleotide mutation in p53 tumor suppressor gene sequence. The biosensor has been applied to detect the PCR amplified samples and the results shows that it can discriminate successfully perfect matched DNA from mutant form. 相似文献