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Growth and Structure of ZnO Nanorods on a Sub-Micrometer Glass Pipette and Their Application as Intracellular Potentiometric Selective Ion Sensors  [PDF]
Muhammad H. Asif,Omer Nur,Magnus Willander,Peter Str?lfors,Cecilia Br?nnmark,Fredrik Elinder,Ulrika H. Englund,Jun Lu,Lars Hultman
Materials , 2010, DOI: 10.3390/ma3094657
Abstract: This paper presents the growth and structure of ZnO nanorods on a sub-micrometer glass pipette and their application as an intracellular selective ion sensor. Highly oriented, vertical and aligned ZnO nanorods were grown on the tip of a borosilicate glass capillary (0.7 μm in diameter) by the low temperature aqueous chemical growth (ACG) technique. The relatively large surface-to-volume ratio of ZnO nanorods makes them attractive for electrochemical sensing. Transmission electron microscopy studies show that ZnO nanorods are single crystals and grow along the crystal’s c-axis. The ZnO nanorods were functionalized with a polymeric membrane for selective intracellular measurements of Na +. The membrane-coated ZnO nanorods exhibited a Na +-dependent electrochemical potential difference versus an Ag/AgCl reference micro-electrode within a wide concentration range from 0.5 mM to 100 mM. The fabrication of functionalized ZnO nanorods paves the way to sense a wide range of biochemical species at the intracellular level.
Photovoltaic Devices from Multi-Armed CdS Nanorods and Conjugated Polymer Composites
LIU Yan-Shan,WANG Li,QIN Dong-Huan,CAO Yong,
刘艳山
,王藜,覃东欢,曹镛

中国物理快报 , 2006,
Abstract: We demonstrate the preparation of composite photovoltaic devices by using the blends of multi-armed CdS nanorods with conjugated polymer, poly2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV). Multi-armed CdS nanorods are prepared by thermolysing single precursor cadmium ethylxanthate Cd(exan)2] in pure hexadecylamine solution under ambient conditions. The photoluminescence of MEH-PPV can be effectively quenched in the composites at high CdS nanocrystal (nc-CdS)//MEH-PPV ratios. Post-treatment of the multi-armed CdS nanorods by refluxing in pyridine significantly increases the performance of the composite photovoltaic devices. Power conversion efficiency is obtained to be 0.17% under AM 1.5 illumination for this composite device.
Photosensitizer-Conjugated Gold Nanorods for Enzyme-Activatable Fluorescence Imaging and Photodynamic Therapy  [cached]
Boseung Jang, Yongdoo Choi
Theranostics , 2012,
Abstract: We report on the development of photosensitizer-conjugated gold nanorods (MMP2P-GNR) in which photosensitizers were conjugated onto the surface of gold nanorods (GNR) via a protease-cleavable peptide linker. We hypothesized that fluorescence and phototoxicity of the conjugated photosensitizers would be suppressed in their native state, becoming activated only after cleavage by the target protease matrix metalloprotease-2 (MMP2). Quantitative analysis of the fluorescence and singlet oxygen generation (SOG) demonstrated that the MMP2P-GNR conjugate emitted fluorescence intensity corresponding to 0.4% ± 0.01% and an SOG efficiency of 0.89% ± 1.04% compared to free pyropheophorbide-a. From the in vitro cell studies using HT1080 cells that overexpress MMP2 and BT20 cells that lack MMP2, we observed that fluorescence and SOG was mediated by the presence or absence of MMP2 in these cell lines. This novel activatable photosensitizing system may be useful for protease-mediated fluorescence imaging and subsequent photodynamic therapy for various cancers.
Two Coregulated Efflux Transporters Modulate Intracellular Heme and Protoporphyrin IX Availability in Streptococcus agalactiae  [PDF]
Annabelle Fernandez ,Delphine Lechardeur,Aurélie Derré-Bobillot,Elisabeth Couvé,Philippe Gaudu,Alexandra Gruss
PLOS Pathogens , 2010, DOI: 10.1371/journal.ppat.1000860
Abstract: Streptococcus agalactiae is a major neonatal pathogen whose infectious route involves septicemia. This pathogen does not synthesize heme, but scavenges it from blood to activate a respiration metabolism, which increases bacterial cell density and is required for full virulence. Factors that regulate heme pools in S. agalactiae are unknown. Here we report that one main strategy of heme and protoporphyrin IX (PPIX) homeostasis in S. agalactiae is based on a regulated system of efflux using two newly characterized operons, gbs1753 gbs1752 (called pefA pefB), and gbs1402 gbs1401 gbs1400 (called pefR pefC pefD), where pef stands for ‘porphyrin-regulated efflux’. In vitro and in vivo data show that PefR, a MarR-superfamily protein, is a repressor of both operons. Heme or PPIX both alleviate PefR-mediated repression. We show that bacteria inactivated for both Pef efflux systems display accrued sensitivity to these porphyrins, and give evidence that they accumulate intracellularly. The ΔpefR mutant, in which both pef operons are up-regulated, is defective for heme-dependent respiration, and attenuated for virulence. We conclude that this new efflux regulon controls intracellular heme and PPIX availability in S. agalactiae, and is needed for its capacity to undergo respiration metabolism, and to infect the host.
RGD-conjugated gold nanorods induce radiosensitization in melanoma cancer cells by downregulating αvβ3 expression
Xu WC, Luo T, Li P, Zhou CQ, Cui DX, Pang B, Ren QS, Fu S
International Journal of Nanomedicine , 2012, DOI: http://dx.doi.org/10.2147/IJN.S28314
Abstract: onjugated gold nanorods induce radiosensitization in melanoma cancer cells by downregulating αvβ3 expression Original Research (3276) Total Article Views Authors: Xu WC, Luo T, Li P, Zhou CQ, Cui DX, Pang B, Ren QS, Fu S Published Date February 2012 Volume 2012:7 Pages 915 - 924 DOI: http://dx.doi.org/10.2147/IJN.S28314 Received: 16 November 2011 Accepted: 29 December 2011 Published: 27 February 2012 Wencai Xu1, Teng Luo2, Ping Li1, Chuanqing Zhou2, Daxiang Cui3, Bo Pang4, Qiushi Ren4, Shen Fu1 1Department of Radiation Oncology, Shanghai Sixth People's Hospital, 2School of Biomedical Engineering, and 3National Key Laboratory of Nano/Micro Fabrication Technology, Key Laboratory for Thin Film and Microfabrication of Ministry of Education, Institute of Micro-Nano Science and Technology, Shanghai Jiao Tong University, Shanghai, 4Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, People's Republic of China Background: Melanoma is known to be radioresistant and traditional treatments have been intractable. Therefore, novel approaches are required to improve the therapeutic efficacy of melanoma treatment. In our study, gold nanorods conjugated with Arg-Gly-Asp peptides (RGD-GNRs) were used as a sensitizer to enhance the response of melanoma cells to 6 mV radiation. Methods and materials: A375 melanoma cells were treated by gold nanorods or RGD-GNRs with or without irradiation. The antiproliferative impact of the treatments was measured by MTT assay. Radiosensitizing effects were determined by colony formation assay. Apoptosis and cell cycle data were measured by flow cytometry. Integrin αvβ3expression was also investigated by flow cytometry. Results: Addition of RGD-GNRs enhanced the radiosensitivity of A375 cells with a dose-modifying factor of 1.35, and enhanced radiation-induced apoptosis. DNA flow cytometric analysis indicated that RGD-GNRs plus irradiation induced significant G2/M phase arrest in A375 cells. Both spontaneous and radiation-induced expressions of integrin αvβ3 were downregulated by RGD-GNRs. Conclusion: Our study indicated that RGD-GNRs could sensitize melanoma A375 cells to irradiation. It was hypothesized that this was mainly through downregulation of radiation-induced αvβ3, in addition to induction of a higher proportion of cells within the G2/M phase. The combination of RGD-GNRs and radiation needs further investigation.
Fabrication and Photoluminescence Properties of ZnO Nanorods
ZHONG Hong-Mei,LU Wei,SUN Yan,LI Zhi-Feng,
钟红梅
,陆卫,孙艳,李志锋

中国物理快报 , 2007,
Abstract: ZnO nanorods are successfully synthesized by annealing the precursors in argon with the chemical precipitation method. The structural and optical properties of ZnO nanorods are investigated. As annealing temperature increases, the intensity of the green emission increases while the intensity of the yellow emission decreases. The result suggests that the green emission depends strongly on the annealing temperature.
Intracellular ATP Assay of Live Cells Using PTD-Conjugated Luciferase  [PDF]
Mi-Sook Lee,Wan-Soon Park,Young Han Kim,Won Gyeong Ahn,Seung-Hae Kwon,Song Her
Sensors , 2012, DOI: 10.3390/s121115628
Abstract: Luciferase is a sensitive, reliable biological sensor used for measuring ATP. However, its widespread application in drug discovery and toxicology studies has been limited due to unavoidable cell extraction processes, which cause inaccurate measurements of intracellular ATP and obstruct the application of homogenous high-throughput screening. Recently, we developed a protein transduction domain-conjugated luciferase (PTD-Luc) for measuring cellular uptake efficacy. In this study, we evaluated the applicability of PTD-Luc to an intracellular ATP assay of live cells. The predominant fluorescence of Alexa 647-PTD-Luc was in the cytosol, whereas the fluorescence of Alexa 647-Luc was visualized surrounding the cell membrane, as confirmed by Western blot analysis. In vitro, PTD-Luc could detect less than 10–9 M ATP, and the correlation between the luciferase activity of PTD-Luc and the ATP content was strong (R = 0.999, p < 0.001). In vivo, luminescence signals of PTD-Luc detected intracellular ATP in as few as 50 HeLa cells, with a strong correlation between luminescence and cell number, suggesting high sensitivity and reliability. Furthermore, two blockers of the glycolytic pathway (2-deoxyglucose and iodoacetic acid) inhibited the signal in a dose-dependent manner, whereas potassium cyanide, an inhibitor of oxidative phosphorylation, had no effect on intracellular ATP in vivo, as seen with the PTD-Luc sensor. These data show that PTD-Luc can directly measure the intracellular ATP content in live cells, allowing real-time kinetic studies, suggesting that it is a promising tool for high-throughput drug screening and cytotoxicity assays.
Enhancement of Photoluminescence Lifetime of ZnO Nanorods Making Use of Thiourea
Erdal S nmez,Kadem Meral
Journal of Nanomaterials , 2012, DOI: 10.1155/2012/957035
Abstract: We have investigated correlation of photoluminescence lifetime between zinc oxide (ZnO) nanorods and thiourea-doped ZnO nanorods (tu: CH4N2S). Aqueous solutions of ZnO nanorods were deposited on glass substrate by using pneumatic spray pyrolysis technique. The as-prepared specimens were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and time-resolved photoluminescence spectroscopy (TRPL). The photoluminescence lifetime of ZnO nanorods and ZnO nanorods containing thiourea was determined as =1.56±0.05 ns (2=0.9) and =2.12±0.03 ns (2=1.0), respectively. The calculated lifetime values of ZnO nanorods revealed that the presence of thiourea in ZnO nanorods resulted in increasing the exciton lifetime. In addition to the optical quality of ZnO nanorods, their exciton lifetime is comparable to the longest lifetimes reported for ZnO nanorods. The structural improvement of ZnO nanorods, containing thiourea, was also elucidated by taking their SEM images which show the thinner and longer ZnO nanorods compared to those without thiourea.
Synthesis and properties of ZnO nanorods by modified Pechini process
Ramasamy Devaraj,Krishnamoorthy Karthikeyan,Kadarkaraithangam Jeyasubramanian
Applied Nanoscience , 2013, DOI: 10.1007/s13204-012-0072-1
Abstract: Zinc oxide (ZnO) nanorods have been successfully synthesized by modified Pechini process. The as-synthesized ZnO nanorods were characterized by X-ray diffraction, scanning electron microscope, Raman spectrum, ultraviolet–visible (UV–vis) spectrum. X-ray diffraction result shows that the ZnO nanorods are oriented in wurtzite phase. Raman spectroscopy measurements revealed the presence of E2 (high) mode at 437 cm 1 indicating the high crystallinity of the as-synthesized ZnO nanorods. The optical property of the ZnO nanorods were studied from their UV–vis spectroscopy analysis which exhibits the absorbance at 373 nm corresponds to the Zn–O absorption. A mechanism for modified Pechini process for the synthesis of ZnO nanorods using citric acid–ethylene glycol precursor has also been proposed.
MOCVD growth mechanisms of ZnO nanorods  [PDF]
Guillaume Perillat-Merceroz,Pierre-Henri Jouneau,Guy Feuillet,Robin Thierry,Milan Rosina,Pierre Ferret
Physics , 2011, DOI: 10.1088/1742-6596/209/1/012034
Abstract: ZnO is a promising material for the fabrication of light emitting devices. One approach to achieve this goal is to use ZnO nanorods because of their expected high crystalline and optical quality. Catalyst free growth of nanorods by metalorganic chemical vapour deposition (MOCVD) was carried out on (0001) sapphire substrates. Arrays of well-aligned, vertical nanorods were obtained with uniform lengths and diameters. A thin wetting layer in epitaxy with the sapphire substrate is formed first, followed by pyramids and nanorods. The nucleation of nanorods occurs either directly at the interface, or later on top of some of the pyramids, suggesting various nucleation mechanisms. It is shown that crystal polarity plays a critical role in the growth mechanism with nanorods of Zn polarity and their surrounding pyramids with O polarity. A growth mechanism is proposed to explain that most threading dislocations lie in the wetting layer, with only a few in the pyramids and none in the nanorods.
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