48 results on '"Suping Jia"'
Search Results
2. Unveiling the effect of carbon dots on the TiO2-involved electron transport in perovskite solar cells
- Author
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Bingchen Huo, Suping Jia, Yangyang Li, Huinian Zhang, Caihong Hao, Huiqi Wang, and Shengliang Hu
- Subjects
Mechanics of Materials ,Mechanical Engineering ,Materials Chemistry ,Metals and Alloys - Published
- 2023
3. Hybrid S-RAID: A Power-Aware Archival Storage Architecture.
- Author
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Jingyu Liu, Yuanzhang Li, Suping Jia, Jiasheng Hong, Jingyong Yan, and Yufeng Guo
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- 2012
- Full Text
- View/download PDF
4. Photothermal, photocatalytic, and anti-bacterial Ti-Ag-O nanoporous powders for interfacial solar driven water evaporation
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Chaorui Xue, Qing Chang, Pengfei Li, Ruirui Huang, Dong Li, Shanshan Chen, Yangsen Li, Jinlong Yang, Huiqi Wang, Ning Li, Shengliang Hu, and Suping Jia
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010302 applied physics ,Materials science ,Nanoporous ,Anodizing ,Process Chemistry and Technology ,Alloy ,Nanoparticle ,02 engineering and technology ,Photothermal therapy ,engineering.material ,021001 nanoscience & nanotechnology ,01 natural sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Chemical engineering ,0103 physical sciences ,Materials Chemistry ,Ceramics and Composites ,engineering ,Photocatalysis ,Wetting ,Irradiation ,0210 nano-technology - Abstract
Interfacial solar driven water evaporation is an attractive and green method to alleviate the scarcity of clean and fresh water, and tremendous efforts have been devoted to prepare efficient photothermal materials. However, the practical condition for interfacial solar driven water evaporation is complex, increasing contamination by pollutants and bacterial can inactive the photothermal materials. Herein, to address this problem, Ti-Ag-O nanoporous powders, which possess photothermal, photocatalytic and anti-bacterial properties, were prepared by TiAg alloy anodization and subsequent laser irradiation method. It was found that metallic Ag nanoparticles, which were mainly formed by TiAg alloy anodization, will be oxidized into Ag2O nanoparticles after laser irradiation. Through this laser induced transformation, the surface wettability of Ti-Ag-O powders can be improved for the hydrophilicity nature of Ag2O, and the Ti-Ag-O powders with Ti90Ag10 alloy anodization and subsequent laser irradiation for 10 min showed the highest water evaporation rate (2.27 kg m−2 h−1). Meanwhile, this Ti-Ag-O powders also showed the highest photocatalytic property due to the junction between TiO2 and Ag2O. Moreover, the diffusion inhibition test indicated that antibacterial property of this Ti-Ag-O powders was excellent for the incorporation of Ag/Ag2O nanoparticles. The as-prepared trifunctional Ti-Ag-O nanoporous powders holds potential for the practical application of interfacial solar driven water evaporation technology, the TiAg alloy anodization and subsequent laser irradiation method could be extended to prepare other multifunctional photothermal materials.
- Published
- 2021
5. Common Program Analysis of Two-Party Security Protocols Using SMV.
- Author
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Yuqing Zhang 0001 and Suping Jia
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- 2006
- Full Text
- View/download PDF
6. Effect of TiO2 surface treatment on electron transfer in dye-sensitized solar cells
- Author
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Suping Jia, Tong Cheng, Huinian Zhang, Hao Wang, and Caihong Hao
- Subjects
General Materials Science - Abstract
Defect states in the TiO2 nanoparticles can cause severe charge recombination and poor electron-transport efficiency when used as a photoanode in dye-sensitized solar cells (DSSCs). Herein, we report a simple and practical way to passivate the surface defects of TiO2 through hydrothermal treating with acetic acid and H2SO4, introducing a high percentage of 101 facets and sulfonic acid functional groups on the TiO2 surface. A high efficiency of 8.12% has been achieved, which is 14% higher than that of untreated TiO2 under the same condition. EIS results prove that the multiacid-treated TiO2 can promote electron transport and reduce charge recombination at the interface of the TiO2 and electrolyte. This work provides an efficient approach to engineer the electron-transport pathway in DSSCs.
- Published
- 2022
7. Unveiling the Effect Of Carbon Dots on The Tio2-Involved Electron Transport In Perovskite Solar Cells
- Author
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Bingchen Huo, Suping Jia, Yangyang Li, Huinian Zhang, Caihong Hao, Huiqi Wang, and Shengliang Hu
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History ,Polymers and Plastics ,Business and International Management ,Industrial and Manufacturing Engineering - Published
- 2022
8. Available photo-charging integrated device constructed with dye-sensitized solar cells and lithium-ion battery
- Author
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Yi Di, Junfei Liang, Xiaoshuang Yan, Suping Jia, and Shengliang Hu
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Battery (electricity) ,business.industry ,Chemistry ,General Chemistry ,Solar energy ,Catalysis ,Lithium-ion battery ,Cathode ,law.invention ,Dye-sensitized solar cell ,law ,Electrode ,Materials Chemistry ,Optoelectronics ,Electric power ,business ,Voltage - Abstract
The development of self-chargeable lithium-ion batteries is of great significance for expanding the usable range of the lithium-ion battery and it has received intensive attention from numerous researchers. Solar cells can generate electricity from the sunlight and ensure sustainable access to electrical power for charging lithium-ion batteries. Herein, a photo-charging integrated device is constructed by combining four conventional dye-sensitized solar cells and a three-electrode hybrid lithium-ion battery, including a dye-sensitized TiO2 photo-anode, LiFePO4 electrode and metal lithium electrode. When the device is operated under solar illumination, DSSCs can match the charging voltage for the hybrid lithium-ion battery. The LiFePO4 electrode in the three-electrode device plays two roles, serving as a reversible redox agent for the regeneration of dye and as the cathode for lithium-ion batteries. The integrated device can effectively harvest solar energy and store it in situ within the hybrid lithium-ion battery through the photo-charging process. The proposed strategy is in favor of exploiting the small-sized, light-weight, self-chargeable battery and may have the potential to be employed as the power supply for miniaturized sensors and mobile devices.
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- 2020
9. Electrocatalytic films of PEDOT incorporating transition metal phosphides as efficient counter electrodes for dye sensitized solar cells
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Ning Li, Huinian Zhang, Yi Di, Hantao Liu, Caihong Hao, Shengliang Hu, and Suping Jia
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chemistry.chemical_classification ,Materials science ,Renewable Energy, Sustainability and the Environment ,020209 energy ,Energy conversion efficiency ,Nanoparticle ,02 engineering and technology ,Polymer ,021001 nanoscience & nanotechnology ,Electrochemistry ,Dye-sensitized solar cell ,PEDOT:PSS ,Chemical engineering ,Transition metal ,chemistry ,Electrode ,0202 electrical engineering, electronic engineering, information engineering ,General Materials Science ,0210 nano-technology - Abstract
Excellent electrocatalytic properties and low cost are main requirements for the suitable counter electrodes of dye sensitized solar cells (DSSCs). In this work, serials of electrocatalytic films were facilely fabricated by blending the PEDOT polymers and transition metal phosphides nanoparticles (Ni2P or Co2P). All yielded films as counter electrodes were assembled into intact cells and their electrocatalytic performances were carefully investigated. Compared to the PEDOT-only electrode or phosphide-only electrode, the achieved composite electrodes display the superior electrocatalytic performances. The continuous PEDOT polymers can significantly alleviate phosphides nanoparticles aggregations and thereby generate more active area for redox couple. DSSCs with the optimal PEDOT-Ni2P-3 electrode and PEDOT-Co2P-3 electrode show the power conversion efficiency (PCE) of 7.14% and PCE of 6.85%, respectively. And PCE value of the optimal PEDOT-Ni2P-3 is comparable to that (7.09%) of Pt electrode on the same test condition. Moreover, electrochemical measurements reveal the type of composite electrode holding decent dissolution-resistant ability. Considering the outstanding and available electrocatalytic activities, the potential application of PEDOT-phosphides electrodes as the substitute of Pt electrode is worth to be expected.
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- 2019
10. TiO2 modification with multi-acid treatment for efficient interfacial perovskite-TiO2 electron transport
- Author
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Huinian Zhang, Chaorui Xue, Tong Cheng, Hao wang, Huiqi Wang, Shengliang Hu, and Suping Jia
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chemistry.chemical_classification ,Anatase ,Materials science ,Passivation ,Mechanical Engineering ,Metals and Alloys ,Electron ,Sulfonic acid ,Electron transport chain ,law.invention ,chemistry ,Chemical engineering ,Mechanics of Materials ,law ,Materials Chemistry ,Electron Transport Pathway ,Crystallization ,Perovskite (structure) - Abstract
There are numerous defect states in the anatase TiO2 nanoparticles, which are most frequently used as the electron transporting layers in perovskite solar cells (PSCs), resulting in severe charge recombination and poor electron extracted efficiency. Herein, we report a simple and practical way to passivate the surface defects of TiO2 by hydrothermal treating with acetic acid and H2SO4. Modified TiO2 with a high percentage of {101} facets and sulfonic acid functional group is proved to be beneficial for the growth and crystallization of FAMA perovskite film. Furthermore, it can facilitate the electron extraction and inhibit the charge recombination at the perovskite-TiO2 interface. A high PCE of 20.27% has been achieved in our modified TiO2-based PSCs, which is 30% higher than that of control devices under the same condition. Simultaneously, the solar cells display negligible hysteresis, improved device reproducibility and stability. This work provides an efficient approach to engineer the electron transport pathway at perovskite-TiO2 interface.
- Published
- 2022
11. Improving methane selectivity of photo-induced CO2 reduction on carbon dots through modification of nitrogen-containing groups and graphitization
- Author
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Nannan Xue, Suping Jia, Na Li, Zhi Liu, Liyi Shi, Li Zhang, Zhijian Wang, Li Li, Shaojun Qing, and Jiazang Chen
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Materials science ,Oxide ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Catalysis ,Methane ,law.invention ,Metal ,chemistry.chemical_compound ,law ,General Environmental Science ,Graphene ,Process Chemistry and Technology ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,chemistry ,Chemical engineering ,Chemisorption ,visual_art ,Photocatalysis ,visual_art.visual_art_medium ,0210 nano-technology ,Selectivity ,Carbon - Abstract
The photocatalytic performance of carbon dots is strongly related to surface modifications and graphitization. Herein, we show that carbon dots without metal loaded can serve as an efficient photocatalyst for reducing CO2. The conjugate carbon great π could stabilize the photogenerated electrons, which turned out to improve the separation of the photogenerated electron-hole pairs and can kinetically promote interfacial reaction. Besides, the strong chemisorption of the nitrogen-containing groups on the carbon dots to the CO would help to further conversion of the intermediate in the demonstrated CO2 photo-reduction systems. As a result of these merits, the highly graphitized carbon dots prepared from graphene oxide with plenty of nitrogen-containing groups exhibit 74.8% electronic selectivity of methane. This strategy provides an important requirement for designing of CO2 photocatalysts.
- Published
- 2018
12. A 2D/1D TiO2 nanosheet/CdS nanorods heterostructure with enhanced photocatalytic water splitting performance for H2 evolution
- Author
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Zhijian Wang, Peng Qu, Jianfeng Zheng, Zhenping Zhu, Qinchao Xu, Jiazang Chen, Junmei Wang, and Suping Jia
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Materials science ,Photoluminescence ,Renewable Energy, Sustainability and the Environment ,business.industry ,Energy Engineering and Power Technology ,Heterojunction ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Electron transfer ,Fuel Technology ,Photocatalysis ,Optoelectronics ,Nanorod ,0210 nano-technology ,business ,Photocatalytic water splitting ,Nanosheet ,Hydrogen production - Abstract
TiO2 with exposed (001) facets were composited with CdS nanorods to construct 2D/1D heterojunction. As comparison, P25 with mainly exposed (101) facets were employed to combine with CdS nanorods. The 2D/1D heterojunction of TiO2 nanosheets and CdS nanorod displayed 3.7 times higher hydrogen generation than that of P25/CdS composites. The results indicated that TiO2 with exposed (001) facets were favorable for enhancing the photocatalytic activity of CdS via optimizing the heterojunction between TiO2 and CdS. Photoluminescence and photoelectrochemical characteristics results demonstrated that the 2D-TiO2/1D-CdS heterojunction exhibits higher separation efficiency of photoinduced carriers and superior electron transfer ability. This work exemplifies that heterojunction modification is an effective strategy to improve the efficiency of the photocatalyst composites.
- Published
- 2018
13. Facile synthesis of nitrogen-doped graphene frameworks for enhanced performance of hole transport material-free perovskite solar cells
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Yanyan Zhu, Jing Wang, Yulong Lin, Suping Jia, Jianfeng Zheng, and Wu Yarong
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Auxiliary electrode ,Materials science ,Graphene ,Energy conversion efficiency ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,law.invention ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,law ,Specific surface area ,Electrode ,Materials Chemistry ,0210 nano-technology ,Sodium carbonate ,Pyrolysis ,Perovskite (structure) - Abstract
Nitrogen-doped graphene frameworks (N-GFs) with a large specific surface area (1149 m2 g−1) are successfully synthesized from fumaric acid in the presence of sodium carbonate with urea added as nitrogen precursor through a facile one-step fast pyrolysis. The N-GFs can be utilized as an excellent counter electrode in hole transport material (HTM)-free perovskite solar cells (PSCs), achieving the power conversion efficiency of 10.32%, higher than the PSCs using undoped graphene frameworks. The enhanced performance of N-GF-based PSCs is probably due to the superiority of N-GFs in enabling increased charge extraction efficiency and transportation to substantially reduce charge recombination losses. This work indicates the great potential of N-GFs to replace expensive organic HTM and noble-metal electrodes in developing low-cost and efficient HTM-free PSCs.
- Published
- 2018
14. Ciprofloxacin and pegylated G-CSF combined therapy mitigates brain hemorrhage and mortality induced by ionizing irradiation
- Author
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Juliann G. Kiang, Georgetta Cannon, Matthew G. Olson, Min Zhai, Akeylah K. Woods, Feng Xu, Bin Lin, Xianghong Li, Lisa Hull, Suping Jiang, and Mang Xiao
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mouse ,Ciprofloxacin ,G-CSF ,radiation ,platelet ,glial fibrillary acidic protein ,Public aspects of medicine ,RA1-1270 - Abstract
IntroductionBrain hemorrhage was found between 13 and 16 days after acute whole-body 9.5 Gy 60Co-γ irradiation (IR). This study tested countermeasures mitigating brain hemorrhage and increasing survival from IR. Previously, we found that pegylated G-CSF therapy (PEG) (i.e., Neulasta®, an FDA-approved drug) improved survival post-IR by 20–40%. This study investigated whether Ciprofloxacin (CIP) could enhance PEG-induced survival and whether IR-induced brain hemorrhage could be mitigated by PEG alone or combined with CIP.MethodsB6D2F1 female mice were exposed to 60Co-γ-radiation. CIP was fed to mice for 21 days. PEG was injected on days 1, 8, and 15. 30-day survival and weight loss were studied in mice treated with vehicles, CIP, PEG, or PEG + CIP. For the early time point study, blood and sternums on days 2, 4, 9, and 15 and brains on day 15 post-IR were collected. Platelet numbers, brain hemorrhage, and histopathology were analyzed. The cerebellum/pons/medulla oblongata were detected with glial fibrillary acidic protein (GFAP), p53, p16, interleukin-18 (IL-18), ICAM1, Claudin 2, ZO-1, and complement protein 3 (C3).ResultsCIP + PEG enhanced survival after IR by 85% vs. the 30% improvement by PEG alone. IR depleted platelets, which was mitigated by PEG or CIP + PEG. Brain hemorrhage, both surface and intracranial, was observed, whereas the sham mice displayed no hemorrhage. CIP or CIP + PEG significantly mitigated brain hemorrhage. IR reduced GFAP levels that were recovered by CIP or CIP + PEG, but not by PEG alone. IR increased IL-18 levels on day 4 only, which was inhibited by CIP alone, PEG alone, or PEG + CIP. IR increased C3 on day 4 and day 15 and that coincided with the occurrence of brain hemorrhage on day 15. IR increased phosphorylated p53 and p53 levels, which was mitigated by CIP, PEG or PEG + CIP. P16, Claudin 2, and ZO-1 were not altered; ICAM1 was increased.DiscussionCIP + PEG enhanced survival post-IR more than PEG alone. The Concurrence of brain hemorrhage, C3 increases and p53 activation post-IR suggests their involvement in the IR-induced brain impairment. CIP + PEG effectively mitigated the brain lesions, suggesting effectiveness of CIP + PEG therapy for treating the IR-induced brain hemorrhage by recovering GFAP and platelets and reducing C3 and p53.
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- 2023
- Full Text
- View/download PDF
15. A green and efficient photo-driven route for the selective oxidation of aqueous isopropanol solution to pinacol (C6) with hydrogen peroxide
- Author
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Zhijian Wang, Wenjun Yan, Na Li, Suping Jia, Hongxia Zhang, Jianfeng Zheng, and Zhenping Zhu
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Aqueous solution ,010405 organic chemistry ,Pinacol ,Alcohol ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Environmentally friendly ,Catalysis ,0104 chemical sciences ,Solvent ,chemistry.chemical_compound ,chemistry ,Alcohol oxidation ,Materials Chemistry ,Organic chemistry ,Selectivity ,Hydrogen peroxide - Abstract
Selective oxidation of alcohols to highly valued chemicals in a clean manner (e.g., with water as a solvent and O2 or H2O2 as the primary oxidant) is the subject of considerable research attention. This paper presents a simple and environmentally friendly approach for the selective oxidation of isopropanol to pinacol C6 (2,3-dimethyl-2,3-butanediol) in water with hydrogen peroxide (H2O2) through UV irradiation under mild conditions. A selectivity of 82–95% is achieved at H2O2 feeding rates below 4 mL h−1. The introduction of TiO2 nanotubes can further accelerate isopropanol conversion and enhance pinacol C6 formation. The highest formation rate of pinacol C6 and the highest conversion rate of isopropanol are 29.4 and 71.4 mmol h−1, respectively. The proposed strategy provides a green solution for the synthesis of aliphatic pinacol and offers a new design for the construction of C–C bonds with alphatic alcohol.
- Published
- 2017
16. Fabricating efficient CdSe–CdS photocatalyst systems by spatially resetting water splitting sites
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Zhenping Zhu, Zhijian Wang, Li Li, Jianfeng Zheng, Junmei Wang, Bin Liu, Suping Jia, and Jiazang Chen
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Materials science ,Nanotechnology ,02 engineering and technology ,Carbon nanotube ,010402 general chemistry ,01 natural sciences ,Redox ,law.invention ,Reaction rate ,law ,General Materials Science ,chemistry.chemical_classification ,Renewable Energy, Sustainability and the Environment ,business.industry ,General Chemistry ,Electron acceptor ,021001 nanoscience & nanotechnology ,Electron transport chain ,Acceptor ,0104 chemical sciences ,Semiconductor ,chemistry ,Chemical physics ,Water splitting ,0210 nano-technology ,business - Abstract
Water oxidation and reduction over semiconductor-based photocatalysts intrinsically occur at different spatial sites. Modulation of the reaction sites and charge transfer between them are logically important in speeding up the reaction. Here, we demonstrate that divorcing a CdSe–CdS–Pt donor–acceptor system on different surface sites of TiO2 can significantly increase the H2 generation rate. The increase is derived from an effective reset of water oxidation and reduction sites. Widening of the site distance by employing a TiO2 membraniform acceptor effectively decreases the electron–hole recombination especially for a membrane of TiO2 nanotube arrays. The oriented charge transfer characteristic of TiO2 nanotube arrays benefits long-range electron transport, thereby increasing the electron lifetime and reaction rate. When more conductive carbon nanotube arrays serve as an electron acceptor to replace TiO2, the electron transport is greatly improved, resulting in an ultrahigh H2 generation rate of 1270 mmol g−1 h−1. This work provides a basis for the design and construction of highly efficient photocatalysts through rational modulation of reaction sites and charge transport.
- Published
- 2017
17. Structure-controlled CdS(0D, 1D, 2D) embedded onto 2D ZnS porous nanosheets for highly efficient photocatalytic hydrogen generation
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Junmei Wang, Jianfeng Zheng, Suping Jia, Jiazang Chen, Zhenping Zhu, Zhijian Wang, and Li Li
- Subjects
Photoluminescence ,Materials science ,Band gap ,business.industry ,General Chemical Engineering ,Solar hydrogen ,Heterojunction ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Photocatalysis ,Transient photocurrent ,Optoelectronics ,0210 nano-technology ,business ,Porosity ,Hydrogen production - Abstract
The morphological characteristics of a photocatalyst is central to its photocatalytic activity for solar energy conversion. Herein, Pt–ZnS/CdS composites comprising ZnS nanosheets, embedded via the geometry and size modulation and tuning of band gap of CdS with 0D, 1D or 2D structure, were investigated for solar hydrogen production. The photoactivity results indicate that the shape and morphology of CdS in the Pt–ZnS/CdS heterojunction play a pivotal role in affecting the photocatalytic performance. CdS with a 1D structure deposited on porous Pt–ZnS nanosheets endow the heterojunction with increased efficiency for the separation and transport of photoinduced electron–hole pairs. The proposed mechanism for the boosted suppression of charge recombination was further confirmed by the transient photocurrent response and photoluminescence.
- Published
- 2017
18. Efficient Structure Transformation Based on Sensitivity-Oriented Structure Adjustment for Inverse-Designed Devices
- Author
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Yuchen Chen, Jifang Qiu, Zhenli Dong, Lihang Wang, Lan Wu, Suping Jiao, Hongxiang Guo, and Jian Wu
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nanophotonics ,inverse design ,structure transformation ,fabrication robustness ,structural sensitivity ,active contour model ,Applied optics. Photonics ,TA1501-1820 - Abstract
Inverse-designed devices with thousands of degrees of freedom could achieve high performance in compact footprints, but typically have complex structure topologies that contain many irregular and tiny features and sharp corners, which tend to lead to a poor robustness to fabrication errors. In order to effectively transform the structure of inverse-designed nanophotonic devices into simple structure topologies that have high robustness to fabrication errors without sacrificing device performance, in this paper, we propose a structure adjustment method that innovatively adjusts the structures of inverse-designed devices by introducing their structural sensitivity to the optical performance, extracting the device substructures with high sensitivity and eliminating those with low sensitivity, and, finally, transforming the device structures into simple structure topologies with high robustness and better performance. Two devices (90° crossing and T-junction) were designed and fabrication tolerance simulation was conducted to verify the method. The results show that the devices designed using the proposed method achieved better performance and were more robust to under/over-etched errors.
- Published
- 2024
- Full Text
- View/download PDF
19. 3D Graphene Frameworks with Uniformly Dispersed CuS as an Efficient Catalytic Electrode for Quantum Dot-Sensitized Solar Cells
- Author
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Huijuan Cui, Suping Jia, Jianfeng Zheng, Zhijian Wang, Zhenping Zhu, Pengju Yang, and Yanyan Zhu
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Tafel equation ,Auxiliary electrode ,Materials science ,Graphene ,General Chemical Engineering ,Composite number ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,law.invention ,Chemical engineering ,Nanocrystal ,Quantum dot ,law ,Electrode ,Electrochemistry ,0210 nano-technology ,Polarization (electrochemistry) - Abstract
Three-dimensional (3D) graphene frameworks (GFs) loading CuS nanocrystals composite (GFs–CuS) are prepared by an in-situ hydrothermal process. We find that 3D graphene frameworks exhibit an excellent supporter for even growth and good distribution of CuS nanocrystals. Such 3D architecture composite could provide multi-direction channels that greatly facilitate electron transport and ion diffusion as well as offer more accessible catalytic active sites. These intrinsic factors are essential for an efficient counter electrode (CE) of quantum dot-sensitized solar cells (QDSSCs). As expected, the CdS/CdSe QDSSCs based on GFs-CuS CE achieves a high power conversion efficiency of 5.04%, which is higher than those of the traditional Pt CE (3.18%), GFs CE (3.60%) and CuS CE (3.75%), even better than 2D graphene–CuS composite CE (4.17%). The electrochemical impedance spectra and Tafel polarization curve analysis reveal that the 3D GFs–CuS composite counter electrode exhibits the lower charge-transfer resistance, faster ion diffusion ability and the higher electrocatalytic activity in comparison with the Pt, GFs, CuS and 2D graphene–CuS electrodes. Furthermore, the GFs–CuS CE exhibits excellent stability, demonstrating its promising potential application as effective counter electrode material in QDSSCs.
- Published
- 2016
20. Tunneling Interlayer for Efficient Transport of Charges in Metal Oxide Electrodes
- Author
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Jiazang Chen, Lin Ma, Hongbin Yang, Hua Bing Tao, Zhenhui Lam, Zhijian Wang, Jianqiang Luo, Bo Li, Bin Liu, Liping Zhang, Suping Jia, Zhenping Zhu, Zhiping Zeng, and Jianfeng Zheng
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Chemistry ,business.industry ,Doping ,Oxide ,Nanotechnology ,Thermionic emission ,02 engineering and technology ,General Chemistry ,Dissipation ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Semiconductor ,Electrode ,Optoelectronics ,0210 nano-technology ,business ,Electrical conductor ,Quantum tunnelling - Abstract
Due to the limited electronic conductivity, the application of many metal oxides that may have attractive (photo)-electrochemical properties has been limited. Regarding these issues, incorporating low-dimensional conducting scaffolds into the electrodes or supporting the metal oxides onto the conducting networks are common approaches. However, some key electronic processes like interfacial charge transfer are far from being consciously concerned. Here we use a carbon-TiO2 contact as a model system to demonstrate the electronic processes occurring at the metal-semiconductor interface. To minimize the energy dissipation for fast transfer of electrons from semiconductor to carbon scaffolds, facilitating electron tunneling while avoiding high energy-consuming thermionic emission is desired, according to our theoretical simulation of the voltammetric behaviors. To validate this, we manage to sandwich ultrathin TiO2 interlayers with heavy electronic doping between the carbon conductors and dopant-free TiO2. The radially graded distribution of the electronic doping along the cross-sectional direction of carbon conductor realized by immobilizing the dopant species on the carbon surface can minimize the energy consumption for contacts to both the carbon and the dopant-free TiO2. Our strategy provides an important requirement for metal oxide electrode design.
- Published
- 2016
21. Green oxidation of bio-lactic acid with H2O2 into tartronic acid under UV irradiation
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Na Li, Xuxia Tian, Ruipeng Hao, Zhijian Wang, Li Li, Zhenping Zhu, Suping Jia, and Pengju Yang
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Tartronic acid ,Preservative ,Aqueous solution ,010405 organic chemistry ,Chemistry ,General Chemical Engineering ,General Chemistry ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Lactic acid ,chemistry.chemical_compound ,Organic chemistry ,Irradiation ,Hydrogen peroxide - Abstract
Tartronic acid (TA) is a high value-added chemical widely used as a pharmaceutical product and a preservative; however, its synthesis technology is complicated and high cost. In this study, aqueous solutions of lactic acid were photochemically converted into TA via green oxidation by using hydrogen peroxide (H2O2).
- Published
- 2016
22. Blocking the back reaction in quantum dot sensitized solar cells via surface modification with organic molecules
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Suping Jia, Yanyan Zhu, Jianhui Dong, and Zhenping Zhu
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business.industry ,Chemistry ,General Chemical Engineering ,Energy conversion efficiency ,02 engineering and technology ,General Chemistry ,Electrolyte ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,Capacitance ,0104 chemical sciences ,law.invention ,Dielectric spectroscopy ,Quantum dot ,law ,Steric factor ,Solar cell ,Optoelectronics ,Surface modification ,0210 nano-technology ,business - Abstract
Back reactions were suppressed effectively by double blocking barrier, organic molecules and ZnS on the photoanode of quantum dot (QDs) sensitized solar cells (QDSSCs), thereby achieving higher conversion efficiency. In this work, four different organic molecules were applied in QDSSCs, the efficiency increased two-fold from 2.21% to 4.25% when co-modifications with 4-tert-butyl pyridine (TBP) and ZnS were sequentially applied. The incident photon-to-current efficiency (IPCE) and parameters obtained from impedance spectroscopy (IS) such as recombination resistance (Rrec), chemical capacitance (Cμ), and electron lifetimes were consistent with the measured photovoltaic performance. We speculated that organic molecules mainly inhibit the charge recombination of the injected electrons in TiO2 with electrolyte, because of its steric factor and the electron-donating property of the tert-butyl group. The selective site of modification has been tested for assessing the dominant mechanism underlying the improvement of solar cell characteristics.
- Published
- 2016
23. Direct C–C coupling of bio-ethanol into 2,3-butanediol by photochemical and photocatalytic oxidation with hydrogen peroxide
- Author
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Suping Jia, Jianfeng Zheng, Na Li, Zhijian Wang, Wenjun Yan, Pengju Yang, Zhenping Zhu, and Hongxia Zhang
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010405 organic chemistry ,Radical ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,Pollution ,0104 chemical sciences ,Catalysis ,Reaction rate ,chemistry.chemical_compound ,Chemical bond ,chemistry ,Photocatalysis ,Environmental Chemistry ,Hydroxide ,Single bond ,0210 nano-technology ,Hydrogen peroxide - Abstract
Theoretically, selective C–H manipulation in ethanol can result in a direct C–C coupling synthesis of 2,3-butanediol (2,3-BDO). However, this process is typically extremely difficult to achieve because of the high complexity of the involved chemical bonds. In this work, we determine that hydroxide radicals generated from the photolysis of H2O2 can selectively attack the α-hydrogen atom in ethanol aqueous solutions and crack the C–H bond to produce hydroxyethyl radicals, which subsequently undergo C–C coupling to form 2,3-BDO. This selective C–H breakage is determined by the reaction rate, which is primarily controlled by the local H2O2 concentration at a given irradiation intensity. At a moderate reaction rate of ethanol (37 mmol h−1), the 2,3-BDO selectivity reaching as high as 91% can be obtained. The introduction of a catalyst can further increase ethanol conversion and enhance the 2,3-BDO formation rate by controlling the reaction rate. This result provides an environment-friendly approach to convert bio-ethanol directly to 2,3-BDO and to manipulate a single bond selectively in complex bonding situations.
- Published
- 2016
24. Graphene frameworks synthetized with Na2CO3 as a renewable water-soluble substrate and their high rate capability for supercapacitors
- Author
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Jianfeng Zheng, Suping Jia, Zhijian Wang, Zhenping Zhu, Yanyan Zhu, and Huijuan Cui
- Subjects
Supercapacitor ,Materials science ,Renewable Energy, Sustainability and the Environment ,Graphene ,Thermal decomposition ,Graphene foam ,Energy Engineering and Power Technology ,Substrate (chemistry) ,Nanotechnology ,Capacitance ,law.invention ,Chemical engineering ,law ,Reagent ,Electrode ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry - Abstract
Substrates are normally required in the chemical synthesis of graphene to enhance its formation. However, removing substrates in the post purification stage is difficult, during which harsh reagents are used and the substrates are usually consumed undesirably. In this paper, we report that universal sodium carbonate (Na 2 CO 3 ) particles can effectively promote the construction of well-structured graphene frameworks based on a quick thermal decomposition of fumaric acids. Notably, the Na 2 CO 3 particles are easily separated from graphene through a simple and green method, namely, washing with water at room temperature. Together with the reused characteristic of the recovered Na 2 CO 3 particles, this approach is undoubtedly beneficial to the low-cost and clean synthesis of graphene. Benefiting from the framework structure, the as-synthesized graphene exhibits excellent performance in the supercapacitor. The specific capacitance of the GFs-modified electrode was calculated to be 242 F g −1 at 0.5 A g −1 , which was almost twice that of the RGO-modified electrode (134 F g −1 ). More importantly, the GFs-modified electrode maintained 92.6% retention of its initial specific capacitance (from current density of 0.5 to 16 A g −1 ), which was much higher than that of 2D graphene-modified electrode.
- Published
- 2015
25. Dynamics Investigation of Graphene Frameworks-Supported Pt Nanoparticles as Effective Counter Electrodes for Dye-Sensitized Solar Cells
- Author
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Yanyan Zhu, Suping Jia, Zhijian Wang, Zhenping Zhu, Huijuan Cui, and Jianfeng Zheng
- Subjects
Tafel equation ,Auxiliary electrode ,Materials science ,Graphene ,General Chemical Engineering ,Energy conversion efficiency ,Nanotechnology ,law.invention ,Dielectric spectroscopy ,Dye-sensitized solar cell ,law ,Electrochemistry ,Cyclic voltammetry ,Polarization (electrochemistry) - Abstract
Graphene with a cellular framework structure (GFs) exhibits unique advantages that facilitate quasi-isotropic electron conduction, promote ion diffusion, and induce transport. GFs can act as an ideal support to uniformly disperse platinum (Pt) nanoparticles to better catalyze molecular or ionic reactions, which are intrinsically important for an effective counter electrode (CE) in dye-sensitized solar cells (DSSCs) systems. The power conversion efficiency of optimized DSSCs with GFs CE is 6.15%, which is comparable to that of the conventional Pt CEs (6.71%) and markedly than that of 2D graphene sheets CE (3.60%). More importantly, the GFs-Pt composite CEs could achieve an efficiency of 7.26%. The dynamic discipline behind the improved performance of GFs-based CEs in DSSCs is systematic investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Tafel polarization analysis, revealing that the better diffusion coefficient of the I3− ion and lower charge transfer resistance at CE interface result in the higher efficiency of GFs based solar cells.
- Published
- 2015
26. Ni-incorporated carbon materials derived from humic acid as efficient low-cost electrocatalysts for dye-sensitized solar cells
- Author
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Suping Jia, Ning Li, Shengliang Hu, Huinian Zhang, Caihong Hao, and Yi Di
- Subjects
Materials science ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,Electrocatalyst ,Electrochemistry ,01 natural sciences ,Biomaterials ,chemistry.chemical_compound ,Materials Chemistry ,Humic acid ,Electrical and Electronic Engineering ,Triiodide ,Inert gas ,chemistry.chemical_classification ,Carbonization ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Dye-sensitized solar cell ,chemistry ,Chemical engineering ,0210 nano-technology ,Carbon - Abstract
The scale-up application of dye-sensitized solar cells (DSSCs) will desire the efficient and low-cost electrocatalytic counter electrodes. Carbon materials derived from the natural materials have been extensively used in the new energy fields owing to numerously distinct advantages. In this work, a new-style carbon matrix incorporated with Ni species is manufactured through pyrolyzing the humic acid-Ni complex compounds under an inert atmosphere. Systematic electrochemical measurements reveal that the Ni-incorporated carbon holds an elevated triiodide reducing properties in contrast to the single carbonized humic acid. The improvement of electrocatalytic ability may be ascribed to Ni incorporated in carbon matrix that offer more electroactive sites. As a result, when the prepared Ni-incorporated material serves as electrocatalyst in iodide-mediated DSSC, the corresponding device yields a PCE of 7.01%, which increases by 14% in contrast to the single carbonized humic acid (6.14%) and is close to that (7.1%) of as-reference Pt electrode. This study indicates that the proposed carbonaceous material may be in favour of large-scale production of low cost and high efficiency DSSCs.
- Published
- 2020
27. Self-assembly of three-dimensional CdS nanosphere/graphene networks for efficient photocatalytic hydrogen evolution
- Author
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Junming Zhang, Jiajian Gao, Jiazang Chen, Bin Liu, Hongbin Yang, Cangjie Yang, Zhi Liu, Suping Jia, Jianqiang Luo, Zhijian Wang, and School of Chemical and Biomedical Engineering
- Subjects
Materials science ,Hydrogen ,3D Graphene Network ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Hydrothermal circulation ,Light scattering ,Catalysis ,law.invention ,Crystallinity ,law ,Electrochemistry ,Graphene ,Chemical engineering [Engineering] ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,CdS Nanosphere ,Fuel Technology ,chemistry ,Photocatalysis ,Self-assembly ,0210 nano-technology ,Energy (miscellaneous) - Abstract
In this work, we report the construction of three-dimensional (3D) CdS nanosphere/graphene networks by a one-step hydrothermal self-assembly route. The 3D graphene networks not only enhance the light scattering, thanks to the interconnected 3D architecture, but also improve the crystallinity of deposited CdS nanospheres, and at the same time provide a direct electron pathway to quickly separate the photogenerated electron-hole pairs from CdS, which thus dramatically improve the photocatalytic activity. The optimized 3D CdS nanosphere/graphene networks with 2 wt% of graphene could produce molecular hydrogen at a rate of 2310 µmol gcatalyst−1 h−1 under visible-light illumination (λ > 400 nm). ASTAR (Agency for Sci., Tech. and Research, S’pore) MOE (Min. of Education, S’pore)
- Published
- 2018
28. P–N co-doping induced structural recovery of TiO 2 for overall water splitting under visible light irradiation
- Author
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Haijun Wu, Suping Jia, Peng Zheng, Zhenping Zhu, Jianhui Dong, and Jialin Guo
- Subjects
Materials science ,Absorption spectroscopy ,business.industry ,Mechanical Engineering ,Doping ,Metals and Alloys ,Analytical chemistry ,chemistry.chemical_element ,Nitrogen ,Oxygen ,Semiconductor ,Optics ,chemistry ,Mechanics of Materials ,Materials Chemistry ,Water splitting ,business ,High-resolution transmission electron microscopy ,Visible spectrum - Abstract
Doping nitrogen in TiO2 crystals is a simple and effective approach to extend the absorption spectrum of TiO2 to visible light range, but it leads to a serious decline in charge transfer and total loss of the catalytic ability for overall water splitting. Here, TiO2 was co-doped with phosphorus and nitrogen by high temperature method and found the sample of P–N–TiO2-I could realize overall water splitting under visible light while the samples of P–N–TiO2-II, P–N–TiO2-III and N–TiO2 cannot do it. The structures of the photocatalysts were described by various analytical techniques. Through XRD and HRTEM, lots of long-range defect such as twins and dislocations could be clearly observed for P–N–TiO2-II, P–N–TiO2-III and N–TiO2. But for P–N–TiO2-I, the long-range defect was decreased drastically. We proposed that because of various sizes and bonding modes of N, O, P and Ti, proper mole ratios of P to N replace Ti and O respectively can reduce the long-range defect, as that of P–N–TiO2-I. Furthermore, this co-doping effect results in a significant improvement in the separation of photo-excited electrons and holes and enables the nitrogen-doping TiO2 to catalyze the overall splitting of water into molecular hydrogen and oxygen under visible light irradiation, in the absence of sacrificial agents. These observations might arouse new strategies to mend the hybrid-atom-doping-induced structural damage in semiconductor crystals and to modulate their functional properties.
- Published
- 2014
29. Graphene Frameworks Promoted Electron Transport in Quantum Dot-Sensitized Solar Cells
- Author
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Zhijian Wang, Li Li, Jianfeng Zheng, Huijuan Cui, Zhenping Zhu, Suping Jia, Xin Meng, Yanyan Zhu, Jianhui Dong, Li Zhang, and Jianghong Zhao
- Subjects
Photocurrent ,Materials science ,business.industry ,Graphene ,Electron transport chain ,Dielectric spectroscopy ,law.invention ,Electron transfer ,Quantum dot ,law ,Electrode ,Optoelectronics ,General Materials Science ,business ,Spectroscopy - Abstract
Graphene frameworks (GFs) were incorporated into TiO2 photoanode as electron transport medium to improve the photovoltaic performance of quantum dot-sensitized solar cells (QDSSCs) for their excellent conductivity and isotropic framework structure that could permit rapid charge transport. Intensity modulated photocurrent/photovoltage spectroscopy and electrochemical impedance spectroscopy results show that the electron transport time (τ(d)) of 1.5 wt % GFs/TiO2 electrode is one-fifth of that of the TiO2 electrode, and electron lifetime (τ(n)) and diffusion path length (Ln) are thrice those of the TiO2 electrode. Results also revealed that the GFs/TiO2 electrode has a shorter electron transport time (τ(d)), as well as longer electron lifetime (τ(n)) and diffusion path length (Ln), than conventional 2D graphene sheets/TiO2 electrode, thus indicating that GFs could promote rapid electron transfer in TiO2 photoanodes. Photocurrent-voltage curves demonstrated that when incorporating 1.5 wt % GFs into TiO2 photoanode, a maximum power conversion efficiency of 4.2% for QDSSCs could be achieved. This value was higher than that of TiO2 photoanode and 2D graphene sheets/TiO2 electrode. In addition, the reasons behind the sensitivity of photoelectric conversion efficiency to the graphene concentration in the TiO2 were also systematically investigated. Our results provide a basic understanding of how GFs can efficiently promote electron transport in TiO2-based solar cells.
- Published
- 2014
30. Kinetic reconstruction of TiO2 surfaces as visible-light-active crystalline phases with high photocatalytic performance
- Author
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Baoyue Cao, Suping Jia, Ruipeng Hao, Zhenping Zhu, Jianghong Zhao, and Peng Zheng
- Subjects
Photocurrent ,Anatase ,Materials science ,Renewable Energy, Sustainability and the Environment ,Nanotechnology ,General Chemistry ,Photochemistry ,Nanocrystal ,Rutile ,Phase (matter) ,Photocatalysis ,General Materials Science ,Visible spectrum ,Hydrogen production - Abstract
Modulation of the TiO2 structure to achieve efficient photocatalytic usage of solar light is still a challenging issue. Here we report that simple bombardment of anatase TiO2 nanocrystals by hot molecules can alter its phase transformation kinetics and lead to the reconstruction of the resulting rutile surfaces into a metastable TiO2 crystalline structure. Moreover, the metastable surface crystalline phase is able to harvest visible light up to 480 nm, and exhibits good properties for photocurrent generation. Photocatalysis tests show that upon irradiation by visible light (λ > 420 nm), the surface-reconstructed TiO2 crystals display excellent and stable photocatalytic activity for hydrogen production from aqueous ethanol solution, with a hydrogen production rate of 302 μmol g−1 h−1. This finding might bring a new approach to kinetically tune the structure of TiO2 or other semiconductor crystals in order to modulate their properties.
- Published
- 2014
31. Regorafenib induces NOX5-mediated endoplasmic reticulum stress and potentiates the anti-tumor activity of cisplatin in non-small cell lung cancer cells
- Author
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Hehuan Sui, Sisi Xiao, Suping Jiang, Siyuan Wu, Haizhen Lin, Liyuan Cheng, Lihua Ye, Qi Zhao, Yun Yu, Lu Tao, Feng-Ming Kong, Xiaoying Huang, and Ri Cui
- Subjects
NSCLC ,Regorafenib ,Cisplatin ,Reactive oxygen species ,NOX5 ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Lung cancer is one of the most commonly diagnosed cancers worldwide. Although cisplatin-based chemotherapy regimens serve a pivotal role in non-small cell lung cancer (NSCLC) treatment, drug resistance and serious side effects limited its further clinical application. Regorafenib, a small-molecule multi-kinase inhibitor, was demonstrated to have promising anti-tumor activity in various solid tumors. In the present study, we found that regorafenib markedly enhanced cisplatin-induced cytotoxicity in lung cancer cells by activating reactive oxygen species (ROS)-mediated endoplasmic reticulum stress (ER Stress), c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) signaling pathways. Regorafenib increased ROS generation by promoting NADPH oxidase 5 (NOX5) expression, and knocking down NOX5 attenuated ROS-mediated cytotoxicity of regorafenib in lung cancer cells. Additionally, mice xenograft model validated that synergistic anti-tumor effects of combined treatment with regorafenib and cisplatin. Our results suggested that combination therapy with regorafenib and cisplatin may serve as a potential therapeutic strategy for some NSCLC patients.
- Published
- 2023
- Full Text
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32. Chlorine-Induced In Situ Regulation to Synthesize Graphene Frameworks with Large Specific Area for Excellent Supercapacitor Performance
- Author
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Zhijian Wang, Li Li, Suping Jia, Zhenping Zhu, Jianfeng Zheng, Pengju Yang, Huijuan Cui, Yanyan Zhu, and Xin Meng
- Subjects
Supercapacitor ,Materials science ,Graphene ,Thermal decomposition ,One-Step ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Capacitance ,0104 chemical sciences ,law.invention ,chemistry.chemical_compound ,chemistry ,law ,Specific surface area ,General Materials Science ,0210 nano-technology ,Sodium chloroacetate ,Current density - Abstract
Three-dimensional (3D) graphene frameworks are usually limited by a complicated preparation process and a low specific surface area. This paper presents a facile suitable approach to effectively synthesize 3D graphene frameworks (GFs) with large specific surface area (up to 1018 m(2) g(-1)) through quick thermal decomposition from sodium chloroacetate, which are considerably larger than those of sodium acetate reported in our recent study. The chlorine element in sodium chloroacetate may possess a strong capability to induce in situ activation and regulate graphene formation during pyrolysis in one step. These GFs can be applied as excellent electrode materials for supercapacitors and can achieve an enhanced supercapacitor performance with a specific capacitance of 266 F g(-1) at a current density of 0.5 A g(-1).
- Published
- 2016
33. Development of microplate-based photoelectrochemical DNA biosensor array for high throughput detection of DNA damage
- Author
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Suping Jia, Liang-Hong Guo, and Yang Liu
- Subjects
Photocurrent ,Working electrode ,Materials science ,DNA damage ,Photoelectrochemistry ,Metals and Alloys ,Analytical chemistry ,Substrate (chemistry) ,Gene mutation ,Condensed Matter Physics ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Bipyridine ,chemistry.chemical_compound ,chemistry ,Electrode ,Materials Chemistry ,Electrical and Electronic Engineering ,Instrumentation - Abstract
Many chemicals have been found to induce DNA damages which may lead to gene mutation and tumor generation. In this report, a microplate-based photoelectrochemical DNA sensor array was developed for the rapid and high throughput screening of DNA damaging chemicals. A 96-well plate with built-in electrodes was fabricated on a plastic substrate by the standard electronics industry processes. The working electrode in each well was deposited with SnO2 nanoparticles, and the resulting film was sintered at low temperatures tolerable for the plastic substrate. The film was characterized by scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. On the plates sintered at 150 degrees C, a significant amount of photocurrent was obtained in a Ru(bpy)(3)(2+) (bpy = 2,2'-bipyridine) solution. To construct a DNA sensor, poly-(diallydimethyl ammonium chloride) and double-stranded DNA were sequentially assembled on the SnO2 electrode by electrostatic interaction, and a DNA intercalator, Ru(bpy)(2)(dppz)(2+) (dppz = dipyrido[3,2-a:2',3'-c]phenazine) was used as the photoelectrochemical signal indicator. After the DNA film was exposed to tetrafluoro-1,4-benzoquinone (TFBQ) or TFBQ/H2O2, the photocurrent dropped by 38% and 73% respectively. The photocurrent reduction can be attributed to less binding of Ru(bpy)(2)(dppz)(2+) to the electrode after DNA damage. Photocurrent measurement of the entire 96-well plate was completed within 22 min automatically. (C) 2011 Elsevier B.V. All rights reserved.
- Published
- 2012
34. Photoelectrochemical detection of oxidative DNA damage induced by Fenton reaction with low concentration and DNA-associated [Fe.sup.2+]
- Author
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Suping Jia, Minmin Liang, and Liang-Hong Guo
- Subjects
Metals -- Anodic oxidation ,Metals -- Analysis ,DNA damage -- Research ,Hydrogen peroxide -- Chemical properties ,Hydrogen-ion concentration -- Measurement ,Hydrogen-ion concentration -- Analysis ,Chemicals, plastics and rubber industries - Abstract
The mechanistic aspects of the photoelectrochemical sensor are examined in order to improve the sensitivity of the sensor. The sensor configuration has provided a unique tool for examining the role of DNA-bound [Fe.sup.2+] in Fenton reaction and DNA damage and the results have shown that [Fe.sup.2+] ions associated with DNA has induced DNA damage in the presence of [H.sub.2][O.sub.2].
- Published
- 2008
35. Nitrogen-Doped Hollow Carbon Nanoparticles with Excellent Oxygen Reduction Performances and Their Electrocatalytic Kinetics
- Author
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Zhenping Zhu, Suping Jia, Jianghong Zhao, Guixiang Ma, Zhijian Wang, Chang Song, and Rongrong Jia
- Subjects
Materials science ,Kinetics ,Inorganic chemistry ,chemistry.chemical_element ,Nitrogen ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Cathodic protection ,Catalysis ,General Energy ,chemistry ,Electrode ,Physical and Theoretical Chemistry ,Cyclic voltammetry ,Voltammetry ,Carbon - Abstract
To propel the commercialization of fuel cells, the development of efficient nonprecious metal catalysts, specifically cathodic oxygen reduction catalysts, is turning into reality because the great advancements have been made on nitrogen-doped carbon materials recently. In this study, we demonstrated that nitrogen-doped hollow carbon nanoparticles (N-HCNPs) exhibit excellent electrocatalytic performance for oxygen reduction reaction (ORR) in alkaline fuel cells. Cyclic voltammetry and rotating ring-disk electrode voltammetry showed that the ORR activity of N-HCNPs approaches that of commercial Pt–C catalyst and is much better compared with nitrogen-free counterparts due to the incorporation of nitrogen atoms into graphitic structures. Kinetic studies indicated that the involvement of nitrogen induces a totally different oxygen adsorption mechanism and a four-electron dominated reaction pathway for N-HCNPs in comparison with nitrogen-free HCNPs, very similar to the observations in Pt–C. Moreover, N-HCNPs ex...
- Published
- 2011
36. Rapid assessment of DNA damage induced by polystyrene nanosphere suspension using a photoelectrochemical DNA sensor
- Author
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Xin Du, Suping Jia, Junhui He, Liang-Hong Guo, and Bintian Zhang
- Subjects
Gel electrophoresis ,chemistry.chemical_compound ,chemistry ,DNA damage ,Covalent bond ,Styrene oxide ,Phenazine ,Analytical chemistry ,A-DNA ,General Chemistry ,Photochemistry ,DNA ,Nanomaterials - Abstract
Nanomaterials have been used increasingly in a wide variety of applications, and some of them have shown toxic effects on experimental animals and cells. In this study, a previously established photoelectrochemical DNA sensor was employed to rapidly detect DNA damage induced by polystyrene nanosphere (PSNS) suspensions. In the sensor, a double-stranded DNA film was assembled on a semiconductor electrode, and a DNA intercalator, Ru(bpy)2(dppz)2+ (bpy = 2,2′-bipyridine, dppz = dipyrido[3,2-a:2′,3′-c]phenazine) was used as the photoelectrochemical signal indicator. After the DNA-modified electrode was exposed to 2.0 mg/mL PSNS suspension, photocurrent of DNA-bound Ru(bpy)2(dppz)2+ decreased by about 20%. The decrease is attributed to the chemical damage of DNA and consequently less binding of Ru(bpy)2(dppz)2+ molecules to the electrode. Gel electrophoresis of DNA samples incubated with PSNS suspension confirmed DNA damage after the chemical exposure. However, in both photoelectrochemical and gel electrophoresis experiments, extensively washed PSNS did not induce any DNA damage, and the supernatant of PSNS suspension exhibited comparable DNA damage as the unwashed PSNS suspension. Furthermore, UV-visible absorption spectrum of the supernatant displayed a pattern very similar to that of styrene oxide (SO), a compound which has been shown to induce DNA damage by forming covalent DNA adducts. It is therefore suggested that styrene oxide and other residual chemicals in the PSNS may be responsible for the observed DNA damage. The results highlight the importance of full characterization of nanomaterials before their toxicity study, and demonstrate the utility of photoelectrochemical DNA sensors in the rapid assessment of DNA damage induced by chemicals and nanomaterials.
- Published
- 2011
37. Role of One-Dimensional Ribbonlike Nanostructures in Dye-Sensitized TiO2-Based Solar Cells
- Author
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Jianfeng Zheng, Bo Li, Jianghong Zhao, Zhenping Zhu, Suping Jia, Huanwang Jing, and Jiazang Chen
- Subjects
business.industry ,Energy conversion efficiency ,Electron ,Electrolyte ,Electron transport chain ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Ion ,General Energy ,Semiconductor ,Depletion region ,Electrode ,Optoelectronics ,Physical and Theoretical Chemistry ,business - Abstract
In dye-sensitized solar cells, there is a competition between transport of electrons through the porous semiconductor electrode toward the conducting substrate and back-reaction of electrons to recombination with I-3(-) ions on the semiconductor electrolyte interface, which determines the charge collection efficiency and is strongly influenced by the electronic site distribution in intraband and geometrical structure of the semiconductors. Herein, we systematically analyze the electrochemical parameters of TiO2 nanoribbon- and nanoparticle-based electrodes by electrochemical impedance spectroscopy. The results show that the intrinsic one-dimensional crystalline structure of TiO2 nanoribbons can promote formation of a space charge layer on the surface of the semiconductor, which effectively blocks the recombination of electrons with I-3(-) ions in the semiconductor electrolyte interface, resulting in an increase of electron lifetime and a higher cell voltage. Furthermore, the boundaryless structure of the TiO2 nanoribbons provides efficient channels for electron transport and therefore increases electron diffusion length. The combination of TiO2 nanoparticle-based electrode with TiO2 nanoribbons can significantly improve energy conversion efficiency of similar to 60%. These data provide a basic understanding of the role of TiO2 geometrical structure in solar energy conversion.
- Published
- 2011
38. Detection and mechanistic investigation of halogenated benzoquinone induced DNA damage by photoelectrochemical DNA sensor
- Author
-
Ben-Zhan Zhu, Suping Jia, and Liang-Hong Guo
- Subjects
inorganic chemicals ,Gel electrophoresis ,Halogenation ,Light ,Chemistry ,DNA damage ,Chloranil ,Photoelectrochemistry ,Fluorescence spectrometry ,Electrochemical Techniques ,Hydrogen Peroxide ,Photochemistry ,Photochemical Processes ,Biochemistry ,Benzoquinone ,Analytical Chemistry ,chemistry.chemical_compound ,Benzoquinones ,Humans ,Nucleic Acid Conformation ,A-DNA ,Hydroxyl radical ,DNA ,DNA Damage - Abstract
Halogenated phenols are widely used as biocides and are considered to be possibly carcinogenic to humans. In this report, a previously developed photoelectrochemical DNA sensor was employed to investigate DNA damage induced by tetra-halogenated quinones, the in vivo metabolites of halogenated phenols. The sensor surface was composed of a double-stranded DNA film assembled on a SnO(2) semiconductor electrode. A DNA intercalator, Ru(bpy)(2)(dppz)(2+), was allowed to bind to the DNA film and produce photocurrent upon light irradiation. After the DNA film was exposed to 300 microM tetrafluoro-1,4-benzoquinone (TFBQ), the photocurrent dropped by 20%. In a mixture of 300 microM TFBQ and 2 mM H(2)O(2), the signal dropped by 40%. The signal reduction indicates less binding of Ru(bpy)(2)(dppz)(2+) due to structural damage of ds-DNA in the film. Similar results were obtained with tetra-1,4-chlorobenzoquinone (TCBQ), although the signal was not reduced as much as TFBQ. Fluorescence measurement showed that TFBQ/H(2)O(2) generated more hydroxyl radicals than TCBQ/H(2)O(2). Gel electrophoresis proved that the two benzoquinones produced DNA strand breaks together with H(2)O(2), but not by themselves. Using the photoelectrochemical sensor, it was also found that TCBQ covalently bound with DNA did not produce additional oxidative damage in the presence of H(2)O(2). The combined photoelectrochemistry, gel electrophoresis, and fluorescence data revealed distinctive differences between TFBQ and TCBQ in terms of DNA adduct formation and hydroxyl radical generation.
- Published
- 2010
39. Photoelectrochemical detection of oxidative DNA damage induced by Fenton reaction with low concentration and DNA-associated Fe2+
- Author
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Minmin Liang, Liang-Hong Guo, and Suping Jia
- Subjects
DNA damage ,Photochemistry ,Radical ,Iron ,Inorganic chemistry ,Electrochemistry ,Metal ,chemistry.chemical_compound ,Materials Chemistry ,Animals ,Humans ,A-DNA ,Physical and Theoretical Chemistry ,Hydrogen peroxide ,Quenching (fluorescence) ,DNA ,Hydrogen Peroxide ,Oxidants ,Surfaces, Coatings and Films ,chemistry ,visual_art ,visual_art.visual_art_medium ,Cattle ,Oxidation-Reduction ,DNA Damage - Abstract
The metal ion dependent decomposition of hydrogen peroxide, the so-called Fenton Reaction, yields hydroxyl radicals that can cause oxidative DNA damage both in vitro and in vivo. We have previously reported a photoelectrochemical sensor for the detection of oxidative DNA damage induced by an Fe(2+)-mediated Fenton Reaction, using a DNA intercalator as a photoelectrochemical signal reporter (Liang, M.; Guo, L.-H. Environ. Sci. Technol. 2007, 41, 658). The intercalator binds less to the damaged DNA in the sensor film than the native form, resulting in a reduction in the measured photocurrent. In this report, some mechanistic aspects of the sensor were investigated. It was found that Fe(2+) alone (without the coexistence of H(2)O(2)) suppressed the photocurrent of the intercalator bound to the DNA film in a pH-dependent manner. Similar pH dependence was observed for the zeta potential of the tin oxide nanoparticle colloid used in the preparation of the semiconductor electrode, leading to the hypothesis that the metal ion binds to the surface oxide groups on the electrode and quenches the photoelectrochemical response. At pH 3, the quenching effect was reduced substantially to permit the detection of DNA damage by as low as 10 muM Fe(2+) and 40 microM H(2)O(2), a concentration that is within the physiologically relevant range. It was also found that Fe2+ ions associated with the DNA in the sensor film and participated in the DNA damage reaction, a mechanism that has been implicated in previous studies on metal carcinogenesis.
- Published
- 2008
40. Photoelectrochemical sensor for the rapid detection of in situ DNA damage induced by enzyme-catalyzed fenton reaction
- Author
-
Liang-Hong Guo, Shengchao Zhu, Minmin Liang, and Suping Jia
- Subjects
Photocurrent ,Photoelectrochemical oxidation ,biology ,DNA damage ,Photochemistry ,Iron ,Phenazine ,chemistry.chemical_element ,General Chemistry ,Hydrogen Peroxide ,Oxidants ,Ruthenium ,chemistry.chemical_compound ,Bipyridine ,Glucose Oxidase ,chemistry ,biology.protein ,Environmental Chemistry ,Glucose oxidase ,Oxidation-Reduction ,DNA ,DNA Damage - Abstract
Photoelectrochemical sensors were developed for the rapid detection of oxidative DNA damage induced by Fe2+ and H2O2 generated in situ by the enzyme glucose oxidase. The sensor is a multilayer film prepared on a tin oxide nanoparticle electrode by layer-by-layer self-assembly and is composed of separate layers of a photoelectrochemical indicator, DNA, and glucose oxidase. The enzyme catalyzes the formation of H2O2 in the presence of glucose, which then reacts with Fe2+ and generates hydroxyl radicals by the Fenton reaction. The radicals attack DNA in the sensor film, mimicking metal toxicity pathways in vivo. The DNA damage is detected by monitoring the change of photocurrent of the indicator. In one sensor configuration, a DNA intercalator, Ru(bpy)2(dppz)2+ (bpy = 2,2'-bipyridine, dppz = dipyrido[3,2-a:2',3'-c]phenazine), was employed as the photoelectrochemical indicator. The damaged DNA on the sensor bound less Ru(bpy)2(dppz)2+ than the intact DNA, resulting in a drop in photocurrent. In another configuration, ruthenium tris(bipyridine) was used as the indicator and was immobilized on the electrode underneath the DNA layer. After oxidative damage, the DNA bases became more accessible to photoelectrochemical oxidation than the intact DNA, producing a rise in photocurrent. Both sensors displayed substantial photocurrent change after incubation in Fe2+/glucose in a time-dependent manner. And the detection limit of the first sensor was less than 50 microM. The results were verified independently by fluorescence and gel electrophoresis experiments. When fully integrated with cell-mimicking components, the photoelectrochemical DNA sensor has the potential to become a rapid, high-throughput, and inexpensive screening tool for chemical genotoxicity.
- Published
- 2008
41. Common Program Analysis of Two-Party Security Protocols Using SMV
- Author
-
Suping Jia and Yuqing Zhang
- Subjects
Protocol (science) ,Computation tree logic ,Program analysis ,Computer science ,business.industry ,Information system ,Cryptographic protocol ,Software engineering ,business ,Computer security ,computer.software_genre ,computer - Abstract
A common framework, which can be used to analyze the two-party security protocols, is proposed in this paper. With the common framework, a common program is developed in order that any two-party security protocol can be automatically analyzed through SMV with slight modification of the common program. Finally, we illustrate the feasibility and efficiency of the common program analysis with the SSL 3.0 protocol as a case study.
- Published
- 2006
42. Synthesis and electrocatalytic performance of nitrogen-doped macroporous carbons
- Author
-
Jianhui Dong, Jianghong Zhao, Jian Zhang, Yanyan Zhu, Suping Jia, Zhenping Zhu, Zhijian Wang, Huijuan Cui, Jianfeng Zheng, and Xin Meng
- Subjects
Materials science ,Renewable Energy, Sustainability and the Environment ,Carbonization ,technology, industry, and agriculture ,chemistry.chemical_element ,Nanoparticle ,General Chemistry ,Electrolyte ,Electrochemistry ,Oxygen ,Nitrogen ,Catalysis ,Chemical engineering ,chemistry ,Organic chemistry ,General Materials Science ,Carbon - Abstract
Nitrogen-doped carbons with highly ordered macroporous structures are fabricated via the assembly and carbonization of polymethylmethacrylate (PMMA)–polyacrylonitrile (PAN) core–shell nanoparticles. During the carbonization, PMMA (acting as a template) is completely removed, and the resulting hollow PAN particles are fused to form ordered macroporous structures. Micropores are present on the macropore walls, providing desirable inter-macropore channels. The nitrogen atoms partially remain in the resulting carbon structures and exhibit mainly pyridinic and quaternary configurations under relatively high carbonization temperatures. The careful control of the pre-stabilization and carbonization conditions is crucially important for the formation of the ordered macroporous structures. As a demonstration, the obtained nitrogen-doped macroporous carbons exhibit excellent electrochemical catalytic activities both for the reduction of Sn2− electrolyte ions in QDSSCs and the reduction of oxygen in fuel cells.
- Published
- 2013
43. Nitrogen-doped hollow carbon nanoparticles as efficient counter electrodes in quantum dot sensitized solar cells
- Author
-
Jianhui Dong, Suping Jia, Jiazang Chen, Bo Li, Jianfeng Zheng, Jianghong Zhao, Zhijian Wang, and Zhenping Zhu
- Subjects
Auxiliary electrode ,Materials science ,Inorganic chemistry ,Exchange current density ,General Chemistry ,Electrolyte ,Carbon nanotube ,Dielectric spectroscopy ,law.invention ,Chemical engineering ,Quantum dot ,law ,Electrode ,Materials Chemistry ,Cyclic voltammetry - Abstract
The functions of nitrogen-doped hollow carbon nanoparticles (N-HCNPs) as counter electrodes in quantum dot sensitized solar cells (QDSSCs) have been studied in this paper. Electrochemical impedance spectroscopy (EIS) and Tafel-polarization tests reveal a low charge transfer resistance and a high exchange current density between polysulfide electrolyte and the N-HCNPs electrode. Cyclic voltammetry results indicate that the N-HCNPs electrode shows high electrocatalytic activity and excellent tolerance toward the S 2� /Sn 2� electrolyte. A power conversion efficiency of 2.67% is achieved for the QDSSCs based on N-HCNPs counter electrodes, which is clearly higher than those of the QDSSCs based on HCNPs, carbon nanotubes and Pt counter electrodes. The results reveal that the N-HCNPs electrode is a promising counter electrode candidate for QDSSCs.
- Published
- 2012
44. Co-Therapy of Pegylated G-CSF and Ghrelin for Enhancing Survival After Exposure to Lethal Radiation
- Author
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Juliann G. Kiang, Min Zhai, Bin Lin, Joan T. Smith, Marsha N. Anderson, and Suping Jiang
- Subjects
radiation ,survival ,G-CSF ,ghrelin ,enhancement ,bone marrow ,Therapeutics. Pharmacology ,RM1-950 - Abstract
Exposure to ionizing radiation (radiation injury, RI) in nuclear-related episode is evident to be life-threatening. RI occurs at levels of organs, tissues, cytosols, or nucleus. Their mechanisms are still not fully understood. FDA approves pegylated granulocyte colony-stimulating factor (Neulasta™, Peg-G-CSF) for acute hematopoietic syndrome and has been shown to save lives after lethal RI. We aimed to test whether Ghrelin enhanced Peg-G-CSF’s efficacy to save more lives after lethal RI. B6D2F1/J female mice were used for the study. They received 9.5 Gy (LD50/30 at 0.4 Gy/min) emitted from the 60Co-γ-photon radiation facility. Peg-G-CSF was injected subcutaneously at 1 mg/kg once on days 1, 8, and 15 after irradiation. Ghrelin contains 28 amino acid and is a hunger peptide that has been shown to stimulate food intake, promote intestinal epithelial cell proliferation, elevates immunity, inhibits brain hemorrhage, and increases stress-coping. Ghrelin was injected subcutaneously at 113 μg/kg once on days 1, 2, and 3 after irradiation. Survival, body weight, water consumption, hematology, spleen weight, splenocytes, bone marrow cells, and histology of bone marrow and ileum were performed. We observed that radiation resulted in 30-days survival by 30%. RI decreased their body weights and water consumption volumes. On the 30th day post-RI, platelets and WBCs such as basophils, eosinophils, monocytes, lymphocytes, neutrophils and leukocytes were still significantly decreased in surviving mice. Likewise, their RBC, hemoglobin, hematocrit, and splenocytes remained low; splenomegaly was found in these mice. Bone marrow in surviving RI animals maintained low cellularity with high counts of fat cells and low counts of megakaryocytes. Meanwhile, ileum histology displayed injury. However, mice co-treated with both drugs 24 h after RI resulted in 30-days survival by 45% above the vehicle group. Additionally, the body-weight loss was mitigated, the acute radiation syndrome was reduced. This co-therapy significantly increased neutrophils, eosinophils, leukocytes, and platelets in circulation, inhibited splenomegaly, and increased bone marrow cells. Histopathological analysis showed significant improvement on bone marrow cellularity and ileum morphology. In conclusion, the results provide a proof of concept and suggest that the co-therapy of Peg-G-CSF and Ghrelin is efficacious to ameliorate RI.
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- 2021
- Full Text
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45. Common Program Analysis of Two-Party Security Protocols Using SMV.
- Author
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Heng Tao Shen, Jinbao Li, Minglu Li, Jun Ni, Wei Wang, Yuqing Zhang, and Suping Jia
- Abstract
A common framework, which can be used to analyze the two-party security protocols, is proposed in this paper. With the common framework, a common program is developed in order that any two-party security protocol can be automatically analyzed through SMV with slight modification of the common program. Finally, we illustrate the feasibility and efficiency of the common program analysis with the SSL 3.0 protocol as a case study. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
46. Kinetic reconstruction of TiO2 surfaces as visible-light-active crystalline phases with high photocatalytic performance.
- Author
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Peng Zheng, Ruipeng Hao, Jianghong Zhao, Suping Jia, Baoyue Cao, and Zhenping Zhu
- Abstract
Modulation of the TiO[sub 2] structure to achieve efficient photocatalytic usage of solar light is still a challenging issue. Here we report that simple bombardment of anatase TiO[sub 2] nanocrystals by hot molecules can alter its phase transformation kinetics and lead to the reconstruction of the resulting rutile surfaces into a metastable TiO[sub 2] crystalline structure. Moreover, the metastable surface crystalline phase is able to harvest visible light up to 480 nm, and exhibits good properties for photocurrent generation. Photocatalysis tests show that upon irradiation by visible light (λ > 420 nm), the surface-reconstructed TiO[sub 2] crystals display excellent and stable photocatalytic activity for hydrogen production from aqueous ethanol solution, with a hydrogen production rate of 302 µmol g[sup -1] h[sup -1]. This finding might bring a new approach to kinetically tune the structure of TiO[sub 2] or other semiconductor crystals in order to modulate their properties. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
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47. Detection and mechanistic investigation of halogenated benzoquinone induced DNA damage by photoelectrochemical DNA sensor.
- Author
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Suping Jia, Ben-Zhan Zhu, and Liang-Hong Guo
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- *
DNA damage , *BIOCHEMICAL genetics , *PHOTOELECTROCHEMISTRY , *BENZOQUINONES , *QUINONE - Abstract
Halogenated phenols are widely used as biocides and are considered to be possibly carcinogenic to humans. In this report, a previously developed photoelectrochemical DNA sensor was employed to investigate DNA damage induced by tetra-halogenated quinones, the in vivo metabolites of halogenated phenols. The sensor surface was composed of a double-stranded DNA film assembled on a SnO2 semiconductor electrode. A DNA intercalator, Ru(bpy)2(dppz)2+, was allowed to bind to the DNA film and produce photocurrent upon light irradiation. After the DNA film was exposed to 300 μM tetrafluoro-1,4-benzoquinone (TFBQ), the photocurrent dropped by 20%. In a mixture of 300 μM TFBQ and 2 mM H2O2, the signal dropped by 40%. The signal reduction indicates less binding of Ru(bpy)2(dppz)2+ due to structural damage of ds-DNA in the film. Similar results were obtained with tetra-1,4-chlorobenzoquinone (TCBQ), although the signal was not reduced as much as TFBQ. Fluorescence measurement showed that TFBQ/H2O2 generated more hydroxyl radicals than TCBQ/H2O2. Gel electrophoresis proved that the two benzoquinones produced DNA strand breaks together with H2O2, but not by themselves. Using the photoelectrochemical sensor, it was also found that TCBQ covalently bound with DNA did not produce additional oxidative damage in the presence of H2O2. The combined photoelectrochemistry, gel electrophoresis, and fluorescence data revealed distinctive differences between TFBQ and TCBQ in terms of DNA adduct formation and hydroxyl radical generation. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]
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- 2010
- Full Text
- View/download PDF
48. Photoelectrochemical Sensor for the Rapid Detection of in Situ DNA Damage Induced by Enzyme-Catalyzed Fenton Reaction.
- Author
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Minmin Liang, Suping Jia, Shengchao Zhu, and Liang-Hong Guo
- Subjects
- *
ELECTROCHEMICAL sensors , *DNA damage , *IRON compounds , *ENZYMES , *NANOPARTICLES , *ELECTRODES , *CATALYSIS , *PHOTOELECTROCHEMISTRY , *CHEMICAL detectors - Abstract
Photo electro chemical sensors were developed for the rapid detection of oxidative DNA damage induced by Fe2+ and H2O2 generated in situ by the enzyme glucose oxidase. The sensor is a multilayer film prepared on a tin oxide nanoparticle electrode by layer-by-layer self-assembly and is composed of separate layers of a photoelectrochemical indicator, DNA, and glucose oxidase. The enzyme catalyzes the formation of H2O2 in the presence of glucose, which then reacts with Fe2+ and generates hydroxyl radicals by the Fenton reaction. The radicals attack DNA in the sensor film, mimicking metal toxicity pathways in viva The DNA damage is detected by monitoring the change of photo current of the indicator. In one sensor configuration, a DNA intercalator, Ru(bpy)2(dppz)2+ (bpy = 2,2'- bipyridine, dppz = dipyrido[3,2-a:2',3'-c]phenazine), was employed as the photo electro chemical indicator. The damaged DNA on the sensor bound less Ru(bpy)2(dppz)2+ than the intact DNA, resulting in a drop in photocurrent. In another configuration, ruthenium tris(bipyridine) was used as the indicator and was immobilized on the electrode underneath the DNA layer. After oxidative damage, the DNA bases became more accessible to photo electro chemical oxidation than the intact DNA, producing a rise in photo current Both sensors displayed substantial photo current change after incubation in Fe2+/ glucose in a time-dependent manner. And the detection limit of the first sensor was less than 50μM. The results were verified independently by fluorescence and gel electrophoresis experiments. When fully integrated with cell-mimicking components, the photo electro chemical DNA sensor has the potential to become a rapid, high-throughput, and inexpensive screening tool for chemical genotoxicity. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
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