Microelectrode arrays(MEAs)have enabled investigation of cellular networks at sub-millisecond temporal resolution.However,current MEAs are limited by the large electrode footprint since reducing the electrode’s geome...Microelectrode arrays(MEAs)have enabled investigation of cellular networks at sub-millisecond temporal resolution.However,current MEAs are limited by the large electrode footprint since reducing the electrode’s geometric area to sub-cellular dimensions leads to a significant increase in impedance thus affecting its recording capabilities.We report a breakthrough ultra-microelectrodes platform by leveraging the outstanding surface-to-volume ratio of nanowire-templated out-of-plane synthesized three-dimensional fuzzy graphene(NT-3DFG).The enormous surface area of NT-3DFG leads to 140-fold reduction in electrode impedance compared to bare Au microelectrodes,thus enabling scaling down the geometric size by 625-fold to ca.2µm×2µm.The out-of-plane morphology of NT-3DFG leads to a tight seal with the cell membrane thus enabling recording of electrical signals with high signal-to-noise ratio(SNR)of>6.This work highlights the possibility to push the limits of the conventional MEA technology to enable electrophysiological investigation at sub-cellular level without the need of any surface coatings.This presented approach would greatly impact our basic understanding of signal transduction within a single cell as well as complex cellular assemblies.展开更多
Lithium-sulfur battery has become one of the most promising candidates for next generation batteries, and it is still restricted due to the low sulfur conductivity, large volume expansion and severe polysulfide shuttl...Lithium-sulfur battery has become one of the most promising candidates for next generation batteries, and it is still restricted due to the low sulfur conductivity, large volume expansion and severe polysulfide shuttling. Herein, we present a novel hybrid electrode with a ternary nanomaterial based on sulfur-impregnated multiwalled carbon nanotubes filled with ordered tin-monoxide nanoparticles （MWCNT-SnO/S）. Using a dry plasma reduction method, a mechanically robust material is prepared as a cathode host material for lithium-sulfur batteries. The MWCNT-SnO/S electrode exhibits high conductivity, good ability to capture polysulfides, and small volume change during a repeated charge-discharge process. In situ transmission electron microscopy and ultraviolet-visible absorption results indicate that the MWCNT-SnO host efficiently suppresses volume expansion during lithiation and reduces polysulfide dissolution into the electrolyte. Furthermore, the ordered SnO nanoparticles in the MWCNTs facilitate fast ion/electron transfer during the redox reactions by acting as connective links between the walls of the MWCNTs. The MWCNT-SnO/S cathode with a high sulfur content of 70 wt.% exhibits an initial discharge capacity of 1,682.4 mAh·g^-1 at 167.5 m·g^-1 （0.1 C rate） and retains a capacity of 530.1 mAh·g^-1 at 0.5 C after 1,000 cycles with nearly 100% Coulombic efficiency. Furthermore, the electrode exhibits the high capacity even at a high current rate of 20 C.展开更多
W-doped TiO2 supported by hybrid carbon nanomaterials of multi-walled carbon nanotubes and C60 fullerene was synthesized by a simple hydrothermal method. The material displayed high visible light photocatalytic activi...W-doped TiO2 supported by hybrid carbon nanomaterials of multi-walled carbon nanotubes and C60 fullerene was synthesized by a simple hydrothermal method. The material displayed high visible light photocatalytic activity. X-ray diffraction, field emission transmission electron microscopy, ultra violet/visible light absorption and photoluminescence spectroscopy were used to characterize the material as photoeatalyst. Photocatalytic activity on the degradation of Rhodamine B dye in an aqueous solution under ultraviolet light and visible light irradiation was also studied. The experimental results indicated that the photocatalytic activity of the material was much higher than that of pure TiO2 or Degussa P25 TiO2.展开更多
Fibers are low-cost substrates that are abundantly used in our daily lives. This review highlights recent advances in the fabrication and application of multifunctional fibers to achieve fibers with unique functions f...Fibers are low-cost substrates that are abundantly used in our daily lives. This review highlights recent advances in the fabrication and application of multifunctional fibers to achieve fibers with unique functions for specific applications ranging from textile electronics to biomedical applications. By incorporating various nanomaterials such as carbon nanomaterials, metallic nanomaterials, and hydrogel-based biomaterials, the functions of fibers can be precisely engineered. This review also highlights the performance of the functional fibers and electronic materials incorporated with textiles and demonstrates their practical application in pressure/tensile sensors,chemical/biosensors, and drug delivery. Textile technologies in which fibers containing biological factors and cells are formed and assembled into constructions with biomimetic properties have attracted substantial attention in the field of tissue engineering. We also discuss the current limitations of functional textile-based devices and their prospects for use in various future applications.展开更多
A core-shell hybrid nanostructure,a hard core of single-crystalline lanthanum hydroxide nanowires and a soft shell of brushes of poly (ε-caprolactone) (PCL), has been successfully prepared by ring-opening polymerizat...A core-shell hybrid nanostructure,a hard core of single-crystalline lanthanum hydroxide nanowires and a soft shell of brushes of poly (ε-caprolactone) (PCL), has been successfully prepared by ring-opening polymerization (ROP) on the surface of nanowires. Such special structures were proved by TEM images. Meanwhile, the thickness of polymer layers was measured. The chemical component and the grafted PCL quantity of the sample were characterized by FTIR and TGA, which provides a simple and universal method to functionalize non-carbon nanowires. The modified lanthanum hydroxide nanowires can be well-dispersed in good solvents for PCL.展开更多
以碳纳米管(CNTs)、高锰酸钾、醋酸锰、聚乙烯吡咯烷酮为原料,通过一步溶液法辅以热处理,制备出以CNTs为核,以碳包覆氧化锰(Mn Ox@C)为壳的一维壳核结构CNTs/Mn Ox@C纳米复合材料,并对该纳米复合材料的结构、形貌及锂电性能进行分析。...以碳纳米管(CNTs)、高锰酸钾、醋酸锰、聚乙烯吡咯烷酮为原料,通过一步溶液法辅以热处理,制备出以CNTs为核,以碳包覆氧化锰(Mn Ox@C)为壳的一维壳核结构CNTs/Mn Ox@C纳米复合材料,并对该纳米复合材料的结构、形貌及锂电性能进行分析。研究结果表明,通过一步溶液法制备的CNTs/Mn Ox@C纳米复合材料表面Mn Ox@C包覆均匀,氧化锰质量分数高达50%。该材料作为锂电负极材料在100 m A/g的恒流充放电下循环100次后放电比容量达到483.5 m Ah/g;在1000m A/g的大电流充放电循环中放电比容量达到368.6 m Ah/g。展开更多
基金T.C.-K.acknowledges funding support from the National Science Foundation under Award No.CBET1552833 and the Office of Naval Research under Award No.N000141712368.J.B.and A.W F.acknowledge financial support from the Dowd Fellowship from the College of Engineering at Carnegie Mellon University.L.M.and F.S.acknowledge Valentina Mollo for ssthe preparation of SEM/FIB samples.We also acknowledge support from the Department of Materials Science and Engineering Materials Characterization Facility(MCF-677785).
文摘Microelectrode arrays(MEAs)have enabled investigation of cellular networks at sub-millisecond temporal resolution.However,current MEAs are limited by the large electrode footprint since reducing the electrode’s geometric area to sub-cellular dimensions leads to a significant increase in impedance thus affecting its recording capabilities.We report a breakthrough ultra-microelectrodes platform by leveraging the outstanding surface-to-volume ratio of nanowire-templated out-of-plane synthesized three-dimensional fuzzy graphene(NT-3DFG).The enormous surface area of NT-3DFG leads to 140-fold reduction in electrode impedance compared to bare Au microelectrodes,thus enabling scaling down the geometric size by 625-fold to ca.2µm×2µm.The out-of-plane morphology of NT-3DFG leads to a tight seal with the cell membrane thus enabling recording of electrical signals with high signal-to-noise ratio(SNR)of>6.This work highlights the possibility to push the limits of the conventional MEA technology to enable electrophysiological investigation at sub-cellular level without the need of any surface coatings.This presented approach would greatly impact our basic understanding of signal transduction within a single cell as well as complex cellular assemblies.
文摘Lithium-sulfur battery has become one of the most promising candidates for next generation batteries, and it is still restricted due to the low sulfur conductivity, large volume expansion and severe polysulfide shuttling. Herein, we present a novel hybrid electrode with a ternary nanomaterial based on sulfur-impregnated multiwalled carbon nanotubes filled with ordered tin-monoxide nanoparticles （MWCNT-SnO/S）. Using a dry plasma reduction method, a mechanically robust material is prepared as a cathode host material for lithium-sulfur batteries. The MWCNT-SnO/S electrode exhibits high conductivity, good ability to capture polysulfides, and small volume change during a repeated charge-discharge process. In situ transmission electron microscopy and ultraviolet-visible absorption results indicate that the MWCNT-SnO host efficiently suppresses volume expansion during lithiation and reduces polysulfide dissolution into the electrolyte. Furthermore, the ordered SnO nanoparticles in the MWCNTs facilitate fast ion/electron transfer during the redox reactions by acting as connective links between the walls of the MWCNTs. The MWCNT-SnO/S cathode with a high sulfur content of 70 wt.% exhibits an initial discharge capacity of 1,682.4 mAh·g^-1 at 167.5 m·g^-1 （0.1 C rate） and retains a capacity of 530.1 mAh·g^-1 at 0.5 C after 1,000 cycles with nearly 100% Coulombic efficiency. Furthermore, the electrode exhibits the high capacity even at a high current rate of 20 C.
基金Funded by the Project for the Academic Leader Program of Wuhan City(No.201150530146)the Natural Science Foundation of Hubei Province(No.20101j0018)
文摘W-doped TiO2 supported by hybrid carbon nanomaterials of multi-walled carbon nanotubes and C60 fullerene was synthesized by a simple hydrothermal method. The material displayed high visible light photocatalytic activity. X-ray diffraction, field emission transmission electron microscopy, ultra violet/visible light absorption and photoluminescence spectroscopy were used to characterize the material as photoeatalyst. Photocatalytic activity on the degradation of Rhodamine B dye in an aqueous solution under ultraviolet light and visible light irradiation was also studied. The experimental results indicated that the photocatalytic activity of the material was much higher than that of pure TiO2 or Degussa P25 TiO2.
基金supported by the Priority Research Centers Program(No.2012-0006689)through the National Research Foundation(NRF)of Korea funded by the Ministry of Education,Science and Technology(MEST)the R&D program of MOTIE/KEIT[10064081,Devclopment of fiber-based flexible multimodal pressure sensor and algorithm for gesture/posture-recognizable wearable devices]+3 种基金partial support from the National Research Foundation of Korea(No.NRF-2017K2A9A2A06013377,NRF-2017M3A7B4049466)the Yonsei University Future-leading Research Initiative and Implantable artificial electronic skin for an ubiquitous healthcare system of 2016-12-0050supported by KIST Project(Nos.2E26900,2E27630)supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(No.2016R1A6A3A03006491)
文摘Fibers are low-cost substrates that are abundantly used in our daily lives. This review highlights recent advances in the fabrication and application of multifunctional fibers to achieve fibers with unique functions for specific applications ranging from textile electronics to biomedical applications. By incorporating various nanomaterials such as carbon nanomaterials, metallic nanomaterials, and hydrogel-based biomaterials, the functions of fibers can be precisely engineered. This review also highlights the performance of the functional fibers and electronic materials incorporated with textiles and demonstrates their practical application in pressure/tensile sensors,chemical/biosensors, and drug delivery. Textile technologies in which fibers containing biological factors and cells are formed and assembled into constructions with biomimetic properties have attracted substantial attention in the field of tissue engineering. We also discuss the current limitations of functional textile-based devices and their prospects for use in various future applications.
基金supported by the National Natural Science Foundation of China (Grant Nos.50373020 and 20836004)National Basic Research Program of China (Grant No.2009CB930602)
文摘A core-shell hybrid nanostructure,a hard core of single-crystalline lanthanum hydroxide nanowires and a soft shell of brushes of poly (ε-caprolactone) (PCL), has been successfully prepared by ring-opening polymerization (ROP) on the surface of nanowires. Such special structures were proved by TEM images. Meanwhile, the thickness of polymer layers was measured. The chemical component and the grafted PCL quantity of the sample were characterized by FTIR and TGA, which provides a simple and universal method to functionalize non-carbon nanowires. The modified lanthanum hydroxide nanowires can be well-dispersed in good solvents for PCL.
文摘以碳纳米管(CNTs)、高锰酸钾、醋酸锰、聚乙烯吡咯烷酮为原料,通过一步溶液法辅以热处理,制备出以CNTs为核,以碳包覆氧化锰(Mn Ox@C)为壳的一维壳核结构CNTs/Mn Ox@C纳米复合材料,并对该纳米复合材料的结构、形貌及锂电性能进行分析。研究结果表明,通过一步溶液法制备的CNTs/Mn Ox@C纳米复合材料表面Mn Ox@C包覆均匀,氧化锰质量分数高达50%。该材料作为锂电负极材料在100 m A/g的恒流充放电下循环100次后放电比容量达到483.5 m Ah/g;在1000m A/g的大电流充放电循环中放电比容量达到368.6 m Ah/g。
