An improved arc discharge method is developed to fabricate carbon nanotube probe of atomic force microscopy (AFM) here. First, silicon probe and carbon nanotube are manipulated under an optical microscope by two hig...An improved arc discharge method is developed to fabricate carbon nanotube probe of atomic force microscopy (AFM) here. First, silicon probe and carbon nanotube are manipulated under an optical microscope by two high precision microtranslators. When silicon probe and carbon nanotube are very close, several tens voltage is applied between them. And carbon nanotube is divided and attached to the end of silicon probe, which mainly due to the arc welding function. Comparing with the arc discharge method before, the new method here needs no coat silicon probe with metal film in advance, which can greatly reduce the fabrication's difficulty. The fabricated carbon nanotube probe shows good property of higher aspect ratio and can more accurately reflect the true topography of silicon grating than silicon probe. Under the same image drive force, carbon nanotube probe had less indentation depth on soft triblock copolymer sample than silicon probe. This showed that carbon nanotube probe has lower spring constant and less damage to the scan sample than silicon probe.展开更多
Three kinds of titanium surface especially the HA surface are analyzed. Titanium was treated by 3 kinds of methods that were acid & alkali, calcic solution and apathe solution. Samples were observed by optic micros...Three kinds of titanium surface especially the HA surface are analyzed. Titanium was treated by 3 kinds of methods that were acid & alkali, calcic solution and apathe solution. Samples were observed by optic microscope and atomic force microscope ( AFM ) . The typical surface morphology of the acid and alkali group is little holes, and on the two HA surface the tiny protuberances is typical. The surface treated by apatite solution was smoother than the two formers. The rough surface treated with acid and alkali was propitious to Ca^+ , P^- and proteins' adhesion, and the relatively smooth HA surface was of benefit to the cell adhesion.展开更多
The dissipation of energy during the process of contact and separation between a tip and a sample is very important for understanding the phase images in the tapping mode of atomic force microscopes(AFMs). In this s...The dissipation of energy during the process of contact and separation between a tip and a sample is very important for understanding the phase images in the tapping mode of atomic force microscopes(AFMs). In this study, a method is presented to measure the dissipated energy between a tip and a sample. The experimental results are found to be in good agreement with the theoretical model, which indicates that the method is reliable.Also, this study confirms that liquid bridges are mainly produced by extrusion modes in the tapping mode of AFMs.展开更多
Additive manufacturing-also known as 3D printing-has attracted much attention in recent years as a powerful method for the simple and versatile fabrication of complicated three-dimensional structures.However,the curre...Additive manufacturing-also known as 3D printing-has attracted much attention in recent years as a powerful method for the simple and versatile fabrication of complicated three-dimensional structures.However,the current technology still exhibits a limitation in realizing the selective deposition and sorting of various materials contained in the same reservoir,which can contribute significantly to additive printing or manufacturing by enabling simultaneous sorting and deposition of different substances through a single nozzle.Here,we propose a dielectrophoresis(DEP)-based material-selective deposition and sorting technique using a pipette-based quartz tuning fork(QTF)-atomic force microscope(AFM) platform DEPQA and demonstrate multi-material sorting through a single nozzle in ambient conditions.We used Au and silica nanoparticles for sorting and obtained 95% accuracy for spatial separation,which confirmed the surfaceenhanced Raman spectroscopy(SERS).To validate the scheme,we also performed a simulation for the system and found qualitative agreement with the experimental results.The method that combines DEP,pipette-based AFM,and SERS may widely expand the unique capabilities of 3D printing and nano-micro patterning for multi-material patterning,materials sorting,and diverse advanced applications.展开更多
In this paper, three different tips are employed, i.e., the carbon nanotube tip, monocrystalline silicon tip and silicon nitride tip. Resorting to atomic force microscope (AFM), they are used for measuring the surfa...In this paper, three different tips are employed, i.e., the carbon nanotube tip, monocrystalline silicon tip and silicon nitride tip. Resorting to atomic force microscope (AFM), they are used for measuring the surface roughness of indium tin oxide (ITO) film and the immunoglobulin G (IgG) proteins within the scanning area of 10 μm×10 μm and 0.5 μm×0.5 μm, respectively. Subsequently, the scanned surface of the ITO film and IgG proteins are analyzed by using fractal dimension. The results show that the ffactal dimension measured by carbon nanotube tip is biggest with the highest frequency components and the most microscopic information. Therefore, the carbon nanotube tip is the ideal measuring tool for measuring super-smooth surface, which will play a more and more important role in the high-resolution imaging field.展开更多
Ordinary AFM probes' characters prevent the AFM' s application in various scopes. Carbon nanotubes represent ideal AFM probe materials for their higher aspect ratio, larger Young' s modulus, unique chemica...Ordinary AFM probes' characters prevent the AFM' s application in various scopes. Carbon nanotubes represent ideal AFM probe materials for their higher aspect ratio, larger Young' s modulus, unique chemical structure, and well-defined electronic property. Carbon nanotube AFM probes are obtained by using a new method of attaching carbon nanotubes to the end of ordinary AFM probes, and are then used for doing AFM experiments. These experiments indicated that carbon nanotube probes have higher elastic deformation, higher resolution and higher durability. And it was also found that carbon nanotube probes can accurately reflect the morphology of deep narrow gaps, while ordinary probes can not reflect.展开更多
An experimental and statistical study was carried out to explore the effects of mechanical forces on the ends of linear double-stranded DNA (dsDNA) fragments. Mechanical force was applied onto individual DNA molecules...An experimental and statistical study was carried out to explore the effects of mechanical forces on the ends of linear double-stranded DNA (dsDNA) fragments. Mechanical force was applied onto individual DNA molecules during atomic force microscope (AFM)-based picking-up manipulation. By comparing the PCR efficiency of two DNA fragments with primers either at ends or at the inner regions, it was found that the ends of DNA fragments were damaged during picking-up process.展开更多
Clinotyrolite is a mineral discovered by Ma et al. in 1980. It is a hydrous copperarsenate and similar to tyrolite in both composition and structure. Its structureformula is Cu<sub>9</sub>Ca<sub>2<...Clinotyrolite is a mineral discovered by Ma et al. in 1980. It is a hydrous copperarsenate and similar to tyrolite in both composition and structure. Its structureformula is Cu<sub>9</sub>Ca<sub>2</sub>[(As, S)O<sub>4</sub>](OH, O)<sub>10</sub>·10H<sub>2</sub>O. Because of a group of perfect展开更多
We have built an integrated imaging system by combining stimulated emission depletion(STED)microscope and atomic force microscope(AFM).The STED microscope was constructed based on the supercontinuum fiber laser and a ...We have built an integrated imaging system by combining stimulated emission depletion(STED)microscope and atomic force microscope(AFM).The STED microscope was constructed based on the supercontinuum fiber laser and a super lateral resolution of42 nm was achieved.With this integrated imaging system,morphological features,mechanical parameters and fluorescence super resolution imaging were obtained simultaneously for both nanobeads and fixed cell samples.This new integrated imaging system is expected to obtain comprehensive information at the nanoscale for studies in nanobiology and nanomedicine.展开更多
DNA is a kind of promising molecule as nano-lead to build or connect nano-devices due to its stable linear structure and certain conductivity. Many methods have been applied to constructing nano-patterns by using DNA ...DNA is a kind of promising molecule as nano-lead to build or connect nano-devices due to its stable linear structure and certain conductivity. Many methods have been applied to constructing nano-patterns by using DNA molecule. In this report it is presented that l-DNA was aligned on Si substrate by using the free-flowing method and then imaged by an atomic force microscope (AFM). After the second liquid flow, a catenary-like pattern and a crossed network of l-DNA were formed. In addition, the alignedl-DNA was successfully cut off by tips of AFM.展开更多
The structural change of purple membrane during storage has been investigated by means of transmission electron microscope and atomic force microscope. It is found that many liposomes have spontaneously evolved from t...The structural change of purple membrane during storage has been investigated by means of transmission electron microscope and atomic force microscope. It is found that many liposomes have spontaneously evolved from the purple membrane sheets isolated three years ago. The membrane proteins on the liposomes, bacteriorhodopsin, are still presented as trimers in 2-D hexagonal structure, which is the same as that in natural cell membrane. However, the cytoplasmic surface of purple membrane faced outside on the liposomes.展开更多
Atomic force microscopy(AFM)is a widely adopted imaging and surface analysis technique that provides resolutions on the nanometer scale.AFM tip-based nanomachining has recently been adopted for the fabrication of arbi...Atomic force microscopy(AFM)is a widely adopted imaging and surface analysis technique that provides resolutions on the nanometer scale.AFM tip-based nanomachining has recently been adopted for the fabrication of arbitrarily shaped nanoscale structures.A major challenge of using AFM tip-based machining for the sculpting of nanoscale plasmonic structures is the build-up of displaced material along the sides of the channels.Here we apply this nanomechanical machining method to create active plasmonic elements and present the strategy we have been using to avoid the formation of such debris.Furthermore,a number of post-manufacturing treatments that can potentially be used to reduce the amount of debris surrounding the fabricated structures are discussed.展开更多
The atomic force microscope has become an established research tool for imaging microorganisms with unprecedented resolution.However,its use in microbiology has been limited by the difficulty of proper bacterial immob...The atomic force microscope has become an established research tool for imaging microorganisms with unprecedented resolution.However,its use in microbiology has been limited by the difficulty of proper bacterial immobilization.Here,we have developed a microfluidic device that solves the issue of bacterial immobilization for atomic force microscopy under physiological conditions.Our device is able to rapidly immobilize bacteria in well-defined positions and subsequently release the cells for quick sample exchange.The developed device also allows simultaneous fluorescence analysis to assess the bacterial viability during atomic force microscope imaging.We demonstrated the potential of our approach for the immobilization of rod-shaped Escherichia coli and Bacillus subtilis.Using our device,we observed buffer-dependent morphological changes of the bacterial envelope mediated by the antimicrobial peptide CM15.Our approach to bacterial immobilization makes sample preparation much simpler and more reliable,thereby accelerating atomic force microscopy studies at the single-cell level.展开更多
Working with a biased atomic force microscope(AFM)tip in the tapping mode under ambient atmosphere,attoliter(10^(-18) L)water droplet patterns have been generated on a patterned carbonaceous surface.This is essentiall...Working with a biased atomic force microscope(AFM)tip in the tapping mode under ambient atmosphere,attoliter(10^(-18) L)water droplet patterns have been generated on a patterned carbonaceous surface.This is essentially electrocondensation of water leading to charged droplets,as evidenced from electrostatic force microscopy measurements.The droplets are unusual in that they exhibit a highly corrugated surface and evaporate rather slowly,taking several tens of minutes.展开更多
Both atomic force microscope (AFM) and scanning tunneling microscope (STM) are devices for investigating material surfaces down to atomic-scale in real space. But unlike STM, AFM can be used to study not only conducto...Both atomic force microscope (AFM) and scanning tunneling microscope (STM) are devices for investigating material surfaces down to atomic-scale in real space. But unlike STM, AFM can be used to study not only conductors and semiconductors but also insulators. So it has a wider application range than STM. As most minerals are insulators,展开更多
The detailed understanding of various underlying processes at liquid/solid interfaces requires the development of interface-sensitive and high-resolution experimental techniques with atomic precision.In this perspecti...The detailed understanding of various underlying processes at liquid/solid interfaces requires the development of interface-sensitive and high-resolution experimental techniques with atomic precision.In this perspective,we review the recent advances in studying the liquid/solid interfaces at atomic level by electrochemical scanning tunneling microscope(EC-STM),non-contact atomic force microscopy(NC-AFM),and surface-sensitive vibrational spectroscopies.Different from the ultrahigh vacuum and cryogenic experiments,these techniques are all operated in situ under ambient condition,making the measurements close to the native state of the liquid/solid interface.In the end,we present some perspectives on emerging techniques,which can defeat the limitation of existing imaging and spectroscopic methods in the characterization of liquid/solid interfaces.展开更多
基金This project is supported by National Natural Science Foundation of China (No.50205006).
文摘An improved arc discharge method is developed to fabricate carbon nanotube probe of atomic force microscopy (AFM) here. First, silicon probe and carbon nanotube are manipulated under an optical microscope by two high precision microtranslators. When silicon probe and carbon nanotube are very close, several tens voltage is applied between them. And carbon nanotube is divided and attached to the end of silicon probe, which mainly due to the arc welding function. Comparing with the arc discharge method before, the new method here needs no coat silicon probe with metal film in advance, which can greatly reduce the fabrication's difficulty. The fabricated carbon nanotube probe shows good property of higher aspect ratio and can more accurately reflect the true topography of silicon grating than silicon probe. Under the same image drive force, carbon nanotube probe had less indentation depth on soft triblock copolymer sample than silicon probe. This showed that carbon nanotube probe has lower spring constant and less damage to the scan sample than silicon probe.
文摘Three kinds of titanium surface especially the HA surface are analyzed. Titanium was treated by 3 kinds of methods that were acid & alkali, calcic solution and apathe solution. Samples were observed by optic microscope and atomic force microscope ( AFM ) . The typical surface morphology of the acid and alkali group is little holes, and on the two HA surface the tiny protuberances is typical. The surface treated by apatite solution was smoother than the two formers. The rough surface treated with acid and alkali was propitious to Ca^+ , P^- and proteins' adhesion, and the relatively smooth HA surface was of benefit to the cell adhesion.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11572031 and 11642013the Opening Fund of State Key Laboratory of Nonlinear Mechanics
文摘The dissipation of energy during the process of contact and separation between a tip and a sample is very important for understanding the phase images in the tapping mode of atomic force microscopes(AFMs). In this study, a method is presented to measure the dissipated energy between a tip and a sample. The experimental results are found to be in good agreement with the theoretical model, which indicates that the method is reliable.Also, this study confirms that liquid bridges are mainly produced by extrusion modes in the tapping mode of AFMs.
基金Open access funding provided by Shanghai Jiao Tong University。
文摘Additive manufacturing-also known as 3D printing-has attracted much attention in recent years as a powerful method for the simple and versatile fabrication of complicated three-dimensional structures.However,the current technology still exhibits a limitation in realizing the selective deposition and sorting of various materials contained in the same reservoir,which can contribute significantly to additive printing or manufacturing by enabling simultaneous sorting and deposition of different substances through a single nozzle.Here,we propose a dielectrophoresis(DEP)-based material-selective deposition and sorting technique using a pipette-based quartz tuning fork(QTF)-atomic force microscope(AFM) platform DEPQA and demonstrate multi-material sorting through a single nozzle in ambient conditions.We used Au and silica nanoparticles for sorting and obtained 95% accuracy for spatial separation,which confirmed the surfaceenhanced Raman spectroscopy(SERS).To validate the scheme,we also performed a simulation for the system and found qualitative agreement with the experimental results.The method that combines DEP,pipette-based AFM,and SERS may widely expand the unique capabilities of 3D printing and nano-micro patterning for multi-material patterning,materials sorting,and diverse advanced applications.
基金National Natural Science Foundation of China(No.50605012).
文摘In this paper, three different tips are employed, i.e., the carbon nanotube tip, monocrystalline silicon tip and silicon nitride tip. Resorting to atomic force microscope (AFM), they are used for measuring the surface roughness of indium tin oxide (ITO) film and the immunoglobulin G (IgG) proteins within the scanning area of 10 μm×10 μm and 0.5 μm×0.5 μm, respectively. Subsequently, the scanned surface of the ITO film and IgG proteins are analyzed by using fractal dimension. The results show that the ffactal dimension measured by carbon nanotube tip is biggest with the highest frequency components and the most microscopic information. Therefore, the carbon nanotube tip is the ideal measuring tool for measuring super-smooth surface, which will play a more and more important role in the high-resolution imaging field.
基金Sponsored by the National Natural Science Foundation of China (Grant No. 50202006)the Multidisciline Scientific Research Foundation of Harbin Institute of Technology (Grant No. HIT. MD. 2001.04)
文摘Ordinary AFM probes' characters prevent the AFM' s application in various scopes. Carbon nanotubes represent ideal AFM probe materials for their higher aspect ratio, larger Young' s modulus, unique chemical structure, and well-defined electronic property. Carbon nanotube AFM probes are obtained by using a new method of attaching carbon nanotubes to the end of ordinary AFM probes, and are then used for doing AFM experiments. These experiments indicated that carbon nanotube probes have higher elastic deformation, higher resolution and higher durability. And it was also found that carbon nanotube probes can accurately reflect the morphology of deep narrow gaps, while ordinary probes can not reflect.
基金Supported by the Major State Basic Research Development Program in China (No.2007CB936000)Chinese Academy of Sciences (No. KJCX2-EW-N03)National Science Foundation of China (Nos.10975175, 90923002, 21073222 and 10874198)
文摘An experimental and statistical study was carried out to explore the effects of mechanical forces on the ends of linear double-stranded DNA (dsDNA) fragments. Mechanical force was applied onto individual DNA molecules during atomic force microscope (AFM)-based picking-up manipulation. By comparing the PCR efficiency of two DNA fragments with primers either at ends or at the inner regions, it was found that the ends of DNA fragments were damaged during picking-up process.
文摘Clinotyrolite is a mineral discovered by Ma et al. in 1980. It is a hydrous copperarsenate and similar to tyrolite in both composition and structure. Its structureformula is Cu<sub>9</sub>Ca<sub>2</sub>[(As, S)O<sub>4</sub>](OH, O)<sub>10</sub>·10H<sub>2</sub>O. Because of a group of perfect
基金supported by the National Basic Research Program of China(2013CB933701)the National Natural Science Foundation of China(91213305,21127901,21121063)Chinese Academy of Sciences
文摘We have built an integrated imaging system by combining stimulated emission depletion(STED)microscope and atomic force microscope(AFM).The STED microscope was constructed based on the supercontinuum fiber laser and a super lateral resolution of42 nm was achieved.With this integrated imaging system,morphological features,mechanical parameters and fluorescence super resolution imaging were obtained simultaneously for both nanobeads and fixed cell samples.This new integrated imaging system is expected to obtain comprehensive information at the nanoscale for studies in nanobiology and nanomedicine.
基金This work was supported by the State Key Basic Research and Development Project(Grant No.199801012).
文摘DNA is a kind of promising molecule as nano-lead to build or connect nano-devices due to its stable linear structure and certain conductivity. Many methods have been applied to constructing nano-patterns by using DNA molecule. In this report it is presented that l-DNA was aligned on Si substrate by using the free-flowing method and then imaged by an atomic force microscope (AFM). After the second liquid flow, a catenary-like pattern and a crossed network of l-DNA were formed. In addition, the alignedl-DNA was successfully cut off by tips of AFM.
基金This work was supported by the State Key Basic I Research and Development Plan Project (Grant No. 1998010102).
文摘The structural change of purple membrane during storage has been investigated by means of transmission electron microscope and atomic force microscope. It is found that many liposomes have spontaneously evolved from the purple membrane sheets isolated three years ago. The membrane proteins on the liposomes, bacteriorhodopsin, are still presented as trimers in 2-D hexagonal structure, which is the same as that in natural cell membrane. However, the cytoplasmic surface of purple membrane faced outside on the liposomes.
基金Funding was provided by Science Foundation Ireland(Grant No.SFI 18/FIP/3551R).
文摘Atomic force microscopy(AFM)is a widely adopted imaging and surface analysis technique that provides resolutions on the nanometer scale.AFM tip-based nanomachining has recently been adopted for the fabrication of arbitrarily shaped nanoscale structures.A major challenge of using AFM tip-based machining for the sculpting of nanoscale plasmonic structures is the build-up of displaced material along the sides of the channels.Here we apply this nanomechanical machining method to create active plasmonic elements and present the strategy we have been using to avoid the formation of such debris.Furthermore,a number of post-manufacturing treatments that can potentially be used to reduce the amount of debris surrounding the fabricated structures are discussed.
基金This work was funded by the Swiss National Science Foundation (Nos.205321_134786, 205320_152675), and by the European Union FP7/2007-2013/ERC under Grant Agreement No. 307338-NaMic, and Eurostars E!8213.
文摘The atomic force microscope has become an established research tool for imaging microorganisms with unprecedented resolution.However,its use in microbiology has been limited by the difficulty of proper bacterial immobilization.Here,we have developed a microfluidic device that solves the issue of bacterial immobilization for atomic force microscopy under physiological conditions.Our device is able to rapidly immobilize bacteria in well-defined positions and subsequently release the cells for quick sample exchange.The developed device also allows simultaneous fluorescence analysis to assess the bacterial viability during atomic force microscope imaging.We demonstrated the potential of our approach for the immobilization of rod-shaped Escherichia coli and Bacillus subtilis.Using our device,we observed buffer-dependent morphological changes of the bacterial envelope mediated by the antimicrobial peptide CM15.Our approach to bacterial immobilization makes sample preparation much simpler and more reliable,thereby accelerating atomic force microscopy studies at the single-cell level.
基金The authors thank Professor C.N.R.Rao,Fellow of Royal Society(FRS)for his encouragement.Support from the Department of Science and Technology,Government of India is gratefully acknowledged.N.K.acknowledges Council of Scientific and Industrial Research(CSIR)for funding.N.K.acknowledges Ritu for reading the manuscript.The authors thank Veeco India Nano-technology Laboratory at Jawaharlal Nehru Centre for Advanced Scientific Research(JNCASR)for the AFM facility.A.S.acknowledges INDO-US Science&Technology Forum(IUSSTF)for funding.
文摘Working with a biased atomic force microscope(AFM)tip in the tapping mode under ambient atmosphere,attoliter(10^(-18) L)water droplet patterns have been generated on a patterned carbonaceous surface.This is essentially electrocondensation of water leading to charged droplets,as evidenced from electrostatic force microscopy measurements.The droplets are unusual in that they exhibit a highly corrugated surface and evaporate rather slowly,taking several tens of minutes.
基金Project supported by the National Natural Science Foundation of China.
文摘Both atomic force microscope (AFM) and scanning tunneling microscope (STM) are devices for investigating material surfaces down to atomic-scale in real space. But unlike STM, AFM can be used to study not only conductors and semiconductors but also insulators. So it has a wider application range than STM. As most minerals are insulators,
文摘The detailed understanding of various underlying processes at liquid/solid interfaces requires the development of interface-sensitive and high-resolution experimental techniques with atomic precision.In this perspective,we review the recent advances in studying the liquid/solid interfaces at atomic level by electrochemical scanning tunneling microscope(EC-STM),non-contact atomic force microscopy(NC-AFM),and surface-sensitive vibrational spectroscopies.Different from the ultrahigh vacuum and cryogenic experiments,these techniques are all operated in situ under ambient condition,making the measurements close to the native state of the liquid/solid interface.In the end,we present some perspectives on emerging techniques,which can defeat the limitation of existing imaging and spectroscopic methods in the characterization of liquid/solid interfaces.