The rabies virus is a neurotropic virus that causes fatal diseases in humans and animals.Although studying the interactions between a single rabies virus and the cell membrane is necessary for understanding the pathog...The rabies virus is a neurotropic virus that causes fatal diseases in humans and animals.Although studying the interactions between a single rabies virus and the cell membrane is necessary for understanding the pathogenesis,the internalization dynamic mechanism of single rabies virus in living cells remains largely elusive.Here,we utilized a novel force tracing technique based on atomic force microscopy(AFM)to record the process of single viral entry into host cell.We revealed that the force of the rabies virus internalization distributed at(65±25)pN,and the time was identified by two peaks with spacings of(237.2±59.1)and(790.3±134.4)ms with the corresponding speed of 0.12 and 0.04µm/s,respectively.Our results provide insight into the effects of viral shape during the endocytosis process.This report will be meaningful for understanding the dynamic mechanism of rabies virus early infection.展开更多
原子力显微镜(Atomic Force Microscopy,AFM)成像常用于研究多糖分子结构,然而针对阴离子多糖,现有的制样方法较难在小范围观察区获得其清晰的单分子束结构图片。因此,本文以黄原胶为阴离子多糖代表,从不改变多糖本身结构、提升成像质...原子力显微镜(Atomic Force Microscopy,AFM)成像常用于研究多糖分子结构,然而针对阴离子多糖,现有的制样方法较难在小范围观察区获得其清晰的单分子束结构图片。因此,本文以黄原胶为阴离子多糖代表,从不改变多糖本身结构、提升成像质量角度出发,对多糖样品浓度,云母片不同金属离子盐种类、浓度和处理时间等AFM制样方法进行了优化。结果表明,在空白云母片上,黄原胶浓度1~5μg/mL时可观测到多糖单分子束结构,但在15μm×15μm扫描范围内可观测的分子束较少。通过对云母片进行处理优化,最佳处理条件选定在0.5 mmol/L的CaCl_(2)溶液处理2 min或2 mmol/L CaCl_(2)溶液处理0.5 min。在此条件下,当黄原胶浓度为5μg/mL时,在3μm×3μm观测范围内,处理后云母片上的黄原胶分子束数量及成像质量相比空白云母片显著提升,且其单分子束高度与分子结构并未发生改变。此外,通过提高云母片干燥温度可以获取更均匀的黄原胶分子结构图片。本研究可为其他阴离子多糖AFM成像的样品制备提供可借鉴的方法参考。展开更多
原子力显微镜(Atomic force microscopy,AFM)由于自身的优势,在生物领域内应用越来越广泛。同时,DNA分子由于其稳定的物理化学性质而成为纳米领域的重要实验材料,近阶段把它作为模板应用在构建纳米线等方面的研究越来越多,而怎样建立有...原子力显微镜(Atomic force microscopy,AFM)由于自身的优势,在生物领域内应用越来越广泛。同时,DNA分子由于其稳定的物理化学性质而成为纳米领域的重要实验材料,近阶段把它作为模板应用在构建纳米线等方面的研究越来越多,而怎样建立有规则图样的DNA模板就成为一个关键问题。本文介绍用原子力显微镜观察液流操纵后的DNA规则图案。展开更多
Nano-manipulation of single atoms and molecules is a critical technique in nanoscience and nanotech- nology. This review paper will focus on the recent development of the manipulation of single DNA molecules based on ...Nano-manipulation of single atoms and molecules is a critical technique in nanoscience and nanotech- nology. This review paper will focus on the recent development of the manipulation of single DNA molecules based on atomic force microscopy (AFM). Precise manipulation has been realized including varied manipulating modes such as “cutting”, “pushing”, “folding”, “kneading”, “picking up”, “dipping”, etc. The cutting accuracy is dominated by the size of the AFM tip, which is usually 10nm or less. Single DNA fragments can be cut and picked up and then amplified by single molecule PCR. Thus positioning isolation and sequencing can be performed.展开更多
Hydrophilic polymer coatings on artificial implants generate excellent tribological properties.The friction properties of polymer coatings are affected by salt ion factors.Herein,the atomic force microscopy(AFM)was us...Hydrophilic polymer coatings on artificial implants generate excellent tribological properties.The friction properties of polymer coatings are affected by salt ion factors.Herein,the atomic force microscopy(AFM)was used to show that the superlubricity was achieved between poly(vinylphosphonic acid)(PVPA)-modified Ti6Al4V and polystyrene(PS)microsphere probe lubricated with monovalent salt solutions(LiCl,NaCl,KCl,and CsCl).Considering that adhesion is an important cause of friction changes,the AFM was further utilized to obtain adhesion between friction pairs in different salt solutions.The results indicated that the larger the cation radius in the lubricant,the smaller the adhesion,and the lower the friction coefficient of the PVPA coating.The electrostatic interaction between the PVPA and one-valence cations in lubricants was analyzed by the molecular dynamics(MD)simulation as it was found to be the main influencing factor of the adhesion.Combined analysis results of friction and adhesion indicated that by adjusting the size of cation radius in lubricant,the adhesion between the tribo-pairs can be changed,and eventually the magnitude of friction can be affected.This study opens up a new avenue for analyzing the friction characteristics of hydrophilic polymer coatings from the perspective of intermolecular forces.展开更多
DNA molecules were stretched on silanized mica surface with the molecular combing technique, and detected with fluorescence microscopy and atomic force microscopy. Meantime, DNA molecules were stretched with a modifie...DNA molecules were stretched on silanized mica surface with the molecular combing technique, and detected with fluorescence microscopy and atomic force microscopy. Meantime, DNA molecules were stretched with a modified dynamic molecular combing technique and studied with atomic force microscopy. The results indicate that, compared with the dynamic molecular combing technique, the modified dynamic molecular combing technique has advantages of less-sample demand and less contamination to sample; as compared with the molecular combing technique, it has better aligning effect and reproducibility. Combination of this kind of DNA molecular manipulating technique with the single DNA molecule detecting technique by atomic force microscopy and fluorescence microscopy will play an important role in the basic research of molecular dynamics and the application of gene research.展开更多
Properties of organelles and intracellular structures play important roles in regulating cellular functions,such as gene expression,cell motility and metabolism.The ability to directly interrogate intracellular struct...Properties of organelles and intracellular structures play important roles in regulating cellular functions,such as gene expression,cell motility and metabolism.The ability to directly interrogate intracellular structures inside a single cell for measurement and manipulation has significant implications in the understanding of subcellular and suborganelle activities,diagnosing diseases,and potentially developing new therapeutic approaches.In the past few decades,a number of technologies have been developed to study single-cell properties.However,methods of measuring intracellular properties and manipulating subcellular structures have been largely underexplored.Due to the even smaller size of intracellular targets and lower signal-to-noise ratio than that in wholecell studies,the development of tools for intracellular measurement and manipulation is challenging.This paper reviews emerging microsystems and nanoengineered technologies for sensing and quantitative measurement of intracellular properties and for manipulating structures inside a single cell.Recent progress and limitations of these new technologies as well as new discoveries and prospects are discussed.展开更多
基金This work was supported by the Project of the Education Department of Jilin Province,China(No.JJKH20220666KJ)the Talent of Jilin Province Development Fund Project,China(No.2021Y004)National Natural Science Foundation of China(No.21773017).
文摘The rabies virus is a neurotropic virus that causes fatal diseases in humans and animals.Although studying the interactions between a single rabies virus and the cell membrane is necessary for understanding the pathogenesis,the internalization dynamic mechanism of single rabies virus in living cells remains largely elusive.Here,we utilized a novel force tracing technique based on atomic force microscopy(AFM)to record the process of single viral entry into host cell.We revealed that the force of the rabies virus internalization distributed at(65±25)pN,and the time was identified by two peaks with spacings of(237.2±59.1)and(790.3±134.4)ms with the corresponding speed of 0.12 and 0.04µm/s,respectively.Our results provide insight into the effects of viral shape during the endocytosis process.This report will be meaningful for understanding the dynamic mechanism of rabies virus early infection.
文摘原子力显微镜(Atomic force microscopy,AFM)由于自身的优势,在生物领域内应用越来越广泛。同时,DNA分子由于其稳定的物理化学性质而成为纳米领域的重要实验材料,近阶段把它作为模板应用在构建纳米线等方面的研究越来越多,而怎样建立有规则图样的DNA模板就成为一个关键问题。本文介绍用原子力显微镜观察液流操纵后的DNA规则图案。
文摘Nano-manipulation of single atoms and molecules is a critical technique in nanoscience and nanotech- nology. This review paper will focus on the recent development of the manipulation of single DNA molecules based on atomic force microscopy (AFM). Precise manipulation has been realized including varied manipulating modes such as “cutting”, “pushing”, “folding”, “kneading”, “picking up”, “dipping”, etc. The cutting accuracy is dominated by the size of the AFM tip, which is usually 10nm or less. Single DNA fragments can be cut and picked up and then amplified by single molecule PCR. Thus positioning isolation and sequencing can be performed.
基金supported by the National Natural Science Foundation of China(51705010)the Beijing Natural Science Foundation(3192003)+2 种基金the General Project of Science and Technology Plan from Beijing Educational Committee(KM201810005013)the Tribology Science Fund of State Key Laboratory of Tribology(STLEKF16A02 and SKLTKF19B08)the training program of Rixin talent and outstanding talent from Beijing University of Technology.
文摘Hydrophilic polymer coatings on artificial implants generate excellent tribological properties.The friction properties of polymer coatings are affected by salt ion factors.Herein,the atomic force microscopy(AFM)was used to show that the superlubricity was achieved between poly(vinylphosphonic acid)(PVPA)-modified Ti6Al4V and polystyrene(PS)microsphere probe lubricated with monovalent salt solutions(LiCl,NaCl,KCl,and CsCl).Considering that adhesion is an important cause of friction changes,the AFM was further utilized to obtain adhesion between friction pairs in different salt solutions.The results indicated that the larger the cation radius in the lubricant,the smaller the adhesion,and the lower the friction coefficient of the PVPA coating.The electrostatic interaction between the PVPA and one-valence cations in lubricants was analyzed by the molecular dynamics(MD)simulation as it was found to be the main influencing factor of the adhesion.Combined analysis results of friction and adhesion indicated that by adjusting the size of cation radius in lubricant,the adhesion between the tribo-pairs can be changed,and eventually the magnitude of friction can be affected.This study opens up a new avenue for analyzing the friction characteristics of hydrophilic polymer coatings from the perspective of intermolecular forces.
文摘DNA molecules were stretched on silanized mica surface with the molecular combing technique, and detected with fluorescence microscopy and atomic force microscopy. Meantime, DNA molecules were stretched with a modified dynamic molecular combing technique and studied with atomic force microscopy. The results indicate that, compared with the dynamic molecular combing technique, the modified dynamic molecular combing technique has advantages of less-sample demand and less contamination to sample; as compared with the molecular combing technique, it has better aligning effect and reproducibility. Combination of this kind of DNA molecular manipulating technique with the single DNA molecule detecting technique by atomic force microscopy and fluorescence microscopy will play an important role in the basic research of molecular dynamics and the application of gene research.
文摘Properties of organelles and intracellular structures play important roles in regulating cellular functions,such as gene expression,cell motility and metabolism.The ability to directly interrogate intracellular structures inside a single cell for measurement and manipulation has significant implications in the understanding of subcellular and suborganelle activities,diagnosing diseases,and potentially developing new therapeutic approaches.In the past few decades,a number of technologies have been developed to study single-cell properties.However,methods of measuring intracellular properties and manipulating subcellular structures have been largely underexplored.Due to the even smaller size of intracellular targets and lower signal-to-noise ratio than that in wholecell studies,the development of tools for intracellular measurement and manipulation is challenging.This paper reviews emerging microsystems and nanoengineered technologies for sensing and quantitative measurement of intracellular properties and for manipulating structures inside a single cell.Recent progress and limitations of these new technologies as well as new discoveries and prospects are discussed.
