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Journal ArticleDOI

High‐resolution imaging and nano‐manipulation of biological structures on surface

01 Jul 2011-Microscopy Research and Technique (John Wiley & Sons, Ltd)-Vol. 74, Iss: 7, pp 614-626
TL;DR: The results demonstrate that not only the high resolution capacity of the AFM is suited to resolve certain biological questions, but can also be applied to single molecule isolation and biomechanical analysis with its unique advantages.
Abstract: In this mini-review we discuss our recent findings on imaging and manipulation of biological macromolecular structures by atomic force microscopy (AFM). In the first part of this review, we focus on high-resolution imaging of selected biological samples. AFM images of membrane proteins have revealed detailed conformational features related to identifiable biological functions. Different self-assembling behaviors of short peptides into supramolecular structures on various substrates under controlled environmental conditions have been systematically studied with AFM imaging. In the second part, we present a novel nano-manipulation technique for manipulating, isolating, amplifying, and sequencing of individual DNA molecules, which may find unique applications in the analysis of difficult sequence structures. Finally, we discuss how to characterize the elasticity of individual biomolecules and live cells. These results demonstrate that not only the high resolution capacity of the AFM is suited to resolve certain biological questions, but can also be applied to single molecule isolation and biomechanical analysis with its unique advantages. Microsc. Res. Tech. 74: 614-626, 2011. (C) 2010 Wiley-Liss, Inc.
Citations
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Journal ArticleDOI
01 Dec 2012-Micron
TL;DR: It is demonstrated that SICM imaging, especially using an ARS/hopping mode, is a useful technique with unique capabilities for imaging the three-dimensional topography of a range of biological samples under physiologically relevant aqueous conditions.

75 citations


Cites background from "High‐resolution imaging and nano‐ma..."

  • ...Micron (2012), doi:10.1016/j.micron.2012.01.012 factors such as tip geometry and lateral forces (Zhang et al., 2011; Braet et al., 2001)....

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Journal ArticleDOI
TL;DR: To investigate the potential of DNA-wrapped HNTs (HD) as a promising drug delivery carrier, doxorubicin (DOX) is introduced as a model anticancer agent and loaded onto HD, showing sustained DOX release over two weeks without initial burst of DOX indicating delayedDOX release inside cells.
Abstract: Halloysite nanotube (HNT)-based supramolecular complexes are synthesized and evaluated with respect to their cytotoxicity and effects on cellular structures. As HNTs are water-insoluble, DNA is applied for wrapping the surface of HNTs to enhance their water-dispersibility. To investigate the potential of DNA-wrapped HNTs (HD) as a promising drug delivery carrier, doxorubicin (DOX) is introduced as a model anticancer agent and loaded onto HD. The DOX-loaded, DNA-wrapped HNTs (HDD) show sustained DOX release over two weeks without initial burst of DOX indicating delayed DOX release inside cells. In addition, effects of DNA-wrapped HNTs (HD) or HDD on the cytoskeleton organization of A549 cells are studied by visualizing the distribution of F-actin filaments using confocal laser scanning microscopy, and cellular morphological changes are observed by scanning electron microscopy and scanning ion conductance microscopy.

73 citations

Journal ArticleDOI
TL;DR: A review of atomic force microscopy (AFM) imaging techniques for nanomaterial research is presented in this article, where the advantages and disadvantages of AFM imaging techniques are discussed.
Abstract: The research and development of nanotechnology has led to materials science and engineering entering the “nanomaterial era”. It is pivotal for analyzing the physicochemical properties of nanomaterials for new nanotechnological instruments to be developed. Over the past three decades, atomic force microscopy (AFM), as a powerful nanotechnological imaging tool, has provided many imaging modes for analyzing nanomaterial properties such as the topography, elasticity, adhesion, friction, electrical properties, and magnetism of the materials. The focus of this review is on the development of AFM imaging observation tools and methods for nanomaterial research. First, AFM and nanomaterials are briefly introduced. Then, AFM imaging techniques for nanomaterial research are comprehensively summarized. Finally, the advantages and disadvantages of AFM imaging techniques for nanomaterial research are discussed. This review will provide comprehensive information of AFM imaging techniques for materials scientists and engineers.

46 citations

Journal ArticleDOI
TL;DR: It is demonstrated that the AFM tip, in either the contact or the tapping mode, can fabricate SF micropatterns on mica with controlled surface topography, and the deposition process requires a mechanical force-induced SF sol-gel transition followed by a transfer to the mica surface at the tip-surface contact.
Abstract: Silk fibroin (SF) is a promising candidate for a variety of application in the fields of tissue engineering, drug delivery, and biomedical optics. Recent research has already begun to explore the construction of nano- and micropatterned SF films under ambient environment. The structure and biocompatibility of SF are dependent on SF state (solution or solid) and the method of drying the SF solution to prepare various biomaterials such as films, sponges, and fibers. Therefore, it is important to explore the construction of SF nano- and micropatterns under aqueous solution. This paper reports a novel application of atomic force microscopy (AFM) under liquid for direct deposition of the relatively hydrophobic protein SF onto hydrophilic mica. We demonstrate that the AFM tip, in either the contact or the tapping mode, can fabricate SF micropatterns on mica with controlled surface topography. We show that the deposition process requires a mechanical force-induced SF sol–gel transition followed by a transfer to ...

43 citations

Journal ArticleDOI
TL;DR: As a powerful nanotech imaging tool, AFM has many advantages for food protein research and will undoubtedly be applied to study a growing number of food proteins in the future.
Abstract: s Background Since atomic force microscopy (AFM) was developed in 1985, AFM has become an important nanotech tool to analyze the morphological properties and mechanical properties of proteins. In the past three decades, many food scientists used AFM to analyze food proteins and to comprehensively understand the relationship between the structure and the function of food proteins. Scope and approach This review focuses on the application of food proteins nanoimaging by AFM and contains two parts. In this part I, the technical information of AFM food protein research is summarized and discussed. Firstly, this review introduces the components and imaging modes of AFM imaging. Secondly, this review summarizes the observation ways of AFM imaging for food proteins. Thirdly, this review discussed the research types of AFM nanoimaging for food protein research according to different research needs. Finally, the advantages and disadvantages of AFM for food protein nanoimaging are summarized. Key findings and conclusions This review part I can provide comprehensive technical information of AFM nanoimaging for food protein research to those who are interested to enter this field. As a powerful nanotech imaging tool, AFM has many advantages for food protein research and will undoubtedly be applied to study a growing number of food proteins in the future. AFM has become an important nanotech tool to analyze proteins and many food scientists have used it to analyze food proteins in the past three decades. This review focuses on the application of AFM nanoimaging and contains two parts. In this part I, the AFM components, imaging modes, observation ways, and research types according to different research needs are reviewed and discussed in this part I. The advantages and disadvantages of AFM for food protein nanoimaging are also discussed. The part I of this review provides comprehensive technical information of AFM nanoimaging for food proteins.

40 citations

References
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Journal ArticleDOI
TL;DR: The atomic force microscope as mentioned in this paper is a combination of the principles of the scanning tunneling microscope and the stylus profilometer, which was proposed as a method to measure forces as small as 10-18 N. As one application for this concept, they introduce a new type of microscope capable of investigating surfaces of insulators on an atomic scale.
Abstract: The scanning tunneling microscope is proposed as a method to measure forces as small as 10-18 N. As one application for this concept, we introduce a new type of microscope capable of investigating surfaces of insulators on an atomic scale. The atomic force microscope is a combination of the principles of the scanning tunneling microscope and the stylus profilometer. It incorporates a probe that does not damage the surface. Our preliminary results in air demonstrate a lateral resolution of 30 A and a vertical resolution less than 1 A.

12,344 citations

Journal ArticleDOI
18 Dec 2003-Nature
TL;DR: The manner in which a newly synthesized chain of amino acids transforms itself into a perfectly folded protein depends both on the intrinsic properties of the amino-acid sequence and on multiple contributing influences from the crowded cellular milieu.
Abstract: The manner in which a newly synthesized chain of amino acids transforms itself into a perfectly folded protein depends both on the intrinsic properties of the amino-acid sequence and on multiple contributing influences from the crowded cellular milieu. Folding and unfolding are crucial ways of regulating biological activity and targeting proteins to different cellular locations. Aggregation of misfolded proteins that escape the cellular quality-control mechanisms is a common feature of a wide range of highly debilitating and increasingly prevalent diseases.

4,440 citations

Journal ArticleDOI
16 May 1997-Science
TL;DR: Single-molecule atomic force microscopy was used to investigate the mechanical properties of titin, the giant sarcomeric protein of striated muscle, and refolding of immunoglobulin domains was observed.
Abstract: Single-molecule atomic force microscopy (AFM) was used to investigate the mechanical properties of titin, the giant sarcomeric protein of striated muscle. Individual titin molecules were repeatedly stretched, and the applied force was recorded as a function of the elongation. At large extensions, the restoring force exhibited a sawtoothlike pattern, with a periodicity that varied between 25 and 28 nanometers. Measurements of recombinant titin immunoglobulin segments of two different lengths exhibited the same pattern and allowed attribution of the discontinuities to the unfolding of individual immunoglobulin domains. The forces required to unfold individual domains ranged from 150 to 300 piconewtons and depended on the pulling speed. Upon relaxation, refolding of immunoglobulin domains was observed.

2,959 citations


"High‐resolution imaging and nano‐ma..." refers background in this paper

  • ...…processes (Goldsbury et al., 1999; Kasas et al., 1997; Petsev et al., 2000), precisely measuring the interacting forces between biomolecules (Allen et al., 1997; Lee et al., 1994; Rief et al., 1997), and nanomanipulating individual biomolecules (Kufer et al., 2008) have all been realized by AFM....

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Journal ArticleDOI
TL;DR: A nanopore-based device provides single-molecule detection and analytical capabilities that are achieved by electrophoretically driving molecules in solution through a nano-scale pore, a unique analytical capability that makes inexpensive, rapid DNA sequencing a possibility.
Abstract: A nanopore-based device provides single-molecule detection and analytical capabilities that are achieved by electrophoretically driving molecules in solution through a nano-scale pore. The nanopore provides a highly confined space within which single nucleic acid polymers can be analyzed at high throughput by one of a variety of means, and the perfect processivity that can be enforced in a narrow pore ensures that the native order of the nucleobases in a polynucleotide is reflected in the sequence of signals that is detected. Kilobase length polymers (single-stranded genomic DNA or RNA) or small molecules (e.g., nucleosides) can be identified and characterized without amplification or labeling, a unique analytical capability that makes inexpensive, rapid DNA sequencing a possibility. Further research and development to overcome current challenges to nanopore identification of each successive nucleotide in a DNA strand offers the prospect of 'third generation' instruments that will sequence a diploid mammalian genome for ∼$1,000 in ∼24 h.

2,512 citations


"High‐resolution imaging and nano‐ma..." refers background in this paper

  • ...As an example for such purpose, recently a nanoporebased sequencing has been achieved with single-molecule detection capability (Branton et al., 2008)....

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Journal ArticleDOI
18 Dec 2003-Nature
TL;DR: Understanding some of the principles of protein folding has helped to explain how such diseases arise, with attendant therapeutic insights, and particularly challenging examples of such disorders occur in the post-mitotic environment of the neuron.
Abstract: Human diseases characterized by insoluble extracellular deposits of proteins have been recognized for almost two centuries. Such amyloidoses were once thought to represent arcane secondary phenomena of questionable pathogenic significance. But it is has now become clear that many different proteins can misfold and form extracellular or intracellular aggregates that initiate profound cellular dysfunction. Particularly challenging examples of such disorders occur in the post-mitotic environment of the neuron and include Alzheimer's and Parkinson's diseases. Understanding some of the principles of protein folding has helped to explain how such diseases arise, with attendant therapeutic insights.

1,398 citations