Living under an atomic force microscope. An optimized approach for in vivo investigations on surface alterations towards biomineral nucleation on cyanobacterial cells

Geobiology ◽  
2005 ◽  
Vol 3 (3) ◽  
pp. 179-193 ◽  
Author(s):  
M. OBST ◽  
M. DITTRICH
Keyword(s):  
Atomic Force Microscope ◽  
Atomic Force

scholarly journals Exocytosis at the Atomic Level

1997 ◽  
Vol 5 (4) ◽  
pp. 3-4
Author(s):  
Stephen W. Carmichael
Keyword(s):  
Atomic Force Microscope ◽  
Atomic Level ◽  
Cellular Structures ◽  
Aqueous Environment ◽  
Yale University ◽  
Atomic Force ◽  
The University

As reviewed in this column on previous occasions, the atomic force microscope (AFM) is steadily making headway as an instrument that can make important contributions to biologic observations. Although the AFM is capable of operating in an aqueous environment, relatively little use has been made of this property to examine cellular structures under conditions that resemble those in vivo. A breakthrough in this regard was recently made by Stefan Schneider, Kumudesh Sritharan, John Geibel, Hans Oberleithner, and Bhanu Jena. of Yale University and the University of Würzburg.

Probing the mechanical stability of proteins using the atomic force microscope

2007 ◽  
Vol 35 (6) ◽  
pp. 1564-1568 ◽  
Author(s):  
D.J. Brockwell
Keyword(s):  
Mechanical Strength ◽  
Atomic Force Microscope ◽  
Mechanical Stability ◽  
Mechanical Deformation ◽  
Mechanical Resistance ◽  
Atomic Force ◽  
Wide Range ◽  
Protein Molecules ◽  
Single Protein

The mechanical strength of single protein molecules can be investigated by using the atomic force microscope. By applying this technique to a wide range of proteins, it appears that the type of secondary structure and its orientation relative to the extension points are important determinants of mechanical strength. Unlike chemical denaturants, force acts locally and the mechanical strength of a protein may thus appear to be mechanically weak or strong by simply varying the region of the landscape through which the protein is unfolded. Similarly, the effect of ligand binding on the mechanical resistance of a protein may also depend on the relative locations of the binding site and force application. Mechanical deformation may thus facilitate the degradation or remodelling of thermodynamically stable proteins and their complexes in vivo.

scholarly journals Photothermal excitation efficiency enhancement of cantilevers by electron beam deposition of amorphous carbon thin films

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Marcos Penedo ◽  
Ayhan Yurtsever ◽  
Keisuke Miyazawa ◽  
Hirotoshi Furusho ◽  
Kiyo-Aki Ishii ◽  
...  
Keyword(s):  
Atomic Force Microscope ◽  
Amorphous Carbon ◽  
Biological Samples ◽  
Oscillation Amplitude ◽  
Carbon Layer ◽  
Stable Operation ◽  
Excitation Efficiency ◽  
Atomic Force ◽  
Excitation Laser

Abstract In recent years, the atomic force microscope has proven to be a powerful tool for studying biological systems, mainly for its capability to measure in liquids with nanoscale resolution. Measuring tissues, cells or proteins in their physiological conditions gives us access to valuable information about their real ‘in vivo’ structure, dynamics and functionality which could then fuel disruptive medical and biological applications. The main problem faced by the atomic force microscope when working in liquid environments is the difficulty to generate clear cantilever resonance spectra, essential for stable operation and for high resolution imaging. Photothermal actuation overcomes this problem, as it generates clear resonance spectra free from spurious peaks. However, relatively high laser powers are required to achieve the desired cantilever oscillation amplitude, which could potentially damage biological samples. In this study, we demonstrate that the photothermal excitation efficiency can be enhanced by coating the cantilever with a thin amorphous carbon layer to increase the heat absorption from the laser, reducing the required excitation laser power and minimizing the damage to biological samples.

Characterization of photosystem II with the atomic-force microscope

1992 ◽  
Vol 50 (2) ◽  
pp. 1146-1147
Author(s):  
Kathleen M. Marr ◽  
Mary K. Lyon
Keyword(s):  
Photosystem Ii ◽  
Atomic Force Microscope ◽  
Three Dimensional ◽  
Biologically Active ◽  
Atomic Force ◽  
Freeze Etching ◽  
Image Averaging ◽  
Oxygen Evolving ◽  
Averaging Techniques

Photosystem II (PSII) is different from all other reaction centers in that it splits water to evolve oxygen and hydrogen ions. This unique ability to evolve oxygen is partly due to three oxygen evolving polypeptides (OEPs) associated with the PSII complex. Freeze etching on grana derived insideout membranes revealed that the OEPs contribute to the observed tetrameric nature of the PSIl particle; when the OEPs are removed, a distinct dimer emerges. Thus, the surface of the PSII complex changes dramatically upon removal of these polypeptides. The atomic force microscope (AFM) is ideal for examining surface topography. The instrument provides a topographical view of individual PSII complexes, giving relatively high resolution three-dimensional information without image averaging techniques. In addition, the use of a fluid cell allows a biologically active sample to be maintained under fully hydrated and physiologically buffered conditions. The OEPs associated with PSII may be sequentially removed, thereby changing the surface of the complex by one polypeptide at a time.

Imaging polymers, proteins and dna in aqueous solutions with the atomic force microscope

1989 ◽  
Vol 47 ◽  
pp. 32-33
Author(s):  
S.A.C. Gould ◽  
B. Drake ◽  
C.B. Prater ◽  
A.L. Weisenhorn ◽  
S.M. Lindsay ◽  
...  
Keyword(s):  
Amino Acids ◽  
Dna Sequencing ◽  
Aqueous Solutions ◽  
Atomic Force Microscope ◽  
Piezoelectric Crystal ◽  
Atomic Force ◽  
Structure Of Molecules ◽  
Optical Lever

The atomic force microscope (AFM) is an instrument that can be used to image many samples of interest in biology and medicine. Images of polymerized amino acids, polyalanine and polyphenylalanine demonstrate the potential of the AFM for revealing the structure of molecules. Images of the protein fibrinogen which agree with TEM images demonstrate that the AFM can provide topographical data on larger molecules. Finally, images of DNA suggest the AFM may soon provide an easier and faster technique for DNA sequencing.The AFM consists of a microfabricated SiO2 triangular shaped cantilever with a diamond tip affixed at the elbow to act as a probe. The sample is mounted on a electronically driven piezoelectric crystal. It is then placed in contact with the tip and scanned. The topography of the surface causes minute deflections in the 100 μm long cantilever which are detected using an optical lever.

The atomic-force microscope and its future in biology

1993 ◽  
Vol 51 ◽  
pp. 704-705
Author(s):  
Jean-Paul Revel
Keyword(s):  
Silicon Nitride ◽  
Laser Beam ◽  
Atomic Force Microscope ◽  
Scanning Tunneling Microscope ◽  
Point Of View ◽  
Scanning Tunneling ◽  
Close Relative ◽  
Tunneling Microscope ◽  
Atomic Force ◽  
Sharp Point

The last few years have been marked by a series of remarkable developments in microscopy. Perhaps the most amazing of these is the growth of microscopies which use devices where the place of the lens has been taken by probes, which record information about the sample and display it in a spatial from the point of view of the context. From the point of view of the biologist one of the most promising of these microscopies without lenses is the scanned force microscope, aka atomic force microscope.This instrument was invented by Binnig, Quate and Gerber and is a close relative of the scanning tunneling microscope. Today's AFMs consist of a cantilever which bears a sharp point at its end. Often this is a silicon nitride pyramid, but there are many variations, the object of which is to make the tip sharper. A laser beam is directed at the back of the cantilever and is reflected into a split, or quadrant photodiode.

The application of atomic force microscope in microbiological research

2014 ◽  
Vol 5 (1) ◽  
pp. 27-30
Author(s):  
Małgorzata Tokarska-Rodak ◽  
Maria Kozioł-Montewka ◽  
Jolanta Paluch-Oleś ◽  
Dorota Plewik ◽  
Grażyna Olchowik ◽  
...  
Keyword(s):  
Atomic Force Microscope ◽  
Atomic Force ◽  
Microbiological Research

Rapid, Refined, and Robust Method for Expression, Purification, and Characterization of Recombinant Human Amyloid-beta M1-42

2019 ◽  
Author(s):  
Priya Prakash ◽  
Travis Lantz ◽  
Krupal P. Jethava ◽  
Gaurav Chopra
Keyword(s):  
Amyloid Beta ◽  
Western Blots ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Set Up ◽  
Short Time

Amyloid plaques found in the brains of Alzheimer’s disease (AD) patients primarily consists of amyloid beta 1-42 (Ab42). Commercially, Ab42 is synthetized using peptide synthesizers. We describe a robust methodology for expression of recombinant human Ab(M1-42) in Rosetta(DE3)pLysS and BL21(DE3)pLysS competent E. coli with refined and rapid analytical purification techniques. The peptide is isolated and purified from the transformed cells using an optimized set-up for reverse-phase HPLC protocol, using commonly available C18 columns, yielding high amounts of peptide (~15-20 mg per 1 L culture) in a short time. The recombinant Ab(M1-42) forms characteristic aggregates similar to synthetic Ab42 aggregates as verified by western blots and atomic force microscopy to warrant future biological use. Our rapid, refined, and robust technique to purify human Ab(M1-42) can be used to synthesize chemical probes for several downstream in vitro and in vivo assays to facilitate AD research.

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