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.

Refinement of Plas Samples by Using Afm Image and First Observation of Plas Signals on Amorphous Carbon Nitridea-CNx Films

1998 ◽  
Vol 507 ◽  
Author(s):  
H. Furukawa ◽  
S. Nitta ◽  
M. Hioki ◽  
T. Iwasaki ◽  
T. Itoh ◽  
...  
Keyword(s):  
Atomic Force Microscope ◽  
Absorption Spectroscopy ◽  
Amorphous Carbon ◽  
Carbon Nitride ◽  
The Other ◽  
Etching Time ◽  
Atomic Force ◽  
Experimental Problem ◽  
Amorphous Carbon Nitride ◽  
First Time

ABSTRACTThe shape of several waveguide end of samples for photoluminescence absorption spectroscopy (PLAS) was studied by atomic force microscope (AFM), because there was an experimental problem where some samples for PLAS did not work. Using the result of AFM, the waveguide end was reshaped by plasma dry etching. The shortening of the etching time was an effective method to improve the structure of the waveguide end. Secondly, the PLAS method was extended to the other materials from a-Si:H. The PLAS signal of amorphous carbon nitride a-CNx was detected for the first time. Amorphous carbon nitride a-CNx film itself and the interface between a-CNx and a-Si02 are found as good as a-Si:H and the interface between a-Si:H and a-Si 3N4+x:H, respectively.

Measurement of the loss tangent of a thin polymeric film using the atomic force microscope

2004 ◽  
Vol 19 (1) ◽  
pp. 387-395 ◽  
Author(s):  
P.M. McGuiggan ◽  
D.J. Yarusso
Keyword(s):  
Atomic Force Microscope ◽  
Loss Tangent ◽  
Oscillation Amplitude ◽  
Polymer Surface ◽  
Pressure Sensitive Adhesive ◽  
Force Microscopy ◽  
Atomic Force ◽  
Microscopy Measurement ◽  
Microscope Technique ◽  
Tan Δ

An atomic force microscope was used to measure the loss tangent, tan δ, of a pressure-sensitive adhesive transfer tape as a function of frequency (0.01 to 10 Hz). For the measurement, the sample was oscillated normal to the surface and the response of the cantilever resting on the polymer surface (as measured via the photodiode) was monitored. Both oscillation amplitude and phase were recorded as a function of frequency. The atomic force microscopy measurement gave the same frequency dependence of tan δ as that measured by a dynamic shear rheometer on a film 20 times thicker. The results demonstrate that the atomic force microscope technique can quantitatively measure rheological properties of soft thin polymeric films.

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.

Modification of a Commercial Atomic Force Microscope for Nanorheological Experiments: Adsorbed Polymer Layers

2000 ◽  
Vol 6 (2) ◽  
pp. 121-128
Author(s):  
Shannon M. Notley ◽  
Vincent S. J. Craig ◽  
Simon Biggs
Keyword(s):  
Atomic Force Microscope ◽  
Phase Difference ◽  
Material Properties ◽  
Biological Samples ◽  
Surface Forces ◽  
Polymer Layers ◽  
Silica Surfaces ◽  
Atomic Force ◽  
Adsorbed Polymer

The atomic force microscope (AFM) has previously been applied to the measurement of surface forces (including adhesion and friction) and to the investigation of material properties, such as hardness. Here we describe the modification of a commercial AFM that enables the stiffness of interaction between surfaces to be measured concurrently with the surface forces. The stiffness is described by the rheological phase difference between the response of the AFM tip to a driving oscillation of the substrate. We present the interaction between silica surfaces bearing adsorbed polymer, however, the principles could be applied to a wide variety of materials including 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.

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