Combined Atomic Force and Fluorescence Microscopy of Biofilms formed by Leaching Bacteria on Opaque Substrata

2007 ◽  
Vol 20-21 ◽  
pp. 371-374
Author(s):  
Stefanie Mangold ◽  
Kerstin Harneit ◽  
Wolfgang Sand
Keyword(s):  
Biofilm Formation ◽  
Epifluorescence Microscopy ◽  
Contact Mode ◽  
Atomic Force ◽  
Afm Probe ◽  
Leaching Bacteria ◽  
Mineral Sulfides ◽  
Spring Constants ◽  
Imaging Conditions ◽  
Fluid Imaging

Leaching bacteria attach to their substrates, i.e. mineral sulfides, and form monolayered biofilms. In this study the biofilm formation of Acidithiobacillus ferrooxidans A2 on pyrite was examined using atomic force and epifluorescence microscopy (AFM and EFM, respectively). A novel system by JPK instruments, the BioMaterial WorkstationTM, allows the investigation of the same location on an opaque sample with AFM and EFM. Until recently this was only possible for translucent samples. Sessile bacteria on pyrite coupons were stained with 4’,6-diamidino-2- phenylindol (DAPI) and visualized by EFM as well as AFM. The best imaging conditions for AFM were assessed. Scans of bacteria attached to pyrite were performed in contact mode in air as well as in tapping mode in fluid. Imaging in fluid was more challenging than imaging in air as bacteria tend to detach from their substratum. To avoid the dislocation of microorganisms by the AFM probe the sample was dried in air for 1 h prior to scanning in fluid. Scanning in air was performed with the whole range of cantilever spring constants tested (k = 0.03 N/m to k = 0.65 N/m) while, for scanning in fluid, best results were achieved using stiffer cantilevers (k = 0.65 N/m).

Attachment Behavior of Leaching Bacteria to Metal Sulfides Elucidated by Combined Atomic Force and Epifluorescence Microscopy

2009 ◽  
Vol 71-73 ◽  
pp. 337-340 ◽  
Author(s):  
Bianca M. Florian ◽  
Nanni Noël ◽  
Soeren Bellenberg ◽  
J. Huergo ◽  
Thore Rohwerder ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Spatial Arrangement ◽  
Epifluorescence Microscopy ◽  
Metal Sulfides ◽  
Mineral Surface ◽  
Planktonic Cells ◽  
Force Microscopy ◽  
Atomic Force ◽  
Leaching Bacteria

The aim of the study was to quantify and to visualize colonization of metal sulfides by pure and mixed cultures. Strains of the genera Acidithiobacillus and Leptospirillum were tested. Sessile and planktonic cells were visualized by fluorescence microscopy using 4',6-diamidino-2-phenylindole (DAPI) and FISH. Additionally, atomic force microscopy was used for the investigations on cell morphology, spatial arrangement of cells on metal sulfides and mineral surface topography. It was shown that the morphology of sessile cells was totally different as compared with planktonic ones. Interactions of different species resulted in increased production of extracellular polymeric substances (EPS) or caused negligible-attaching bacteria to be incorporated into a biofilm by the good attaching ones. Consequently, biofilm formation was furthered.

scholarly journals Novel Combination of Atomic Force Microscopy and Epifluorescence Microscopy for Visualization of Leaching Bacteria on Pyrite

2007 ◽  
Vol 74 (2) ◽  
pp. 410-415 ◽  
Author(s):  
Stefanie Mangold ◽  
Kerstin Harneit ◽  
Thore Rohwerder ◽  
Günter Claus ◽  
Wolfgang Sand
Keyword(s):  
Atomic Force Microscopy ◽  
Extracellular Polymeric Substances ◽  
Metal Sulfide ◽  
Epifluorescence Microscopy ◽  
Bacterial Cells ◽  
Cell Integrity ◽  
Force Microscopy ◽  
Topographic Features ◽  
Atomic Force ◽  
Leaching Bacteria

ABSTRACT Bioleaching of metal sulfides is an interfacial process comprising the interactions of attached bacterial cells and bacterial extracellular polymeric substances with the surface of a mineral sulfide. Such processes and the associated biofilms can be investigated at high spatial resolution using atomic force microscopy (AFM). Therefore, we visualized biofilms of the meso-acidophilic leaching bacterium Acidithiobacillus ferrooxidans strain A2 on the metal sulfide pyrite with a newly developed combination of AFM with epifluorescence microscopy (EFM). This novel system allowed the imaging of the same sample location with both instruments. The pyrite sample, as fixed on a shuttle stage, was transferred between AFM and EFM devices. By staining the bacterial DNA with a specific fluorescence dye, bacterial cells were labeled and could easily be distinguished from other topographic features occurring in the AFM image. AFM scanning in liquid caused deformation and detachment of cells, but scanning in air had no effect on cell integrity. In summary, we successfully demonstrate that the new microscopic system was applicable for visualizing bioleaching samples. Moreover, the combination of AFM and EFM in general seems to be a powerful tool for investigations of biofilms on opaque materials and will help to advance our knowledge of biological interfacial processes. In principle, the shuttle stage can be transferred to additional instruments, and combinations of AFM and EFM with other surface-analyzing devices can be proposed.

The Study of Nanolithography Processing on the Photoresistor Thin Film by Atomic Force Microscopy

2014 ◽  
Vol 997 ◽  
pp. 379-382
Author(s):  
Jen Ching Huang ◽  
Fu Jen Cheng
Keyword(s):  
Thin Films ◽  
Atomic Force Microscopy ◽  
Groove Depth ◽  
Cutting Depth ◽  
Contact Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
On Line ◽  
Afm Probe ◽  
Mode Atomic Force Microscopy

In this paper, the nanomachining experiments on the SPR3001 photoresistor thin films were processing by contact mode atomic force microscopy (AFM). After the experiment, it can be found, in the nanomachining, the greater the indented distance along the Z-axis depth, carved out of the groove depth and groove width of nanoline is greater. The influences of cutting directions on line width and cutting depth during nanomachining were quite a few and the cutting situation was stable by lateral nanomachining. This article also successfully processed the regular hexagonal nanopattern, also proves the nanomachining ability of the AFM probe is good at nanoscale patterned on photoresistor thin films.

Biofilm Formation and Extracellular Polymeric Substances (EPS) Analysis by New Isolates of Leptospirillum, Acidithiobacillus and Sulfobacillus from Armenia

2015 ◽  
Vol 1130 ◽  
pp. 153-156 ◽  
Author(s):  
Arevik K. Vardanyan ◽  
Narine S. Vardanyan ◽  
Levon Markosyan ◽  
Wolfgang Sand ◽  
Mario Vera ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Epifluorescence Microscopy ◽  
Sulfide Ores ◽  
Uronic Acids ◽  
Force Microscopy ◽  
Atomic Force

Biofilm formation by new isolates, Leptospirillum sp. strain ZC, Acidithiobacillus sp. strain 61 and Sulfobacillus sp. strain 6 isolated from different biotopes of sulfide ores in Armenia on pyrite was studied by atomic force microscopy (AFM) combined with epifluorescence microscopy (EFM). It was revealed that all the tested species formed monolayer biofilms The results showed that in contrast to Acidithiobacillus sp. strain 61 and Sulfobacillus sp. strain 6, cells of Leptospirillum sp. strain ZC were often observed by clusters and aggregates.The composition of capsular and colloidal EPS formed by isolated Leptospirillum sp. strain ZC, Acidithiobacillus sp. strain 61 and Sulfobacillus sp. strain 6 was studied. It was revealed that the EPS of all three species grown on iron (II) mainly consisted of carbohydrates, proteins as well as uronic acids.

Analysis on the Contact Mechanics between Tip and Sample in Atomic Force Acoustic Microscope Method

2013 ◽  
Vol 800 ◽  
pp. 325-329
Author(s):  
Gai Mei Zhang ◽  
Li Ping Yang ◽  
Chen Qiang ◽  
Yuan Wei ◽  
Jian Dong Lu ◽  
...  
Keyword(s):  
Contact Stiffness ◽  
Sample Surface ◽  
Acoustic Microscopy ◽  
Contact Model ◽  
Contact Theory ◽  
Ultrasonic Technique ◽  
Contact Mode ◽  
Atomic Force ◽  
Resonance Frequencies ◽  
Afm Probe

Atomic force acoustic microscopy (AFAM) is a technique combining the atomic force microscope (AFM) and ultrasonic technique, where the cantilever or the sample surface is vibrated at ultrasonic frequencies while a sample surface is scanned with the sensor tip contacting the sample. At a consequence, the amplitude of the cantilever vibration as well as the shift of the cantilever resonance frequencies contain information about local tip-sample contact stiffness and can be used as imaging quantities. It has been demonstrated to be a powerful tool for the investigation of the local elastic prosperities of sample surface. The sample is tested in the contact mode, the resonant frequency of the cantilever is measured, by which the contact stiffness is calculated based on the model of vibration of the cantilever, and then the elastic property of sample is evaluated according to the contact theory. Therefore, the contact model has an important impact on the calculation of elastic modulus. This paper analyzes the contact model between the AFM probe and the sample, and it is investigated based on finite element method (FEM) that the results of the test are affected by parameters.

Surface roughness measurements of vanadium-contaminated fluidized cracking catalysts by atomic force microscopy

1996 ◽  
Vol 54 ◽  
pp. 866-867
Author(s):  
H. Kinney ◽  
M.L. Occelli ◽  
S.A.C. Gould
Keyword(s):  
Surface Roughness ◽  
Zeolite Y ◽  
Atomic Level ◽  
Microporous Structure ◽  
Contact Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Before And After ◽  
Roughness Measurements ◽  
Cracking Catalysts

For this study we have used a contact mode atomic force microscope (AFM) to study to topography of fluidized cracking catalysts (FCC), before and after contamination with 5% vanadium. We selected the AFM because of its ability to well characterize the surface roughness of materials down to the atomic level. It is believed that the cracking in the FCCs occurs mainly on the catalysts top 10-15 μm suggesting that the surface corrugation could play a key role in the FCCs microactivity properties. To test this hypothesis, we chose vanadium as a contaminate because this metal is capable of irreversibly destroying the FCC crystallinity as well as it microporous structure. In addition, we wanted to examine the extent to which steaming affects the vanadium contaminated FCC. Using the AFM, we measured the surface roughness of FCCs, before and after contamination and after steaming.We obtained our FCC (GRZ-1) from Davison. The FCC is generated so that it contains and estimated 35% rare earth exchaged zeolite Y, 50% kaolin and 15% binder.

scholarly journals Magnetic Driven Two-Finger Micro-Hand with Soft Magnetic End-Effector for Force-Controlled Stable Manipulation in Microscale

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 410
Author(s):  
Dan Liu ◽  
Xiaoming Liu ◽  
Pengyun Li ◽  
Xiaoqing Tang ◽  
Masaru Kojima ◽  
...  
Keyword(s):  
Magnetic Force ◽  
Force Feedback ◽  
Soft Magnetic ◽  
End Effector ◽  
Force Microscopy ◽  
System A ◽  
Atomic Force ◽  
Afm Probe ◽  
End Effectors ◽  
Fixed End

In recent years, micromanipulators have provided the ability to interact with micro-objects in industrial and biomedical fields. However, traditional manipulators still encounter challenges in gaining the force feedback at the micro-scale. In this paper, we present a micronewton force-controlled two-finger microhand with a soft magnetic end-effector for stable grasping. In this system, a homemade electromagnet was used as the driving device to execute micro-objects manipulation. There were two soft end-effectors with diameters of 300 μm. One was a fixed end-effector that was only made of hydrogel, and the other one was a magnetic end-effector that contained a uniform mixture of polydimethylsiloxane (PDMS) and paramagnetic particles. The magnetic force on the soft magnetic end-effector was calibrated using an atomic force microscopy (AFM) probe. The performance tests demonstrated that the magnetically driven soft microhand had a grasping range of 0–260 μm, which allowed a clamping force with a resolution of 0.48 μN. The stable grasping capability of the magnetically driven soft microhand was validated by grasping different sized microbeads, transport under different velocities, and assembly of microbeads. The proposed system enables force-controlled manipulation, and we believe it has great potential in biological and industrial micromanipulation.

scholarly journals Dynamic friction energy dissipation and enhanced contrast in high frequency bimodal atomic force microscopy

Friction ◽  
2021 ◽  
Author(s):  
Xinfeng Tan ◽  
Dan Guo ◽  
Jianbin Luo
Keyword(s):  
Atomic Force Microscopy ◽  
Energy Dissipation ◽  
Contact Friction ◽  
Measuring Instruments ◽  
Dynamic Friction ◽  
Contact Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Friction Energy ◽  
New Applications

AbstractDynamic friction occurs not only between two contact objects sliding against each other, but also between two relative sliding surfaces several nanometres apart. Many emerging micro- and nano-mechanical systems that promise new applications in sensors or information technology may suffer or benefit from noncontact friction. Herein we demonstrate the distance-dependent friction energy dissipation between the tip and the heterogeneous polymers by the bimodal atomic force microscopy (AFM) method driving the second order flexural and the first order torsional vibration simultaneously. The pull-in problem caused by the attractive force is avoided, and the friction dissipation can be imaged near the surface. The friction dissipation coefficient concept is proposed and three different contact states are determined from phase and energy dissipation curves. Image contrast is enhanced in the intermediate setpoint region. The work offers an effective method for directly detecting the friction dissipation and high resolution images, which overcomes the disadvantages of existing methods such as contact mode AFM or other contact friction and wear measuring instruments.

scholarly journals Redesigned Sensor Holder for an Atomic Force Microscope with an Adjustable Probe Direction

2021 ◽  
Author(s):  
Janik Schaude ◽  
Maxim Fimushkin ◽  
Tino Hausotte
Keyword(s):  
Atomic Force Microscope ◽  
Piezoelectric Actuator ◽  
High Speed ◽  
Closed Loop ◽  
Coefficient Of Thermal Expansion ◽  
Measuring System ◽  
Contact Mode ◽  
Loop Control ◽  
Atomic Force ◽  
Measuring Machine

AbstractThe article presents a redesigned sensor holder for an atomic force microscope (AFM) with an adjustable probe direction, which is integrated into a nano measuring machine (NMM-1). The AFM, consisting of a commercial piezoresistive cantilever operated in closed-loop intermitted contact-mode, is based on two rotational axes, which enable the adjustment of the probe direction to cover a complete hemisphere. The axes greatly enlarge the metrology frame of the measuring system by materials with a comparatively high coefficient of thermal expansion. The AFM is therefore operated within a thermostating housing with a long-term temperature stability of 17 mK. The sensor holder, connecting the rotational axes and the cantilever, inserted one adhesive bond, a soldered connection and a geometrically undefined clamping into the metrology circle, which might also be a source of measurement error. It has therefore been redesigned to a clamped senor holder, which is presented, evaluated and compared to the previous glued sensor holder within this paper. As will be shown, there are no significant differences between the two sensor holders. This leads to the conclusion, that the three aforementioned connections do not deteriorate the measurement precision, significantly. As only a minor portion of the positioning range of the piezoelectric actuator is needed to stimulate the cantilever near its resonance frequency, a high-speed closed-loop control that keeps the cantilever within its operating range using this piezoelectric actuator further on as actuator was implemented and is presented within this article.

scholarly journals Atomic force microscopy comparative analysis of the surface roughness of two posterior chamber phakic intraocular lens models: ICL versus IPCL

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Juan Gros-Otero ◽  
Samira Ketabi ◽  
Rafael Cañones-Zafra ◽  
Montserrat Garcia-Gonzalez ◽  
Cesar Villa-Collar ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Intraocular Lenses ◽  
Posterior Chamber ◽  
Anterior Surface ◽  
Contact Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Phakic Intraocular Lenses ◽  
Roughness Measurements

Abstract Background To compare the anterior surface roughness of two commercially available posterior chamber phakic intraocular lenses (IOLs) using atomic force microscopy (AFM). Methods Four phakic IOLs were used for this prospective, experimental study: two Visian ICL EVO+ V5 lenses and two iPCL 2.0 lenses. All of them were brand new, were not previously implanted in humans, were monofocal and had a dioptric power of − 12 diopters (D). The anterior surface roughness was assessed using a JPK NanoWizard II® atomic force microscope in contact mode immersed in liquid. Olympus OMCL-RC800PSA commercial silicon nitride cantilever tips were used. Anterior surface roughness measurements were made in 7 areas of 10 × 10 μm at 512 × 512 point resolution. The roughness was measured using the root-mean-square (RMS) value within the given regions. Results The mean of all anterior surface roughness measurements was 6.09 ± 1.33 nm (nm) in the Visian ICL EVO+ V5 and 3.49 ± 0.41 nm in the iPCL 2.0 (p = 0.001). Conclusion In the current study, we found a statistically significant smoother anterior surface in the iPCL 2.0 phakic intraocular lenses compared with the VISIAN ICL EVO+ V5 lenses when studied with atomic force microscopy.

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