Analysis of force distance curve for biomolecule imaging

Choi, Seong Soo; Anh, Viet; Joo, Moon Sig; Kim, Y.C.; Kim, K.J.; Kim, D.W.

doi:10.1016/j.cap.2006.01.049

Cited by 4 publications

(2 citation statements)

References 7 publications

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“…Forces between AFM probes and sample surfaces can be measured in both air and liquid. In humid air a water capillary forms between the tip and specimen introducing a meniscus force (or capillary force), which dominates the adhesion force in air ,, . Immersion of specimen and tip in liquid eliminates this contribution allowing estimation of van der Waals and other small forces , .…”

Section: Introductionmentioning

confidence: 99%

Investigation of Surface Properties of Soil Particles and Model Materials with Contrasting Hydrophobicity Using Atomic Force Microscopy

Cheng

Bryant

Doerr

et al. 2009

Environ. Sci. Technol.

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Surface images and force measurements obtained using atomic force microscopy (AFM) were used to assess the hydrophobicity of particles from soils and model soil material (smooth glass and acid-washed sand (AWS) exposed to soil-derived humic acid (HA) or lecithin (LE)). Height and phase images, and phase distributions (from soil particles) show complex morphology and heterogeneously distributed organic matter. Forces at model surfaces indicate that, in air, reduction in adhesion corresponded with increased hydrophobicity, but in water, corresponded with a decrease (and serve to guide interpretation of data from natural particles). Adhesion forces on hydrophobic soil particles in water were larger than those for hydrophilic ones, but surface roughness and complexity may obscure any opposite trend for measurements in air. Combination of force measurements, applied forthe first time to soil particles, together with those on model surfaces, and independent assessments of hydrophobicity of corresponding single particle layers, indicate good, but not consistent qualitative agreement between hydophobicity at bulk and nanoscales. AFM is likely to facilitate detailed evaluation of soil particle surface hydrophobicity, which contributes to bulk wetting behavior of soils and other porous systems, including assessments of the potential for contributons to supehydrophobicity from surfaces at the micro- and nanoscales.

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Section: Introductionmentioning

confidence: 99%

Investigation of Surface Properties of Soil Particles and Model Materials with Contrasting Hydrophobicity Using Atomic Force Microscopy

Cheng

Bryant

Doerr

et al. 2009

Environ. Sci. Technol.

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“…The adhesion force, arising from the capillary forces, electrical double layer interactions and chemical bonding forces, have been calculated from force–distance measurements. The larger adhesion forces measured on hydrophilic surfaces in comparison with hydrophobic ones has been assumed to reflect the significant contribution made to the former by capillary forces (Thundat et al , 1993; Cappella & Dietler, 1999; Choi et al , 2006). Therefore, adhesion forces measured in ambient environments can be used to determine surface hydrophobicity, which may result from the presence of organic matter adsorbed on the surfaces of hydrophilic mineral particles in soil.…”

Section: Introductionmentioning

confidence: 99%

Application of atomic force microscopy to the study of natural and model soil particles

Cheng

Bryant

Doerr³

et al. 2008

Journal of Microscopy

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Summary The structure and surface chemistry of soil particles has extensive impact on many bulk scale properties and processes of soil systems and consequently the environments that they support. There are a number of physiochemical mechanisms that operate at the nanoscale which affect the soil's capability to maintain native vegetation and crops; this includes soil hydrophobicity and the soil's capacity to hold water and nutrients. The present study used atomic force microscopy in a novel approach to provide unique insight into the nanoscale properties of natural soil particles that control the physiochemical interaction of material within the soil column. There have been few atomic force microscopy studies of soil, perhaps a reflection of the heterogeneous nature of the system. The present study adopted an imaging and force measurement research strategy that accounted for the heterogeneity and used model systems to aid interpretation. The surface roughness of natural soil particles increased with depth in the soil column a consequence of the attachment of organic material within the crevices of the soil particles. The roughness root mean square calculated from ten 25 μm2 images for five different soil particles from a Netherlands soil was 53.0 nm, 68.0 nm, 92.2 nm and 106.4 nm for the respective soil depths of 0–10 cm, 10–20 cm, 20–30 cm and 30–40 cm. A novel analysis method of atomic force microscopy phase images based on phase angle distribution across a surface was used to interpret the nanoscale distribution of organic material attached to natural and model soil particles. Phase angle distributions obtained from phase images of model surfaces were found to be bimodal, indicating multiple layers of material, which changed with the concentration of adsorbed humic acid. Phase angle distributions obtained from phase images of natural soil particles indicated a trend of decreasing surface coverage with increasing depth in the soil column. This was consistent with previous macroscopic determination of the proportions of organic material chemically extracted from bulk samples of the soils from which specimen particles were drawn. Interaction forces were measured between atomic force microscopy cantilever tips (Si3N4) and natural soil and model surfaces. Adhesion forces at humic acid free specimen surfaces (Av. 20.0 nN), which are primarily hydrophilic and whose interactions are subject to a significant contribution from the capillary forces, were found to be larger than those of specimen surfaces with adsorbed humic acid (Av. 6.5 nN). This suggests that adsorbed humic acid increased surface hydrophobicity. The magnitude and distribution of adhesion forces between atomic force microscopy tips and the natural particle surfaces was affected by both local surface roughness and the presence of adsorbed organic material. The present study has correlated nanoscale measurements with established macroscale methods of soil study. Thus, the research demonstrates that atomic force microscopy is an important addition to soil s...

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Nanoprobe spectroscopy of capillary forces and its application for a real surface diagnostics

Ефремов¹

2010

Semicond. Phys. Quantum Electron. Optoelectron.

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The paper presents an overview and analysis of the most reliable and at the same time rather simple theoretical models describing liquid nanomeniscus geometry and forces occurring between atomic force microscope (AFM) probe and a real surface. There are experimental results in capillary bridge force rupture measured in air, and interaction force under water buffer obtained over surfaces of different nature. It is shown that the theoretical models quite adequately describe the processes observed experimentally and, in particular, bridge ruptures dynamics at the vertical probe withdraw for different speeds. Discussed here are some methodological peculiarities and nanocapillary force spectroscopy diagnostic capabilities for surface energy mapping, prospects of using of a liquid nanomeniscus in local nanochemistry, nanolithography and nano-electrochemistry of a surface.

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Analysis of force distance curve for biomolecule imaging

Cited by 4 publications

References 7 publications

Investigation of Surface Properties of Soil Particles and Model Materials with Contrasting Hydrophobicity Using Atomic Force Microscopy

Investigation of Surface Properties of Soil Particles and Model Materials with Contrasting Hydrophobicity Using Atomic Force Microscopy

Application of atomic force microscopy to the study of natural and model soil particles

Nanoprobe spectroscopy of capillary forces and its application for a real surface diagnostics

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