A non-contact, thermal noise based method for the calibration of lateral deflection sensitivity in atomic force microscopy

Mullin, Nic; Hobbs, Jamie K.

doi:10.1063/1.4901221

Cited by 46 publications

(46 citation statements)

References 39 publications

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“…Each cantilever was calibrated using its thermal spectrum 58 yielding a typical stiffness of 0.33 (±0.05) N m −1 in solution. Calibration of the torsional cantilever inverse optical lever sensitivity (InvOLS) and spring constant, k t , is a more demanding procedure 59 and was hence performed only on 5 cantilevers. We found k t = 184 (±1) N m −1 .…”

Section: Atomic Force Microscopy Measurementsmentioning

confidence: 99%

Lubricating properties of single metal ions at interfaces

Cafolla

Voïtchovsky

2018

Nanoscale

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The behaviour of ionic solutions confined in nanoscale gaps is central to countless processes, from biomolecular function to electrochemistry, energy storage and lubrication. However, no clear link exists between the molecular-level behaviour of the liquid and macroscopic observations. The problem mainly comes from the difficulty to interrogate a small number of liquid molecules. Here, we use atomic force microscopy to investigate the viscoelastic behaviour of pure water and ionic solutions down to the single ion level. The results show a glassy-like behaviour for pure water, with single metal ions acting as lubricants by reducing the elasticity of the nano-confined solution and the magnitude of the hydrodynamic friction. At small ionic concentration (<20 mM) the results can be quantitatively explained by the ions moving via a thermally-activated process resisted by the ion's hydration water (Prandtl-Tomlinson model). The model breaks down at higher salt concentrations due to ion-ion interaction effects that can no longer be neglected. The correlations are confirmed by direct sub-nanometre imaging of the interface at equilibrium. The results provide a molecular-level basis for explaining the tribological properties of aqueous solutions and suggest that ion-ion interactions create mesoscale effects that prevent a direct link between nanoscale and macroscopic measurements.

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Section: Atomic Force Microscopy Measurementsmentioning

confidence: 99%

Lubricating properties of single metal ions at interfaces

Cafolla

Voïtchovsky

2018

Nanoscale

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“…When the AFM tip slides on the calcite surface, it experiences a lateral force due to the friction force between tip and calcite, which leads to a lateral deflection of the cantilever. The lateral force F L is determined during both trace and retrace with the lateral deflection and the lateral spring constant ( k lat ) obtained from a noncontact thermal noise‐based calibration method (Mullin & Hobbs, ). Figure S1c shows one friction loop that is collected from one reciprocal measurement.…”

Section: Experimental Setup and Data Processingmentioning

confidence: 99%

Effect of Fluid Chemistry on the Interfacial Composition, Adhesion, and Frictional Response of Calcite Single Crystals—Implications for Injection‐Induced Seismicity

Diao

Espinosa‐Marzal

2019

JGR Solid Earth

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While it has been shown that the mechanical properties and the reactivity of carbonate‐bearing rocks may be influenced by the chemical composition of the fluids, little is known about how the fluid composition affects their frictional response. Here, we have used atomic force microscopy to investigate the frictional characteristics of single calcite crystals in calcium carbonate saturated solutions and in two brines, NaCl and CaCl2, at a wide range of geologically relevant concentrations. Surface forces were measured to determine the ion‐specific composition of the confined fluid films and the adhesion between the confining surfaces. The effect of fluid chemistry on calcite's (dynamic) frictional response significantly depends on the normal stress. At low stresses, the confined fluid film lubricates the single‐asperity contact efficiently, resulting in low friction coefficients, especially in the case of NaCl solutions. When the pressure solution of calcite is triggered at sufficiently high stress, a significant reduction of the friction coefficient was observed, and in this case, CaCl2 solutions were shown to promote this frictional weakening more significantly than NaCl. This is the first experimental investigation of the ion‐specific frictional characteristics of calcite at the level of a single‐asperity contact. The presence of infiltrated fluids in carbonate faults may also play a critical role in fault dynamics. Hence, the results of this nanoscale study are extrapolated to carbonate fault friction in the presence of infiltrated fluids, and they contribute to advance our understanding of induced seismicity at geological scale.

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“…Pyramidal silicon nitride MSCT cantilevers (Bruker) with a nominal spring constant of 0.1 N/m were used for contact mode imaging and indentation measurements. Determination of the spring constant of all cantilevers was carried out using the thermal noise method [45]. Images were recorded in air at a line rate of 1 Hz.…”

Section: Atomic Force Microscopymentioning

confidence: 99%

GSK3787-Loaded Poly(Ester Amide) Particles for Intra-Articular Drug Delivery

et al. 2020

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Osteoarthritis (OA) is a debilitating joint disorder affecting more than 240 million people. There is no disease modifying therapeutic, and drugs that are used to alleviate OA symptoms result in side effects. Recent research indicates that inhibition of peroxisome proliferator-activated receptor δ (PPARδ) in cartilage may attenuate the development or progression of OA. PPARδ antagonists such as GSK3787 exist, but would benefit from delivery to joints to avoid side effects. Described here is the loading of GSK3787 into poly(ester amide) (PEA) particles. The particles contained 8 wt.% drug and had mean diameters of about 600 nm. Differential scanning calorimetry indicated the drug was in crystalline domains in the particles. Atomic force microscopy was used to measure the Young’s moduli of individual particles as 2.8 MPa. In vitro drug release studies showed 11% GSK3787 was released over 30 days. Studies in immature murine articular cartilage (IMAC) cells indicated low toxicity from the drug, empty particles, and drug-loaded particles and that the particles were not taken up by the cells. Ex vivo studies on murine joints showed that the particles could be injected into the joint space and resided there for at least 7 days. Overall, these results indicate that GSK3787-loaded PEA particles warrant further investigation as a delivery system for potential OA therapy.

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A non-contact, thermal noise based method for the calibration of lateral deflection sensitivity in atomic force microscopy

Cited by 46 publications

References 39 publications

Lubricating properties of single metal ions at interfaces

Lubricating properties of single metal ions at interfaces

Effect of Fluid Chemistry on the Interfacial Composition, Adhesion, and Frictional Response of Calcite Single Crystals—Implications for Injection‐Induced Seismicity

GSK3787-Loaded Poly(Ester Amide) Particles for Intra-Articular Drug Delivery

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