AFM Force Measurements

AFM is a powerful tool capable of measuring the mechanics of material, ranging from soft biomaterial (molecules, cells, tissues, etc.) to polymers and harder inorganics. Depending on the spring constant of the cantilevers pN-scale forces can be measured as either an individual molecule is unfolded (intramolecular) or two molecules are pulled apart (intermolecular).
 

Capabilities

  • Single molecule force spectroscopy
  • Pull molecules at pN force resolution
  • Push against material at a controlled triggered (force or deflection) to measure Youngs Modulus
  • Force clamping
  • Force ramping
  • Operate in relevant solutions and temperatures
  • Chemical force microscopy
  • Colloidal probe AFM
 

Common Applications

  • Unraveling/unfolding modular proteins; measure/observe energy landscape
  • Unzipping/melting DNA molecules (B-S transition)
  • Polymer conformational changes
  • Measure forces between molecules: ligand-receptor pairs, antibody-antigen binding, protein-mineral
  • Measure specificity between functional groups and a surface
  • Measure adhesion forces
  • Mechanical measurements of cells (both fixed and living), polymers, gels
 

Interactions Between Oil Droplets Probed by Force Spectroscopy with the MFP-3D™ AFM
Understanding the interactions between the colloidal particles found in emulsions is important to a range of applications from the food and pharmaceutical industries through to oil recovery and mineral flotation. The interactions which occur between emulsion droplets are of huge importance in determining the functional properties of such systems. These interactions can be modified by the adsorption at the oil-water interface of surface-active species such as small molecule surfactants, proteins or polymers. However, the physical interactions which occur between emulsified oil droplets have traditionally been a difficult area to study, with work historically being carried out on model rigid colloidal particles. This has changed recently following the development of methods to attach oil droplets to atomic force microscope (AFM) cantilevers. These methods have demonstrated that the measurements are sensitive to the nature of the interfacial film and have allowed detailed study of the force interactions between single pairs of droplets, including recent mathematical modeling.4 In this application note we will illustrate the advantages of studying a real fluid droplet system, capturing effects in the AFM data which are unique to deformable particles with a mobile interfacial layer. All work for this note was performed with an MFP-3D-BIO™ AFM from Asylum Research.
 
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Selected Publications

S. Assemi, J. Nalaskowski, and W. P. Johnson, "Direct force measurements between carboxylate-modified latex microspheres and glass using atomic force microscopy," Colloids Surf., A 286, 70-77 (2006). doi:10.1016/j.colsurfa.2006.03.024

A. Calò, D. Reguera, G. Oncins, M.-A. Persuy, G. Sanz, S. Lobasso, A. Corcelli, E. Pajot-Augy, and G. Gomila, "Force measurements on natural membrane nanovesicles reveal a composition-independent, high Young's modulus," Nanoscale 6, 2275 (2014). doi:10.1039/c3nr05107b

W.-J. Chung, K.-Y. Kwon, J. Song, and S.-W. Lee, "Evolutionary Screening of Collagen-like Peptides That Nucleate Hydroxyapatite Crystals," Langmuir 27, 7620-7628 (2011). doi:10.1021/la104757g

C. Dika, M. Ly-Chatain, G. Francius, J. Duval, and C. Gantzer, "Non-DLVO adhesion of F-specific RNA bacteriophages to abiotic surfaces: Importance of surface roughness, hydrophobic and electrostatic interactions," Colloids Surf., A 435, 178-187 (2013). doi:10.1016/j.colsurfa.2013.02.045

E. K. Dimitriadis, F. Horkay, J. Maresca, B. Kachar, and R. S. Chadwick, "Determination of Elastic Moduli of Thin Layers of Soft Material Using the Atomic Force Microscope," Biophys. J. 82, 2798-2810 (2002). doi:10.1016/s0006-3495(02)75620-8

T. Dugdale, R. Dagastine, A. Chiovitti, and R. Wetherbee, "Diatom Adhesive Mucilage Contains Distinct Supramolecular Assemblies of a Single Modular Protein," Biophys. J. 90, 2987-2993 (2006). doi:10.1529/biophysj.105.079129

R. W. Friddle, K. Battle, V. Trubetskoy, J. Tao, E. A. Salter, J. Moradian-Oldak, J. J. D. Yoreo, and A. Wierzbicki, "Single-Molecule Determination of the Face-Specific Adsorption of Amelogenin's C-Terminus on Hydroxyapatite," Angew. Chem. Int. Ed. 50, 7541-7545 (2011). doi:10.1002/anie.201100181

C. A. Grant, J. E. McKendry, and S. D. Evans, "Temperature dependent stiffness and visco-elastic behaviour of lipid coated microbubbles using atomic force microscopy," Soft Matter 8, 1321-1326 (2012). doi:10.1039/c1sm06578e

A. P. Gunning, A. R. Kirby, C. Fuell, C. Pin, L. E. Tailford, and N. Juge, "Mining the 'glycocode'--exploring the spatial distribution of glycans in gastrointestinal mucin using force spectroscopy," The FASEB Journal 27, 2342-2354 (2013). doi:10.1096/fj.12-221416

T. Gutsmann, T. Hassenkam, J. A. Cutroni, and P. K. Hansma, "Sacrificial Bonds in Polymer Brushes from Rat Tail Tendon Functioning as Nanoscale Velcro," Biophys. J. 89, 536-542 (2005). doi:10.1529/biophysj.104.056747

Á. Karsai, M. S. Kellermayer, and S. P. Harris, "Mechanical Unfolding of Cardiac Myosin Binding Protein-C by Atomic Force Microscopy," Biophys. J. 101, 1968-1977 (2011). doi:10.1016/j.bpj.2011.08.030

M. S. Z. Kellermayer, L. Grama, A. Karsai, A. Nagy, A. Kahn, Z. L. Datki, and B. Penke, "Reversible Mechanical Unzipping of Amyloid β-Fibrils," J. Biol. Chem. 280, 8464-8470 (2004). doi:10.1074/jbc.m411556200

C. Lesoil, T. Nonaka, H. Sekiguchi, T. Osada, M. Miyata, R. Afrin, and A. Ikai, "Molecular shape and binding force of Mycoplasma mobile's leg protein Gli349 revealed by an AFM study," Biochem. Biophys. Res. Commun. 391, 1312-1317 (2010). doi:10.1016/j.bbrc.2009.12.023

A. Li, S. N. Ramakrishna, E. S. Kooij, R. M. Espinosa-Marzal, and N. D. Spencer, "Poly(acrylamide) films at the solvent-induced glass transition: adhesion, tribology, and the influence of crosslinking," Soft Matter 8, 9092 (2012). doi:10.1039/c2sm26222c

B. H. Lower, L. Shi, R. Yongsunthon, T. C. Droubay, D. E. McCready, and S. K. Lower, "Specific Bonds between an Iron Oxide Surface and Outer Membrane Cytochromes MtrC and OmcA from Shewanella oneidensis MR-1," J. Bacteriol. 189, 4944-4952 (2007). doi:10.1128/jb.01518-06

J. A. C. Santos, L. M. Rebêlo, A. C. Araujo, E. B. Barros, and J. S. de Sousa, "Thickness-corrected model for nanoindentation of thin films with conical indenters," Soft Matter 8, 4441 (2012). doi:10.1039/c2sm07062f

P. Schwaderer, E. Funk, F. Achenbach, J. Weis, C. Bräuchle, and J. Michaelis, "Single-Molecule Measurement of the Strength of a Siloxane Bond," Langmuir 24, 1343-1349 (2008). doi:10.1021/la702352x

M. Seydou, Y. J. Dappe, S. Marsaudon, J.-P. Aimé, X. Bouju, and A.-M. Bonnot, "Atomic force microscope measurements and LCAO-S2 + vdW calculations of contact length between a carbon nanotube and a graphene surface," Phys. Rev. B 83, 045410 (2011). doi:10.1103/physrevb.83.045410

R. F. Tabor, C. Wu, F. Grieser, R. R. Dagastine, and D. Y. C. Chan, "Measurement of the Hydrophobic Force in a Soft Matter System," J. Phys. Chem. Lett. 4, 3872-3877 (2013). doi:10.1021/jz402068k

K. V. Vliet, G. Bao, and S. Suresh, "The biomechanics toolbox: experimental approaches for living cells and biomolecules," Acta Mater. 51, 5881-5905 (2003). doi:10.1016/j.actamat.2003.09.001