AFM Nanoindentation Experiments on Protein Shells: A Protocol

  • Yukun Guo
  • Wouter H. RoosEmail author
Part of the Methods in Molecular Biology book series (MIMB, volume 1886)


Proteinaceous assemblies are ubiquitous in nature. One important form of these assemblies are protein nanoshells such as viruses; however, a variety of other protein shells exist. To deepen our knowledge on the structure and function of protein shells, a profound insight into their mechanical properties is required. Nanoindentation measurements with an atomic force microscope (AFM) are increasingly being performed to probe such material properties. This single particle approach allows us to determine the spring constant, the Young’s modulus, as well as the force and deformation at which failure occurs of the nanoshells. The experimental procedures for these mechanical measurements are described here in detail, focusing on surface preparation, AFM imaging and nanoindentation, and the subsequent data analysis of the force–distance curves. Whereas AFM can be operated in air and in liquid, the described methods are for probing single particles in liquid to enable studies in close to physiological environments.

Key words

Protein shell Virus Bacteriophage Capsid Atomic force microscopy Nanoindentation Force spectroscopy Mechanical properties Materials science Biophysics 


Justification and Acknowledgments

A first version of this chapter was published in Methods in Molecular Biology Vol. 783 pp 251–264. The current version is an overhaul and extended version of the previous protocol. This work is supported by a Nederlandse Organisatie der Wetenschappen Vidi vernieuwingsimpuls grant (to WHR).


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Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Moleculaire Biofysica, Zernike Instituut, Rijksuniversiteit GroningenGroningenThe Netherlands

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