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We investigate the structure-function relationship of biomaterials; how do mechanics control biological function? Currently, our research is focused on protein cages like viruses and clathrin coats and whole cells. These structures often show a remarkable correlation between their life stage and mechanical response. Viruses for example are very robust when they travel between host organisms but once they enter a target cell they undergo structural changes that eventually allow them to open up to release their genetic material. Because we perform our experiments in a controlled liquid environment, we can mimic events that are triggered by temperature, chemicals, pH, or force, which enables us to investigate the mechanical transitions during the unpacking of influenza viruses and adenoviruses.
In addition, we use our knowledge about the architecture of natural biomaterials to improve the application of biomolecules in nanotechnology. In recent work we showed that clathrin proteins, normally involved in the formation of transport vesicle in cells, can be applied to form very regular and stable lattices on almost any type of surface. This surface functionalization could be a first step to fabricate more efficient sensors or biosynthetic reactors.

To measure the mechanical response we indent or stretch our samples on a sub-micrometer length-scale. Depending on the composition of the material we expect either a elastic response (regular protein assemblies like viruses), or a more complex visco-elastic behaviour that depends on both the time- and length-scale of the deformation experiment (heterogeneous structures like cells). For the more robust samples we use atomic force microscopy and for fragile samples a vertical laser trap, a special in-house development for very soft materials. Finite element analysis is employed to model the experiments in order to extract the intrinsic mechanical parameters of the tested materials.

Much of our research is carried out as national or international collaborations, in which we provide the nano-mechanical expertise while our partners are experts on a specific biological system.

We have now moved to the Institute of Biological Chemistry, Biophysics and Bioengineering (IB3) at the Heriot Watt University in Edinburgh, UK.

Till 2015 our research group was part of the Third Institute of Physics - Biophysics at the Georg August Universität in Göttingen, Germany.

We acknowledge support from the Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)
Cluster of Excellence 171, the SFB 860, and the Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences (GGNB).

Dr. Iwan A.T. Schaap

tel: +44 131 451 4145
i.schaap (at)

Institute of Biological Chemistry, Biophysics and Bioengineering
School of Engineering and Physical Sciences
Heriot-Watt University
EH14 4AS  Edinburgh, UK

© Iwan Schaap