Forces, mechanics and scales in biological systems

Biology is hierarchically built up by evolution from the molecular to the organism level. Mechanical properties at the nm and micron scales are key to bridge the spatial scales from nm (proteins, DNA) to micron (cells) to higher order scales. We have worked for several years to identify some of the ways in which biological systems use forces, mechanics and vibrations to couple the nm with the micron in the cell membrane in signalling and transport processes. I will overview some of our results using the atomic force microscope (AFM) to directly quantify the mechanical properties of artificial1 and native membranes2. I will show how the mechanical properties of a single membrane protein relate to its local interface properties3, dynamics using high-speed AFM4, 5 individual function and the coupling with neighbouring proteins.4 Using a quantitative method to determine solid-liquid adhesion energy with sub-nm resolution 6 we have quantified the complex electrostatics of membrane proteins measuring ionic effects on the water structure at the interface3.

Finally using multifrequency AFM we are to quantitatively map the nanomechanical properties of living cells and tissues with unprecedented speed and accuracy7. I will finally show some of the biomedical applications that our work on mechanical properties of biological systems are leading us to.

(1) Zhou, Liang, Contera, Nanoscale, 2015.

(2) Voitchovsky, Contera, et. al. Biophysical Journal, 2006.

(3) Contera, Voitchovsky, Ryan,. Nanoscale, 2010.

(4) Voitchovsky, Contera, Ryan, Soft Matter, 2009.

(5) Yamashita, Voïtchovsky, Uchihashi, Contera, et. al. J. Struct. Biol., 2009.

(6) Voitchovsky, Kuna, Contera, Tosatti, Stellacci, Nature Nanotechnology, 2010.

(7) Raman, Trigueros, Cartagena, Susilo, Nauman, Contera. Nature Nanotechnology, 2011.