Over the past twenty years, several techniques have been developed to probe the mechanical properties of biological material on scales ranging from nanometers to micrometers. These techniques have revealed the crucial importance of mechanical aspects in the regulation of many biological (cell migration and division, differentiation, etc.) or pathological (cancer, atherosclerosis, etc.) processes. The spatial scales involved, from nanometers to micrometers, limit experimental access to a limited number of mechanical quantities. This course provides the basics to understand what are these measurable quantities, and according to which principle (for example deflection of a cantilever, photonic or magnetic force, stretching of a soft substrate). The problems linked to the two nanometric (1-10 nm) and micrometric (1-10 µm) “worlds” are tackled: single molecules subjected to thermal fluctuations (example of the rupture of an adhesive ligand-receptor bond), or measurement of cellular viscoelastic properties by micro-indentation using basic contact mechanics. The course also aims to make students aware of the context of fundamental and applied research at the interface between mechanics and biology.
Topics covered:
- cellular architecture, molecules, mechanics and organelles (membrane, cytoskeleton, nucleus, etc.),
- cell rheology,
- contact mechanics and micro-indentation (Hertz, Sneddon model),
- behavior laws: elasticity, cellular viscoelasticity, power-law relaxation / creep function,
- Experimental techniques (non-exhaustive list): optical tweezers, magnetic tweezers, atomic force microscopy, micropipettes, ‘traction force microscopy’, force spectroscopy.
Course sequence.
During the course a significant number (5-7) of researchers will come to present their work related to cellular mechanics. The course will also consist of lectures and associated problems solved during class hours. One to two sessions of experimental demonstration will be carried out in the laboratory (cellular microindentation, viscoelasticity of white blood cells). Students will be asked to present scientific articles in pairs. At the start of each session, a multiple choice questionnaire will be given based on compulsory reading given from week to week.
Evaluation :
- weekly multiple choice questionnaire (30%),
- presentation of scientific articles (30%),
- final exam (multiple choice questionnaire + open questions, 30%),
- participation during lessons (10%).
Numerus clausus : 20
Langue du cours : Français ou Anglais selon la présence de non francophones / French or English depending on the presence of non French speakers in the audience
Credits ECTS : 4
Mise à jour : 14 avril 2020
- Teaching coordinator: Husson Julien