Position of the project – The mechanical properties of biological systems play a complex role in determining the physiological functions of tissues and appear to be dominant factors in many diseases progression. Interestingly, tissues with properties as different as bone, skin or tendon are mainly composed of the same elementary units, primarily fibrillar collagen. Hence, their specific mechanical properties are directly linked to their sub-microscopic organisation. Nowadays, understanding the structure/function relation in connective tissues faces the challenge of probing the multiple scales involved in constructing macroscopic properties from individual structures in highly complex samples.
The advent of multiphoton microscopy, based on the nonlinear interaction between laser pulses and biological samples, has revolutionised the way we observe living organisms. Notably, Second Harmonic Generation (SHG) microscopy is now considered as the gold standard to visualize collagen distribution in thick samples [1]. In parallel, Brillouin microscopy has recently emerged as a new paradigm to map viscoelastic properties with micrometer resolution in soft and heterogeneous medium [2].
Objectives – In this context, the rational of the project is to combined Brillouin imaging with interferometric and polarimetric SHG. Together with advanced image analysis, this will enable to quantify collagen architecture and viscoelastic properties at sub-micron scale in articular cartilage. Notably, previous studies from Légaré’s group have shown micron-scale domains of constant fibrillar polarity in the vicinity of chondrocytes [3]. Using Brillouin microscopy, we will investigate the role of these domains in determining local mechanical response. This project will provide new insights into the complex morpho-functional relationship in connective tissues as well as a framework to analyse their patho-physiological behaviour.
Environment – As part of an international collaborative effort, this project will be carried on half time at the INRS (University of Quebec, Laval) to perform interferometric SHG, and half time at the LP2N (Institute of Optics, Bordeaux) for Brillouin microscopy, both teams working at the crossroad between nanoscience, optics and bio-imaging. Additionally, Prof. Cameron Brown (Queensland University of Technology, Brisbane) will be involved to guide the interpretation of the microscopic of mechanical properties.
Candidate – This project is primarily experimental and involves aspects of nonlinear microscopy (optical alignment, image acquisition), data analysis (ImageJ /Python/ Matlab) and basic tissue preparation. We are seeking for candidates with a background in optics/biophysics and motivated to work in an interdisciplinary environment. Experience in microscopy, nonlinear optics and image/signal processing will be an asset.
To apply for this job please visit cnrs.fr.