M2 Internship proposal : Investigation of denaturation and aggregation of tear proteins on contact lens surfaces by rheofluidic approach

Back to jobs listing

INRAE presentation

The French National Research Institute for Agriculture, Food, and Environment (INRAE) is a major player in research and innovation. It is a community of 12,000 people with 272 research, experimental research, and support units located in 18 regional centres throughout France. Internationally, INRAE is among the top research organisations in the agricultural and food sciences, plant and animal sciences, as well as in ecology and environmental science. It is the world’s leading research organisation specialising in agriculture, food and the environment. INRAE’s goal is to be a key player in the transitions necessary to address major global challenges. Faced with a growing world population, climate change, resource scarcity, and declining biodiversity, the Institute has a major role to play in building solutions and supporting the necessary acceleration of agricultural, food and environmental transitions.

Work environment, missions and activities

Tear proteins such as lysozyme and lactoferrin play a key role in maintaining ocular surface lubrication, antimicrobial defense, and tear film stability. When a contact lens is placed on the eye, proteins are rapidly adsorbed on its surface. This can lead to protein denaturation and aggregation due to i) surface charge, ii) repeated drying/re-wetting cycles, and iii) shear stress from blinking. The deposit of protein aggregates on contact lenses surface has different drawbacks, such as altering their roughness and wettability and triggering inflammatory states on the ocular surface. The consequences for the comfort of the wearers are evident, resulting in irritation, dryness and risks of infection.
The main goals of this internship project (6 months) are: i) to investigate the behavior of tear film proteins upon contact with different contact lens materials, and ii) explore the link between their denaturation and aggregation and the mechanisms underlying contact lens discomfort. Building on the recent work carried out at the UMR STLO on the study of fouling mechanisms in falling-film evaporators using a rheofluidic approach, and on the collaboration with the Department of Materials Science of the University of Milano-Bicocca, our specific objectives are:
1. Model System Development
Establishing simplified model systems using saline buffer solutions and commercially available tear proteins (e.g., lysozyme and lactoferrin) to study protein–material interactions under controlled conditions;
2. Protein-Material Interaction Analysis
Evaluating how different contact lens materials influence protein adsorption, conformational changes, and aggregation at their surface;
3. Rheofluidic Simulation of In Vivo Conditions
Coupling rheometry approach and microfluidic tests to mimic the shear stress induced by eyelid motion, enabling a more physiologically relevant evaluation of protein behavior on lens surfaces;
4. Characterization of Surface Defects
Analyzing micrometric imperfections previously observed on worn lenses using scanning electron microscopy (SEM), assessing their potential role as nucleation sites for protein aggregates;
5. Correlation with Contact Lens Discomfort:
Relating the observed protein aggregation and surface changes to possible mechanisms contributing to contact lens discomfort in wearers.

Training and skills

Profile required: Students in process engineering, chemical engineering, physics

How to apply

I send my CV and my motivation letter