Terahertz ATR Sensor for real-time study of cell membrane permeabilization – TeraCellATR

Methods to monitor in real time the molecular exchanges across the membrane of living cells are still rare. Benefiting from recent technological developments, the terahertz domain of the electromagnetic spectrum offers significant potential in the biomedical field.
Our project, based on a close two-year collaboration between a terahertz biosensor development team at LOB and a team of biologists and chemists at IMRCP, will design a routine terahertz sensor to provide real-time information and quantification of cell membrane exchange, on multiple replicates in parallel and in an environment compatible with long-term cell culture (several hours). Our guideline will be a constant comparison of the evaluation of plasma membrane integrity with the terahertz sensor and with standard biological techniques, to evaluate the complementarity of the terahertz sensor on two main biological axes: cells in contact with polymeric nanovectors or proteins and in the context of oxidative stress in relation to different therapeutic situations such as Alzheimer's disease.
The work will be organized in two tasks:
- The first one will include all the technological development aspect of the terahertz sensor platform, by evolving the already existing device towards a system with a controlled environment in temperature and CO2, allowing a parallelization of the measurements and a reduction of the studied volumes.
- The second will focus on the comparison of terahertz measurements with those obtained by classical biological tests (electron microscopy, exchange of different ions, molecules of different sizes). The permeations will be induced either by the presence of (bio)macromolecules or by oxidative stress.

The originality and strengths of the project will be based on:
- The development and use of the QCL-ATR terahertz contrast technique for real-time monitoring of cell membrane permeabilization in both early and late processes (minutes to hours), in a biocompatible environment,
- Direct comparison of well-established bioassays and the new terahertz biosensor,
- Simultaneous access to a large number of replicas by parallelization of measurements,
- A strong reduction of detected volumes for rare or expensive samples.

The potential applications of the terahertz sensors developed in this project are numerous. In biology: demonstration of molecule exchange across the membrane, electroporation, drug delivery, viral vectors... The study of bacterial biofilms would be particularly interesting: adhesion of the biofilm to the surface, monitoring of microbial growth dynamics, colonisation, antibiotic resistance.... Biofilms represent a major societal and industrial issue in Europe: health, environmental pollution, corrosion, etc. From a more fundamental point of view, these sensors will also be very useful in chemistry and physical chemistry by measuring the terahertz dielectric constant of liquids with unequalled precision: solvation layer of ions or proteins in water, polarisable intermolecular potential...