Développement des systèmes biomédicaux à la base des cristaux liquides

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Liquid crystal (LC) materials have gone through an extraordinary journey evolving from exotic and fascinating materials to an industry of flat panel LC displays amounting to $100 Billion / year. The main physical mechanism of this “transformation” is their sensitivity to the electric field (without mentioning the importance of visual communication for humans). However, those materials have much more to offer. Indeed, an increasing amount of evidence is available pointing to the important role of the same fundamental physical mechanisms (as those governing LC materials) in biological systems and processes. For example, it was shown that the anisotropic LC phase can be observed in solutions of chitin or collagen. Natural mucus and synovial fluid can also show an LC phase. Biological tissue has many other elastic anisotropic liquid or gelly states, probably the biological membrane (such as myelin) being one of the most striking examples. At the same time, it is well known that the majority of drugs are chiral molecules and the role of chirality is extremely important in the biological world. In addition, we have recently discovered that chirality could also significantly affect the drug diffusion processes where many key questions remain unanswered. For example, a drug injected into the cerebrospinal fluid poorly penetrates into brain tissue owing to the limitations of diffusion, the mechanisms of which are not well understood yet. A better understanding of those mechanisms might thus help in optimizing drug fabrication and delivery methods that represent huge social and economic interest. There is no doubt that many fundamental processes taking place in the biological world (such as molecular diffusion, orientational organization, elastic structural deformation of cell membranes, electric conductivity in axons, etc.) have deep analogies with physical processes present in LC materials. I believe that the use of our knowledge of the physics of LCs accumulated during the last century will help us to better understand the biological processes and to enable new medical solutions. In the framework of this research program, we shall study the physical mechanisms of interaction of chiral molecules with various LC tissue models corresponding to specific biological cases, such as membranes, mucus, etc. We shall collaborate with experts from the biomedical community to identify the most realistic conditions for such experimental simulations. We shall then use the results obtained to design and execute experiments with real biological samples and real chiral drugs (instead of arbitrarily chosen chiral molecules). This will be done first in-vitro (on tissue slices) and then in-vivo (using our adaptive endoscopy tools). Finally, we shall explore the possibilities of increasing the effect of the chiral diffusion barrier (for drug filtering) or, in contrast, the ways of reducing it for better drug delivery.