Published on 23 August 2017

Researchers from École polytechnique and CNRS have designed a new method to track the flow of fluids on a very small scale.

Thrombosis (or phlebitis) acts as the formation of clots in blood vessels, which can hinder blood circulation. As for atherosclerosis, which characterizes as plates developing inside an artery, complications can be significant, especially if the clot breaks off and starts to circulate in the body. Close monitoring of blood vessels is then paramount.

Luminous nanorods

In collaboration with a Dutch team, researchers from Laboratoire de Physique de la Matière Condensée (PMC) and Laboratoire d'Hydrodynamique (LadHyX), two laboratories shared by CNRS and École polytechnique, both members of Université Paris-Saclay, proposed a new tracking method. They used the optical properties of rods containing phosphorus P and europium Eu. Only a few nanometers long, these sticks produce polarized light: observed by microscope, this light can provide information on the nanorods’ positioning.

Scattered in a fluid, the nanorods are thus used as probes and can establish a real-time map of the fluid. In particular, they highlight the shear forces. Elongated sticks are spontaneously moving in the direction of the current, as logs in a river would do.

Given their size, these rods allow a resolution never reached before and can observe flows in very small channels, such as blood vessels. This innovation could then have applications in medicine, but also in other areas using fluids. Published in Nature Nanotechnology, this technique could also serve as biomarkers to track cells, genes or proteins.

A selective scholarship for a Korean student

Jeongmo Kim received a prestigious scholarship from the Kwanjeong Educational Foundation (KEF). This scholarship rewards the talented Korean students who continue their studies at prestigious universities outside Korea. To validate his "Technological Innovation: engineering and entrepreneurship" master’s degree at Université Paris-Saclay, Jeongmo Kim did an internship on nanorods at Laboratoire de Physique de la Matière Condensée (CNRS/École polytechnique). He will now pursue a Ph.D. with the following subject: "Development, optical properties and applications of luminescent individual or self-assembled nanorods".

Learn more:

  • read the PMC article (in French)
  • access the scientific article: Monitoring the orientation of rare-earth doped nanorods for flow shear tomography Nature Nanotechnology, published online 19 June 2017. DOI : 10.1038/NNANO.2017.111