Crusoé: mimicking nature's language to repel mosquitoes
On the occasion of the Innovation Awards ceremony taking place in July, UM is honoring its previous winners. Today, Claude Grison, winner of the 2020-2021 Innovation Award. Director of the ChimEco laboratory, this chemist and her team have developed an innovative mosquito repellent using a combination of natural molecules that are harmless to humans. Named Crusoé, this repellent is directly inspired by the language of nature.
Claude Grison is the woman who whispers in the tiger mosquito's ear. Director of the ChimEco laboratory for bio-inspired chemistry and ecological innovations (CNRS/University of Montpellier), the researcher embarked on this adventure in 2017. At the time, she herself was annoyed by this insect that spoils our summer evenings, and she noticed that the repellents on the market were either ineffective or entirely chemical-based. "The most effective molecule to date was DEET. However, it is a chemical molecule that is not well suited to the mosquito's functioning. And the latest studies have shown that it can be harmful to health, " explains Claude Grison. Conversely, she also noticed that no one had yet taken inspiration from nature in this area. "We know how nature communicates in the field of attraction, but I was surprised to see that the same reasoning had not been applied to repulsion."
100% bio-based and with no environmental impact
Halfway between sustainable chemistry and ecology, Claude Grison has therefore set herself the task of remedying this scientific oversight. "Mosquitoes have more than 100 olfactory receptors, and many other receptors are involved in chemical communication with their environment. The aim was therefore to develop a repellent designed in a combinatorial manner, in order to trigger a strong reaction, whether pleasant or unpleasant," explains the researcher. Her goal at the time was to find the right combination of natural molecules so that they would be recognized by as many receptors as possible.
After promising initial trials, the CNRS awarded her €140,000 to finance the "pre-maturation" stage of the project. "It turns out that one of the most repellent natural molecules is also very scarce. So we had to synthesize it. And my challenge, in order to be consistent with my values and my work, was to obtain it using completely natural processes. Our syntheses are based solely on plant materials. They are 100% bio-based and have no environmental impact, " insists Claude Grison.
The ecocatalysis method
To achieve this, the ChimEco laboratory team used the ecocatalysis method developed in situ by the researcher. The principle: "using the mineral resources of certain plants to transform them into catalysts." This innovative process has been the subject of 36 patents and has earned Claude Grison numerous awards, including the CNRS Innovation Medal in 2014. Using this mechanism, the researchers carried out more than 4,000 behavioral tests on over 24,000 insects. To refine their mixture, they also carried out 300 molecule syntheses. The experiments were conducted at Vectopôle Sud, an entity comprising nine partners (including CIRAD, CNRS,IRD,EID, the University of Montpellier, andANSES).
In practical terms, the tests consisted of placing 10 mosquitoes in a cup attached to a membrane covered with repellent on one side and animal blood on the other. After an hour, the mosquitoes were asleep, collected one by one, then crushed on a sheet of paper so that the number of bloodstains could be examined, i.e., the number of insects that had actually bitten the skin... "We worked non-stop for two and a half years, with virtually no holidays, because mosquito behavior is different in winter and summer," explains Claude Grison. It was intense work, but it quickly hit the mark. The researchers soon identified two combinations of molecules with very strong repellent effects. According to Claude Grison, this product, called Crusoé, is around 90% effective, compared to 55% for DEET under the conditions of the study. It also shows great promise against tick bites...
“I wanted it to be useful to society.”
In 2021, through her start-up Bioinspir, which had previously been working on invasive plant species, Claude Grison joined forces with Technofounders. Together, they co-founded a company called Laboratoire Bioprotection with a view to producing and distributing Crusoé. "I wanted it to be useful to society, so we had to find a partner who shared our ethics to bring the repellent to market. The CNRS and the University, co-owners of the patents on ecocatalysis, were never obstructive, quite the contrary," says Claude Grison. From a more pragmatic point of view, this partnership enabled him to round out his skills in regulatory and administrative matters. "That was the only thing we were lacking, " adds the scientist. It also enabled him to increase the company's capital thanks to CNRS Innovation, which made this possible on behalf of the CNRS and the University of Montpellier through a debt settlement.
That same year, the team also received support through the Companies And Campus call for projects, launched as part of the University of Montpellier's Muse program of excellence. The result: an additional budget of €50,000. This was a crucial contribution at a time when the team was finalizing the last details before commercialization. "It was extremely important. It enabled us to make progress on the regulatory side, but also to validate our composition on wild mosquito strains in tropical areas," explains Claude Grison.
In the wake of this, in just six months Crusoé obtained Ecogarantie certification and entered the pharmaceutical market. Since then, more than 400,000 products have been sold in France and internationally. At the same time, Claude Grison has also been showered with awards for her famous patents. In 2022, for example, she received the European Inventor Award from the Patent Office, followed by the Woman of Influence Award in the economics category in 2023. But between trophies, she never stopped working on the next step. Now, she aims to launch a version of Crusoé designed to repel bed bugs. With her team, she is also trying to develop a technique for diffusing the product in homes.