Current technologies make it possible to measure the mass of objects ranging from that of a truck of several tons to a hydrogen atom; on the other hand, a technological vacuum exists for a whole range of intermediate masses, in particular in the field of nanometric objects like most viruses, or nanoparticles. The researchers wanted to fill this void by designing an instrument consisting of three stages: nebulization of the species in solution, focusing of the particle beam by an aerodynamic lens, and measurement of the mass of these particles by a network of mechanical nanoresonators.

Thanks to this new system, researchers at Leti and at our laboratory have been able to measure the mass of a virus capsid, that of the phage T5 (100 megadaltons) which is studied at I2BC (University Paris-Sud). This bacterial killer virus is a representative of bacteriophages considered as a promising alternative to conventional antibiotic therapies. Its molecular composition and theoretical mass are known, but the commercial instruments could not, so far, accurately weigh the phage. This new capacity may allow, for example, the quality control of the production of viral particles for the production of vaccines or the characterization of bacteriophages for phagotherapy.

The system that has been designed and developed, meets these objectives with a gain in detection efficiency of one million times compared to pre-existing nano-mechanical systems. This is done in a time of analysis and with a consumption of sample which makes it possible to envisage a use in routine.