Nanoparticle screening breakthrough

Scientists in Switzerland have discovered an innovative method to enable them to screen the safety of nanoparticles for medicinal use.

The scientists are now able to determine if nanoparticles are suitable for use in the human body in less than a week – previously this would take several months. Nanoparticles are small enough for use as markers for diagnostics or to deliver therapeutic molecules to specific areas in the body.

Professor Carole Bourquin, from the University of Geneva (UNIGE), said: “Researchers can spend years developing a nanoparticle, without knowing what impact it will have on a living organism. So there was a real need to design an effective screening method that could be implemented at the beginning of the development process. Indeed, if the nanoparticles aren’t compatible, several years of research were simply thrown away.”

Nanoparticles are between one and 100nm, similar in size to a virus. There are three criteria for consideration before nanoparticles are deemed suitable for human use. These are non-toxicity, unlikeliness to activate the immune system and avoiding ingestion by macrophages.

Inés Mottas, also from UNIGE and first author, said: “When you begin to develop a new particle, it’s very difficult to ensure that the recipe is exactly the same every time. If we test different batches, the results may differ. Hence our idea of finding a way to test the three parameters simultaneously - and on the same sample — to establish the product’s biocompatibility.”

Professor Bourquin and her research team used flow cytometry to determine nanoparticle suitability. Macrophages were incubated with nanoparticles for 24 hours, before being passed in front of a laser beam. As the nanoparticles tested were fluorescent, the amount ingested by the macrophages could be quantified. Fluorescence emitted by the macrophages enabled them to be counted and their activation levels measured in response to the nanoparticles. The whole process is completed in two or three days.

This method, developed in conjunction with the university of Freiburg, is part of the ‘Bio-inspired Materials’ programme at the National Centres of Competence in Research. As well as cost savings in research, the researchers believe that this new approach limits the use of animal testing.

The research was published in Nanoscale.