What happens to creams and drugs in space? COLIS studies the behaviour of soft matter in weightlessness

COLIS is the latest facility developed for the ESA project ‘Colloids in Space’, a product of the Politecnico di Milano and the Université de Montpellier’s partnership.

Milan, Montpellier, 27th November 2025– The shelf life of a sunscreen, the stability of a mayonnaise, the effectiveness of a drug; these all depend on what is happening within the materials that make up gels or glasses, disordered structures that change slowly over time.
To truly understand how they change, a group of researchers from the Politecnico di Milano and the Université de Montpellier & CNRS decided to study them in near-zero gravity – in space.

This led to the development of COLIS, a new facility (an experimental laboratory installed on the International Space Station) devoted to studying soft and complex matter in microgravity.
The project is part of the European Space Agency (ESA)’s ‘Colloids in Space’ programme, with the support of the Italian Space Agency (ASI) and the Centre National d’Études Spatiales (CNES).

COLIS is the result of a longstanding partnership between Luca Cipelletti (physicist at the Laboratoire Charles Coulomb of the Université de Montpellier & the CNRS), and Roberto Piazza (professor of Condensed Matter Physics at the Politecnico di Milano’s ‘Giulio Natta’ Department of Chemistry, Materials and Chemical Engineering, where he runs the Soft Matter laboratory).

‘Studying these materials in microgravity allows us to isolate the effect of gravity, a silent but decisive force in how they change over time,’ explains Roberto Piazza.
‘Understanding these processes will help us design more stable formulations, from controlled-release drugs to self-assembling materials.’

COLIS uses dynamic light scattering and correlation imaging techniques to analyze ‘speckle patterns’ – tiny variations in how laser beams pass through a sample – to monitor how gels and colloidal glasses restructure over time.
It also has controlled thermal stimulation systems, making it possible to trigger and then observe the aging processes of materials in a precise and reproducible way.

Another innovation is the ability to measure polarization fluctuations in scattered light, useful for early detection of crystalline phase formation.
This functionality will be used by the teams of Dominique Maes and James Lutsko of Vrije Universiteit Brussel to study protein crystallization in microgravity, a key step towards improving drug stability and biotechnological production.

‘COLIS is the culmination of more than 25 years’ work with the Politecnico di Milano,’ adds Luca Cipelletti. ‘Bringing soft matter physics to the ISS is a technological and scientific step that opens up new frontiers when it comes to studying disordered matter.’

Designed by scientists and built by Redwire Space, COLIS was transported to the ISS by NASA’s Cygnus NG-21 freighter.
The facility is already fully operational, analyzing gel and glass samples consisting of colloidal nanoparticles, which are ideal for investigating the internal reorganization and aging processes of matter.

Luca Cipelletti, Roberto Piazza, Stefano Buzzaccaro (Politecnico di Milano’s Co-PI for this project) and Alessandro Martinelli (post-doc at Montpellier, funded by the French CNES), have obtained the first results, which indicate that gravity affects the structure of soft matter more markedly than expected, influencing its properties even in the long term.

‘It’s amazing to see how much gravity, so familiar in our daily lives, acts behind the scenes to shape the materials we use every day,’ concludes Piazza. ‘These observations help us understand and improve the behaviour of matter over time – a goal that directly affects the quality of life on Earth.’

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