Algae tunnelling out of glass jails could lead to new materials for biomedical devices, French scientists have revealed. 

Pascal Lopez from Ecole Normale Supérieure, Paris, and colleagues trapped single celled algae, called diatoms, in silica gel. The group found that the captured organisms lived longer and changed the gel properties as they dug away at their silica cage. 

Trapped algae dissolve their silica cages.

In nature, diatoms use silicon to encase themselves inside silica shells. The scientists wondered whether this feature would allow the organisms to survive inside silica gels. When we tested this, we were surprised to find that the diatoms dissolve the silica surrounding them, said Lopez. 

Lopez suggests that understanding how the diatoms dissolve the silica cages will help to explain their roles in the silicon biogeochemical cycle. 'Encapsulation inside silica gels may be a suitable approach to model the interactions between living organisms and minerals,' he said. 

David Avnir, an expert in entrapment in sol-gel materials, from the Hebrew University of Jerusalem, Israel, is enthusiastic about the work's applications. 'This is an exciting new addition to the library of materials that are hybrids of biomolecules and inorganic matrixes. Such "living materials" are potentially important for applications in biotechnology, in the synthesis of drugs, and in the design of sophisticated sensors,' he said. 

Rebecca Gillan