And it can be hacked.

The authors of a new study in Nature Catalysis reprogrammed these blobs—called exosomes—into an army of living nanobioreactors. It’s a seemingly simple process of mix and match: each blob is filled with a different chemical that’s involved in a biological reaction. By bringing two together, the blobs merge into a single squishy container, allowing the two chemicals to react.

The results were explosive. The tiny bioreactors pumped out energy molecules, called ATP, inside living cells. The burst of energy saved injured cells, providing them with a boost of power to fight back against dangerous molecules that otherwise lead to cell death.