Nature Commun 4, 2239 (2013)

Credit: © 2013 NPG

Artificial, cell-like microcapsules made of lipids, polymers, peptides or colloidal particles have enabled huge progress in drug delivery, synthetic biology and biocatalysis, in part because they can be imbued with relevant functionality such as stimuli-responsiveness or selective permeability. Stephen Mann and colleagues now show that containers of amphiphilic protein–polymer conjugates have advantageous multifunctionality that may allow further technological developments in these fields. The researchers demonstrate that microdroplets of the conjugates self-assembled at the oil/water interface are elastic after being transferred to a water-based phase following polymer crosslinking and oil removal (they can be air-dried and rehydrated), can encapsulate hundreds of components and have temperature-dependent permeability to external proteins. These so-called proteinosomes are thus enzymatically active, and can serve as a gene-directed protein-synthesis container (a protocell) with temperature-switchable reaction rates. The researchers also show that the proteinosomes are robust to temperatures up to 70 °C for hours.