Urease encapsulation in nanoorganized microshells.

Stable hollow polyelectrolyte capsules were produced by means of the layer-by-layer assembling of poly(allylamine), PAH, and poly(styrenesulfonate), PSS, on melamine formaldehyde microcores followed by the core decomposition at low pH. These capsules are nonpermeable for urease in water and become permeable in a water/ethanol mixture. The capsules were loaded with urease in water/ethanol mixture and then resuspended in water. The urease molecules are kept in the capsule, whereas the small urea molecules rapidly diffuse through the capsule wall providing a substrate for the biocatalytic reaction.