Encapsulation of biological materials

Colloidosomes have received considerable attention over the past decade. These capsules comprise aqueous cores surrounded by a layer of (typically polymeric) colloidal particles, which fuse to produce a shell. However the use a 200 nm polymer shell does not provide a significant barrier for small molecule leakage. Consequently these capsules have not been used to encapsulation of dyes and fragrances. The biologically benign synthesis and inherent leakage of colloidosomes makes these capsules attractive for encapsulation of biological materials. We have demonstrated the encapsulation of yeast and bacteria with continued metabolic activity. For encapsulation of enzymes we encountered a leakage, due to the small enzyme size. To counter this, a secondary shell of calcium carbonate seals the capsule until a mechanical or acidic trigger is applied. For targeted delivery of these capsules we create a secondary shell of either silver or gold. The silver shell creates an impermeable barrier, whilst the gold forms as discrete nanoparticles on the colloidosome surface. The use of these metal layers to anchor proteins will be discussed References Polly H. R. Keen, Nigel K. H Slater and Alexander F. Routh, Encapsulation of yeast cells in colloidosomes, Langmuir, 28(2):1169-1174 2012 Polly H. R. Keen, Nigel K. H Slater and Alexander F. Routh, Encapsulation of lactic acid bacteria in colloidosomes, Langmuir 28(46):16007-16014 2012. Polly H. R. Keen, Nigel K. H. Slater & Alexander F. Routh, Encapsulation of amylase in colloidosomes, Langmuir 30:1939-1948 201