CLSM images of a group of hydrogel microspheres prepared as in (b) and recorded before (left,t=0 h) and 24 h after (right) the addition of urea, glucose and HRP. Initially, the hemispheres consist of FITC-labelled GOx-containing colloidosomes (1, green domain,t=0) and Ca2+-crosslinked alginate, or Ca2+-crosslinked alginate (39 wt %)/RITC-labelled alginate (33 wt %, red,t=0)/tyramine-alginate (28 wt %) with urease-containing colloidosomes (2, red domain,t=0). Selective disassembly leads to release of the FITC-GOx-containing colloidosomes and unlabelled alginate into the bulk solution (green background,t=24 h) while the urease-loaded colloidosomes remain immobilized in the tyramine-crosslinked RITC-alginate hemispheres (red fragments,t=20 h). Scale bar, 400 μm.
