Figure 2.
Examples of encapsulation systems and modification of islets. (A) Overview of microencapsulation. Microcapsules incorporate individual or small groups of islets in a spherical hydrogel polymer with a stable structure. (B) Beta-O2 macroencapsulation system. Islets immobilized within the alginate compartment, which is covered by a polytetrafluoroethylene (PTFE) membrane. Alginate and PTFE provide immune protection and facilitate neovascularization. The double-chambered bioreactor is connected to subcutaneous refueling ports through which an oxygen–CO2 mixture is delivered by daily injection. (C) Monolayer cellular device. The collagen support is covered by a mono/bilayer of porcine islets and embedded with alginate. (D) Conformal coating. Cell surfaces can be modified with amphiphilic polymers that interact both with the lipid membrane and the bioactive substance.