 Islets encapsulated in immunoprotective microcapsules are being proposed as an alternative for insulin therapy for treatment of type 1 diabetes. Alginates for medical application should have an extreme high degree of purity and lack pathogen associated molecular patterns, PAMPs, to avoid activation of the recipient's immune system. This article was authored by Genaro Alberto Paredes Juarez, Milica Especijevic, Marieke Faus and others.