Fig. 1.

Schematic procedure. a) Sugar recipe preparation, b) 3D printing of the sugar glass construct loaded with calcium chloride, c) Preparation and casting of the alginate mixture, containing CaCO₃ and GDL, (t = 0), d) Immediately after casting the alginate mixture, formation of a membrane at the sugar/ALG interface due to the release of the Ca²⁺ ions from the CaCl₂ contained in the fugitive ink, (t = 0+), e) Completed internal gelation of alginate, (t = 600 s), f) Dissolution of the remaining sugar glass template in a demineralized water bath, g) Perfusion of the alginate gel with red food dye.