The construction of the primary capsule is a necessary step for the construction of a spherical shape which is coated afterwards. In the following figure is shown an example of a primary capsule:
Figure 1: Primary capsules made of alginate and calcium ions.
In the best-case scenario, the core contains the all the encapsulating material. However, for a good process control, additional compounds are needed. As instance, the use of Ca2+-ions is needed for cross-linkage of alginate.
Figure 2: Different wall sizes due to variation of cross-linking agents and shell material.
In our department, we focus mainly on two factors:
- Firstly, the ideal cross-linking agents, which are influencing different parameters of the shape, like permeability, stability or thickness of the wall.
- Secondly, on additives, which are necessary to adjust the viscosity and supports the building of the outer shell.