Layer-by-Layer Structured Capsules
The walls of polyelectrolyte capsules are in general semi-permeable i.e. for molecules with a molecular weight less than 10 kDa they are permeable, while for higher molecular weight molecules they are impermeable.
A number of techniques have been developed which allow the loading of polyelectrolyte LbL capsules with proteins, enzymes or DNA/RNA. In addition to loading, the capsules can also be equipped with fluorescent dyes, magnetic charge and various surface functionalities.
Image: Capsules (Ø 8-10 µm) which are filled with a solution of the glycoprotein Concanavalin A-Cy5. The walls of the capsule are impermeable to 100 kDa-sized protein molecules. (Image size 40 µm x 40 µm.)