Filled LbL Capsules

The walls of polyelectrolyte capsules are in general semi-permeable, e.g. for molecules with a molecular weight less than 10 kDa they are permeable, while for higher molecular weight molecules they are impremeable.

There have been a number of techniques developed which allow the in-filling of polyelectrolyte LbL capsules with proteins, enzymes, or DNA/RNA. In addition to in-filling, the capsules can also be endowed with fluorescence, a magnetic charge and various surface functionalities.


Some Applications

Macromolecules inside the polyelectrolyte capsule are well protected against any attack by bacteria or enzymes, however, small molecules for reactions or scavenging can still pass through the wall and be immobilised within. Vice versa, the release of molecules from within the capsule is also possible by adjusting the bulk media (pH, salt concentration, polarity). 

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.)