Polyelectrolyte Capsules As Carrier Systems For Local Delivery Of Cargo

One of the possible contributions of nanomedicine would be in building biocompatible multifunctional carrier systems that are able to navigate within living organisms using remote guidance and activation for the local release of their cargo. Such carrier systems are used to improve cargo stability, to sustain and control their release rates, to increase the bioavailability of cargo substances, and to target them to specific sites within the body. To the best of our knowledge, a system which combines all these functionalities into one structure has still not been developed. The requirements of such a system can be conceptually divided into several steps.

First, the cargo (in general bioactive molecules) has to be encapsulated. This not only allows for high local concentration inside the carrier, but also for protection of both the cell and the cargo molecules against cytotoxic damage and enzymatic degradation, respectively. Next, the cargo has to be delivered to the target cells while sparing the surrounding cells. Finally, the cargo has to be locally released from the carrier inside the target cells using an external trigger. In the following section the perspectives of using polyelectrolyte capsules for target delivery and controlled release will be discussed, whereby the encapsulation of biological molecules has already been described.