Scientists at the Max Planck Institute of Colloids and Interfaces have presented a new method with which to precisely control the permeability of microcapsules using the salt content and the temperature of the solution. In order to accomplish this, the researchers developed a theoretical model which exactly describes the processes in the polymer shell of the capsules. This means that is possible to predict, without any experimental investigations, how the properties of the hollow spheres will change if the temperature and salt content are altered (Physical Review Letters, November 3, 2006). This opens up new possibilities for using the capsules to transport active substances in the body, as components of self-repairing car paints or as microsensors and micropumps.
Ideally, medicines should only go to the sick regions of the body to prevent side-effects and to be as effective as possible. This requires intelligent transport systems which initially enclose the active substances and then release them at the location where they are to be effective given the presence of certain conditions. Scientists at the Max Planck Institute of Colloids and Interfaces in Potsdam are working on a microtransport system which meets these requirements exactly. Polymer capsules of just a few micrometres, i.e. thousandths of a millimetre, transport drugs through the organism. The walls of the microcapsules are constructed from alternate layers of positively and negatively charged polymer molecules so that molecules with very different properties can be used to make the capsules.
To maximize the usefulness of the capsules, it is important that the permeability of the capsule wall can be adjusted precisely. When the microcontainer is filled, the wall must initially allow the active substance through to the inside. Then the capsule shell must be sealed to enclose the contents so that they can be released at the location where they are to take effect. The scienti
Contact: Karen Khler