Chemistry . Material Sciences
POISONOUS PARCELS FOR TUMOR CELLS
For doctors at the university hospital in Ulm, the chemists in Mainz have prepared more complex nanocapsules that could help heal damaged tissue. The nanocapsules contain substances that stimulate the stem cells to differentiate. The doctors smuggle stem cells and nano capsules into the diseased tissue, where the nanovehicle’s load stimulates the stem cells to form healthy heart tissue. As part of the same project, the Mainz-based chemists have also packed fluorescent substances and magnetic contrast media into nanoparticles that penetrate into the stem cells. The doctors in Ulm use suitable microscopes and MR imaging methods to enable the particles to show them the route the stem cells follow in the tissue.
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Katharina Landfester’s team has designed a container for active substances for biotechnologists at the University of Stuttgart. The container is designed like a hazelnut and could fight breast tumors. Its core is formed by a nanoparticle whose surface is coated with a strong toxin. The chemists encapsulate the core and address the toxic parcel to the cancer cells using appropriate antibodies so that it attacks only the tumor – but this it does with that much more vigor. Healthy cells are largely spared by the poison. The pharmaceutical industry would have to develop the active substance container further for it to become a marketable drug. “In my view, people here have become less willing in recent years to take risks involving approaches that are still at the basic research stage,” says Katharina Landfester.
Maybe particles from several capsules will also be used in genetic engineering, or even in gene therapy. Such particles could serve as a vehicle for DNA or RNA. The outer shell could carry the door opener for the cell, while the inner shell could give the particles access to the nucleus. The colloid researchers are working with researchers from the University of Mainz to investigate the best way to smuggle genes into the genome. They are currently studying what form the surfaces of the particles must take in order to penetrate into the nucleus.
A similar problem confronts them in their attempts to smuggle nanoparticles through the blood-brain barrier. These physiological barriers protect the central nervous system from invaders and also prevent most drugs from gaining access.
This is why many potential drugs for the treatment of nervous diseases are thwarted here. The polymer researchers in Mainz are now doing all the finetuning they can to provide their particles with the means to access the brain. Katharina Landfester suspects that, here too, the surfaces of the particles are key. “I do think we should take another close look at the chemical details of the blood-brain barrier,” she says. Medical researchers have concentrated too much on the system as a whole, she thinks. She therefore wants to approach this problem from the same point of view that once revealed the potential of the miniemulsions – namely the point of view of the colloid chemist.
