A new technology for storing molecules, which allows the introduction of drugs under the skin and activate them at the right time, was developed by scientists from the University of Freiburg in Germany. A controlled delivery of bioactive substances with local restriction is of interest in medicine and life sciences, covering a large field from basic research to practical applications. For this purpose, spatial and temporal control of release is as important as the possibility to precisely adjust the number of released substances which can be from small-sized ions to large molecules or proteins.
Different applications demand different properties of the release systems which can generally be categorized according to their functionality into passively or actively eluting systems. Furthermore, active systems can be separated into direct systems with storage and release functionality combined in one single material. Hence being small and compact, or indirect systems which only provide the control and rely on an external drug supply, namely valve-like structures in microfluidic devices. A promising approach to cover relevant requirements for an active implantable release system employing conducting polymers has recently been proposed.
Developers of microsystems, electrical engineers, and scientists worked on this project, among them Christian Boehler, Firat Güder, Umut M. Kücükbayrak, Margit Zacharias & Maria Asplund. They studied the properties of materials, created a mixture of organic and inorganic materials, which can store small doses of pharmacologically active substances.
At the beginning, scientists turned the liquid synthetic material into a solid, using a method of atomic-layer deposition using gas. Gas, penetrating the molecular structure of the material, strengthens it from the inside.
In the tests, the researchers used polymeric polyethylene glycol. When reacting with zinc oxide during the precipitation process, it creates an organo-inorganic hybrid. The molecular structure of this hybrid is ideal for storing medicinal substances. Since the material is water soluble, it can easily act as a 'courier' for medicines and direct the necessary substances into the bloodstream.
Scientists used the polymer PEDOT to make the dosage clear. This polymer works as a kind of colander, the openings in which open with a negative charge and close with a positive charge. This allows the release of the necessary molecules in limited doses.
Then the scientists improved the system, made it more compact and capacious and learned how to store molecules with different charges. Experiments have shown that the development allows you to release a certain number of molecules at a certain point in a certain period of time.
The technology will be especially useful for various methods on the principle of a laboratory on a chip when the exchange and analysis of various substances take place in a confined space. For example, the technology can be used to treat cancer (lat. Carcinoma). Drugs from the micro-capacity under the skin will be sent directly to the tumor area. Scientists from the University of Freiburg have already conducted experiments that prove that such implants can function in the human body.