In a novel method of treatment, repair genes are targeted to a diseased organ. To this end, health professionals use so-called vectors or "gene ferries", which are developed, for example, on the basis of viruses. They load them with therapeutic genes and magnetic nanoparticles and navigate them through the body with the aid of an external magnetic field. Now it has become possible, with magnetic relaxometry – a detection method developed at PTB – to validate the efficiency of the magnetic navigation, accurate to the picogram per cell.
In a novel method of treatment, repair genes are targeted to a diseased organ. To this end, health professionals use so-called vectors or "gene ferries", which are developed, for example, on the basis of viruses. They load them with therapeutic genes and magnetic nanoparticles and navigate them through the body with the aid of an external magnetic field. Now it has become possible, with magnetic relaxometry – a detection method developed at PTB – to validate the efficiency of the magnetic navigation, accurate to the picogram per cell.Magnetic nanoparticles today are often used as a contrast medium in magnetic resonance imaging, thus in diagnostics. However, they could also be helpful for purposes of treatment. A novel approach here is the gene transfer with the aid of magnetic nanoparticles. Health professionals send therapeutic genes on their way through the blood stream so that they can, for example, repair tissue damage in arteries. Often, modified viruses, which transfer genetic material into foreign cells anyway, serve as the carrier. In order to transfer the therapeutic genes, the "gene ferries" must stay at the cell long enough for the genes to penetrate its wall. For this purpose, magnetic nanoparticles are linked to the viral vectors. With the aid of an applied magnetic field, pharmacologists navigate the "gene ferries" with its cargo to the desired site and detain it there until the therapeutic genes have been transferred.
With the magnetic relaxometry method developed at PTB it was possible for the first time to accurately determine under clinically relevant test conditions the amount of magnetic nanoparticles with their gene material that was absorbed by the cells at the target site. The method is based on the SQUID precision measurement technique and enables measurements in the range of a few picograms (billionth of a milligram) per cell. By measuring with several SQUID sensors simultaneously, the magnetic nanoparticles can be accurately localized to a few millimeters. It was demonstrated that the magnetic navigation drastically increases the efficiency of the treatment or even makes it possible in the first place.
The tests are a part of a research project under the management of the University of Bonn, in which in addition to PTB also the Technical and the Ludwig Maximilian Universities of Munich are involved. It is focused mainly on the heart circulation system, with the aim of navigating therapeutic agents more accurately in order to avoid side effects. The project has been funded by the German Research Foundation with approx. two million euros.
The results suggest that magnetic relaxometry is suited to control the efficiency of the gene and cell transfers also in vivo, i.e. directly on the patient.