Magnetic nanoparticles navigate therapeutic genes through body and measure effectiveness

6 March 2009

Scientists of the German metrology institute, the Physikalisch-Technische Bundesanstalt (PTB) in a joint study with the University of Bonn, have developed a highly sensitive method that uses magnetic nanoparticles to navigate therapeutic genes to the desired cells in a body and also measure the efficiency of gene transfer to the cells.

The experiment was conducted on mice, but will have application in gene therapy where health professionals send genes and healthy cells through a patient's bloodstream so that they can, for example, repair tissue damage to arteries. It is been difficult to determine whether genes or cells reach their destination in sufficient quantities. The research was published in the Proceedings of the National Academy of Sciences[1].

Scientists of the PTB can attach magnetic nanoparticles to the implanted genes or on the implanted cells and with the aid of an external magnetic field direct these genes or cells to the location of the damage. There the researchers can determine, accurate to the picogram per cell, the quantity of the magnetic material — and thus also the quantity of the therapeutically effective genes or cells.

It was also found that the use of magnetic nanoparticles dramatically increased the efficiency of the gene transfer in comparison to the non-magnetic method.

An additional welcome side effect is the 'magnetization' of the cells after the incorporation of nanoparticles. This may enable the targeted transport of the cells to regions of interest.

A closer look at the underlying mechanism of magnetic gene transfer was taken by the quantification of the magnetic material that was delivered to the cells. The required highly sensitive measurements in the range of a few picogram per cell were made by PTB using magnetorelaxometry. The good correlation between measurement data and gene transfer encourages to use magnetorelaxometry for monitoring the efficiency of gene and cell transfer, possibly even in vivo.


1. Combined targeting of lentiviral vectors and positioning of transduced cells by magnetic nanoparticles. PNAS 106 (1), S.44-49. (abstract can be viewed. Full article can be purchased)

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