Targeted Drug Delivery by Ultrasound Contrast Agents: Sonoporation

One field of research of the institute for Medical Engineering is the investigation in targeted drug delivery induced locally by ultrasound. Ultrasonic contrast agents based on gas filled microbubbles stabilized by spherical shells play an important role in this application.

Some physical effects render these agents useful for targeted drug delivery: they can be fragmented on purpose or project a thin jet of liquid with high speed towards a hard wall, all at diagnostic ultrasound levels. They can also be used as carriers of drugs, but also of viruses or plasmids for gene therapy: e.g. plasmid loaded microbubbles can be destroyed by a short high energy ultrasound pulse to release the plasmids.

Another method for targeted drug delivery can be sonoporation, the temporal opening of cell membranes by ultrasound. That is enhanced by nearby large-scale oscillating microbubbles producing microstreaming. Drugs and plasmids can enter the cell. The mechanisms of sonoporation are not completely understood, so targeted drug delivery does not exhibit reliable reproducibility yet.

This research project covers the investigation of the participating mechanisms in sonporation. The goal is the adjustment of the ultrasound parameters for optimal and reproducible therapy. In cooperation with the Molecular GI-Oncology, Ruhr-University Bochum and the Medical Clinic and Polyclinic C of the University Hospital of Münster in vitro and in vivo sonoration studies are accomplished.

Durch SonoVue(TM) transfizierte GFP-expressionierende Plasmid-DNA in 293T-Zellen bei unterschiedlichen DNA-Konzentrationen.