Microcomputed tomography analysis of ferrofluids used for cancer treatment.

In order to reduce the side effects generated by the most common cancer treatment therapies, chemo- and radiotherapy, two new approaches are being investigated. These new approaches are magnetic drug targeting (MDT) and magnetic hyperthermia, and are based on the use of magnetic nanoparticles. In the first one, these magnetic nanoparticles are used as drug carriers and the success of the treatment depends on the correct distribution of the drug within the tumour tissue. Computed tomography analysis has been performed on tumour tissue after MDT in order to find out the distribution of the nanoparticles. The measurements have been carried out in two different laboratories, one based on a synchrotron beamline and another one with a cone x-ray source. First results show that the drug carriers form clusters within the tumour tissue.

Quantification of magnetic nanoparticles by magnetorelaxometry and comparison to histology after magnetic drug targeting.

Magnetic nanoparticles can be used in medicine in vivo as contrast agents and as a drug carrier system for chemotherapeutics. Thus local cancer therapy is performed with Magnetic Drug Targeting (MDT) and allows a specific delivery of therapeutic agents to desired targets, i.e., tumors, by using a chemotherapeutic substance bound to magnetic nanoparticles and focused with an external magnetic field to the tumor after intraarterial application. Important for this therapeutic principle is the distribution of the particles in the whole organism and especially in the tumor. Therefore we used magnetorelaxometry to quantify ferrofluids delivered after MDT. Tissue samples of some mm3 volume of a VX2 squamous cell carcinoma were measured by magnetic relaxation and the amount of iron was determined using the original ferrofluid suspension as a reference. From this the distribution of the magnetic particles within the slice of tumor was reconstructed. Histological cross-sections of the respective tumor offer the opportunity to map quantitatively the particle distribution and the vascularisation in the targeted tumor on a microscopic scale. Our data show that the integral method magnetorelaxometry and microscopic histological methods can complete each other efficiently.

Medical applications of magnetic nanoparticles.

In recent years biomedical research indicated, that magnetic nanoparticles can be a promising tool for several applications in vitro and in vivo. In medicine many approaches were investigated for diagnosis and therapy and offered a great variety of applications. Magnetic cell separation, magnetic resonance imaging (MRI), magnetic targeted delivery of therapeutics or magnetically induced hyperthermia are approaches of particular clinical relevance. For medical use, especially for in vivo application it is of great importance that these particles do not have any toxic effects or incompatibility with biological organism. Investigations on applicable particles induced a variability of micro- and nanostructures with different materials, sizes, and specific surface chemistry.

[Magnetic Drug Targeting--a new approach in locoregional tumor therapy with chemotherapeutic agents. Experimental animal studies]. / Magnetisches Drug Targeting--ein neuer Ansatz in der lokoregionären Tumortherapie mit Chemotherapeutika. Tierexperimentelle Untersuchungen.

BACKGROUND: Advanced squamous cell carcinomas of the head and neck region were often treated with combined radio-chemotherapy. Radiotherapy allows a focused treatment of the tumor, and healthy tissue can be protected from radiation. Chemotherapy, however, is mostly given systemically and the unwanted negative side effects also develop in many other organs. AIM OF THE STUDY: Locoregional application of chemotherapeutic agents with Magnetic Drug Targeting on an animal experimental study. METHODS AND RESULTS: Magnetic Drug Targeting is a new approach to the locoregional treatment of tumors. Ferrofluids (colloidal dispersion of magnetic nanoparticles) were reversibly bound to chemotherapeutic agents and injected intra-arterially, while focused with an external magnetic field to a certain body compartment (i.e. the tumor). With only 20% or 50% percent of the regular systemic chemotherapeutic dose, we achieved an up to 26 times higher concentration in the tumor region with this application compared to the usual systemic administration. CONCLUSION: Magnetic Drug Targeting offers an unique opportunity to treat tumors locoregionally with chemotherapeutic agents.