*2.7. Method for Determination of the USPIONs Content in the Tissues*

Determination of USPION content in tissue and blood samples was done by measuring their magnetic properties. A Quantum Design (San Diego, CA, USA) SQUID magnetometer MPMS-XL 7AC was used. Magnetic characterisation of USPIONs was done by measuring the temperature dependence of the mass magnetisation *M* in both the ZFC (zero field cooled) and FC (field cooled) conditions (at the applied magnetic field of 50 Oe), in the temperature range from 1.8 to 300 K and the isothermal magnetisation curves (*M* vs. *H* dependence) measured at the temperatures of 2 and 300 K and the applied field up to 7 T.
