Highly sensitive room-temperature method of non-invasive in vivo detection of magnetic nanoparticles

Methods of non-invasive in vivo quantification of magnetic nanoparticles (MP) have been proposed and realized. The methods are based on non-linear MP magnetization at two frequencies and measuring the response at combinatorial frequencies. The first method is developed for real-time study of MP dynamics and their clearance from the blood system of animals. High sensitivity of 3 ng of Fe3O4 in 0.1 ml was achieved for MP detection in mice tail veins. The second technique is proposed for MP detection inside animal tissues by an external probe. The proposed methods could essentially widen capabilities of biomedical research which involves magnetic nanoparticles.