Magnetic properties of "doped" DNA

Highlights: • Deviations from the Curie-Weiss law can not be explained by SG behavior. • Computer simulation allows distinguish between interacting and non-interacting centers. • EPR technique is very sensitive to contaminations in DNA-based systems. A series of double-stranded DNA samples, containing cholesteric liquid crystal droplets, were investigated. Binding of DNA molecules with Gd³⁺, La³⁺, Cu²⁺, ions was carried out. The samples were characterized by X-ray, optical circular dichroism and EPR techniques. Magnetic SQUID magnetometer research showed significant deviations of Gd³⁺ paramagnetism from the Curie-Weiss law. A possibility of spin-glass-like interactions was analyzed. The dispersion of magnetic parameters was claimed as a main reason of magnetic anomalies observed in the liquid crystal DNA-metal systems. Such systems can be useful in biomedical applications as low-toxic magnetic labels.