ИСТИНА

Biomedicine needs special chemical or physical techniques to provide novel methods of treatment on the molecular and cellular-scale. Metallic nanostructures have some opportunities to be considerated as a tool for some bioaplications, such as targeted delivery by magnetic field, and both nanowires and nanotubes are the perfect ones. Fe20Ni80 nanotubes have been synthesized by electrochemical method using polyethyleneterephthalate templates. Detailed study of their structural and magnetic characteristics was carried out. The Mössbauer spectrum of nanotubes was processed by the reconstruction of the hyperfine parameter distributions and model fitting under the assumption of a linear correlation between the hyperfine spectrum parameters. The mean values of the isomeric shift`d = 0.023±0.002 mm/s,the quadrupole shift `e = 0.007 ±0 .004 mm/s and the hyperfine magnetic field`Hn = 290.7 ± 0.3 kOe indicate that this contribution corresponds to the iron atoms in the solution of iron with nickel, which is the main material of synthesized nanotubes. The wide (~50 kOe) distribution of hyperfine magnetic fields is caused by a fairly random distribution of Fe and Ni atoms over the positions of the crystal structure. In connection with this, different numbers of Ni and Fe atoms are in the first coordination sphere for Fe atoms from position to position, that leads to a noticeable change in the magnetic field DHn = –13.6 ± 0.2 кЭ. In this case, the isomer shift d and the quadrupole shift e vary less significantly. The coefficients of linear correlation with the magnetic field are equal to: Dd/DHn = (1.2 ± 0.8)×10-4 mm/s/kOe and De/DHn = (9.6 ± 0.8)×10-4 mm/s/kOe. In the Mössbauer spectrum the ratio of the intensities of the sextet resonance lines depends on the angle between the direction of the gamma quantum passage that is directed along the nanotubes in the experiment and the magnetic field Hn that is co-directed with the magnetic moment of the Fe atom in the sample. For the studied sample of nanotubes, the intensity ratio of the resonance lines indicates a magnetic texture along the nanotube axis with an average value of the angle`J = 47.6 ± 0.3º. Dependences of composition, wall thickness and crystallinity on deposition potential were shown and the effect of these parameters on magnetic properties have been defined. In compressing with well-established nanowires, we demonstrate the advantages of nanotubes: homogeneous magnetic field, lower specific density and larger specific surface area. Listed features allow nanotubes to become preferable in biomedicine. In addition, FeNi alloys has low coercivity and hight remanent magnetization relative to other materials. Moreover, we show possible way of FeNi nanotubes preparation for targeted delivery of drugs and proteins.