Effect of temperature on the physical specifications of contrast agent in magnetic resonance imaging: chitosan-MnFe2O4 magnetic nanoparticles

In this study, manganese ferrite nanoparticles (MnFe2O4) coated with chitosan (Ch-MnFe2O4) was investigated at different temperatures. We reported the study of synthesis, and characteristics of this superparamagnetic agent, which were well prepared in nano-size via the chemical co-precipitation method. The Ch-MnFe2O4 NPs were annealed at the temperatures of 300, 400 and 500˚C. The structure, morphology, and magnetic properties of the samples were characterized by the X-ray powder diffraction (XRD) and vibrating sample magnetometer (VSM), respectively. The results are indicating that the Ch-MnFe2O4 NPs are biocompatible, and have a cubic spinel crystal structure. The average sizes of the FA-Ch-MnFe2O4 NPs were found to be dependent on the applied temperature. Also, their sizes as well as the magnetization property will extend as the temperature is increased up to 400˚C. By further increasing the temperature, however, they tend to decrease. These NPs have exhibited uperparamagnetic behavior most likely at the 400˚C temperature. Furthermore, the VSM results have been demonstrated that the number of the magnetic momentums will increase by growing the size, so that they are used as contrast agents and able to affect the relaxation time through the dipole-dipole interaction, which is useful in MRI.