RESUMO
Room-temperature measurements of the magnetic susceptibility of Bovine Serum Albumin-based nanocapsules (50 to 300 nm in size) loaded with different amounts of maghemite nanoparticles (7.6 nm average diameter) have been carried out in this study. The field (H) dependence of the imaginary peak susceptibility (fp) of the nanocomposite samples was investigated in the range of 0 to 4 kOe. From the analysis of the fp x H curves the concentration (N) dependence of the effective maghemite magnetocrystalline energy barrier (E) was obtained. Analysis of the E x N data was performed using a modified Mørup-Tronc [Phys. Rev. Lett. 72, 3278 (1994)] model, from which a huge contribution from the magnetocrystalline surface anisotropy was observed.
Assuntos
Compostos Férricos/química , Nanopartículas , Soroalbumina Bovina/química , Magnetismo , Microscopia Eletrônica de VarreduraRESUMO
The aim of this study was to prepare bovine serum albumin-based beads containing maghemite nanoparticles incorporated via ionic magnetic fluid and to evaluate the cell toxicity of this biocompatible system using the J774-A1 cell line. Transmission electron micrographs obtained from the magnetic fluid sample were used to estimate the average particle diameter around 7.6 nm and diameter dispersion of 0.22. The BSA-based magnetic beads were prepared using the heat protein denaturation route. The nanoparticle concentration in the magnetic fluid sample used for the synthesis of the magnetic beads was in the range of 1.2 x 10(16) to 2.3 x 10(17) particle/ml. The methodology used to investigate the cell toxicity of the magnetic beads was the classical MTT assay. Our observation showed that the toxicity against the J774-A1 cell line depends upon the amount of magnetic material incorporated into the magnetic nanobeads and was found to be 14, 11, 9, 5, and 3% for 2.3 x 10(17), 1.2 x 10(17), 4.6 x 10(16), 2.3 x 10(16), and 1.2 x 10(16) particle/ml, respectively.