On the preparation and characterization of superparamagnetic nanoparticles with Gelidium robustum agar coating for biomedical applications

Abstract

Superparamagnetic nanoparticles coated with natural polysaccharides are of great interest for biomedical applications due to their fast response to an external and high-frequency electromagnetic field and their biocompatibility. One of the greatest challenges in the development of these nanoparticles is related to the specific characteristics and properties of the polysaccharide used, which could guarantee the development of specific sizes, crystalline structure, magnetic response and its reproducibility. In this study, we present the preparation of magnetite (Fe 3 O 4) and cobalt ferrite (CoFe 2 O 4) nanoparticles by the co-precipitation method in aqueous solutions at different concentrations (1, 2, 3, 4 and 5%) of a very well-characterized agar obtained from the red marine algae Gelidium robustum. It is shown that under the same experimental conditions and using the adequate precursors, coated high-crystallinity magnetite nanoparticles are obtained. In contrast, for cobalt ferrite, our results indicated the formation of coated low-crystallinity CoFe 2 O 4 particles. Superparamagnetic nanoparticles (with crystal grain size < 8 nm) of Fe 3 O 4 agar coated at ≥ 3% agar showed high-saturation magnetization and high degree of biocompatibility and can be considered as promising candidates for biomedical applications.

Fabrication and Characterization of Montmorillonite Clay/Agar-Based Magnetic Composite and Its Biological and Electrical Conductivity Evaluation

“…The second step of weight loss is at about 280 °C, where a main thermal degradation of galactose units, release of SO 2 , and fragmentation of AG carbohydrates start. Finally, a complete decomposition of AG occurred at 500 °C with a weight loss of 24% which corresponds to the exothermic peak at DTA …”

“…In 2% MNPs (MMT,AG) MNP composite as the content of iron oxide increase in AG/MMT nanocomposite, the formation of homogeneously distributed MNPs sheet. MNPs are agglomerated and stuck to each other, thus making the surface bumpy and coarse . 0.5 and 2% MMT metaphors specify that a greater dispersion of clay in the nanocomposite was acquired at a low degree of clay content less than 1 g, and perceptibly clay agglomerates were pragmatic with a higher degree of clay content more than 1 g. The presence of floc clumps suggested the poor dispersion of MNPs in MMT and AG …”

“…The XRD outlines of MNPs–AG nanoparticles presented that the crystalline structure is conserved after the layering of AG. According to the Scherrer equation, the MNP–AG nanoparticle crystal grain size is spherical . Large filling sum of the MNPs in the composite sheets and the high crystalline nature of the MNPs deteriorated the comparative intensity of the diffraction peaks of MMT …”

“…Finally, a complete decomposition of AG occurred at 500 °C with a weight loss of 24% which corresponds to the exothermic peak at DTA. 53 3.4. X-ray Diffraction Analysis.…”

“…According to the Scherrer equation, the MNP−AG nanoparticle crystal grain size is spherical. 53 Large filling sum of the MNPs in the composite sheets and the high crystalline nature of the MNPs deteriorated the comparative intensity of the diffraction peaks of MMT. 55 The XRD results of 0.5, 1, and 2% MMT (MNPs and AG) magnetic composite sheets are shown in Figure 4A.…”