Multifunctional magnetic iron oxide nanoparticles: diverse synthetic approaches, surface modifications, cytotoxicity towards biomedical and industrial applications

Magnetic iron oxide nanoparticles (MIONPs) play a major role in the emerging fields of nanotechnology to facilitate rapid advancements in biomedical and industrial platforms. The superparamagnetic properties of MIONPs and their environment friendly synthetic methods with well-defined particle size have become indispensable to obtain their full potential in a variety of applications ranging from cellular to diverse areas of biomedical science. Thus, the broadened scope and need for MIONPs in their demanding fields of applications required to be highlighted for a comprehensive understanding of their state-of-the-art. Many synthetic methods, however, do not entirely abolish their undesired cytotoxic effects caused by free radical production and high iron dosage. In addition, the agglomeration of MIONPs has also been a major problem. To alleviate these issues, suitable surface modification strategies adaptive to MIONPs has been suggested not only for the effective cytotoxicity control but also to minimize their agglomeration. The surface modification using inorganic and organic polymeric materials would represent an efficient strategy to utilize the diagnostic and therapeutic potentials of MIONPs in various human diseases including cancer. This review article elaborates the structural and magnetic properties of MIONPs, specifically magnetite, maghemite and hematite, followed by the important synthetic methods that can be exploited for biomedical approaches. The in vivo cytotoxic effects and the possible surface modifications employed to eliminate the cytotoxicity thereby enhancing the nanoparticle efficacy are also critically discussed. The roles and applications of surface modified MIONPs in medical and industrial platforms have been described for the benefits of global well-being.This work was supported by Department of Science and Technology Nano‑ mission, Government of India [Grant No. DST/NM/NB-2018/10(G)], Science and Engineering Research Board, Department of Science and Technology, India [Grant No. YSS/2014/00026] and University Grants Commission, India [Grant No. F. 4-5(24-FRP)/2013(BSR)]. This article is a result of the project NORTE-010145-FEDER-000012, supported by Norte Portugal Regional Operational Pro‑ gramme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). This work was also fnanced by FEDER-Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020-Operacional Programme for Competitiveness and Internationalisation (POCI), Portugal 2020, and by Portuguese funds through FCT-Fundação para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia e Ensino Superior in the framework of the project “Institute for Research and Innovation in Health Sciences” (POCI-01-0145-FEDER-007274).info:eu-repo/semantics/publishedVersio

Influence of Cr on structural, spectroscopic and magnetic'' properties CoFe2O4 grown by the wet Chemical method

The Cr doped CoFe2O4 nano crystalline ceramics are synthesized using wet chemical method. The structural, morphological, functional, spectroscopic and magnetic properties of pure CoFe2O4 and Cr doped CoFe2O4 are characterized by XRD, FESEM, FTIR, Raman, Mossbauer spectroscopy and M-H hysteresis loop. The X-ray diffraction (XRD) patterns of undoped (x = 0) and doped (x not equal 0) samples reveal the formation of single phase cubic spinel structure. The lattice parameters and cation distribution between tetrahedral (A) and octahedral (B) sites of the samples (AB(2)O(4)) were obtained by Rietveld refinement of XRD patterns. The FESEM micrographs exhibit dense micro structure with small voids. The energy dispersive x-ray studies confirm the presence of Cr in CoFe2O4. The FTIR spectrum confirms that the peaks corresponding to the metal-oxygen bonds have shiftedtowards higher wavelength region. Raman spectrum exhibits broad peaks which confirm the existence of local disorder due to the inter-site cation migration between tetrahedral and octahedral sites. The Mossbauer spectroscopy reveals that the magnitude of magnetic hyperfine field of tetrahedral site (H-A) and octahedral site (H-B) decreases with increase in Cr doping in CoFe2O4 and that the decrease is more rapid in tetrahedral site (H-A) compared to that in octahedral site (H-B). And also confirm that the magnetic hyperfine fields (B-hf) are smaller relative to pure cobalt ferrite representing that super exchange interaction which is decreases as the Cr concentration increases. The magnetization studies reveal a decrease in the saturation magnetization (M-s) of CoFe2O4 with increase in Cr substitution. A similar and non-monotonic variation of coercivity (H-c) and magneto crystalline anisotropy (K) suggests that H-c is mainly determined by K