ABSTRACT
Ferrites as soft and hard magnetic materials have been the center of attraction for researchers and technologists for the last many decades owing to their wide range of practical applications in communication, electronics, magnetic recording, microwave absorption-based devices, etc. In nanoferrites, the structural, morphological, and synthesis procedure decides the availability of large surface area to volume ratio for surface activity, electrical, and magnetic properties for a particular application. The superparamagnetic nature of ferrites nanoparticles (NPs) opened the door for new advanced high-tech applications in the field of biotechnology and biomedical sciences, sensors, nanoelectronics, microwave devices, food processing, catalytic performance, and environmental remediation. In the present scenario, large numbers of pure and co-doped ferrites NPs have been explored for their usage as effective magnetic probes in magnetic resonance imaging (MRI) and multimodal imaging techniques, drug delivery, i.e., transport of pharmaceutical compounds to the infected part of body and the medical therapies for hyperthermia treatment, etc. For biomedical application, the high magnetocrystalline anisotropy, moderate saturation magnetization, a high coercive field, mechanical hardness, resistivity, and low loss behavior 186properties of ferrite nanoparticles are stabilized by coating them with the biocompatible surfactant. NPs exhibit core-shell structure and its shell prevents the agglomeration of ferrite NPs and provides the very large active surface for the biomolecular conjugation as desired for biomedical applications. The present chapter reports the development in nanoferrites field pertaining to biomedical applications from 2000 onwards. The investigations are discussed in terms of the biocompatibility and permissible toxicity level of ferrite nanoparticles by appropriate selection of chemicals for magnetic cores and outer shell compositions with a view to enhance stability and swift delivery of NPs, optimization of size and morphological shapes like dot, spherical, rod, wire, cubical, tetrapods, needle, and polyhedron, etc. pH and ionic strength sensitive fluid properties and the probable interactions between ferrite NPs with cells, proteins, enzymes, drugs, contrast agents and molecules which are involved in the oxidation/reduction activity undergoing in the human body or by taking orally or directly injecting into the bloodstream. These are some key factors which influences the stability, in vivo activity and restriction of NPs as effective contrast agent for imaging purpose, drug-delivery, and cancer medication. This chapter summarizes all the major developments that took place in this field in terms of different ferrite nanoparticles, synthesis routes, and their characterization by different analytical techniques to confirm their formation and better understanding of the science behind tentative mechanisms with all possible advantages and shortcomings. We will try to unfold some new concepts for future exploration with the help of earlier reported studies and new recent reported ideas.
