This review offers a hierarchical preview of the emergence of magnetic nanoparticles (MNPs) and their composites in the biomedical field providing an insight into their essential features. The need for coating their surfaces with stabilizers such as polyethylene glycol (PEG) and silica has also been explained. This is required for reducing their agglomeration and appropriate functionalization for final application. A magnetic material for such an application is required to be nanosized, superparamagnetic and biocompatible; all these requisites have been well discussed. Various research conducted on magnetic materials as maghemite, magnetite and ferrite based nanoparticles of Ni, Co, Mn, Zn, Ca and K have been described in detail, along with their composites such as PEG and silica. Folic acid conjugation is done on the coated MNPs as folate receptors are over-expressed on the tumor cells; this makes their targeting efficiency better and precise. In addition, various challenges associated with magnetic nanoparticles/nanocomposites such as nanoparticle-biomolecule interface, drug loading, drug release properties, blood barrier etc., which inhibit their desired role, have also been described.

这篇综述提供了磁性纳米颗粒（MNP）及其在生物医学领域的复合材料的出现的层次预览，从而深入了解了其基本功能。还已经解释了用稳定剂例如聚乙二醇（PEG）和二氧化硅涂覆其表面的需求。这对于减少它们的聚集和最终应用的适当功能化是必需的。用于这种应用的磁性材料要求是纳米尺寸，超顺磁性和生物相容性。所有这些前提条件都得到了充分的讨论。已经详细描述了对磁性材料（如磁铁矿，磁铁矿和铁氧体基的Ni，Co，Mn，Zn，Ca和K）进行的各种研究，以及它们的复合材料（例如PEG和二氧化硅）。叶酸受体在被包被的MNPs上完成，因为叶酸受体在肿瘤细胞上过度表达。这样可以使他们的定位效率更好，更精确。另外，还描述了与磁性纳米颗粒/纳米复合材料相关的各种挑战，例如纳米颗粒-生物分子界面，药物载量，药物释放特性，血液屏障等，这些挑战抑制了它们的所需作用。