Fe3O4 magnetic nanoparticles (MNPs) are biomedical materials that have been approved by the FDA. To date, MNPs have been developed rapidly in nanomedicine and are of great significance. Stem cells and secretory vesicles can be used for tissue regeneration and repair. In cell therapy, MNPs which interact with external magnetic field are introduced to achieve the purpose of cell directional enrichment, while MRI to monitor cell distribution and drug delivery. This paper reviews the size optimization, response in external magnetic field and biomedical application of MNPs in cell therapy and provides a comprehensive view.

At present, iron oxide nanoparticles (IONPs) are widely used in the biomedical field. They have unique advantages in targeted drug delivery, imaging and disease treatment. However, there are many things to pay attention to. In this paper, we reviewed the fate of IONPs in different cells and the influence on the production, separation, delivery and treatment of extracellular vesicles. It aims to provide cutting-edge knowledge related to iron oxide nanoparticles. Only by ensuring the safety and effectiveness of IONPs can their application in biomedical research and clinic be further improved.

Extracellular vesicles (EVs), including exosomes, have inherent homing ability in damage repair and drug delivery. However, they have poor targeting and low enrichment efficiency and are easily internalized/cleared by monocyte phagocyte system. If the targeting ability of exosomes can be improved through a series of means, better use can be made of the advantages of exosome therapy and drug delivery. It is necessary to ensure a certain retention rate to study signal pathways and potential mechanisms, especially in flowing blood. This article mainly reviews the research progress of specific targeting based on exosomes, including intrinsic targeting, enhanced targeting, and drug delivery. Inherent targeting is mainly analyzed from different cell sources, and enhanced targeting is mainly from ligand modification and the application of nano materials to improve the targeting ability. To be successfully applied in clinical practice, many problems and challenges still need to be faced in exosome therapy. Herein, the latest knowledge of using EVs as a natural delivery system for disease treatment is summarized.