The exosome membrane contains proteins and lipids derived from secretory cells. Among those components, phosphatidylserine (PS) is known to be oriented inside the cell membrane of intact cells by the enzymatic activity of lipid flippase, and be known to be exposed also on the outer surface of exosome membrane3). In addition, T-cell immunoglobulin domain and mucin domain-containing protein 4 (Tim4), the receptor involved in phagocytosis of apoptotic cells by macrophages, is known to bind PS via the IgV domain located within the extracellular region in a calcium ion-dependent manner.4)
Based on these findings, we developed a new and unprecedented method for exosome purification using Tim4-immobilized magnetic beads (capable of capturing exosomes in samples such as culture supernatants and serum in the presence of calcium ions and releasing them by elution with a buffer supplemented with a chelating reagent) in collaboration with Professor Rikinari Hanayama (Department of Immunology, Kanazawa University Graduate School of Medical Sciences) and successfully constructed an exosome purification kit based on these magnetic beads5).
This exosome purification kit, MagCapture™ Exosome Isolation Kit PS, has realized easy purification of intact exosomes with higher purity than that obtained by any conventional methods for exosome purification. It is currently being established as a new exosome purification method replacing ultracentrifugation, the conventional gold standard.
MagCapture™ Exosome Isolation Kit PS Ver.2 (V2.0 Kit) is an improved version of MagCapture™ Exosome Isolation Kit PS (conventional kit). V2.0 kit realizes improved recovery efficiency, reduced reaction time, and reduced cytotoxicity.