Isolating Exosomes

A new exosome isolation kit, developed by FUJIFILM Wako Pure Chemical, could help researchers establish a better understanding of the extracellular vesicles’ many functions.

Exosomes are small, membranous vesicles released from cells, that were originally considered simply as removers of cellular waste. Now, as their roles in cell-cell communication and transportation of useful molecules are being discovered, exosome studies occur in many biology research fields. 

To enable these investigations, exosomes must be isolated from samples and purified. Ultracentrifugation has traditionally been the go-to method to isolate exosomes, but it can be inconsistent, and often results in sample contamination which affects the interpretation and validity of results.

The MagCapture Exosome Isolation Kit PS, developed by FUJIFILM Wako Pure Chemical, uses a calcium-dependent phosphatidylserine (PS)-binding protein called Tim4 to avoid these drawbacks.

In the Isolation Kit PS, samples are reacted with magnetic beads immobilizing Tim4 and calcium. Tim4 is bound to a phospholipid called phosphatidylserine, which is present on exosome surfaces, so any exosomes within the sample bind to the beads. The beads are then separated using magnets. Following this, a chelating agent, called EDTA, is used to remove calcium, so that purified exosomes are eluted from beads under physiological conditions.

“Exosome isolation using this technology can isolate very pure and intact exosomes with less physical damage than those isolated through ultracentrifugation,” says Dr. Takahiro Nishibu, a manager at FUJIFILM Wako Pure Chemical’s Life Science Research Laboratories. He explains that the Isolation Kit PS allows for better reproducibility of results, and that by producing pure and intact exosomes, the technology can enable better studies to deepen understanding of exosome functionality.

FUJIFILM Wako Pure Chemical also produces Tim4-affinity-based analytical assays for the detection and quantification of exosomes and exosome marker antibodies and related reagents, for a range of studies into these increasingly exploitable extracellular messengers. The team has also published two studies1,2 detailing their Tim4-affinity-based technique. “Establishing a greater understanding of exosome functions has the potential for creating an innovative way of treating disease,” says Nishibu, adding that the high biocompatibility of exosomes means they could serve as an attractive drug delivery platform. In addition, exosomes released by certain cancer cells are linked to metastasis, and those released by some stem cells have anti-inflammatory properties — bringing potential for new therapeutics.

For more information on Exosome research, click here.

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