1.  Products for Exosome Isolation

          Our exosome Size and Density-based exosome isolation kits are suitable for all body fluids (biofluids), plant juice, and supernatants from cell cultures, bacteria, yeast and fungi cultures.

 

Exosome in Urine

 

           Urine is the most noninvasive, easy samples to obtain in large volumes for biomarker measurement. Pisitkun et al 2004 initially isolated and described urine exosomes, which, in addition to the common exosome molecular markers, contained urinary tubule specific proteins and microRNAs. However, the presence of nano- to micro-scale particles in urine, such as salt crystals, cells and virus, severely interferes with urine sub-fraction and downstream exosome isolation. One of the most abundance proteins in urine, Tamm–Horsfall protein (THP), is the main contributor to this problem. THP molecules exist not only as a mono protein molecule but also as polymerized micron long fibrils. These linear fibrils further form a three-dimensional gel which entraps a large amount of exosomes. In classical urine assay, urine is separated into various fractions by the differential centrifugation. Our data demonstrate that even low (2,000g) speed centrifugation co-precipitates cells and salt crystals with THP gel which entrapped exosomes. This low-speed pellet is usually discarded during exosome isolation procedures, as reported in the current literatures and commercial kits. However, this low-speed pellet contains at least 40% of total urine exosomes. Given the fact that urine has very low exosome load, the exosomes in this low-speed pellet thus have to be released to increase total urine exosome yield. Several labs utilized the reducing agent DTT or the detergent 3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonic (CHAPS) to break down the urine THP gel to release exosomes. DTT and CHAPS treatment did not only break down urine THP gel, but also damaged the integrity of cells and exosomes, and thus resulted in the inaccurate measurement and misleading discovery of proteins and miRNAs.

            We thus developed a ME buffer, which efficiently released the entrapped exosomes from THP gel, as well as kept the integrity of exosomes and cells. After treated with ME buffer, urine exosomes can be concentrated with the density-based ExoEZ exosome isolation kit (ExoUT50) within less than 30 minutes. The isolated exosomes are suitable for most of applications nowadays. 

          A procedure for urine exosome isolation is outlined below.

 

 

 

 

 

 

 

                

 

Exosome in Breast Milk

 

           Milk is not only a nutrition source, but also contains biologically important components, cells, and nanoparticles, which have an immune regulatory function. Inappropriate storage of milk at room temperature or colder for more than one hour causes milk cell apoptosis and death, which contaminates the pool of naturally present exosomes. Exosome isolation from milk is further complicated by the abundance presence of fat globules (MFGs), casein micelles, cells and cellular debris. MFG, a lipid droplet covered by proteins and phospholipids, is a kind of vesicle that has largely heterogeneous size and density. Efficient removal of cells and cell debris, casein micelles, and MFGs would significantly improve the quality and yield of the isolated exosomes.

 

lty obtaining exosome-depleted serum, you can use serum-free or serum-reduced media. Conditioned medium should be stored in either stored at 4°C for days or kept frozen at -80°C for longer periods. Strictly avoid repeated thaw and freeze cycles. 

 

 

 

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