uBiome’s Stabilization Buffer

Have you ever wondered what is in your uBiome sampling tube? It’s one of the most important things in our kit, and we are very proud of it!

After you swab your toilet paper (or your nose, mouth, vagina, or skin), you stir the swab into the sampling tube, and the sample gets released in the liquid. Once the sample has been added, the tube can be safely shipped to our laboratory by regular mail. Our patented technology ensures that noo overnight shipping or ice packs are needed!

 

What’s in the tube?

If you look carefully, you’ll see that the tube is filled with a liquid and tiny glass beads.

The liquid is a special buffer that is designed to stabilize and preserve your sample. As soon as you transfer your sample from the swab to the sampling tube, the microbes within it will stop growing. This is very important because we want to know exactly what your sample looked like the moment you collected it. If microbes were allowed to continue growing, the contents of the tube would be very different upon receipt in our lab. (See below for more details on this!)

Your sample contains hundreds of different strains of bacteria, and some of these grow faster than others. In a tube without the buffer, the proportion of microbes might change over time, with the fast-growers taking over from the slow-growing strains. uBiome’s special buffer prevents that from happening. Even if the package spends a couple of hours or days at a high temperature (say, in a hot car or on the tarmac) or very low one (say, outside in a mailbox in winter), the ratios of your sample’s microbes will not change.

To demonstrate how effective the stabilization buffer in our tubes is, we did some experiments. We just can’t help it — we love to do science!

 

Let’s do some science!

We tested how much the microbiome in freshly collected stool samples looked like that of samples kept at different temperatures for a week all stored in our stabilization fluid. The temperatures ranged from freezing to room temperature to 104 degrees F. After processing in our laboratory, all samples looked very similar to each other, regardless of storage temperature (Figure 1). Our stabilization buffer makes sure that your results reflect your microbiome exactly how it was on the day you sampled, even if your sample encounters hot temperatures on its way to our lab.

You can read about these and other experiments in our blog post about the reproducibility of our test. At uBiome we always want to make sure that our products are based on science and to contribute to science ourselves. We also published our results as a scientific preprint on bioRxiv, where it is free for all our users and the scientific community to read.

 

What happens if you don’t stabilize your samples?

We are very proud of our stabilization buffer, in particular because not all microbiome sampling tubes are created equal.

Some organizations don’t provide any stabilization buffer for their customers’ microbiome samples. As we discussed above and as shown in many scientific studies (for example, here, here, and here), the composition of a sample shipped without stabilization buffer might look very different by the time it gets analyzed in the lab than it did when you sampled yourself.

Other organizations might tell you that their stabilization buffer is much better than that of uBiome but if you look at their data, they never compared their product to ours. They only compared their product to storage in ethanol, in an RNA storage buffer, or on paper cards used to store blood samples. None of these methods are optimized for storage of complex mixtures of DNA in a biological sample, and they therefore do not preserve the DNA as well as uBiome’s proprietary buffer does.

 

How about those tiny beads?

These little glass beads help us crack open all the different microbes in your sample, so we can access the DNA inside their cells. Some bacteria have very thick cell walls, and those are hard to break open. These beads help us to open up the cell walls of all microbes, thick or thin.

As soon as your sample arrives in our laboratory, we will put it into a tube-shaking machine. It is very similar to a paint shaker you might find at a home-improvement store. The shaking action will move the glass beads up and down very quickly, grinding up the microbial cells into tiny pieces, and freeing up their DNA. After the bead shaking, the microbial genomes are ready to be analyzed.

So there you have it: our collection tube contains a great stabilization buffer and is optimally designed to conserve and prepare your sample for the best possible results.

uBiome stabilization buffer

Figure 1: Stool samples from 8 different persons were immediately extracted or extracted after storage for a week at different temperatures (freezer, room temperature, 87F or 104F; all in duplicate). Panel A on the left shows that all 10 samples from the same person had nearly identical microbiome profiles, no matter what temperature they were stored at. On the other hand, samples from each individual were very different from one another. Panel B on the right shows the same data in a different way, and confirms that samples cluster per subject, with no apparent effect of temperature treatment.