Bullet Blender® Homogenizer

Overview	FAQ	Protocols	Beads and Accessories

Frequently Asked Questions

Want to know more about homogenization methods in general? Click here for an overview.

Air Cooling™

What is Air Cooling™?

The Air Cooling™ models have fans which exchange air with their surroundings; they have nothing that actually chills the instrument. Air Cooling™ is useful if you're running several sample cycles in a row or if your samples are extra sensitive to heating up. Normally, the samples in the Bullet Blender® only heat up a few degrees and stay quite cool. However, if you're running a second batch of samples soon afterwards, they will heat up a little more because the Bullet Blender® is starting out slightly warmer. The Air Cooling™ keeps the Bullet Blender® cooler so that the first batch of samples heat up a little less and subsequent batches are kept just about as cool as the first batch.

Which models have Air Cooling™?

The Air Cooling™ feature comes on the "Blue" models: Bullet Blender® Blue which uses microcentrifuge tubes, the Bullet Blender® Blue 5 which uses 5 mL tubes and the Bullet Blender® Blue 50 which uses 50 mL tubes. In fact, because the 50 mL tubes require more time to homogenize the bigger samples, all Bullet Blenders for 50 mL tubes come with Air Cooling™.

Use and Operation:

Before using, please see our General Guidelines for Use

What types of tubes can be used?

The Bullet Blender® and Bullet Blender® Blue work with 1.5 mL, 1.7 mL, and 2.0 mL polypropylene sample tubes, including conical and round bottom microcentrifuge snap-cap tubes. We recommend Eppendorf Safe-Lock tubes. The screw cap models use Axygen and Corning 1.5 ml screw cap tubes. The Bullet Blender%reg; Blue 5 units work with 5ml Axygen brand screw top transport tubes. The Bullet Blender 50-DX units work with 50 mL skirted (self-standing) polypropylene tubes, such as Axygen brand. The slightly hazy polypropylene tubes are tougher and resist the striking better than the clearer tubes, which might crack at higher speeds. Use high quality tubes, rather than bargain brand tubes which are not as strong.

How do you set the Bullet Blender� to mix, disrupt, or homogenize different types of samples?

You can adjust the speed and the duration. Adjusting the speed affects how firmly the balls will strike the sample tubes, while adjusting the duration affects the total number of impacts. Homogenizing tough tissue requires longer durations at full speed, while mixing requires lower speeds.

How easy is it to operate the Bullet Blender®?

Simply place up to 24 sample tubes in the holders (located in a circle, just as with most centrifuges), set the desired duration and speed, and push start. All the samples will be processed simultaneously, without any chance of cross contamination.

How much volume of sample can be homogenized in each microcentrifuge tube?

As for the amount of tissue to use in the Bullet Blender, we recommend from 50-300mg of tissue in a standard microcentrifuge tube. Less than 50mg will work, but it requires careful attention to the amount of beads and volume of homogenization buffer. As with any experiment, errors become larger as the measured quantity gets smaller, so reproducibility becomes an issue. Samples larger than 300mg are not recommended. The air volume inside the tube is critical to allow the sample to be ground up inside the tube, so if the tube is more than 75% full, the efficiency of the homogenization is reduced. The 5 mL tubes can hold up to about 1 g of sample tissue or cultured cells, and a total of 3 mL of sample, buffer, and beads combined.The 50 mL tubes can hold up to about 3.5 g of sample tissue or cultured cells, and a total of 20 mL of sample, buffer, and beads combined.

Do sample tubes need to be placed symmetrically?

No. There are no restrictions as to which holes to place your sample tubes in, however you may get better results if you space them apart somewhat.

How do you retrieve the sample from the tubes?

After the Bullet Blender� stops, centrifuge the tubes to clarify the lysate prior to use in your molecular biology applications.

Which beads should I use?

The protocols page contains suggested beads, speeds, and durations for processing many types of tissues and cells. The Bullet Blender®beads page has a bead selection table. If you are working with a sample not shown on the table, check the table below which has guidelines to use for selecting beads. The two basic rules: (1) use denser beads for tougher samples, and (2) use beads of a comparable size to the size of your samples to maximize the effectiveness of collisions between beads and samples. For example, if you wanted to lyse bacterial cells with a soft membrane, use small glass beads. If you want to homogenize larger pieces of tough tissue, use large steel beads.

I previously owned another bead mill homogenizer. Can I use the same protocols that we developed for the other homogenizer with the Bullet Blender®?

No, the mechanism of action is different from all other homogenizers on the market. Our patented striking technology makes the Bullet Blender both highly efficient and effective. If you use another product's protocol with the Bullet Blender, you are very likely to experience different results. Please use one of our established protocols, or emperically determine a protocol that works best for your samples.

We would like to use Fisherbrand tubes with the Bullet Blender®. Do they perform well?

Due to difference in shape, Fisherbrand tubes are more susceptible to wear in the Bullet Blender. We therefore recommend that you avoid using Fisherbrand tubes with the Bullet Blender. If you must use Fisherbrand tubes, do not use them in runs of more than four minutes.

Why is there a three tube minimum for Bullet Blender® 5? A two tube minimum for the Bullet Blender® 50-DX?

In the Bullet Blenders with larger motors, if all the energy were directed at a single tube, the tube might break. Tubes partly filled with water can be used.

Is it possible to homogenize tissue that has been frozen in liquid nitrogen?

It is possible to homogenize tissue that was frozen in liquid nitrogen. Immerse the frozen tissue in cold buffer and allow it to thaw, then treat it as you would any other sample. If the tissue was dried before it was frozen, you can pulverize the tissue by running the tissue with beads only (no buffer), then adding the cold buffer and running again to complete the homogenization. You cannot homogenize "wet" tissue while it is still frozen, as it will effectively be a block of ice and homogenization efficiency will be very poor.

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