Bullet Blender™ FAQ

Air Cooling™ Use/Operation

Air Cooling™:

Q: What is Air Cooling™?

A: 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

Q: Which models have Air Cooling™?

A: The Air Cooling™ feature comes on the "Blue" models: Bullet Blender™ Blue which uses microcentrifuge 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

Q: What types of tubes can be used?

A: The Bullet Blender™ and Bullet Blender™ Blue work with 1.5 mL, 1.7 mL, and 2.0 mL polypropylene sample tubes, such as Axygen brand, including conical, and round bottom microcentrifuge tubes, with the caps that flip closed – not the screw caps. The different shapes will provide different results. The Bullet Blender™ Blue 50 work with 50 mL BD Falcon™ and Krackeler brand polypropylene tubes. 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.

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

A: 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.

Q: How easy is it to operate the Bullet Blender™?

A: 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.

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

A: 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 also possible-- the problem there becomes the mobility of the tissue sample and beads in the tube. 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 50 mL tubes can hold up to about 2 g of sample tissue or cultured cells, and a total of 15 mL of sample, buffer, and beads combined.

Q: Do sample tubes need to be placed symmetrically?

A: 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.

Q: Is it possible to homogenize tissue, which is frozen in liquid nitrogen?

A: It is possible to homogenize tissue that was frozen in liquid nitrogen. Immerse the frozen tissue in cold buffer, allowing it to thaw. Then treat it as other fresh tissue samples.
One of the significant advantages of the Bullet Blender™ is that samples remain in individual tubes without the introduction of probes or pestles. Thus cross-contamination will not occur. Adding liquid nitrogen to freeze your samples, which inherently adds exogenous material to your sample, increases the likelihood of contamination.

Q: How do you retrieve the sample from the tubes?

A: After the Bullet Blender™ stops, centrifuge the tubes as you would to clarify the lysate prior to use in your molecular biology techniques.

Q: Can we use all listed beads (glass, zirconium, steel balls) for all purposes?

A: The different beads are recommended for different applications, as shown in our bead selection guide. Generally, glass beads are for yeast, bacteria, and low density tissues (brain, liver, etc.). Zirconium silicate and zirconium oxide beads are for tougher tissue, and stainless steel beads for very fibrous or dense samples. That being said, often customers would like to standardize their homogenizations using one type of bead, so if they use difficult tissues (heart, lung, etc) they will use stainless beads and try to stick with them for their other applications because they know how they behave. We offer a variety of types of different sizes and density to give our customers flexibility in developing their own protocols. Given that some tissues are tougher than others, and heavier beads will carry more momentum, it is easy to imagine that one type of bead of a given size and density will have a better grinding behavior than another for a specific tissue.

Q: Which beads should I use?

A: The Protocols page contains suggested beads, speeds, and durations for processing many types of tissues and cells. The Bullet Blender™ beads web 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 porportionate 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. You can also contact our technical support staff at techsupport@nextadvance.com if you have any doubts.