Bullet Blender™ FAQ

Air Cooling™ Use/Operation

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

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. While other homogenizers produce much more heat and require liquid or dry ice to cool, the simple Air Cooling™ in the Bullet Blender™ is capable of maintaining all batches of samples within just a few degrees of the ambient temperature.

Q: Which models have Air Cooling™?

A: The Air Cooling™ feature comes on the "Blue" models: the Bullet Blender™ Blue, the Bullet Blender™ Blue 5, and the Bullet Blender™ Blue 50. Because of the larger motor in the 5 mL version and the longer run times in the 50 mL version, all Bullet Blenders for 5 mL or 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, including conical and round bottom microcentrifuge snap-cap tubes. We recommend Eppendorf Safe-Lock tubes. Screw-cap tubes may not be used in the standard Bullet Blender 24! If you need to use screw-cap microtubes, please let us know and we can build you a custom unit at no additional cost. The Bullet Blender™ Blue 50 works with 50 mL BD Falcon™ and Krackeler brand polypropylene tubes. The Bullet Blender™ Blue 5 works with 5ml Axygen™ 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 add beads to the tubes, place the tubes directly into the Bullet Blender, just as with most centrifuges), set the desired duration and speed, and push start. All the samples will be homogenized simultaneously, without any chance of cross contamination. For mixing / vortexing, beads are not necessary.

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 precision is required to ensure reproducibility. Samples larger than 300mg are possible, especially for softer tissue, but are not recommended-- 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 3 g of soft tissue or cultured cells, a total of 15 mL of sample, buffer, and beads combined, and a minimum volume of 0.1 mL. The Bullet Blender™ 5 can hold up to 1g of tissue / cells / small organisms, a total of 3 mL of sample, buffer, and beads combined, and a minimum volume of 0.1mL.

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 has been frozen in liquid nitrogen?

A: 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.

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

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

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.

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

A: NO! Because of our patented striking technology, which is necessary to make the Bullet Blender both highly efficient and effective, the mechanism of action is different from all other homogenizers on the market. 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.

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

A: 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.

Q: I'm using just one tube at a time, and it sometimes opens. How do I solve this?

A: Some customers have reported problems with tubes opening when using a small number of tubes. If you experience this problem, use at lesat four tubes per run. You may simply add empty tubes to the Bullet Blender and have these in place while you run the tubes(s) with your sample.

Q: Why is there a three-tube minimum for Bullet Blender™ 5 use?

A: The larger, more powerful motor creates more striking force, and due to this single tubes will be susceptible to breaking in the Bullet Blender 5. Using multiple tubes absorbs some of the impact. Empty tubes can be used for this purpose if you have less than three samples to homogenize.