Troubleshooting

Mechanical

Problem: The Bullet Blender stopped prematurely and will not restart.

Solution: The Bullet Blender contains a thermal fuse which prevents the device from overheating. Wait a little while, and when it cools off, you will be able to restart it.

Problem: The Bullet Blender will not start.

Solution: Make sure the unit is plugged in. Check your electrical connection.

Problem: The lids of the centrifuge / microcentrifuge tubes open or leak during operation of the Bullet Blender.

Solution: Make sure the tops of your tubes are securely fastened. Try to ensure that the interface regions or screw threads between the lids and the caps is dry when you close the caps or screw them on, so that there is enough friction for the caps to remain tightly sealed. For best results with the Bullet Blender, we recommend Eppendorf Safe-Lock tubes. The Bullet Blender 50 is designed for use with BD Falcon™ brand tubes, so make sure you are using Falcon tubes or tubes of the same dimensions.

Problem: The centrifuge tubes broke.

Solution: Use high-quality polypropylene centrifuge tubes. In general, these will not break. Even polypropylene 50ml tubes may occasionally crack or break with extended usage. We do not recommend using a single tube in the Bullet Blender 50 more than twice. As a general rule, 1.5 – 2.0ml polypropylene microcentrifuge tubes will not break in the Bullet Blender. However, they may become brittle when exposed to extreme low temperatures. Use caution when using liquid-nitrogen supercooled samples to ensure that you are not supercooling your microcentrifuge tubes as well.

Homogenization

The first and easiest solution to any difficulties in homogenization is to rerun the samples at a higher speed (if not already at the maximum speed). In general, if you have further problems homogenizing a sample, play with the ratio of sample to beads. First try using more beads, then try adding less sample. Most samples will be able to be homogenized at a sample to bead ratio of 1:1, however some may require as low a ratio as 1:3. You can also try using more dense beads, or changing the bead size. Harder tissue will often require denser, larger beads.

Some potential homogenization issues are addressed below:

Problem: The samples float in the buffer, and do not homogenize.

Solution: Pack your samples as far down in the microfuge tubes as possible with a pipette, forceps, or a similar tool. Place your beads evenly on top of the sample to prevent it from floating when you add your buffer. The beads should be of sufficient mass and density to weigh your sample down. If not, try increasing the amount of beads or decreasing the amount of sample until the beads successfully weigh down the sample.

Problem: The tissue is fibrous, and does not homogenize well.

Solution: Fibrous tissue will always be difficult to homogenize. Increase the time and the speed of the homogenization, and if you still have difficulty homogenizing the tissue, try using denser beads, using more beads, or adding less sample per tube.

Problem: The microfuge / centrifuge tubes leak inside the Bullet Blender

Problem: The sample is too hard to homogenize.

Solution (BB standard): While the Bullet Blender is a very powerful instrument, some very hard samples, such as bone, may not homogenize well. Still, there are a few options to explore. You may try soaking your tissue and / or breaking it up into smaller pieces. Depending on your application, you may be able to weaken it with an acid* or solvent.

Solution (BB50): The Bullet Blender 50 is designed to allow you to homogenize large amounts of soft tissue, and some tissues may be too hard for it to easily homogenize. Still, there are a few options to explore. You may try soaking your tissue and / or breaking it up into smaller pieces. Depending on your application, you may be able to weaken it with an acid or solvent. If none of these are viable options, we recommend using a Bullet Blender standard model, which is capable of homogenizing much harder tissue.

Upon request, we can also custom build you a Bullet Blender that works with skirted 5mL tubes. This model has more capacity than a standard model, and more homogenization capability than a Bullet Blender 50. Call or e-mail us for details.

[*Note: Always use caution when handling acids, and wear proper safety equipment.]

Problem: I am using a kit, and the kit calls for a different amount of buffer than the Bullet Blender homogenization protocol.

Solution: If your kit calls for more buffer than your homogenization with the Bullet Blender does, use the amount recommended for use with the Bullet Blender - usually 2 units volume of buffer for every 1 unit mass of sample – then add the rest of the buffer afterward. If your kit calls for less buffer than needed for homogenization with the Bullet Blender, then either use more buffer or dilute your buffer until you have the appropriate volume for use with the bullet blender. If neither of these are viable options, you can always try running the Bullet Blender with less or more buffer than is recommended.

Problem: My sample is smaller than the minimum sample size (10mg / 10ml for the Bullet Blender standard, 0.1g / 100ml for the Bullet Blender 50).

Solution: Depending on the requirements of your downstream application, you may still be able to use the Bullet Blender with samples smaller than the minimum recommended size. In these situations, use an amount of beads and buffer as if you had the minimum recommended amount of sample – in other words, you would never use less than 10mg of beads and 20ml of buffer in the Bullet Blender standard, or 0.1g of beads and 200ml of buffer in the Bullet Blender 50, regardless of how small your sample may be.

Problem: I have done everything else according to your recommendation and my sample should not be too hard, but it just doesn't homogenize.

Solution: If nothing else seems to work, then try running fewer samples at a time, and spacing them apart. The motor in the Bullet Blender will run faster when there is less resistance, so this may improve the effectiveness of the homogenization.

Have a question that we didn't answer here? Contact us and ask!