Preparation of Sample
Use 0.1 mm beads for bacteria, 0.5 mm beads for yeast, fungi and tissue culture cells and 1.0 mm or 2.5 mm beads for fresh plant and animal tissue. If you have solid tissue, pre-chop it into pieces having approximate 1mm cross-section with a single-edge razor blade or fragment the tissue at liquid nitrogen temperatures with a BioPulverizer (available from BioSpec Products). Up to 400 mg (wet wt) of biomaterial can be disrupted per ml of extraction media. In most applications, beads made of glass or zirconia-silica give excellent results. In special cases (grinding dry leaf material, wet grinding soaked seeds, disrupting skin or cartilage) beads made of denser material such as steel may be required. See beads here.
Fill the 2 ml screw-cap microtube one-half to two-thirds full with beads. Then add extraction media and cells, being sure to fill the microtube almost to the top. Exclude as much air from the microtube as possible. Use screw-cap microtubes with integral o-ring seals in order to eliminate aerosol formation during the homogenization. Be sure there are no beads on the threads of the microtubes when screwing down the cap.
(CAUTION - All snap-top microtubes release aerosol. Nevertheless, it is possible to use snap-top microtubes in the MBB-8. Reverse the black cap of the MBB-8 so that its lip pushes into the chamber holder when screwed on.)
Operating the Mini-BeadBeater-8
1) Insert one to eight microtubes into the chamber holder. Distribute symmetrically. Screw in the black plastic chamber cap, flat side down, until it is in contact with the tops of the microtube caps. Finally, screw on tight the white nylon wing nut.
2) Set the toggle switch on the control box to 'Time' and select the speed. A typical setting for cell disruption is 3 minutes at Homogenize. If you are working with heat-sensitive material, consider homogenizing for 1 minute, then cooling the vials in ice-water for 1 minute. Cycle for a total 'On' time of three minutes. Nucleic acid extraction in denaturing extraction media does not need cooling.
3) Start the homogenization by pushing the white button in the middle of the timer dial. The timer dial resets itself automatically at the end of the run.
CAUTION - While the MBB-8 is running, changing the Timer settings will damage the timer. If you must change the time setting, press and hold down the white start button while changing the position of the timer dial.
Operate the MBB-8 with the black plastic hood over the chamber. This prevents the user from coming in contact with the shaker during operation and will help trap anything that might break free.
The noise level of the disrupter exceeds 85 dB. You may want to isolate the MBB-8 to a side room. But, do not isolate the MBB-8 to a cold room as it will lead to premature motor failure and is not efficient in keeping samples cold during homogenization.
Important Notice - The Mini-Beadbeater-8 has a Limited One Year Warranty. It took three different prototypes to develop the MiniBeadbeater-8. The problem is that the shaking energies needed for good cell disruption are so high that it's mechanical components are stressed to their limits. The lifetime of the Mini-Beadbeater-8 is about 1000 'On' hours. That figures out to be about 20 thousand samples or, depending on frequency use, about one year of use in the laboratory.