MINIBEADBEATER-24 OPERATING INSTRUCTIONS
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 less than 1 mm in cross-section with a scalpel or single-edge razor blade**. 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) use beads made of denser material such as zirconia or chrome steel may be required. Click here for additional guidelines on selecting bead media.
** If your sample is already frozen, do not thaw. This is especially important if you are isolating nucleic acids. Rather, Cryopulverize the still frozen sample into smaller pieces. For information on this method see https://www.biospec.com/products/biopulverizer?taxon_id=28
Use screw-cap microtubes with integral o-ring seals. Fill the screw-cap microvial at least 1/2 full with beads (1/2-3/4 is okay). Then add extraction media and cells or tissue, being sure to fill the microtube almost to the top. Exclude as much air from the microtube as possible in order to minimize aerosol formation during the homogenization. Be sure there are no beads on the threads of the microtubes when screwing down the cap. Because they can release an aerosol during a beadbeating, avoid using Snap-top microtubes.
Operating the Mini-BeadBeater
1) Load 1 to 24 microvials into the vial holding ring. The vial holding ring can be conveniently placed on a provided blue vial ring holder (AKA: up-side-down tumbler)). Distribute the microvials symmetrically -- as you would do when loading a centrifuge. If beadbeating less than 4 sample microvials, insert additional empty microvials so that there are at least four microvials in the vial holding ring.
2) Place the loaded vial holder ring on the aluminum wiggle-head (the latter being attached to the motor): Rotate the loaded vial holder ring to a position where the hole in the vial holder ring is aligned with the anti-rotation pin sticking out of the wiggle-head. Slide the vial holder ring down the pin and seat it on the wiggle-head. Next, align the large, black plastic hold-down cap and slide it down to make contact with the tops of the microtube.
3) Screw on and firmly hand-tighten the stainless steel knob: To do this, the locking pin, which is part of the knob, must be in the "down" position. A slight twist of the pin keeps it in either a down or a raised position. As you tighten the knob a clicking sound will be heard as the locking pin engages the circle of metal teeth in the black hold-down cap. Tighten the knob by hand until you cannot go further. Do not use a tool to tighten the knob.
IMPORTANT! The locking pin on the knob is an important safety feature. After hand-tightening the knob until you can get no additional clicks, test that the pin has engaged one of the teeth on the hold-down cap by attempting to UNtighten the knob. Do not proceed if the knob did not lock. Raise up the pin on the knob and repeat the tightening, locking and testing process. Failure to sufficiently tighten the knob or to engage the locking pin can result in the rapid destruction of the central shaft of the aluminum wiggle head.
4) Set the timer. A typical setting for cell disruption is 2-3 minutes. If you are working with heat-sensitive material, consider homogenizing for a shorter period, say 1 minute, then remove the vial holder with its microvials and cool the vials in an ice-water mix for 1 minute. Cycle this beadbeating/cooling sequence, for a total runtime of three minutes. No cooling is needed for nucleic acid extraction providing you are disrupting tissue or cells in a commercial nucleic acid extraction media.
5) Select the shaking speed with the slide knob on the top of the MBB-24. The speed can be varied from about 2000 oscillations/minute (2.0 on the speed label) to 3450 oscl/min. Speed settings less than the maximum are seldom used in cell disruption applications. Converting settings described in the literature for FastPrep 24 (MP Biomedicals) machines are problematic as their speed setting are ill-defined units of M/sec. As a rule, operating the MBB-24 at its maximum speed (3450 rpm) delivers optimal cell disruption yields and that applies to other high-energy bead mills as well.
6) Start the machine by pressing the start/stop button. The timer resets itself automatically at the end of the run.
7) Remove the microvials and vial holding ring. First, lift the locking pin on the stainless steel knob to the raised position. A slight turn of the locking pin knob will temporarily keep it in the raised position. Unscrew the stainless steel knob, lift off the black vial hold-down cap, and finally, move the homogenized samples in the microvial holding ring to its blue vial ring holder (AKA: up-side-down tumbler).
The MBB-24 will only operate with the black plastic hood closed over the shaking mechanism. This prevents the user from coming in contact with the shaker during operation and helps contain any material that might leak or break free.
Internal components of the MBB-24 have no serviceable parts. A large sealed bearing inside the wiggle head can get hot during prolonged running times. While not a requirement, allowing the bearing to cool down between runs will increase its overall lifetime. Lubrication inside the sealed bearing is compromised at colder temperatures. Operation of the MBB-24 in a cold room is not recommended. And furthermore, cold air is not an efficient way to cool vials during the beadbeating process.
The large, black O-ring just below the aluminum wiggle head will need replacing from time to time. Without the O-ring the aluminum wiggle head will spin rather than oscillate. Should the O-ring break, go to BioSpec's https://biospec.com/category/parts_accessories link on our home page to purchase a repair kit. Because the O-ring is accessible on the outside of the MBB-24, change-out is a simple five minute task.