• When working with Bacteria use the 0.1mm diameter glass beads.
• When working with Yeast/Fungi use the 0.5mm diameter glass beads.
• When working with Most Tissue use the 1.0mm diameter glass beads or zirconia/silica beads.
• When working with Skin or "soft" plant material use a 2.0mm diameter zirconia beads.
• When working with really tough or fibrous tissue use the same sized beads (see above) but choose a more dense bead material. For example, researchers prefer 0.1mm zirconia-silica beads for disruption of spores or 2.3 mm chrome-steel beads for extraction of tough fibrous plant material like monocot leaves. Some users have had good results using the MiniBeadbeater in a "dry grinding" process at liquid nitrogen temperatures.

• Glass has a density of 2.5 g/cc (most commonly used bead media for "Beadbeating")
• Zirconia/Silica has a density of 3.7g/cc (50% more dense than glass - good for spores and most tissues)
• Silicon Carbide (sharp particle, not a bead) has a density of 3.2 g/cc (May work faster on tissue samples because the particles have sharp cutting edges. Their utility is still under investigation, but see Brein's comments below)
• Zirconia has a density of 5.5g/cc (100% more dense than glass - good for tough tissue)
• Steel, stainless or not, has a density of 7.9g/cc (used mostly for grinding leaves - stainless steel beads are expensive and but can be reused. Chrome steel beads are 10X cheaper - cheap enough to be use one time and thrown away.)
• Tungsten Carbide has a density of 14.9g/cc (While very dense, this bead is not recommended for biopreps - leaves prep dirty)

• Quick and easy plating of yeast and bacteria. Add a few sterile 6.3mm diameter glass beads to the plate to evenly spread yeast and bacteria inoculums. No need to remove them afterward.
• Pack roller bottles, tubes or vials with 6.3 mm diameter glass beads to greatly increase the surface area for tissue culture growth. In this application the beads should be packed tightly to prevent movement of the beads during rolling or shaking. When growing cell in non-agitated culture flasks, confluence is reached faster and cell density is enhanced by adding a layer of 0.1 mm diameter beads (see Growth of Three Established Cell Lines on Glass Microcarriers by James Carani, et. al., Biotechnology and Bioengineering, Vol.25, p.1359-1372 (1983).
• Create a bio-reactor by packing a column with glass beads and inoculate with select surface-adhering micro-organisms or cells.
• Keep dialysis tubes vertical during dialysis by adding a few large beads before sealing.

Feed Back, Oct 2006. Santhosh Chelian of UC Davis. Fresh rice leaves or tree needles were powdered or pulverized with a MiniBeadbeater using several 2.5 mm or 3.2 mm chrome steel beads in a microvial. The capped vial contents were immersed 1/2 way into liq. N2 and and then quickly inserted into a MBB. No liq. N2 is added to the vial. Pulverize for one minute. Refreeze and repeat for another 1/2 min, if necessary. 40-60 mg of plant material was used in each well. (BIOSPEC NOTE: Do not use 6.35 mm steel beads for dry milling in our MBB machines, as they will blast right through the vials! Glass beads of the same 6.35 mm size, however, are okay. For MiniBeadbeater-96 users, the same cryogenic protocol works using 12 strips of 1.2 ml micro dilution tubes (96 well format, USA Scientific, #1212-8000). Also, consider using the solid aluminum vial holder, Cat. No. 702ALU, chilled to liq. N2 temperatures, with an array of individual microvials in the MBB-96).

After cryo-pulverizing the above tissue, DNA or RNA extraction solution was added to the vial and the mixture was "beadbeat" for an additional 1-3 minutes at room temperature. Nucleic acids were recovered in high yield. (BIOSPEC NOTE: Cryo-pulverized tissue, gently extracted with DNA extraction solution with no further physical homogenization, yields very large molecular weight DNA.)

Freeze-dried leaf tissue can also be dry ground. In this case, cryo-temperatures are not needed during grinding. Use a few 3.5mm or two 6.35mm glass beads per well or vial and grind for 3-5 minutes.
Preliminary information suggests that plant and animal tissue can be disrupted more quickly with sharp-edged material rather than smooth beads. Furthermore, it may not be necessary to prechop larger sized tissue into small pieces before "beadbeating". If you want to check this out, we now stock three sizes of Silicon Carbide sharp particles.

Feedback, Mar 2006. James Brien of Health & Science, University in Portland, OR. Brien reports that several whole organs from mice, cut into 3-4 pieces, were completely homogenized using 1 mm dia. SiC sharp particles. His objective was to measure virus load using a plaque assay. He found that the usual prechopping of the tissue to 1mm cross-section pieces was not necessary. Using a dye permeability test, he estimated that better than 99% of the cells were lysed after 2 minutes of shaking in a MiniBeadbeater-96. Lysis in both 2 ml and 7 ml vials was tested. One half of the vial volume was filled with the sharp particles. Controls using similar loads of 1 mm dia. spherical glass beads gave poorer results.

• Coating beads is a waste of time. The coating will be quickly removed during shaking.
• Most bead media is reusable. Wash with lab detergent (not acid!) and rinse well (see Bead Washing link below).