For Cell Disruption we suggest:
- 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 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 - either at ambient or at liquid nitrogen temperatures. For example, a single seed can be pulverized into a fine powder in 30 seconds using one 6.3 mm diameter chrome steel bead in our 2 or 7 ml vials.
- 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 tough tissue samples because the particles have sharp cutting edges. Their utility is still under investigation, but see Brein's comments below)
- Garnet (an iron-aluminum silicate, sharp particle) has a density of 4.1 g/cc. Like SiC particles, it may accelate lysis of tough tissue due to its sharp edges. However, garnet particles are easily fragmented during beadbeating Separation of the final grinding media from the homogenate can be problematic.
- Zirconia has a density of 5.5g/cc (100% more dense than glass - good for tough tissue). Chemically inert and resistant to fragmentation.
- Steel has a density of 7.9g/cc . (Used mostly for grinding leaves and seeds). Stainless steel beads are expensive but reusable. Only 1-3 steel beads are added to the microvial. Chrome steel beads are a recommended substitute for s.s. beads. They are 10X cheaper - cheap enough to be use once and thrown away. Thus, no cleaning or cross-contamination concerns.
- Tungsten Carbide has a density of 14.9g/cc. While very dense, this bead is generally not used for biopreps - it leaves prep dirty.
Other uses for beads:
- 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.
- Increase the surface area for tissue culture growth by packing roller bottles, tubes or vials with 6.3 mm diameter glass beads. In this application, the beads should be packed tightly to prevent movement of the beads during rolling or shaking. When growing cells in non-agitated culture flasks, confluence is reached faster and cell density 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 BioSpec stainless steel microvial equiped with silicone rubber caps. 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 into the vial. Pulverize for one-half minute. Refreeze and repeat for another 1/2 min, if necessary. Forty to sixty mg of plant material was used in each vial. After cryo-pulverizing the above tissue, DNA or RNA extraction solution was added to the vial and beads and the mixture was beadbeat for an additional 1-3 minutes at room temperature. Nucleic acids were recovered in high yield.
BIOSPEC NOTES: Larger steel beads used for dry milling at liq N2 temperatures in our MBB machines blast right through common plastic microvials! However, glass beads of 6.3 mm are okay. (Update: BioSpec has developed a new, much stronger 2 ml microvial called "XXTuff". This vial should be used when dry milling with steel beads); For MiniBeadbeater-96 users, this same cryogenic protocol works well using 12 strips of 1.2 ml micro dilution tubes (96 well format, USA Scientific, #1212-8000). Also, consider using the MBB-96 solid aluminum vial holde (Cat. No. 702ALU) chilled to liq. N2 temperatures to maintain microvials at ultralow temperatures.
If very high molecular weight DNA is desired, cryo-pulverize the tissue using the above beadbeater method or with a BioPulverizer followed by gentle extraction with DNA extraction solution without further physical homogenization.
Freeze-dried leaf tissue or dry seeds can also be dry ground. In this case, cryo-temperatures are not needed during grinding. Use two 6.3 mm diameter glass beads or a single 6.3 mm chrome steel bead per vial and grind for 15 - 60 seconds. When dry grinding with steel beads BioSpec's "XXTuff" polypropylene vials or BioSpec's Stainless Steel vials with silicone rubber caps should be used.
Preliminary information suggests that plant and animal tissue can be disrupted more quickly with sharp-edged material rather than smooth beads. In this case, it may not be necessary to prechop larger sized tissue into smaller pieces before 'beadbeating'. If you want to check this out, we now stock three sizes of Silicon Carbide sharp particles. See report below...
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 Mini-BeadBeater-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.
BIOSPEC NOTE: A minor 'downside' on use of sharp particles is the particles abrade during beadbeating and the raw homogenate will have a gray apprearence due to the colloidal-sized SiC suspended in the homogenate. The SiC is essentialy chemically inert and can be separated from the homogenate by the usual down-stream steps of filtration, centrifugation, adsorption or precipitaion.
- 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 cleaning link above).
Most beads are sold in one pound bottles with easy-to-use pour spouts.
Our listed bead sizes given are median values. Because beads are sorted by sieves, the actual bead sizes will range between +/-10% of the listed value.
We also offer PRELOADED beads in 2ml screw cap vials. Because of the many possible combinations of bead size, bead composition and bead load, we do this on a custom basis. Let us know what you need at email@example.com and we will give you a price quote.
The sharp, hard edges of these irregular particles impart a knife-like cutting action during high-energy shaking in MiniBeadbeater vials. They may abrade and micro-chop tough tissue faster than beads. For softer tissues beads are prefered. Read more >
Like Silicon Carbide sharp particles, these abrasive particles have sharp cutting edges that may accelerate lysis of plant and tough animal tissue in a MiniBeadbeater vial. Read more >