Any researcher who has had to process samples by grinding tissue with a mortar and pestle, cracking cells by vortexing, disrupting cells by sonication, or shearing tissues with a handheld homogenizer understands the difficulty of increasing throughput. Though these methods are effective, they are usually best used when the sample number is small. When higher throughput is needed, homogenization needs to be performed in a higher density using microplates, vial sets, or disruption tubes. Microplates and vial sets have the advantage of the SBS format so that homogenized samples can be subsequently processed with liquid handling workstations.
With explosions in genomics and proteomics research, several companies developed high throughput homogenizers, with the most popular being mixer mills (also known as bead beaters). A mixer mill uses balls made of glass, ceramic, or steel to grind samples. A typical mixer mill will oscillate a deep well plate or 24 well vial set at around 1600 rpm thus providing sufficient energy for grinding balls to homogenize the sample. Mixer mills use one of two motions for shaking samples, either a "figure-8" paint shaker motion , or a linear, reciprocating motion. An evaluation between linear and figure-8 motion mixer mills shows that these instruments have different efficiencies when lysing cells in microwell plates. Data reveals that figure-8 bead beating is less effective than linear motion homogenization. Furthermore, an evaluation of the lysis efficiency between wells shows greater variation when using a figure-8 pattern over the more homogeneous lysis imparted by linear motion homogenizers.
Currently three high throughput homogenizers are available that provide linear motion bead beating. The 2010 GenoGrinder®, 1600 MiniG™ and HT Homogenizer™ fill this niche. For a comparison of these units see the figure below. The popular Geno/Grinder 2000 was discontinued in 2010.