Several automated sample-homogenization systems are currently available. MP Biomedicals manufacturers one such family of systems, including FastPrep-24™ and FastPrep-96™ (Figure 1).
The FastPrep systems consist of an instrument and a disposable lysing matrix, which includes standard labware ranging from 96-well plates and 2 mL tubes, up to 250 mL bottles, loaded with an optimized mixture of inert lysing matrix particles.
The lysing matrix beads are application specific, and their composition is optimized to provide fast and quantitative lysis of a selected sample type, in most cases within 40 seconds or less. The lysing beads are made of advanced ceramic materials with different hardness values, sizes, and densities, wherein the larger beads play the role of cascading impactor, and the smaller sharper beads are mainly performing lysis by shearing.
The FastPrep-24 instrument uses a unique, optimized 3-D motion to disrupt tissues and cells through the multidirectional, simultaneous beating of specialized lysing matrix beads on the sample material. The macroscopic motion of nutation results in an in-tube formation of the strong force fields, which accelerate tube content both alongside the vertical axis of the tubes, as well as in a sideways, angular motion.
This combination of force fields creates the in-tube environment into which the larger and heavier particles perform grinding homogenization and lysis by cascade impaction, and the smaller sharper particles are taken into the fluid vortex, moving in spiral or circular patterns and performing the shearing of the sample.
Concurrently, the liquid vortex, as a result of its velocity gradient differentials, performs fluid shearing by vortexing. As there are three simultaneous processes being performed in the tube on a sample, the result is a rapid lysis of even the most difficult samples like bone or plant materials within 40 seconds or less. A table of the most common lysis parameters settings for FastPrep-24 system is provided above.
The FastPrep system has optional temperature control adapters for cryogenic lysis by passive sample cooling with dry ice. Figure 2 represents RNA extracted from Cassava root, an RNase-rich plant material that is both mechanically difficult to homogenize and represents a special challenge for RNA extraction due to extra high content and activity of the RNase enzymes.