Spotting a molecular biologist in the lab used to be quite easy. He was usually the scientist with a bucket of ice in one arm and a mortar and pestle in the other arm. While this stereotype might still hold true at many universities and, perhaps, in some private laboratories, molecular biologists are now using more advanced sample preparation tools such as benchtop cryogenic mills.

Cryogenic mills are a special breed of sample preparation equipment used to prepare samples for DNA extraction. They are usually used for difficult samples, such as bones, teeth and hair, which are difficult to pulverize with normal equipment. By keeping tissues and cells at extremely cool temperatures, typically with liquid nitrogen, cryogenic mills make the sample brittle and easier to pulverize into a fine powder. The liquid nitrogen also preserves the structural and compositional characteristics of the sample that are generally lost if the sample is pulverized at room temperature.

Benchtop cryogenic mills are quite common in life science research labs, especially for the study of genetic materials. They are particularly useful for forensics testing and for metabolite testing by the pharmaceutical industry. Beyond life science applications, cryogenic grinders are also used for polymer, plastic and rubber samples, which are next to impossible to grind at normal temperatures.

The three leading suppliers of benchtop cryogenic mills are SPEX CertiPrep, RETSCH GmbH and Bel-Art Products. RETSCH recently introduced the CryoMill benchtop cryogenic grinder. The system employs an integrated cooling system that circulates liquid nitrogen within the system, keeping the grinding vessel at temperatures near -200 °C. The sample is mechanically ground by impact and friction, which allows for finer particles. The CyroMill is designed for plastic materials, as well as other temperature-sensitive materials and samples with volatile components.

With a more life science focus, SPEX CertiPrep offers several systems including the 6770 and 6870 Freezer/Mill. The 6770 Freezer/Mill can grind one sample and precool up to two other samples. The 6770 and 6870 both have interfaces for programming grinding sequences. The 6870 Freezer/Mill is suitable for larger samples. For higher-throughput applications, SPEX CertiPrep offers the 2000 Geno/Grinder, which prepares samples contained in standard deep-well microplates. The system uses a unique up-and-down grinding/pulverizing motion, and the samples are kept cool with the Cryo-Station accessory.

The total market for benchtop cryogenic mills and pulverizers is less than $40 million, driven in large part by the demand for replacement parts and accessories. In the near term, the market is expected to post robust growth, fueled by increasing demand from life science and forensic applications.

Benchtop Cryogenic Mills

at a Glance

Leading Suppliers

• SPEX CertiPrep

• RETSCH

• Bel-Art Products

Largest Markets

• Academia/Government

• Biotechnology

• Pharmaceutical

Instrument Cost

• $2,000–$10,000