Cell Disrupters

To study biological materials, such as proteins, nucleic acids and enzymes, they must first be released from cell samples using a procedure called cell disruption or cell lysis. In many cases, cell disruption is the first step in the purification or analytical process.

Cell disruption is, therefore, a critical step and the method chosen influences the yield and quality of results. Cell disruption can be categorized as nonmechanical or mechanical. Nonmechanical techniques include organic solvents, sucrose mediums to alter osmotic pressure and enzymatic degradation of membranes. Mechanical methods include ball or bead mills, blenders, ultrasonic disruption and pressure systems. The method used depends on cell quantity and type. The technique must have sufficient power to disrupt the toughest cell membranes, such as cell walls, but be gentle enough to preserve cellular contents in their natural form.

One of the most common laboratory- or research-scale cell disruption techniques is sonication or ultrasonic disruption. The technique uses ultrasonic sound waves to create a phenomenon known as cavitation, which is the rapid formation and collapse of minute bubbles. These imploding bubbles vibrate violently, creating mechanical waves that disrupt the surrounding cells.

Many life scientists are reluctant to use these devices, particularly in high-throughput applications, because they can generate large amounts of heat that can change or destroy the sample. Thus, researchers often use ball or bead mills and blenders for higher-throughput applications; one such product is Next Advance’s Bullet Blender, which is capable of lysing up to 24 cell or tissue samples per run. The Bullet Blender uses standard polypropylene microcentrifuge tubes, which are then vigorously struck by beads in the blender. An optional cooling system can be added, which minimizes the effects of mechanical heat generated by the instrument.

While microcentrifuge tube–based configurations are more common, Biospec and SPEX sell systems that can be configured for use with microplates. The MiniBeadbeater-96 from Biospec holds 45 standard microvials in a vial holder or up to two standard 96 deep-well microplates, and uses a figure 8 motion for cell disruption. The SPEX 2000 Geno/Grinder also holds up to two microplates, but uses a unique up-and-down grinding and pulverizing action.

Pressure systems for mammalian cells often use dissolved gases to create a pressure change. For example, cell cultures can be saturated with large quantities of nitrogen within a pressurized vessel. When the pressure is suddenly decreased, the dissolved nitrogen comes out of solution as expanding bubbles, stretching the cell membranes until the cell bursts.

The total market for cell disrupters totaled $20–$25 million in 2006 and is expected to post solid growth over the coming years, fueled by nucleic acid–based testing (PCR diagnostics) and life science research.

< | >