Cell Disruption is a process of releasing the biological content from a cell or a process of obtaining intracellular fluid via methods that opens up cell wall. An overall goal in cell disruption is to obtain intracellular fluid without disrupting any of its components.
It is of two types: Mechanical and Non-mechanical.
Mechanical method of cell disruption can be divided into solid shear methods and liquid shear methods. The major principle of mechanical disruption method is cells are being subjected to high stress via pressure, abrasion with rapid agitation with beads, or ultrasound. Intensive cooling of suspension after treatment is required in order to remove heat generated by dissipation of mechanical energy.
Mechanical methods include bead mill and high-pressure homogenizer, high-pressure methods such as French press and Hughes press etc.
Bead mills are adapted for cell disruption in both small scale and large scale production. The main principle requires a jacketed grinding chamber with a rotating shaft, running in its center. Agitators are fitted with shaft, and provide kinetic energy to small beads that are present in chamber which makes beads collide with each other. Choice of bead size and weight is greatly dependent on type of cells.
Increased number of beads increases degree of disruption, due to increased bead-to-bead interaction. However it also affects heating and power consumption. An optimal condition for bead load is considered between 80 and 85% of free volume. Glass beads with a diameter greater than 0.5 mm are considered best for yeast cells, and diameter lesser than 0.5 mm is optimal for bacterial cells.
Disruption of cells is caused by ultrasonic vibrators that produce a high frequency sound with a wave density of about 20 kHz/s. This method is suitable for small volume of suspension of cultured or microbial cells. It is used for both bacterial and fungal cell disruption. Bacterial cell can be disrupted in 30 to 60 sec, and yeast between 2 and 10min.
A sonicator probe generates high frequency sound waves (<20 KHz) for 30-60 secs. These sound waves cause disruption of cells by shear force and cavitation.
Cavitation refers to an area of alternate compression and rarefaction which causes tension in a cell that causes rupturing of cell. In cavitation, gas bubbles are formed which explodes as they decompress after applying pressure that produces a local shock wave. Cells are disrupted by pressure change. Since, considerable amount of heat is generated during this process sample must be kept on ice during treatment.
Download Link: Cell Disruption (Mechanical Methods)- Part 1.pdf