Biological Materials—Cell Disruption

Many biological cells contain degradative enzymes (proteases) that catalyze the hydrolysis of peptide linkages. In the intact cell, functional proteins are protected from these destructive enzymes because the enzymes are stored in cell organelles (lysosomes, etc.) and released only when needed. The proteases are freed upon cell disruption and immediately begin to catalyze the degradation of protein material. This detrimental action can be slowed by the addition of specific protease inhibitors such as phenylmethyl-sulfonyl fluoride or certain bioactive peptides. These inhibitors are to be used with extreme caution because they are potentially toxic. 

A tubular sonicatlon device was recently reported by Borthwick et al. [93] (see Fig. 3.9). The device requires the addition of no chemical, enzyme or particles that might complicate the subsequent determination step. Furthermore, denaturatlon of target DMA or proteins for detection Is minimized as the device tolerates moderate temperature rises this allows the use of sensitive and specific Immunological detection methods on sonicated biological materials. Because the tubular device Is composed of a piezoelectric resonator made of several material layers, selection of an appropriate operating frequency Is essential to ensure proper performance (i.e. acceptable cell disruption efficiency). This device can be used for batchwise treatment of small sample volumes or In flow systems without the risk of hazardous aerosol formation inherent in probe sonloators. 

Once the cellular materials are separated, those with intracellular proteins need to be ruptured to release their products. Disruption of cellular materials is usually difficult because of the strength of the cell walls and the high osmotic pressure inside. The cell rupture techniques have to be very powerful, but they must be mild enough so that desired components are not damaged. Cells can be ruptured by physical, chemical, or biological methods. 

---