Cell lysis mechanical methods

Cell lysis Mechanical methods pressure shearing, ultrasonic disintegration, bead-mill homogenizers Nonmechanical methods enzymatic lysis, osmotic lysis, freezing and thawing, detergent-based lysis and electroporation... 

Enzymes target specific bonds in the cell wall and provide the most gentle cell lysis with minimum mechanical damage. This method is often limited to releasing periplasmic or surface enzymes. Some common enzymes involved in cell lysis are / (1,6) and //(1,3) glycanases, proteases, and mannase. 

In terms of cell lysis on-chip, Li and Harrison [39] were the first to report cell lysis through combination of a chemical method using SDS and electrical techniques. Since then, other on-chip lysis methods have appeared, including mechanical [40], thermal [41], ultrasonic [42], and electrophoretic [43, 44]. 

In general, cell lysis is performed by either chemical or physical means to rupture the cell phospholipid membrane with the predominant goal of extracting various intracellular contents. On microfluidic devices, there are many cell lysis methods that have been developed, such as chemical lysis, mechanical lysis, electrical lysis, thermal lysis, and other lysis methods. Some of them have been integrated on chip for chemical cytometry, but others are rather difficult to be integrated on chip. 

For mechanical lysis, nanostructured filter-Uke contractions are employed in microfluidic channels with pressure-driven cell flow. Prinz et al. utilized rapid diffusive mixing to lyse Escherichia coli cells and trap the released chromosome via dielectrophoresis (DEP). Kim et al. developed a microfluidic compact disk platform for mechanical lysis of cells using spherical particles with an efficiency of approximately 65 % however, this method is difficult to be apphed for single-cell analysis. Lee et al. fabricated nanoscale barbs in a microfluidic chip for mechanical cell lysis by shear and frictional forces. Munce et al. reported a device to lyse individual cells by electromechanical shear force at the entrance of 10 mm separation channels. The contents of individual cells were simultaneously injected into parallel channels for electrophoretic separation, which can be recorded by laser-induced fluorescence OLIF) of the labeled cellular contents. The use of individual separation channels for each cell separation eliminated possible cross-contamination from multiple cell separations in a single channel. 

Electrical lysis of cells on a microfludic platform has been an area of extensive research interest due to its speed and reagentless procedure compared to chemical and mechanical methods. 

The choice of cell lysis method depends to a large extent on sample type. Mammahan cells, bacteria, and yeast all have different requirements for lysis depending on the presence or absence of a cell wall. In some cases, a combination of chemical and mechanical disruption may yield best results. Another important factor in the choice of lysis method is the sample size of cells to be dismpted. If only a very small volume of sample is available, care must be taken to reduce loss and avoid cross-contamination. Consideration should also be given to the compatibility of the chosen method with downstream applications. 

Salonen A, Nikkila J, Jalanka-Tuovinen J, et al. Comparative analysis of fecal DNA extraction methods with phylogenetic microarray effective recovery of bacterial and archaeal DNA using mechanical cell lysis. J Microbiol Methods. 2010 81(2) 127—134. 

Vigorous lysis methods are employed when cells are less easily disrupted, for example, cells in solid tissues. These methods include sonication [31-33], French pressure [29, 30, 34], grinding [32, 35-37], mechanical homogenization [24, 25, 38], and glass bead homogenization [29, 30]. Vigorous lysis methods usually result in complete disruption of the cell membranes and some organelles. 

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