Lysate processing cell lysis

On-chip cell lysis is a crucial component of integrated micro total analysis systems (pTAS). In order to perform biochemical analysis of intercellular molecules (i. e. proteins, lipids and nucleic acids), the cells at first have to be disrupted releasing the biomolecules from inside the cell. The molecules of interest can then be separated or purified from the cell lysate using affinity purification, charge-and size-based separation, filtration, precipitation etc. The process of on-chip cell lysis followed by extraction of the desired biomolecules is collectively referred to as on-chip sample preparation. 

The simplest downstream processes include direct use of the entire fermentation broth, cells and all. This is suitable for low-cost industrial products. Another cost-effective method is the lysis of cells in the crude broth and direct use of the lysate. Yet another method that avoids lengthy purification steps... 

Quake and coworkers [16] developed a PDMS microfluidic device (shown in Fig. 4c) for nucleic acid purification from a small number of bacterial or mammalian cells. This multilayer device contained fluidic channels and a system of membrane-actuated pneumatic valves and pumps, which enabled precise control of buffers, lysis agents, and cell solution and also allowed for parallel processing. Bacterial cells, dilution buffer, and lysis buffer are first introduced into the chip and then transferred into the rotary mixer. Once mixed, the lysate is flushed over a DNA affinity column and drained. The DNA... 

In the sample preparation step, the nucleic acid content from the sample is extracted, concentrated, and purified to meet the quality required by the downstream amplification process. Sample preparation of nucleic acid targeting technologies involves several processes. In most cases, lysis is an initially required process to break open intact structures of targeted species (e.g., cell wall, membrane, and capsules) and to release nucleic acids. Additional purification or extraction of the released nucleic acids from the lysate may be conducted to minimize inhibitory effects on downstream amplification. Following the lysis step, the chemicals introduced (e.g., membrane-solubilizing ionic detergents or proteinases), cell debris, and other interferents that come with samples are removed. For diluted specimens (i.e., urine), nucleic acid concentration may be required in order to reduce the limit of detection of amplification and detection assays. 

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