A lysis buffer is a buffer solution used for the purpose of lysing cells for use in molecular biology experiments that analyze the compounds of the cells (e.g. western blot). There are many different kind of lysis buffer that one can apply, depending on what analysis the cell lysate will be used for e.g. red blood cell lysis buffer. Generally, lysis buffers contain tris-HCl, EDTA, EGTA, SDS, deoxycholate, tritonX and/or NP-40. In some cases the buffer may also contain NaCl(150 mM).
In studies like DNA fingerprinting the lysis buffer is used for DNA isolation. Dish soap can be used in a pinch to break down the cell and nuclear membranes, allowing the DNA to be released. Other such lysis buffers include the proprietary Qiagen product Buffer P2.