A new design of pressure-driven microbiological filter unit suited for 'on-the-filter' cell lysis in DNA-testing applications.

DNA analysis techniques such as Polymerase Chain reaction are invaluable for the detection of microorganisms in a range of sample types, many of which are bulk liquids such as natural and potable waters, homogenised foodstuffs, blood and other clinical fluids. In each case, the first stage is the collection and pre-concentration of cells and particles using filtration, followed by the preparation of a lysate for DNA extraction and testing. For this purpose, single-use pressure-driven filter units and on-filter lysis protocols are often preferable for speed and practicality, as well as to reduce contamination. This study presents a new design of pressure filter unit and a battery-powered device to achieve this sample preparation in a manner that may be advantageous over current, commercially available units and typical laboratory apparatus and practices. The filter design is thin, flexible and features an inflatable filter chamber that accommodates lysis reagents. The device efficiently heats and agitates the filter membrane in a direct manner resulting in the generation of a lysate, which can be easily removed for further processing. Testing against a market leader, Sterivex™, the new design was shown to support the generation of DNA with equivalent or greater yield, dependent on starting sample, and equivalent quality. The development and adoption of the new design may, for some applications, offer a more convenient and cost-effective approach.