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In the clinical/microbiological laboratory there are currently several ways of separating specific cells from a fluid suspension. Conventionally cells can be separated based on size, density, electrical charge, light-scattering properties, and antigenic surface properties. Separating cells using these parameters can require complex technologies and specialist equipment which may damage sensitive cells. The pumping mechanism described here leaves samples undamaged either mechanically or chemically unlike many other current filtration techniques. This paper proposes new Bio-MEMS filtration chips manufactured using micro systems technology (MST) that, when used in conjunction with an optical microscope and a syringe, can filter and grade cells for size without the requirement for additional expensive equipment. These chips also offer great versatility in terms of design and their low cost allows them to be disposable, eliminating sample contamination.