Patented, Gentle Air Sorting Mechanism
Samples travel from a continuously stirred sample cup to a flow cell where they are surrounded by a sheath solution which hydrodynamically focuses them into the center of the stream for interrogation by up to four lasers. By default, all fluid exiting the flow channel is diverted by an air stream to a ‘waste/recovery container’ unless a ‘sort’ signal is produced. In that case the air diverter is briefly turned off to generate a droplet of fluid containing the sortable object which then falls directly below the exit nozzle.
The COPAS and BioSorter platforms are based on the basic principles of flow cytometry, however, they differ from traditional flow cytometers in several important design areas:
- First, the large-bore fluidics and COPAS flow cells can accommodate objects as large as 201500 microns (101500 for BioSorter) which is much larger than standard flow cytometry instruments used for sorting small single cells.
- Second, COPAS and BioSorter systems operate at slower flow rates and lower pressures thereby avoiding the potentially disruptive high shear forces inherent in standard flow cytometers.
- The third difference is the heart of the COPAS and BioSorter technology. A patented pneumatic sorting mechanism, located downstream of the flow cell, utilizes an air diverter to dispense organisms and large cells in a fluid drop. Comparatively, traditional cytometers typically rely on mechanical sorting or application of a large electrostatic charge. Both of these have limitations when large particle samples are involved.
Diagram of the object flow path and COPAS/BioSorter sorting principle
Taken together, these design features of the BioSorter system permit high speed analysis and gentle sorting of large objects. This gentle handling maintains viability while delivering high recoveries of purified biological materials.