How Deterministic Lateral Displacement (DLD) Works
Similar to mechanical "coin sorters" which were used to separate coins on the basis of size, GPB's DLD uses the same approach on a micro-scale to achieve highly efficient biological separations. In a biological realm, complex cell mixtures, such as blood or apheresis product, passively interact with a series of precisely located micro-posts to deliver exceptionally robust particle separations without incurring cell loss or damage, unlike most cell processing approaches in use currently. In the case of blood or apheresis samples separation of white blood cells from red cells and platelets can be done in a simple closed system that does not require opening or other intervention.
To achieve these separations, individual cells as a function of their size and the geometry of the array predictably move to the left or the right when interacting with a micro-post, not unlike passing through a capillary bed. Simply repeating this process hundreds of times enables enough spatial separation to be created, ultimately allowing for high resolution sized based cell separations +/- 0.5 micron in diameter. Processing more cells simply requires higher degrees of parallelization.
In addition to separating on the basis of size - DLD, as a result of the physical movement of cells or particles through a medium, can be used to achieve highly efficient cell washing - demonstrated below by measuring the removal of unbound fluorescent antibody from an Immunostaining reaction. This degree of washing in one step is equivalent to multi-step cell washing performed by centrifugal processing.
In addition to washing, by simply omitting the clean buffer wash stream, DLD acts as a very effective cell concentrator for cells or particles larger than the critical diameter. Internal testing has shown concentration to be nearly identical to mathematical predictions, with >12 fold concentration possible.