DLD output showing no red in WBC fraction
DLD Output from whole Blood

GPB's liquid biopsy platform is based on the company's patented deterministic lateral displacement technology (DLD) combined with a unique magnetic bead approach. The system processes an 8ml tube of whole blood to gently but robustly remove red cells and normal white cells, resulting in an enriched and viable population of rare tumor cells - a major breakthrough.

The DLD technology uses a microchip design with an array of posts, designed to establish a laminar flow that deflects cells larger than a specific dimension in one direction while cells and serum that are smaller than the specific dimension follow a different path. Cells are sorted continuously according to size as they gently flow through the array. Depending on the configuration and spacing of the posts, cells above a certain threshold size will always be deflected in a predetermined direction, resulting in an exceptionally pure, gentle separation based on size. For rare cells, such as circulating tumor cells, the specific dimension is set to ensure that all sizes of tumor cells, including smaller less differentiated cells, are included in the DLD derived cell product, unlike cell sieving approaches which select primarily only larger cells.

Flow cytometric plot of mouse spleen CD3 (green) & lymphocytes (blue) in DLD product output

Flow cytometric analysis of mouse spleen CD3+ lymphocytes mixed with normal human lymphocytes demonstrates that the DLD is capable of fine resolution cell separation - the mean peak of the green cells represents an mean size of 6.1um as determined by impedance, compared to a theoretical cut off of 4.5um. Normal human lymphocytes are between 6 and 8.0um.

Huang et al., Science 304, 987