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RedSift Filter Array


Isolating nucleated cells from blood or complex biological solutions presents challenges that impact downstream analysis

Biological fluids, such as blood, are comprised of diverse subpopulations of cells, most of which provide complicating background noise for varyous analytical techniques. Blood is made up of red blood cells, platelets, white blood cells, and a wide variety of rare cells, such as plasma cells, reticulocytes, tumor cells, fetal cells, stem cells, and other immature cell types. Separating and capturing a desired cell subpopulation using physical capture or disruptive techniques results in modification of surface characteristics often producing metabolic changes or cellular destruction from osmotic pressure, cell loss from complicated, tedious techniques, or introduction of undesired analytes. These problems reduce productivity and create unneeded variability—problems that complicate effective diagnostic and research efforts.


Until now.

Introducing RedSift Cell Processor Technology.


AVIVA's RedSift Technology takes advantage of biological, physical and chemical forces to enrich total nucleated cells from blood.


RedSift separates cells of interest from plasma, thrombocytes, erythrocytes, and any unbound particles or biotes.

Using Micro-Electro-Mechanical Systems, or MEMS techniques, we incorporate a micromachined substrate with a smooth surface that is charged to repel leukocytes, while allowing the smaller and more malleable non-nucleated cells to pass through pores on that substrate.

Although the smallest T-cells from blood are the same size as erythrocytes, the presence of a nucleus does not allow them to conform to the pores and hence they are retained with all other nucleated cells on top of the filter.






  • Process minimal blood volumes from 10µl-1000µl
  • Complete enrichment in 8 minutes
  • Obtain up to ~3 Million Nucleated Cells
  • Adjust output volume from 80µl-1000µl to concentrate cells



At the end of the filtering process, better than 99% of erythrocytes, thrombocytes, plasma and all smaller particles, along with excess wash buffer, are collected from the post-filtration chamber of the filter and all nucleated cells are recovered from the pre-filtration chamber into a user defined volume. The user is therefore able to recover enriched nucleated cells as diluted or as concentrated as needed.


Remove red blood cells and platelets


Complete Blood Cell (CBC) Counts were performed on Peripheral Blood and Bone Marrow samples from normal individuals, then filtered using RedSift Filter Array technology. CBC Counts performed and compared to lysis method – efficiency defined as percent of total nucleated cells (WBC), red blood cells (RBC) or Platelets (PLT) recovered. On average, 99% of RBCs and 95% of Platelets are removed from sample. WBC counts are 97% for peripheral blood, nearly 80% for bone marrow.


Debulk your blood, bone marrow or biological material to enable rapid downstream analysis


RedSift Total Nucleated Cell (TNC) enrichment is the perfect companion technology for many modern downstream analytical techniques such as flow cytometry, next generation sequencing and RNA analyses, fluorescence in-situ hybridization staining, etc. By removing erythrocytes, better than 99% of the RNA background is cleared from the sample, as well as better than 99% of the absorption and fluorescence background of the hemoglobin. Furthermore, the removal of thrombocytes results in less cell aggregation in the enriched product, and improved handling times for many assays. Finally, since many antigens may be exported or liberated from cells and into plasma, the removal of unbound antigen from plasma greatly reduces background signal in sensitive fluorescence assays.



Following filtration, cells were stained with different antibody markers to detect specific cells including RBCs and Platelets.



Recover cells of interest



Leukocyte Population Ratios



Effect on Leukocyte Subpopulations


The RedSift filter technology enriches nucleated cells and maintains all of white blood cell (wbc) subpopulations in ratios equal to lysis method. CBC analysis (left graph) and flow cytometry data (right graph) demonstrate the comparable recovery of WBCs between RedSift filters and lysis methods. After filtration, the wbc subpopulations remain intact and are at least equal to lysis, filters do not bias distribution of specific cell types.

The RedSift Filter is able to isolate the same populations as the lysis method of cell preparation, and RedSift does not require the use of chemicals that will cause cell swelling. Cells processed by the RedSift platform are also more viable and intact than cells from lysed samples. Harsh lysis conditions may cause cell death and cell loss, which may result in too few viable cells to perform downstream experimental analysis. Also, RedSift filters do not require any centifugation, and are much gentler to cells. Scientists often want to treat their cells as carefully as possible – use RedSift for gentle enrichment of total nucleated cells.


  • Obtain total nucleated cells for analysis in a short amount of time, with minimal damage to cells, using the RedSift filter technology in place of lysis or ficoll gradient preparation.
  • Get superior removal of RBCs and platelets than in lysis, healthy cells with less debris and an overall cleaner sample.
  • Analyze the cleaner sample easily by flow cytometry - cell populations are more distinct.
  • Internal experience shows lysis is less consistent than RedSift filters, and varying cell population yields from lysis is common. RedSift technology improves experimental reproducibility by reducing variable conditions.


For research use only