Cell Purification: A New Challenge for Biobanks

Abstract

Performing ‘-omics' analyses on heterogeneous biological tissue samples, such as blood or bone marrow, can lead to biased or even erroneous results, particularly when the targeted cells and/or molecules are present at relatively low percentages/amounts. In such cases, whole sample analysis will most probably dilute and mask the features of the cell and/or molecules of interest, and this will negatively impact the results and their interpretation. Therefore, frequently it is critically important to have well-characterized and high-quality purified cell populations for the reliable detection of subtle variations in their specific features, such as gene expression profile, protein expression pattern and metabolic status. Biobanks are technological platforms which aim to provide researchers access to a large number of high-quality biological samples and their associated data, particularly to support high-quality scientific and clinical research projects, and such projects will benefit enormously by having access to high-quality purified cell populations or their biological components (e.g. DNA, RNA, proteins). Therefore, a clear opportunity exists for preparative cell sorting techniques in biobanks. Although multiple different cell purification approaches exist or are under development (e.g. cell purification techniques based on cell adherence, density and/or cell size properties, methods based on antibody binding as well as new lab-on-a-chip purification techniques), the choice for a specific technology depends on multiple variables, including cell recovery, purity and yield, among others. In addition, most cell purification approaches are not well suited for high-throughput (HT) purification of multiple cell populations coexisting in a sample. Here we review the most (currently) used cell sorting methods that may be applied for sample preparation in biobanks. For the different approaches, technical considerations about their advantages and limitations are highlighted, and the requirements to be met by a HT cell sorting technology to be used in biobanks are also discussed.

All-in-one processing of heterogeneous human cell grafts for gene and cell therapy

“…Existing methods, however, do not support simultaneous elimination and transfection in heterogeneous cell systems. 1–20 Cell destruction (elimination, separation) uses filtering, centrifuging, fluorescent-activated flow sorting, and magnetic, and adsorbent removal of target cells. The best results were achieved with target-specific antibodies conjugated to either magnetic beads or biotin to bind to the target cells and then to pass through columns to select the target cells.…”

“…The best results were achieved with target-specific antibodies conjugated to either magnetic beads or biotin to bind to the target cells and then to pass through columns to select the target cells. 1–12 When applied to human grafts, the limitations of immunotargeting are in the incomplete removal of unwanted cells or the excessive removal of important immune cells, 1 , 8–12 as well as the lack of selectivity due to unavoidable nonspecific binding of antibodies to nontarget cells. Cell transfection is similarly limited.…”

A Trisymmetric Magnetic Microchip Surface for Free and Two‐Way Directional Movement of Magnetic Microbeads

“…A node structure or a switch is necessary in such structures. Limitations in efficiency of movement is another factor that affects the adaptability of magnetic chip based approaches . Overall, using magnetically labeled superparamagnetic beads for selective and free or flexible lateral cell moving together with sorting has not been realized for microfluidic lab‐on‐chip applications.…”

High-throughput assessment of mechanical properties of stem cell derived red blood cells, toward cellular downstream processing

“…Traditionally, target cell separation is performed by Fluorescent Activated Cell Sorting (FACS) and Magnetic Activated Cell Sorting (MACS). Both techniques are very specific since they utilize molecular biomarkers but require the addition of costly modifying agents, such as antibodies or DNA stains, and separate quality-control processes 18 , 19 . Furthermore, the throughput of these techniques is limited ( e.g .…”