Scientists from the Lerner Research Institute at Cleveland Clinic have demostrated a novel method to enrich a sample of peripheral blood progenitor cells with the help of magnetic nanoparticles.
NCI’s Alliance for Nanotechnology in Cancer reports:
Reporting its work in the journal Biotechnology and Bioengineering, a research team headed by Maciej Zborowski, Ph.D., demonstrated that magnetic nanoparticles, combined with antibodies, successfully enriches peripheral blood progenitor cells (PBPCs) in samples of whole blood. Clinical trials have shown that PBPCs are more effective than bone marrow transplantation at restoring an individual’s blood cells population following high-dose chemotherapy or radiation therapy.
Current magnetic separation methods, while effective, operate in batch mode rather than flow mode, making them too slow and inefficient for optimal use in a high-throughput clinical setting. In previous work, Zborowski and his colleagues had developed a quadruple magnetic flow sorter (QMS) similar to a fluorescence activated cell sorter (FACS) but with up to a 1,000-fold faster throughput than this widely used device, on the order of 10 million cells per second.
PBPCs are known as CD34+ cells because they express a protein, known as CD34, on their cell surfaces. CD34 is a well-studied molecule and antibodies that bind to this marker are commercially available. In a long series of experiments, the investigators tested a wide variety of methods to develop a procedure for labeling an anti-CD34 antibody with magnetic nanoparticles and using that labeled antibody to bind to CD34+ cells.
Next, the investigators conducted a second set of experiments aimed at optimizing flow conditions and other instrument parameters to maximize the ability of their QMS instrument to separate CD34+ cells from other blood cells. The researchers noted that theoretical modeling of cell flow in magnetic fields was critical to the success of this phase of their study.
Finally, the investigators tested their optimized protocol on human blood samples. These experiments demonstrated that this technique was able to recover between 18 percent and 60 percent of the PBPCs in human blood samples, while the purity of the CD34+ cells ranged from 60 percent to 90 percent. Both parameters fall well within the clinical useful range. The researchers note that they will now develop a sterile protocol as the next step toward clinical trials.
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