Centrifugo-Magnetophoretic Purification of CD4+ Cells from Whole Blood Toward Future HIV/AIDS Point-of-Care Applications

Abstract

In medical diagnostics, detection of cells exhibiting specific phenotypes constitutes a paramount challenge. Detection technology must ensure efficient isolation of (often rare) targets while eliminating nontarget background cells. Technologies exist for such investigations, but many require high levels of expertise, expense, and multistep protocols. Increasing automation, miniaturization, and availability of such technologies is an aim of microfluidic lab-on-a-chip strategies. To this end, we present an integrated, dual-force cellular separation strategy using centrifugo-magnetophoresis. Whole blood spiked with target cells is incubated with (super-)paramagnetic microparticles that specifically bind phenotypic markers on target cells. Under rotation, all cells sediment into a chamber located opposite a co-rotating magnet. Unbound cells follow the radial vector, but under the additional attraction of the lateral magnetic field, bead-bound target cells are deflected to a designated reservoir. This multiforce separation is continuous and low loss. We demonstrate separation efficiently up to 92% for cells expressing the HIV/AIDS relevant epitope (CD4) from whole blood. Such highly selective separation systems may be deployed for accurate diagnostic cell isolations from biological samples such as blood. Furthermore, this high efficiency is delivered in a cheap and simple device, thus making it an attractive option for future deployment in resourcelimited settings.

Advances in Magnetic Nanoparticles for Biomedical Applications

“…A dual‐force cellular separation strategy using centrifuge–magnetophoresis was also developed and demonstrated separation efficiency up to 92% for cells expressing CD4 + from whole blood. The system uses a combination of super‐paramagnetic Dynabeads CD4 MNPs that specifically bind phenotypic markers on target cells and centrifugal force to isolate magnetically specific cellular phenotype . Another system to isolate magnetically tagged CD4 + cells directly from patient blood works by dual‐force CD4 + magnetophoresis, through which the interplay of magnetic forces and flow controls the trajectory of target cells depending on whether the cells binds to a magnetic bead.…”

Cluster size distribution of cancer cells in blood using stopped-flow centrifugation along scale-matched gaps of a radially inclined rail

“…Standard protocols for disc fabrication, polydimethylsiloxane priming, blood processing and cell culture were used and have been described elsewhere [33][34][35][36][37] . These protocols are also briefly outlined in the Supplementary Information.…”

“…In cases where cells were stained with NucBlue, the relative fluorescent signal across the bins was calculated as described elsewhere 36 and as also briefly outlined in the Supplementary information. For qualitative analysis in which only the binary state of occupancy was required, the presence of events in each bin was visually observed using DIC microscopy.…”

Differential leukocyte counting via fluorescent detection and image processing on a centrifugal microfluidic platform

“…The majority of research in centrifugal microfluidics has focused on the detection of chemistries, 20,21 proteins, 22,23 nucleic acids, 24,25 and rare cells, 26,27 with several analyzers entering the market. For example, the Abaxis Piccolo Xpress device automates the detection of chemistries on-disc 28 , and the Samsung LabGEO IB10 performs automated immunoassays with multiplexing capabilities.…”