Ultrasensitive Clinical Enumeration of Rare Cells ex Vivo Using a Micro-Hall Detector

Abstract

The ability to detect rare cells (< 100 cells per ml of whole blood) and obtain quantitative measurements of specific biomarkers on single cells is increasingly important in basic biomedical research. Implementing such methodology for widespread use in the clinic, however, has been hampered by low cell density, small sample sizes, and requisite sample purification. To overcome these challenges, we have developed a microfluidic chip-based micro-Hall detector (μHD), which can directly measure single, immunomagnetically tagged cells in whole blood. The μHD can detect single cells even in the presence of vast numbers of blood cells and unbound reactants, and does not require any washing or purification steps. In addition, the high bandwidth and sensitivity of the semiconductor technology used in the μHD enables high-throughput screening (currently ~107 cells/min). The clinical utility of the μHD chip was demonstrated by detecting circulating tumor cells in whole blood of 20 ovarian cancer patients at higher sensitivity than currently possible with clinical standards. Furthermore, the use of a panel of magnetic nanoparticles, distinguished with unique magnetization properties and bio-orthogonal chemistry, allowed simultaneous detection of the biomarkers EpCAM, HER2/neu, and EGFR on individual cells. This cost-effective, single-cell analytical technique is well-suited to perform molecular and cellular diagnosis of rare cells in the clinic.

Circulating Tumor Cells: Liquid Biopsy of Cancer

“…Recently, investigators in the field have seen the introduction of both a new CTC chip, called "Ephesia," which uses columns of biofunctionalized superparamagnetic beads selfassembled in a microfluidic channel onto an array of magnetic traps, and another microfluidics system that uses high-throughput selection, enumeration, and electrokinetic manipulation of low-abundance CTCs (7 ). The new microfluidics chip-based micro-Hall detector can directly measure single CTCs tagged with a panel of magnetic nanoparticles in a whole-blood sample (9 ). Capturing CTCs lacking EpCAM expression has involved the use of cocktails of antibodies against various other epithelial cell surface antigens [human epidermal growth factor receptor 2 (HER2), mucin-1 (MUC1), epidermal growth factor receptor (EGFR), folate-binding protein receptor, TROP-2] and against Physical properties include size (membrane filter devices), deformability (microfluidics system in a chip), density (Ficoll centrifugation), and electric charge (dielectrophoresis).…”

Characterizing asthma from a drop of blood using neutrophil chemotaxis

“…Microfluidic systems have several characteristics that make them wellsuited for clinical use, including low sample-volume requirements (13,14); simple integration with automated fluid handling systems (15); and diffusion-dominant laminar fluidic phenomena that allow for precise control of a cell's microenvironment (16)(17)(18). Indeed, microfluidic-based tools are increasingly being used in clinical research for diagnostic purposes (19)(20)(21)(22)(23)(24)(25)(26). Neutrophils have been used to diagnose clinical conditions in human patients Significance Asthma is a chronic inflammatory disorder that is notoriously difficult to diagnose, characterize, and properly treat with tests that are available to clinicians today.…”

Complex Tumor Genomes Inferred from Single Circulating Tumor Cells by Array-CGH and Next-Generation Sequencing

“…However, no singlecell approach that effectively combines the reliable mapping of copy number changes with next-generation sequencing approaches to detect nucleotide changes has been published so far. Second, CTCs are extremely rare events and, despite many efforts (2,13,14), there is still a lack of technologies capable of isolating them in sufficient numbers. As a consequence, usually only very limited numbers of cells are available for analysis.…”