The integration of 3D carbon-electrode dielectrophoresis (carbon-DEP) on a Compact Disk (CD)-like centrifugal platform is presented in this work towards developing an automated platform for label-free cell sorting with application in point-of-care diagnostics and cell-based therapies. The use of DEP can eliminate functionalized magnetic beads or fluorophores required by other separation techniques such as magnetophoresis and flow cytometry and reduce assay complexity, time and costs. This can expand the availability of diagnostic tests, such as for HIV, and make therapies for cancer or degenerative diseases available to a broader number of patients.

Glass-like carbon electrodes are used here to enable DEP-assisted cell sorting. These electrodes are obtained after the pyrolysis of organic polymer structures previously fabricated using photolithography following the C-MEMS technique. Carbon-electrode DEP (carbon-DEP) combines the advantages of other more traditional DEP techniques such as metal-based and insulator-based DEP and represents a new alternative for DEP applications. The use of carbon electrodes yields advantages such as (1) wide electrochemical stability to minimize the possibility of sample electrolysis, (2) excellent biocompatibility and (3) chemical inertness to almost all solvents/electrolytes. The integration of DEP with centrifugal microfluidics significantly reduces the footprint and complexity of traditional DEP platforms which tend to rely on a combination of syringes, tubing, valves, and fluidic ports for fluid manipulation. Key benefits of centrifugal pumping over other forms of propulsion techniques include (1) its insensitivity to most pysicochemical properties of the sample being pumped, such as pH, ionic strength or chemical composition, (2) the vented nature of the system and (3) the fact that the system is easy to miniaturize and that it lends itself easily to assay multiplexing.