Premium
A 3‐D dielectrophoretic filter chip
Author(s) -
Iliescu Ciprian,
Xu Guolin,
Loe Felicia Celeste,
Ong Poh Lam,
Tay Francis E. H.
Publication year - 2007
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200600431
Subject(s) - materials science , dielectrophoresis , filtration (mathematics) , microfabrication , electrode , electric field , filter (signal processing) , capacitor , voltage , dielectric , trapping , suspension (topology) , chip , composite material , optoelectronics , nanotechnology , microfluidics , fabrication , electrical engineering , chemistry , alternative medicine , mathematics , ecology , pathology , engineering , biology , quantum mechanics , homotopy , medicine , statistics , physics , pure mathematics
Abstract The paper presents a 3‐D filter chip employing both mechanical and dielectrophoretic (DEP) filtration, and its corresponding microfabrication techniques. The device structure is similar to a classical capacitor: two planar electrodes, made from a stainless steel mesh, and bonded on both sides of a glass frame filled with round silica beads. The solution with the suspension of particles flows through both the mesh‐electrodes and silica beads filter. The top stainless steel mesh (with openings of 60 μm and wires of 30 μm‐thickness) provides the first stage of filtration based on mechanical trapping. A second level of filtration is based on DEP by using the nonuniformities of the electric field generated in the capacitor due to the nonuniformities of the dielectric medium. The filter can work also with DC and AC electric fields. The device was tested with yeast cells (Saccharomyces cerevisae) and achieved a maximal trapping efficiency of 75% at an applied AC voltage of 200 V and a flow rate of 0.1 mL/min, from an initial concentration of cells of 5×10 5 cells/mL. When the applied frequency was varieted in the range between 20 and 200 kHz, a minimal value of capture efficiency (3%) was notticed at 50 kHz, when yeast cells exhibit negative DEP and the cells are repelled in the space between the beads.