A MICROFLUIDIC SYSTEM WITH NON-EMBEDDED TILTING INTER-CASTELLATED ELECTRODE FOR DIELECTROPHORETIC SEPARATION

摘要

A dielectrophoretic (DEP) separation device with non-embedded intercastellated electrode design is proposed. The dielectrophoretic force is enhanced by a tilting electrode where an electric field gradient along the flow direction is generated. The maximum strength of the electric field is reached at the outlet where the separation occurs. Yeast cells with different dielectric properties (viable vs. non-viable) were used to study the separation efficiency under different operation conditions. The effect of medium conductivity on the DEP spectrum was modeled by a smear-out sphere model for yeast cells. The results show that low medium conductivity has high DEP force and is advantageous for separation. The number of collected yeast cells was calculated based on spectrophotometer readings. The optimal collection frequencies for viable and non-viable cells are 10 MHz and 5 MHz, respectively. The different DEP characteristics for viable and non-viable cell is the primary reason for such a discrepancy. Good collection efficiency in yeast cells shows that a non-embedded tilting intercastellated electrode is an efficient way to separate different dielectric property materials.