Biomedical Engineering Reference
In-Depth Information
Chapter 11
Dielectrophoretic Characterization
and Continuous Separation of Cells in a PDMS
Microfluidic Device with Sidewall Conducting
PDMS Composite Electrodes
Nuttawut Lewpiriyawong and Chun Yang
Abstract
A complete polymer microfluidic device with sidewall conducting
PDMS composite electrodes represents a new class of dielectrophoresis (DEP)
devices used for manipulation of cells. This chapter summarizes the key functions
of such a novel device for characterization of cells in stagnant flow and for
continuous-flow separation of microparticles and cells based on size or electrical
polarizability. These novel conducting PDMS composites can be synthesized by
mixing 1
m silver particles into PDMS gel. Unlike other existing fabrication
techniques relying heavily on glass and silicon, the proposed technique yields
sidewall conducting PDMS electrodes which are strongly bonded to PDMS
microfluidic channels and allows for straightforward device assembly with only
one-step oxygen plasma treatment.
m
11.1
Introduction
Separation of target cells in biofluids such as blood or bone marrow is one of the
most important bioanalytical tasks for medical practitioners to diagnose patients'
pathological states [
1
]. These complex biofluids usually contain various biosamples
such as healthy cells, cancer cells, and even pathogenic microorganisms (e.g.,
E. coli
O157:H7). Some of them are of similar sizes but possess different electrical
properties; some are of similar electrical properties but have different sizes. For
example, MCF10A, MDA-MB-231, and MCF7 human breast cancer cells are of
similar sizes but not much difference in electrical properties [
2
]. Normal
erythrocytes become less electrically conductive as they are injected by malaria
N. Lewpiriyawong • C. Yang (
*
)
School of Mechanical and Aerospace Engineering, Nanyang Technological University,
50 Nanyang Avenue, Singapore 639798, Singapore
e-mail:
lewp0001@e.ntu.edu.sg
;
mcyang@ntu.edu.sg
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