SERF
536
Principal
investigator: Prof. Jayne Wu
Email: jaynewu@utk.edu
Phone: 865-974-5494 (Wu Office) 865-974-6334 (Lab)
世间没有真理,只有对知识的永恒探询。
Research
Areas:
· Micro- and nano-fluidics, esp. AC electrokinetics for bio-nano-applications,
e.g. pumping, preconcentration and sorting
in-situ protein preconcentrator
Continuous separation and trapping of diluted DNAs
On-chip pumping and manipulation of hysiological
fluids
· Bio-electronics, and lab-chip analysis
devices
Lab-chip based fluorometer, ACEK enhanced magnetostrictive
sensor
· Instrumentation for low noise
detection& & implantable applications
Inductive
transmission of biphasic waveform for electrical stimulation
Low-noise differentiator for low frequency signals, esp. heat transfer
application
· MEMS power applications, e.g. inductive
powering, design of integrated power inductors, and light and heat scavenging.
Design of micromachined power inductors, planar transformers,
inductive links
Solid
electrolyte dye-sensitized solar cells for large area applications
Heat-harvesting
micropumps
A Brief Overview of Electrokinetics
Acknowledgement:
The material presented here is
based upon work supported by the National Science Foundation under Grant No.
0448896.
A microfluidic chip
should have following functions: mixing, pumping, concentration step to assist
detection, etc., as shown schematically here.
As device dimension scales down, pressure driven flow becomes
increasingly inefficient due to high surface-volume ratio. In contrast, electrokinetics
is gaining popularity as a microfluidic actuation mechanism, due to its no
moving parts and easy implementation.
Traditional electrokinetic pumping requires
applying high DC voltage across the microchannel, and the electric field drives
the mobile charges at the fluid/channel interface (i.e. electroosmosis)
to transport fluid. High voltage causes
bubble generation and pH gradients from electrochemical reactions. To minimize these adverse effects, AC electrokinetics (ACEK) has emerged recently for on-chip
pumping and particle manipulation for its low voltage operation.
ACEK investigates the
behavior of particles in fluid and the motion of electrolytic fluids when they
are subjected to AC electrical fields.
Charges are induced in the bulk of the fluids where there is an
interface (e.g. electroosmosis) or gradients in fluid
attributes (e.g. electrothermal effect). Because the electric fields and induced
charges in fluid change polarity simultaneously, steady (not oscillatory) fluid
motion can be generated in ACEK. There
are mainly three types of ACEK phenomena, dielectrophresis
(studied since 1991), AC electroosmosis (since 1999,
our group initiated “biased ACEO”) and AC electrothermal
effect (our group is the first to have developed ACEK micropumps). ACEO is mainly effective for low-conductivity
fluid (e.g. water), thus limiting its application in lab-chips. We have developed capabilities for conductive
fluids, making an important step towards practical EK devices.
ACEK can also
manipulate micro/nano particles in the fluid, which
include
My group is at the
forefront of ACEK research, contributing to both its fundamental understanding
and practical applications. In this
burgeoning field, only imagination is the limit.
Current Projects:
·
2005 National
Science Foundation (NSF) CAREER Award
“CAREER:
Developing Asymmetric-Polarization AC Electroosmosis
for Lab-on-a-chip”
·
User projects at
the Center for Nanophase Materials Sciences, ORNL
1. “Electrokinetic Labchip for Rapid Detection of Low-Concentration Micro/Nano-Size Bioparticles”
2. “Fabrication
Of Nano-Injection Needles
For Neural Pathway Study In Mice”
·
DOE Retinal
Prosthesis Research
“PDMS (Polydimethylsiloxane)-Based
Microelectrode Chips for Retinal Prosthesis”
11/03/2005-11/02/2006.
·
Joint Laboratory
Directed Research and Development
“ACEO Synthesis of Nanocomposite
Dielectrics/Polymer: Applications for Electric Power Grid”
·
NSF
“Rate-Based Sensor Development for
Advancing Heat Transfer Measurements”
·
Integration of Particle Trapping with
Cantilever Arrays for Ultra-High Sensitivity Chemical and Biological Agent
Detection
Past Projects:
·
Development of Instructional MEMS
Laboratory, Engineering
Fee, CoE, UTK, $203,000, with M. Mahfouz, FY
2005-2006.
·
Electrokinetic Labchip for Rapid Detection
of Low-Concentration Micro/Nano-Size Bio-particles,
Oak Ridge National Laboratory (ORNL), Center for Nanophase
Materials Sciences (CNMS), 01/03/2005-11/30/2006.
·
Fabrication of Nano-Injection Needles for Neural Pathway Study in Mice,
ORNL, CNMS, 12/08/2005-11/30/2006.
·
Inductive Links
with Integrated Receiving Coils for MEMS and Implanted Applications
·
Fabrication,
Characterization and Simulation of Power AlGaInP/GaAs HBTs