Transcript precision microfluidic oscillators for on

Philip N. Duncan, Transon V. Nguyen and
Elliot E. Hui
Department of Biomedical Engineering, University
of California, Irvine, CA, USA
Professor: Cheng-Hsien, Liu
Student: Hao-Ran, Shih (9933533)
Date: 2010/12/28
Outline
 ABSTRACT
 INTRODUCTION
 THEORY
 EXPERIMENTAL
 CONCLUSION
ABSTRACT
1.A precision pneumatic oscillator which
provides timing signals for integrated
microfluidic digital logic circuits
2.The design is based on the classical ring
oscillator circuit and requires only a vacuum
supply for power
3.Integrate pneumatic and fluidic circuits to create an
autonomously driven peristaltic pump
INTRODUCTION
1.Microfluidic Large-Scale-Integration has been a highly
successful technology for the automation of
multiplexed chemical reactions
2.A control system built solely out of microfluidic
components would be attractive because it could be
manufactured in parallel with fluid-handling elements
on a single chip
3.Lab-on-a-chip devices require timing to control fluidhandling elements such as peristaltic pumps must be
driven by carefully coordinated waveforms
THEORY
Device fabrication
Mathies technology
IN
OUT
Vacuum
Source
Ground
Ring Oscillator Circuit
1.The system is inherently unstable and will thus
oscillate indefinitely. (odd number )
2.The frequency of oscillation should vary linearly with
1/(pneumatic resistance ), allowing tuning of the
oscillator.
EXPERIMENTAL
mask layout for a 3inverter ring oscillator
photodiode detector
Movement of the elastomeric membrane in the valve
causes a deflection of the laser beam resulting in a
change in measured intensity
Frequency Design
other resistances in the circuit begin to dominate, such
as the resistance of the lines connecting the 3 inverter
stages
saturate
changing the mask layout to minimize interconnect
distances
The worst long-term drift was measured to be
approximately 4% per hour.
The timing of a 1-hour chemicalreaction should be
accurate to within 3 minutes.
The use of an oscillating pneumatic circuit to drive the
operation of a peristaltic pump
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CONCLUSION
1.The tuning of oscillator frequency through the
variation of resistor sizes in the circuit, achieving a
range of 1 Hz to 100 Hz.
2.No characterized oscillator stability,but establishing in
devices that the short-term fluctuation and longterm
drift is suitable for lab-on-a-chip applications.
3.The only external input required is a vacuum source, it
may be possible to use such devices in limited-resource
settings.
Thanks for your listening~