Transcript 下載/瀏覽Download

Optically induced flow cytometry
for continuous microparticle
counting and sorting
Student: Chin – wei Hsu
Professor: Yi-Chu Hsu
Class: Nano-electro mechanical
Systems
Date ：Nov 04 2011
Powerpoint Templates
Page 1
Outline
Introduction
Chip design
Results
Conclusion
Powerpoint Templates
Page 2
Introduction
• This enables it to continuously count and to sort micro
particles based on optically induced dielectrophoretic(ODEP)
forces.
• Using 20.9 and 9.7um polystyrene microparticles, the average
light intensity were about 63.67 and 8.80 units,with a
coefficient-of-variation (CV) of 7.46 and 25.57%, respectively
• The development of the OIFC device is a major advancement in
the design of micro particle counting and sorting devices
Powerpoint Templates
Page 3
Chip design
(a)Schematic illustration of the optically induced flow cytometer chip for
counting and sorting of microparticles.
(b) Conceptual illustration of continuous separation of microparticles.
Powerpoint Templates
Page 4
An alternating current (ac) voltage is supplied between the top
and bottom ITO layers. Since amorphous silicon has a high
electric impedance prior to illumination, it causes a weak, uniform
electric field inside the liquid layer.
Thus, the microparticles do not sustain any non-uniform ODEP
force. When a projected light source hits the amorphous silicon
layer, electron–hole pairs are excited, thus decreasing the
impedance of the amorphous silicon layer by 4 to 5 orders of
magnitude
Powerpoint Templates
Page 5
(c)The negative ODEP force is induced by an ac voltage when illuminating
an amorphous silicon layer to form a non-uniform electric field
(d)Exploded view of the microfluidic chip.
Powerpoint Templates
Page 6
After the fabrication processes, the ITO glass with the SU-8
structures were then bonded with another ITO glass with the
photoconductive layer by using an epoxy glue. A Teflon tube was
connected with the upper ITO glass to mechanically drilled via
holes using epoxy glue
Powerpoint Templates
Page 7
(a)Simplified fabrication process for the microfluidic chip
(b)SEM image of the etched optical fiber inserted in the SU-8 structure.
The diameter of the etched optical fiber is 55m.
Powerpoint Templates
Page 8
Experimental setup for counting, analyzing and sorting of
microparticles by using the optically induced flow cytometer chip
Powerpoint Templates
Page 9
Results
• In this study we proposed a new device utilizing the ODEP force
to focus the particles in the sample flow and to sort the
microparticles dynamically into the subsequent virtual channels.
• A pair of buried optical fibers were inserted into the device to
count the number of the microparticles. Note that all these
functions were achieved without using any lithography process to
pattern the metal electrodes.
Powerpoint Templates
Page 10
(a)Microparticles are focused by
virtual electrodes induced by
illuminating the photoconductive
layer to generate a negative ODEP
force.
(b)When the virtual channel is
increased to 130 um, the trajectory of
the microparticles is an arc line as
marked in the figure.
While the microparticles passed
though the optical fiber, the ODEP
switch is activated
Powerpoint Templates
Page 11
(c)Smaller microparticles are switched (d)Larger microparticles are switched
upwards
downwards
Powerpoint Templates
Page 12
Fig. 6. Microparticles are continuously separated by weaker
and stronger virtual electrodes induced by different
illumination intensities.
Powerpoint Templates
Page 13
Conclusion
Experimental data showed that a perfect total count of 83 particles was
achieved for 20.9 m diameter microparticles.For 9.7um microparticles, 77
particle counts, with 3 missed counts, were observed.
The intensity of the detection signals was reasonably stable due to the fact that
microparticles were aligned in the vertical direction inside the fluid channel.
Finally, the 9.7 and 20.9um microparticles were successfully sorted by an
ODEP switch.
continuous microparticle separator was also demonstrated by using different
illumination intensities.
Powerpoint Templates
Page 14
Thank you for your attention
Powerpoint Templates
Page 15