Transcript No Slide Title - University of Connecticut

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Micro-pipette Motion Detection
by using Optical Fiber Sensors
Ali Fuat Ergenc Nejat Olgac
University of Connecticut, Mechanical Engineering
Storrs
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What is ICSI?
Intracytoplasmic sperm injection is a method of fertilization .
Methods of ICSI
• Conventional ICSI (success rate for mouse < 10%)
• Piezo-assisted ICSI (N/A for mouse)
• Piezo-assisted ICSI with mercury (success rate for mouse 68%)
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Piezo-assisted ICSI
Zona
Zona penetration
Taking out the
dissected zona
Oolemma
Penetration
Sperm injection
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Current Setup
Manipulator drive signal
Current
Feedback &
Controller
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Control signal
Controller
Computer !
Feedback?
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Feedback Mechanism
Current feedback mechanism is CAMERA!
• Camera is a slow feedback element.
• Image processing is a difficult way to get position feedback.
• Only 2-D position can be detected by using conventional
microscope and camera
Why do we need fast feedback ?
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High speed movies of the pipette in the air and in
the dish
• 1000 fps is used for detecting the motion
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116 m
50 m
25 m
Pipette is
steady
Frame #4
After 3 msec
30 m
Frame #2
After 1 msec
Frame #5
Dissected piece
After 4 msec
Frame #3
After 2 msec
14 m
Frame #1
18 m
10 m
Zona
pellucida
37 m
Frames of the pipette in the dish
Frame #6
After 5 msec
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After 1 msec
After 2 msec
Frame #5
Frame #6
After 3 msec
70 m
100 m
150 m
Frame #4
210 m
380 m
50 m
Frame #3
Frame #2
Frame #1
270 m
10 m
Frames of the pipette in the air
After 4 msec
After 5 msec
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Motion of the Micro-Pipette
It is shown that (Kerem Ediz, Nejat Olgac, “Micro-dynamics of
the piezo-driven pipettes in ICSI”,Biomedical Engineering, IEEE
Transactions on ,Volume:51)
•The flexible pipette shows extensive lateral oscillations during
the piercing process.
•The amplitudes of the axial oscillations of the pipette tip are
much smaller than the amplitudes of the lateral oscillations.
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Optical Fiber Sensor
LASER GUN
=650 nm
5mW
Holding
Pipette
Injection
pipette
10
y
m
1 mm
Optical
Sensors
Optical
Fiber
x
z
1cm
Optical
Fiber
z
It is fast, it can detect fast oscillations of the pipette tip.
It is miniature, it can be attached to the holding pipette.
It is non-contact, it doesn’t have any effect to the piercing process.
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Operation Principles of the Sensor
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Sensor amplifier
Low pass DC coupled Filter
x
x
y
y
z
z
Differential Amplifier
y
Optical Sensor
x
•x-y axes position detection is obtained by voltage differentiation
of quad sensors.
•z axis position detection is obtained by average light flux.
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Preliminary Experiments
Transmitter fiber
Detector fibers
Voltage Measurements
Laser Light
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Summary
 Piezo impulses causes lateral oscillations at the
tip of pipette.
 Camera isn’t fast enough feedback element to
capture all motions.
 A new sensor is designed and preliminary
experiments are done.
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Future Work
Development of more sensitive optical detector
Miniaturization of the fiber optic detector tip
In-situ experiments and investigating the effects
of the cell on the light dispersion
The usage of the light with different wavelengths.
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Acknowledgement
This work is partly sponsored by NIH grant, number
1 R24 RR018934-01
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Questions ?
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