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Micro-pipette Motion Detection Micro-pipette Motion Detection by using Optical Fiber Sensorsby using Optical Fiber Sensors

Ali Fuat Ergenc Nejat OlgacAli Fuat Ergenc Nejat Olgac

University of Connecticut, Mechanical EngineeringUniversity of Connecticut, Mechanical Engineering

StorrsStorrs

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Intracytoplasmic sperm injection is a method of fertilization .

Methods of ICSIMethods 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%)

What is ICSI?What is ICSI?

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Piezo-assisted ICSIPiezo-assisted ICSI

Zona penetration

Zona

Taking out the dissected zona

Oolemma Penetration

Sperm injection

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Manipulator drive signal

Current Feedback & Controller

Current SetupCurrent Setup

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Feedback?

Control signalController

-

Computer !

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Feedback MechanismFeedback 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 ?Why do we need fast feedback ?

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High speed movies of the pipette in the air and in High speed movies of the pipette in the air and in the dishthe dish

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• 1000 fps is used for detecting the motion

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Frames of the pipette in the dishFrames of the pipette in the dish

37 m

After 2 msec

30 m

116 m

Frame #2

After 1 msec

Frame #3

Frame #4

After 3 msec

25 m

Frame #6

After 5 msec

14 mFrame #5

After 4 msec

18 m

Dissected piece

Zona Zona pellucidapellucida

Frame #1

Pipette is steady 50 m

10 m

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Frame #2

After 1 msec

270 mFrame #5

After 4 msec

100 m

Frame #6

After 5 msec

70 mFrame #1

10 m

380 m 50 m

210 m

Frame #3

After 2 msec

150 m

Frame #4

After 3 msec

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Frames of the pipette in the airFrames of the pipette in the air

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Motion of the Micro-Pipette 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 SensorOptical Fiber Sensor

It is fast,It is miniature, It is non-contact,

it can detect fast oscillations of the pipette tip.it can be attached to the holding pipette.

it doesn’t have any effect to the piercing process.

1cm

OpticalSensors

HoldingPipette

OpticalFiber

Injectionpipette

z

LASER GUN=650 nm

5mW

OpticalFiber

z

y

x

10 m 1 mm

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Operation Principles of the Sensor

•x-y axes position detection is obtained by voltage differentiation of quad sensors.

•z axis position detection is obtained by average light flux.

Optical Sensor

0

000

0

000

Sensor amplifier

x

z

y

0

000

0

Differential Amplifier

0

000

0

000

0

Low pass DC coupled Filter

x

z

y

y

x

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Preliminary ExperimentsPreliminary Experiments

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Transmitter fiber

Detector fibersLaser Light

Voltage Measurements

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SummarySummary

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 WorkFuture 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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AcknowledgementAcknowledgement

This work is partly sponsored by NIH grant, number

1 R24 RR018934-01

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Questions ?Questions ?