Micropipette Motion Detection by using Optical Fiber Sensors

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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 lt
  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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Frames of the pipette in the dish
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Frames of the pipette in the air
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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 ,Volume51)
• 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
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 doesnt have any effect to the piercing
process.
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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.

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Preliminary Experiments
Voltage Measurements
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Summary

• Piezo impulses causes lateral oscillations at
  the tip of pipette.
• Camera isnt 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 ?