Muscle Testing Apparatus

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Muscle Testing Apparatus

• Michael Berry
• Danielle Senge
• Aidan Yandell
• Group 1
• Dr. Borschel

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Overview of Need

• Muscle tissue transplants
• Trauma, surgery, functional damage
• Relocate the flap of a healthy muscle in the body
• Risk of infection
• Long healing process
• Two procedures

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Overview of Need

• Research suggests that engineered tissue could
  eventually serve as a replacement that functions
  similarly to natural muscle
• Method of testing is vital to the advancement of
  tissue engineering

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Project Scope and Requirements

• Apparatus to measure the force generated by
  isometric skeletal and cardiac muscle tissue
  contractions in vitro
• Range 10µNltFlt10mN
• Resolution 1 µN
• Software which acquires data and produces
  relationship curves
• length-tension
• force-stimulation
• force-frequency curves

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Project Scope and Requirements

• Both natural and synthetic tissues
• Typical length 1 cm
• Maximum length 2 cm
• Contractions will be induced
• Tetanic and twitch
• Reproducible, quantifiable, and variable
• Temperature held at 37C
• Budget 2,000

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Independent Components

• Force measurement
• Tissue stimulation
• Temperature regulation
• Software and data acquisition
• Integrated setup

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Option 1 Foil Strain Gauge (load cell)

• Mechanical force ? electrical signal
• Strain causes the foil resistance to change in a
  certain way that is linearly proportional to the
  strain
• Change in resistance unbalances Wheatstone
  bridge, resulting in an voltage output signal

Force Measurement
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Option 1 Foil Strain Gauge (load cell)

• Cons
• Fatigue
• Small tensions can be lost in noise

• Pros
• Low Cost 10 - 100
• High availability
• Small in size (mm)

Force Measurement
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Option 2 Semiconductor Strain Gauge

• Load cells
• Functionally similar
• Strips of semi-conducting silicon

Grass Technologies Model FT-03
Force Measurement
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Option 2 Semiconductor Strain Gauge

• Pros
• Produce a much greater sensitivity
• 25 50 times more sensitive than foil
• Longer lifespan
• More accurate
• Complications rarely occur

• Cons
• Expensive 880 (1,600)
• Fragile
• Sensitive to Temperature

Force Measurement
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Option 3 Piezoelectric Crystal

• Specific crystals generate electric charge when
  mechanically stimulated
• Creates a dipole
• Dipole is related to the rate of change of the
  force
• Recommended for dynamic measurements, not load
  cells for static applications
• Static force will cause the charge to leak to
  zero

Force Measurement
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Option 3 Piezoelectric Crystal

• Pros
• No power supply is needed
• Very sensitive

• Cons
• Dynamic applications
• Newer technology
• Very sensitive
• 1,130

Miniature Series 209C PCB Piezotronics, Inc.
Force Measurement
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PUGH Chart Criteria
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Component 1 Force Measurement
Pugh Chart
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Option 1 Physical Injection of Ions

• Method
• Cation injection to cause voltage gated K
  channels to open and depolarization
• Pros
• Quantifiable, moderate price
• Cons
• Physical contact with muscle, alters
  physiological conditions, does not mimic natural
  stimulation

Programmable Syringe pump
Tissue Stimulation
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Option 2 Chemical Bath

• Neurotransmitters in bath (acetylcholine or
  caffeine) causes depolarization
• Pros
• Quantifiable, reproducible, moderate price,
  modeled after in vivo muscle contraction
• Cons
• Some neurotransmitters can accumulate in bath,
  setup time

Tissue Stimulation
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Option 3 Electrical Stimulation

• Electrical system to induce a current
• Depolarize parallel platinum wire electrodes
• Ca2 Release from S.R.
• Pros
• Highly quantifiable, easily varied, most
  reproducible, common, reusable without
  modification
• Cons
• More expensive

Programmable voltage source
Tissue Stimulation
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Component 2 Tissue Stimulation
Pugh Chart
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Option 1 Analog Hot Plate

• Pros
• Cheap
• Cons
• Least reproducible, manual calibration and
  temperature adjustment introduces human error, no
  feedback loop

Temperature Control
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Option 2 Digital Hot Plate

• Pros
• Reproducible, easily configurable, comes
  calibrated, self adjusting, moderate price
• Cons
• No feedback loop, appropriate plate temperature
  must be determined for sample temperature of 37C
  (account for conduction and convection)

Temperature Control
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Option 3 Temperature Monitoring

• Plate temperature is adjusted to meet target
  sample temperature
• Pros
• Most reliable and accurate system, sample
  temperature is controlled, self-monitored
• Cons
• Much more expensive than other options, complex

Temperature Control
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Component 3 Temperature Control
Pugh Chart
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Option 1
Option 2

• Data Acquisition, Manipulation, and
  Instrumentation Package (LabVIEW)
• Pros
• Acquire, analyze, present data
• Instrument control and interfacing
  compatibilities
• Cons
• Programming required
• Interfacing components

• Data Acquisition (BIOPAC)
• Pros
• Sell compatible hardware
• Interface with Matlab
• Cons
• Not as universal
• Processing/Analysis (MATLAB)
• Pros
• Easy, familiar programming
• Powerful data processor
• Cons
• No data acquisition
• No instrumentation interfacing capabilities

Data Acquisition and Processing
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Pugh Chart Data and Software
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Tissue Specimen

• Anchoring Setup
• Minuten pins
• Artificial tendons

• Connection
• Rigid
• Canning Wax

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Tissue Specimen

• 2-Axis Positioner
• Manual
• Elevate out of silicon
• Length compensation

Model MT-XY Newport Corporation
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Updated Schedule
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Updated Allocation of Responsibilities

• Michael
• Stimulation Method
• Temperature Control System
• Final Presentation
• Danielle
• Force Transducer
• 2- axis positioner
• Progress Presentation
• Aidan
• Software
• Preliminary Presentation

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References

• www.syringepump.com/oem.htm
• www.vokogawa.com/tm/gmi/tm-gmi.htm
• www.corning.com/lifesciences/products_services/fea
  tures/hotplates.asp
• www.npl.co.uk/force/faqs/transtypes.html
• www.pcb.com/techsupport/tech_force.php
• www.societyofrobots.com/sensors_forcetorque.shtml
• www.dfe.com/straingage.html
• www.grasstechnologies.com/products/transducers/ft0
  3.html
• Keynes, R.D. and D.J. Aidley. Nerve and Muscle.
  2001
• www.nmbstraingages.com/gages1234.pdf
• zone.ni.com/devzone/cda/tut/p/id/3642

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Questions?