Transcript Tissue Loading, Flow Through Microchamber for Microscope

Tissue Loading
Micro-Chamber
Flow-Through Environment for HighPower Microscopic Observation
Aaron Desjarlais
Jessica Kornfeld
Michael Lee
Matthew McGrath
Jeff Perry
Problem Statement
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Mechanism to apply small uniaxial load to
live tissue sample
Record strain, load, displacement while
operation is underway
Provide interface with the Nikon TE2000E
Inverted Optical Microscope
Temperature-controlled environment
Provide for media flow through device to
sustain specimen for long time periods
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Background - Collagen
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Collagen is the most abundant protein on Earth
Structural molecule of choice for vertebrates
Bears and transmits tensile loads applied to the
body
Connective collagenous tissue naturally
degenerates
Decline of usable collagen-based tissue
Increase in growing tissue in the laboratory
environment
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Background - Project
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Collagenous tissue adapts to its
environment
When applying a load, extracellular
matrix remodels in response to strain
Difficult to observe in vivo due to
need for high-power objectives
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Literature Search
Instron PlanarBiaxial Soft
Tissue Test
System
Instron - BioPuls
Submersible
Pneumatic Grips
and TemperatureControlled Bath
Bose
BioDynamic
test systems
Bioptechs Chamber
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Capstone Project
(Spring 2005)
Refined by Kelli
Church for master’s
thesis (Spring 2007)
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Requirements - Specifications
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Must be attachable to Nikon TE2000E
stage
Placement: ≤200μm from objective lens
Micro-chamber volume: <200 micro-liters
Temperature: 37°C ± 0.5°
Tissue size: 1cm x 1cm x ~10 - 1000μm
Uni-axial Load: minimum ~0.1N
Strain Accuracy: ± 1μm
Record displacement, load, strain, and
temperature
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Prototype Mounted on Microscope
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Proposed Design
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Linear Guide System
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Guide System - Design Constraints
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Linearity
 The system must remain in camber
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Rigidity
 The system must be rigid enough so
any displacement in the system does
not add error to the measurement
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Size constraint
 Must fit under the condenser of the
microscope
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Micro-Chamber Base
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Micro-Chamber Base - Design
Constraints
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Rigidity
 The system must be rigid enough so
any displacement in the system does
not add error to the measurement
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Size
 The base must interface with existing
mounting location on the microscope
stage
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Micro-Chamber - Interior
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Material Selection
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316 Stainless Steel
High thermal conductivity:
 16.3 W/m-K (113 BTU-in/hr-ft²-°F)
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Operate at environmental temperature
 Melting Point: 1370 - 1400 °C (2500 2550 °F)
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Corrosion resistant
Can survive repeated common sterilization
methods
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Micro-Chamber Exterior
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Material Selection
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Polycarbonate
Low thermal conductivity
 0.142 - 0.26 W/m-K (0.985 – 1.8 BTU-in/hr-ft²°F)
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Corrosion resistant
Sterilization
 Compatible with common clinical disinfectants;
isopropyl alcohol (rubbing alcohol)
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Low permeability
 Water absorption: 0.0500 - 0.700%
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Micro-Chamber Bacteria Sealing
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Dynamic elements:
two seals with
antibacterial solution
injected in between
both seals
Static elements:
single seal or gasket
through compression
to fill the gap
 0.1 pounds of force is
required per bolt on the
Top Cover
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Drive/Sensor System
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Drive System Design Concepts
Pulley Drive Mechanism
Direct Drive Mechanism
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Rack and Pinion Mechanism
Direct Drive with Spring Mechanism
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Linear Actuator
Chosen Motor:
Zaber Technologies
T-LA60A
Requirements:
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Control and measure
strain to 1 µm
Allow for minimum
10mm of travel
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Accuracy: 0.1 µm
 Already used on existing
system
 Has manual control to
ease setup
 Holds up to 15N
continuous load
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Force Transducer
Requirements:
 Uni-axial Load:
minimum ~0.1N
 Miniature
 Submersible
 Corrosion resistant
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Selected Load Cell:
Sensotec Model 31
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Load capacity range
from 50 g to 500 g
(0.5 N to 5 N)
17-4 PH stainless
steel
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Control System
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LabView Control
System
Capable of Load
or Strain
Desired
Force
Control
Adjustable PID
Parameters
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Force
Transducer
(Load Cell)
PID
Controller
(Labview)
Linear
Actuator
Encoder
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Control System
NI Labview Data Acquisition
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PID Toolkit
Uses existing
interface as baseline
Signal conditioning
card
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Load Control Tests
Load Control Test (0.1N Load)
0.11
0.1
0.09
0.08
Load (N)
0.07
0.06
0.05
0.04
0.03
0.02
0.01
0
0
50
100
150
200
250
300
350
400
Time (seconds)
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Used Med-4720 silicone elastomer as specimen
Tested using 0.1N as required load
Max. error of ± 0.002N once steady state
reached
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Tissue Grip Mechanism
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Grip Design
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Requirements:
 Apply even clamping pressure
 Easy to operate
 Accommodate specimens up to 10mm
wide, 10 μm to 1000 μm thick
 Must be small to minimize chamber
volume
 No part of the clamp must be lower than
the sample
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Grip Design
Hinged Clamp
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Sliding Plates
Sliding Bar Clamp
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Grip Design
Requirement
Weight
Hinged Clamp
Sliding Plates
Sliding Clamp
Ease of Use
3
1
3
2
Size
2
2
1
1
Even Clamping
Pressure
1
2
1
1
Ease of Manufacture
4
3
2
1
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20
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Totals
Chosen Design:
Sliding Bar Clamp
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Thermal Control
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Selected Temperature Controller
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Omega CNi 3222-C24
 AutoTune PID High Accuracy ±0.5°C (0.9°F),
0.03% Reading
 2 Outputs
 Dual Alarm
 Universal Input - Accepts all t/c and RTD’s
 PC RS-232 output
 Free Software
 Ramp to Setpoint
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Cartridge Heaters
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Do not restrict design evolution
Versatile, easily mounted
Compact Design
Powerful Element
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From Spring 2005 Capstone Design Group
Previous System
Cartridge heater
Embedded in
Copper Block
Quartz glass
environmental
Chamber
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Drawings From Spring 2005 Capstone Design Group
Heating System Components
Insulating Plexiglas
Grips
Stainless Inner Lining
Copper Blocks
Cartridge Heater
Fluid Flow
Silicone Tubing
Entering Fluid
Entering Fluid
Exiting Fluid
Heat Transfer Model Comparison
Previous Model
Present Model
Rcond,conv,fin
Rcond,conv
(Top)
(Top)
Rcond,conv
(Back)
Rcond,conv
(Front)
UP
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Rcond,conv, fin
(Back)
Rcond,conv,fin
(Front)
Rcond,conv,fin
Rcond,conv –
Robj cond, conv
(Bottom)
(Bottom)
UP
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Temperature Controller Testing
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Temperature Testing Results
Temperature Test
50
45
Temperature (°C)
.
40
Copper Blocks
Stainlless Inner Wall
Max Temp Range
Min Temp Range
35
30
25
20
0
5
10
15
20
25
30
Time (min)
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Future Work
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Finish machining parts to
specifications, primarily the
adjustable piston
Program system to operate in
parameters of strain control
Fully functional testing including,
cornea loading and fluid heating
assessment
Micro-Chamber volume minimization
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Questions?
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Backup Slides
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Linear Actuator
Trade Study
Feature
Weight
LinMot
Zaber Tech
Nook Ind.
Resolution
10
8
10
1
Interface
7
7
7
1
Max stroke
N ≥ 40mm = 0
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-
-
Overall size
5
5
7
2
Price
7
7.6
8.4
10
214.8
251.2
99
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From Spring 2005 Capstone Design Group
Heat Source
Property
Device
Weight
s
Cartridge
Heaters
OMEGA
Cartridge Heaters
WATLOW
Silicone Pads
OMEGA
Kapton
Material
WATLOW
Area
9
7
9
6
8
Power/ Area
(W/in2)
7
3
10
5
8
Heater Placement
6
9
9
8
8
Uniform Heat
Release to
Specimen
5
6
8
9
9
Cost
5
7.2
3
6.08
2
204
260
212.4
226
Weighted Results
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From Spring 2005 Capstone Design Group
Temperature Controller
Trade Study
Omega
Feature
Temp
Stability
Weight
Cni
32
22
Omron
Cni 3222-C24
E5CS
E5CS-X
10
9
9
7
9
Accuracy
7
10
10
6
8
Universal
Input
5
10
10
5
5
PC Interface
3
0
5
0
0
Autotue PID
7
10
10
6
10
2 Outputs
8
5
5
0
0
ramp to set
point
5
5
5
5
5
Free
Software
3
0
5
0
0
Price
8
9
7
9
8
431
276
330
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TOTAL
417
From Spring 2005 Capstone Design Group
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Results of Heat Transfer Analysis:
Heating Chamber
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From Spring 2005 Capstone Design Group
Nodal Analysis
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System Divided into
37 Nodes, 6 fluid
Nodes
Boundary Conditions:
• System begins at
ambient temperature in
air
• Fluid enters at room
temperature and exits
into large reservoir at
room temperature
• System is symmetrical
on either side of the
chamber.
1
∙ ∙ ∙∙ ∙
2
3
4 5
* *34*35
*32
33
11
∙ ∙ ∙∙ ∙
12
13
14
15
∙ ∙ ∙∙ ∙
*31
21
22
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24
25
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From Spring 2005 Capstone Design Group
Equivalent Circuit Analysis
Equivalent Circuit for Node 1
qin= qout + qstored
(ρcV)cu∙dT = ΣCij∙(Tji) + (q” ∙A)
dt
(ρcV)cu∙ΔT = ΣCij∙(Tji) + (q” ∙A)
Δt
ΔT = Δt ∙[ΣCij∙(Tji) + (q” ∙A)]
(ρcV)cu
Tf -Ti = Δt ∙[ΣCij∙(Tji) + (q” ∙A)]
(ρcV)cu
Tf = Ti + Δt∙[ ΣCij∙(Tji) + (q” ∙A)]
Equivalent Circuit for Node 31
Ein = Eout +Estored
qin = qout +qstored , q= qcond + qe
(qc + qe)in= (qc + qe)out+ qstored
(ρc)l ∙ ve ∙ Af ∙ dT/dt = q31-32+ q31-cu+ qe
(ρc)l ∙ ve ∙ Af ∙ ΔT/Δt = q31-32 + q31-cu + qe
ΔT = Δt / (ρc)l ∙ ve ∙ Af ∙ (q31-32 + q31-cu + qe)
Tf-Ti = Δt / (ρc)l ∙ ve ∙ Af ∙ (q31-32 + q31-cu + qe)
Tf = T31 + Δt / (ρc)l ∙ ve ∙ Af ∙ (q31-32 + q31-cu + qe)
Tf = T31 + Δt / (ρc)l ∙ ve ∙ Af ∙ (C31-32 ∙(T32-T31)+ q31-cu (ρc)l ∙ ve ∙ Af /2 ∙(T32-T∞))
T∞, h∞
1/hA (kA/L)ins (kA/L)cu
q”heater
(Top face)
(Left face)
C12=kA/L
2 (right face)
C16=kA/L
(Back face)
6 (front face)
1
C1-11
11 (bottom
face)
32
ρcveAf(T32+T31)/2
1/hlAf
2πrcukcu/ln(rcu/ro)
22
2πrcukcu/ln(rcu/ro)
23
27
28
ρcveAf(T∞+Ti)/2
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T∞, h∞
From Spring 2005 Capstone Design Group
ri ro rcu
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Results of Heat Transfer Analysis:
Chamber Fluid
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From Spring 2005 Capstone Design Group
Results of Heat Transfer Analysis:
Tubing Fluid Temperature
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From Spring 2005 Capstone Design Group
Translation Block Stress Analysis
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Base Stress Analysis
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Base Deflection Analysis
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Stainless Steel 316
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Thermal Conductivity:
 16.3 W/m-K (113 BTU-in/hr-ft²-°F)
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Melting Point:
 1370 - 1400 °C (2500 - 2550 °F)
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Common Applications:
 Food and pharmaceutical processing
equipment
 Marine exterior trim
 Surgical implants
 Industrial equipment for corrosive process
chemicals
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http://www.matweb.com/search/SpecificMaterial.asp?bassnum=MQ316J
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Polycarbonate
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Low permeability
 Water absorption : 0.0500 - 0.700 %
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Low thermal conductivity
 0.142 - 0.26 W/m-K (0.985 – 1.8 BTU-in/hrft²°F)
Sterilization –dependent on the grade
 Ethylene oxide (EtO), Irradiation (both gamma
and electron-beam), Steam autoclaving
 Cannot withstand repeated autoclaving
 Can be disinfected with common clinical
disinfectants, isopropyl alcohol (rubbing
alcohol)
Common Applications:
 IV connectors; Surgical Instruments/Products
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http://devicelink.com/mpb/archive/98/09/003.html
Clamp Force Calculation for Gasket
Fh  P  m  A
Fk 
n
(Governing Equation)
Fk : Minimum required clamp force from each bolt in the joint
Fh : Hydrostatic end force acting on the joint
P
m
: Internal pressure acting on the joint
: Gasket factor
A : Total area of gasket based upon using an effective gasket width
n : Number of bolts in the joint
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Internal Chamber Pressure
Internal Chamber Pressure
P  Po  h
Specific weight of water at 37°C
Specific weight of water at 30°C:  30
kN
 9.764 3
m
Specific weight of water at 40°C:  40
kN
 9.730 3
m
 37 
9.730  9.764
37  30  kN3  9.764 kN3
40  30
m
m
 37  9.7402
kN
m3
Po  0 as the chamber opens to Atmosphere
h5
cm: equivalent height of water to
height of saline bath
kN 
1m 

P  0   9.7402 3  5cm

100
cm
m
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
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P  0.48701kPa
P  0.07063483psi
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Gasket Calculations
Fh  0.317857lb
Hydrostatic Force
Fh  P  A
P : Internal pressure (calculated)
A : Total area pressure acts upon
(from Solidworks model)

Fh  0.07063483psi 4.5in2
A  2.452105in
m  0 .5
n4
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
Total Area of Gasket (from Solidworks)
Gasket Factor for Rubber
Number of Bolts/Screws (from model)
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Gasket Calculations
Fh  P  m  A
Fk 
n
lb
2
0.317857lb  0.07063483 2 0.5 2.452105in
in
Fk 
4
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Fk  0.101115lb
0.1 pounds of force is required per bolt
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
Spring
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Actuator limits the displacement
Used to exert the force
 Must not exceed capabilities of actuator
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Small Parts Part No. CSMW-0154-10
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OD 0.36 in.
Wire Size 0.026 in.
Free Length 2 in.
Spring Rate 2.1 lbs/in
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