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Perfusion Chamber
with Porous Membrane
for Cellular-Level
Glaucoma Research
Joey Labuz
Holly Liske
Laura Piechura
Kellen Sheedy
Donna Peters, PhD
Department of Pathology and Laboratory Medicine
William Murphy, PhD
Department of Biomedical Engineering
Overview
Project Motivation
 Design Specifications
 Design Alternatives and Final Design
 Design Matrix
 Expected Budget
 Future Work
 Questions

Glaucoma



2nd leading cause of
blindness
3 million suspected cases in
America
Progression:



Elevated intraocular pressure
Optic nerve damage
Loss of vision
(National Eye Institute)
Fluid Outflow Pathways
normal
glaucoma
(Modified from Lewis et al., 1999)
Glaucoma Treatment

Current



Prescription eye drops
To decrease production of ocular fluid
Dr. Peters’s research


Injection of ECM peptides
To increase fluid release through the trabecular
meshwork
Approach to Research

Isolate cells of the trabecular meshwork

Treat cells with the ECM peptide β-catenin

Induce disassembly of the actin cytoskeleton

Measure fluid flow across the cell layer
Client Motivation


Identify peptides as potential glaucoma
therapies
Cellular-level experimentation

Replicates

Cost
(Johnson and Tschumper, 1987)
Problem Statement




Cells are more readily available than whole eyes
Device to control fluid flow across cells adhered to
membrane
Variable pressure from above and below cells
Secure membrane to membrane holder and
pressure device
Design Criteria

Ability to withstand 30 mmHg above and below

Compatibility with various membranes

Ability to perform simultaneous replicates

Integration with existing equipment

Sterile system
Alternative Design One
Top Chamber
To Transducer
From Syringe
=
Membrane Holder
Bottom Chamber
From Syringe
To Transducer
Stand
Design One Evaluation
+ Simple design
+ Interchangeable membrane
+ No fluid leakage
– Difficult to assemble in a sterile setting
– Unstable on a laboratory bench
Alternative Design Two
Upper Pressure Chamber
Membrane Holder
=
Lower Pressure Chamber
Alternative Design Two
From Syringe
To Transducer
Plan View of Lower Chamber
Design Two Evaluation
+ Interchangeable membrane
+ Stable on a laboratory bench
+ Simple assembly for user
– Potential for leakage
– Wells cannot be disassembled
– Unequal pressure application
Final Design
Upper Pressure Chamber
Membrane Holder
=
Lower Pressure Chamber
Final Design
To Transducer
Front View of Assembled Device
Side View
From Syringe
Final Design Evaluation
+ Magnets provide tight membrane seal
+ Independent pressure chambers
+ Minimal user interaction
– Upper chamber pressure regulation
– Coating of membrane holder
Design Matrix
Criteria
Rank
Design 1
Design 2
Design 3
Reliability
0.25
2
3
4
User Interaction
0.25
1
3
4
Ease of Use
0.20
3
1
2
Replicate
Independence
0.20
4
1
4
Ease of Manufacture
0.10
3
2
5
Total
1.00
2.50
1.74
3.70
Estimated Budget

Plexiglas



$20 set of 25
Small hardware


$20 upper chamber
$25 lower chamber
Neodymium magnets


(www.professionalplastics.com)
$30
Total = $95
(www.amazingmagnets.com)
Future Work

Coating and sterilizing magnets

Maintaining a constant back pressure

Ordering of materials

Construction

Testing
 Fluid flow and measurement
 Sealing of membrane
http://www.omega.com
Questions
References

“Acrylic Sheets: Plexiglas.” Professional Plastics. <http://www.professionalplastics.com> 17 October 2007.

“Back Pressure Regulator.” Plastomatic Valves, Inc. <http://www.plastomatic.com>

“Glaucoma Resource Guide.” National Eye Institute. <http://www.nei.nih.gov/health> 17 October 2007.

Johnson, DH and Tschumper RC. 1987. “Human trabecular meshwork organ culture. A new method.”
Investigative Ophthalmology & Visual Science 28: 945-953.

Lewis, Peter R., Phillips, Grant T., and Sassani, Joseph W. April 1, 1999. “Topical therapies for glaucoma: What
family physicians need to know.” American Family Physician 59.

“Miniature Back Pressure Regulators.” Omega Process Measurement and Control. <http://www.omega.com>
17 October 2007.

Peters, Donna M. “Use of cell-matrix interactions to treat glaucoma.” PowerPoint presentation. University of
Wisconsin-Madison Departments of Pathology and Laboratory Medicine and Opthamology and Visual
Sciences.

“Rare Earth Neodymium Magnets.” Amazing Magnets. <http://www.amazingmagnets.com> 17 October 2007.

The Eye Digest. “Glaucoma Treatment.” University of Illinois Eye & Ear Infirmary. 17 June 2007.
<http://www.agingeye net/glaucoma/glaucomadrugtreatment.php> 15 October 2007.