Mark BradfordKevin FeeleyTony MartinelliJeff SnyderJacob Stephens

Our sponsor sought a device capable of recreating in vivo conditions on cell cultures. This device applies the mechanical stresses and strains that a particular type of cell culture would encounter within the body. There is a device available commercially for this purpose; however, it is prohibitively expensive. The purpose of this project was to design an alternative that is less expensive, thus enabling more researchers access to this type of machine.

Must be considerably less expensive to manufactureMust use standard well platesMust be computer controlledMust fit in an incubatorMust tolerate humidity up to 100%Must be easy to useMust allow easy access to well plateMust measure forces applied to culturesMust measure displacement applied to culturesMust have high repeatability

Several concepts were brainstormedAll concepts accomplish same functions but with different componentsThose components included the clipping mechanism, driver, and type of well plateFigure 1: Clipping Mechanism Concept

One of these concepts is sketched below

Figure 2: Concept 2

The clips secure the membrane to the stretch plateThe version shown below was determined to be the most user-friendly, while accomplishing their primary function

The stretch plate transfers force from the driver to the membranesThe final version is designed for standard 8-well platesFigure 4: Solid Model of Stretch Plates

The base constrains the stretch plate and holds the well plate in placeIt was also designed to allow easy removal of the well plate

The driver in the final design was picked to be a linear actuatorThe driver provides force to stretch the membrane

Two sensors were needed, one that measured force and the other to measure displacementThe force sensor was a Load Cell strain gage, and the displacement sensor was a Baumer Inductive sensor

The machine needs to be computer controlled, and use software that is easy to useNational Instruments LabVIEW was chosen

CONCEPTSFINAL DESIGNClipsUsed staples or screwed-down clampWell PlatesUsed 6-well or 8-well platesDriverUsed solenoid or piezoelectric motorsBaseRequires removal of stretch plate to access well plateClipsUses ridged clampsWell PlatesUses 8-well platesDriverUses electric linear actuatorBaseWell plate can be removed without touching stretch plate

A prototype was produced, but a production run would use different materialsOf particular interest are the polymers whose resins are commercially available through Solvay. They provide the necessary mechanical properties and environmental stability needed for this product.

The displacement sensor may need to be replaced with a more accurate linear laser sensorThe motor might interfere with the force sensors signal and may need replacement

We would like to thank Cook Biotech, Dr. Omar El-Mounayri, Dr. Hazim El-Mounayri, and Mr. Rudy Earlson.