Mark Bradford Kevin Feeley Tony Martinelli Jeff Snyder Jacob 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 manufacture Must use standard well plates Must be computer controlled Must fit in an incubator Must tolerate humidity up to 100% Must be easy to use Must allow easy access to well plate Must measure forces applied to cultures Must measure displacement applied to cultures Must have high repeatability

   Several concepts were brainstormed All concepts accomplish same functions but with different components Those components included the clipping mechanism, driver, and type of well plate Figure 1: Clipping Mechanism Concept

 One of these concepts is sketched below Figure 2: Concept 2

  The clips secure the membrane to the stretch plate The version shown below was determined to be the most user-friendly, while accomplishing their primary function Figure 3: Solid Model of the Clip

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

  The base constrains the stretch plate and holds the well plate in place It was also designed to allow easy removal of the well plate Figure 5: Base with mounting sub-assembly

  The driver in the final design was picked to be a linear actuator The driver provides force to stretch the membrane Figure 6: RRA-23 Linear Actuator

  Two sensors were needed, one that measured force and the other to measure displacement The force sensor was a Load Cell strain gage, and the displacement sensor was a Baumer Inductive sensor Figure 7: Strain Gage Figure 8: Baumer Inductive Sensor

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

CONCEPTS     Clips  Used staples or screwed down clamp Well Plates  Used 6-well or 8-well plates Driver  Used solenoid or piezoelectric motors Base  Requires removal of stretch plate to access well plate FINAL DESIGN     Clips  Uses ridged clamps Well Plates  Uses 8-well plates Driver  Uses electric linear actuator Base  Well plate can be removed without touching stretch plate

  A prototype was produced, but a production run would use different materials Of 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 sensor The motor might interfere with the force sensor’s signal and may need replacement

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