Mark BradfordKevin Feeley

Tony MartinelliJeff 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 FINAL DESIGN

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

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.