Tendon Stress Apparatus

Tendons are collagenous tissues that transfer forces from muscle to bone. Tendons have poor healing capabilities and can be easily injured due to overuse. In order to develop therapies for preventing injury and improving regeneration more knowledge must be gained on how mechanical forces influence tendon cell behavior.

Problem Definition
Our client has designed and built a mechanical bioreactor controlled by Labview to test mechanical properties of soft tissues such as tendon. Currently the client is able to measure the force applied to the tissue and the displacement between the grips holding the tissue. Our objective is to develop and design a non-contacting video system to measure the strain within soft biologic tissues in real time and improve the capability of the system already in place.

Project Requirements and Goals
 * Camera resolution: less than 1 mm, between 0.5 mm and 1 cm is optimal
 * LabView must link to and utilize the non-contacting video system
 * The system will be placed inside and incubator so all components must be hardened to humidity, moisture, and heat
 * Our system must work for the length of time that a test will run which can be multiple hours.

Background
Tendons are the tissues are responsible for transferring forces between muscle and bone. Tendon injuries are quite common among athletes, with causes ranging from chronic overuse to acute tears. The regenerative process for tendons can take over a year and often complete regeneration does not occur. This has led to a demand in clinical alternatives for replacement. ​Before mechanical tissue replacements can be engineered, more data is needed on the mechanical and biological factors that govern tendon injury and regeneration.

Project Learning
As our project progresses in development, we solve one problem after another. The following is a categorical breakdown of the project learning for each major conceptual milestone.

Camera
Originally, we wanted to do a GoPro type of camera. After the first Snapshot and talking with our client we decided a CMOS or CCD camera would be more logical. Through researching, we found that CMOS cameras would most likely be the way to go.

Below is the comparison of cameras we have researched or found used in similar video systems. We have listed what we believe to be some of the more important factors of the camera system. As you can see, they are only a few minor details that differ per camera.

Camera research is still an aspect we continue to work on. As a team, we have decided the camera system is one of our top priorities and this will most likely be our biggest expense. We are hopeful to have a camera selected and purchased before the beginning of the second semester. This will allow us to move onto the next design phase of implementing the video system with the existing apparatus and computer programs.

Programing
Matlab

During the camera-to-Matlab integration process, the team spent some time getting to know the image capture and image processing toolboxes that Matlab provides (for a price, of course). With these toolboxes, the camera is able to digitally subtract pixel from pixel and mathematically determine the difference in pixel change.

Additionally, the team spent more time becoming comfortable with Matlab terminology and procedural equations.

Labview



The Labview code was given to us by our client and currently controls the load cell that can stretch the tendon at a constant load or with cyclic loading.

The interface for the MATLAB integration module is shown to the right. This module will allow a user to utilize MATLAB code without leaving the LABview window. One goal of this project is to create a seamless, straightforward system to allow for efficient data acquisition. Once complete, the LABview code combined with the integrated MATLAB code will be able partly control the apparatus, stream a live feed of the tissue being tested, and calculate the strain being applied over a time interval.

Mounting
Some specifications for mounting the camera to the frame of the bioreactor include:
 * The mounting system needs to be able to move the camera out of the way when the user is preparing the sample
 * The camera needs to come back to a fixed location for image acquisition
 * The mounting device needs to be able to support the weight of the camera

Our team will begin to put more emphasis on a mounting design in the second semester of senior design. We will test different potential materials for encasing the camera in the incubator to see if there is condensation formed that could interfere with the image.

Final Product
Camera

Matlab

LabView

Mounting

Resources and Documentation
Meeting Minutes [[Media:Meeting Minutes Dev-elopers.pdf|First Semester]]

Other Documents [[Media:Team Contract Dev-elopers.pdf|Team Contract]]