1. Department of Bioengineering Instron Uniaxial Tensile Testing: Mechanical Failure Properties of Suturing and Steri-Strips GROUP #5 Seungyon Kim – Background & Hypothesis Ricky Chung – Methods & Protocol Aron Gera – Deliverables & Pitfalls Raina Wallace – Equipment & Budget

2. Department of Bioengineering Background: The mechanical behavior of biologic tissue is dependent on many different properties such as its geometry and the material properties, and the nature of load application. Performance of surgical suturing techniques and application of Steri-Strips are both formulated to optimize a number of mechanical outcomes of an object, including its strength. Hypothesis & Objectives: Objectives To perform a double-sided suture technique and apply the Steri-Strips on the wounds of chicken skin samples To compare the structural properties of both controlled sample groups under the load application Hypothesis The skin samples with Steri-Strips will show stronger structural properties than the samples with a suture technique under the load application. Seungyon Kim

3. Department of Bioengineering Methods & Protocol: Cut the chicken skin pieces into 40 - 1 in. by 1 in. rectangle samples Take half (20) of the cut pieces stitch them together in pairs using surgical thread with the double sided stitch pattern. The other 20 are “taped” together in pairs using 4 Steri-strips. Set the speed of the crosshead and the direction of movement of the Instron machine to 75mm/min and upward, respectively. Run the Instron machine with the 10 sutured skin samples and the 10 Steri-strip samples. Record the displacement of an edge of the sample according to the force loaded for each trial. Plot the force-displacement curves and tabulate the relevant initial geometric measurements and mechanical failure properties for both sutured sample tests and Steri-strip sample tests. Ricky Chung

4. Department of Bioengineering Proposed Deliverables/Findings: Potential Pitfalls:  From the experiment, we will yield Force vs. Displacement curves. These graphs can be further analyzed to get Ultimate Strength and Failure Displacement values.  For the final results, it is expected that the Steri-Strips will have a larger Ultimate Strength but smaller Failure Displacement. Chicken skin may rupture at points other than site of suturing or steri-strip application - This means that the trial will not be testing the strength of the suturing or steri-strip, but rather the material properties of the chicken skin - To solve this problem, the lab group should make the distance smaller between the application of the suturing/steri-strips and/or try using a slower time interval. Aron Gera

5. Department of Bioengineering Equipment/Materials and Budget & Justification: Raina Wallace Equipment Supplies ~ Instron Model 4444 - Justification: The Instron 4444 uses force vs. displacement to accurately measure the ultimate strength & failure displacement on the chicken skin that is repaired with sutures or Steri- Strips. Newly Purchased Equipment ~ Sterile Sutures – Safety Central –Black nylon, non-absorbable –Size: 5-0 –Cost: $10 per package of needle & suture ~ Steri-Strips – 3M United States –Size: 3mm X 75mm –Cost: $2 for pack of 5 strips - Justification: Both products are of medical grade & will be used on chicken skin to provide a realistic model of the strength of wound healing products