Department of Bioengineering FRACTURE PROPERTIES OF CHICKEN BONES WITH AND WITHOUT MARROW 101A1 Edwin Akrong – Background & Hypothesis Ping-Chien (Sam) Wu – Methods & Protocol Sagar Singh – Deliverables & Pitfalls Reesa Child – Equipment & Budget Deeksha Gulati – Budget Justifications

Department of Bioengineering Background: Bone structural properties are important in treating fractures. A bone’s susceptibility to fracture is correlated to its modulus of elasticity and its capacity to absorb energy. Similar to rods and beams, bones deform when a load is applied. Bones absorb energy that is released when fractured, which occurs when sufficient loads are applied. Maximum force and stiffness for chicken bone with marrow were experimentally determined to be ±26.79N and ±94.1N/m, respectively. Hypothesis(es) & Aim(s) or Objective(s): Aims To use a 3-Point Bending Test to determine the failure properties of chicken bones with marrow and without marrow. Hypothesis Chicken bones without marrow will have weaker structural properties than those with marrow and will demonstrate a 10% reduction in maximum force, and 5% reduction in stiffness. Edwin Akrong

Department of Bioengineering Methods & Protocol: Set up Instron machine and calibrate. Use previously determined loading and sampling rate. Remove meat from each chicken leg bone. Store each bone in a dampened paper towel until time of use. 5 samples of chicken bone will be used. Cut off the ends of the bone with tendons attached with the bone saw to expose the inner part of the bone. Remove bone marrow with the seeker. Using a dial caliper, make necessary geometric measurements of the bone specimen. Mount the specimen in the bending jig. Note the orientation and point of contact of the bone. Determine the position and length between clamps, which will be the same for all bone specimens. Conduct the bending test and record resulting fracture pattern. Repeat the above steps with the four other bone specimens, acquiring data for each test. Stiffness will be determined by fitting a linear regression to the data points in between 5% and 75% of the maximum force. A two-tailed unpaired t-test with α=0.05 will be used to compare the stiffness and maximum force of bone with marrow and bone without marrow. Ping-Chien (Sam) Wu

Department of Bioengineering Proposed Deliverables/Findings: Sagar Singh BONE PROPERTIES DIAMETER (mm) THICKNESS (mm) AREA (10^- 3m^2) STIFFNESS (N/cm) MAX FORCE (N) Chicken Chicken Chicken Chicken Chicken Mean Standard Deviation Variance Fracture Point Maximum Force Figure 1: Table of Preliminary results of breaking marrow-filled bones along with a sample specimen graph of Force against Displacement. Table above demonstrates the preliminary results of specimen breaking with bone marrow present. Relative numerical results indicate it is feasible to remove the bone marrow and obtain measurable results. It is expected that maximum force and stiffness in specimens without marrow would be about 10% smaller and 5% smaller, respectively, than the results shown above. Specimen Force-Displacement graphs would be similar in shape, but would show less variance in results.

Department of Bioengineering Potential Pitfalls: Possible Problems: Determining and applying a consistent means of removing the bone marrow from each specimen. Hollow bones do not provide a completely homogeneous specimen for breakage, since the internal geometry of the bones may differ. Hence, there might be inconsistency within groups of results. Proposed Solutions: Using a photoresistor and sending a beam of light through the hollow portion of the bone and assigning an arbitrary threshold amplitude of light (threshold voltage), which each bone specimen must adhere to, ensuring consistency. The light will allow the determination of how much of the bone marrow has been removed. Sagar Singh

Department of Bioengineering Equipment/Materials and Budget & Justification: Equipment: The 3-point bending test will be conducted using the Instron Model 4444 materials testing machine and bending jig. Supplies: 5 chicken legs to provide sufficient data; knives and cutting board to remove the meat from the chicken bones; calipers and rulers to make measurements of the specimen. New Purchased Equipment: 1)Mopec Inc. Bone Cutting Autopsy Saw, Supplier: Fisher Scientific (Fisher Catalogue), Catalogue Number: NC , Price: $75.90; 215.9mm blade, open frame 304.8mm. This is needed to cut both ends off of the bones so that the bone resembles a uniform rod. 2) Fisherbrand Seeker with Bent End, Supplier: Fisher Scientific (Fisher Catalogue), Catalogue Number: , Price: $12.32 (Ea); nickel-plated steel probe with round handle, curved point tapered and blunt at end, overall length: 152mm. This will be used to remove the marrow inside the bone, so that the bone mimics a hollow uniform rod. Reesa Child & Deeksha Gulati