Department of Bioengineering Effect of Decalcification on Fracture Strength in Chicken Bones Group 102A5 Tim Bakke Vincent Cina Jonathan Lee Wee Siong Goh

Department of Bioengineering Background: Calcium is an essential mineral in the body; it is integral in controlling muscle contraction, blood clotting, cell structure, and blood pressure regulation. Calcium, the most abundant mineral in humans, is responsible for over 1.5% of body weight and 21% of bone composition (95% of all the calcium in the body). In osteoporosis, a decrease in the bone mineral density occurs, leading to weaker structural integrity of the bones. In a laboratory setting, chelating chemicals such as Rapid Decalcification Formulation (RDF) are able to mimic the effects of osteoporosis by decalcifying bone. Hypothesis(es) & Aim(s) or Objective(s): The purpose of this experiment is to determine whether the relationship between fracture strength and amount of decalcification is linearly decreasing, evidenced by an R 2 value of >0.95.

Department of Bioengineering Methods & Protocol: 1) For 5 separate groups of 5 chicken legs, strip off muscles and tendons, and measure the mass of each chicken bone. 2) For each bone, extract calcium from it by immersing completely in 100ml Rapid Decalcification Formulation (RDF) in a 150mL beaker. 3) Soak one group of bones for 4 hours. Repeat for other groups at 0, 1, 2, 3 hours respectively. 4) Immediately after soaking, put each bone in the jig. Set a crosshead speed of 5 in/min and a sampling rate of 10 points/sec on the Instron machine, Run the machine until the bone breaks, and then press stop. 4) In each beaker of used RDF, add 0.1 mol of phosphoric acid (excess) to precipitate extracted calcium. Extract precipitate via Gravity Filtration and let it air dry for 1.5 hours. Mass the extracted precipitate to calculate moles of calcium extracted. 5) Tabulate and plot values for fracture strength (N) vs. moles of calcium per bone mass extracted.

Department of Bioengineering Proposed Deliverables/Findings: As the bone is soaked in RDF for a longer duration, a larger amount of calcium will be extracted. Since calcium loss has been linked to bone weakening in osteoporosis, a proposed finding is a negative linear relationship between moles of calcium extracted per bone mass and fracture strength as evidenced with a R 2 value > Figure 1. Effects of calcium on bone fracture strength

Department of Bioengineering Potential Pitfalls: Calcium phosphate may not be the only precipitate formed when phosphoric acid is added to the RDF solution. - Both Zinc and Magnesium (found in bone) could also precipitate. The RDF concentration may be too low; it may be saturated with calcium before the allotted soaking time is over. Not all of the precipitate may be recovered during the Gravity Filtration process. Non-uniform mass and shape among the individual specimen. This introduces other variables that could effect fracture strength. Extremities of the bone also effect fracture strength readings.

Department of Bioengineering Equipment/Materials and Budget & Justification: Materials already in the lab: 1. Instron Model Watch Glass8. Graduated Cylinder 2. Knives6. Glass rod9. Analytic Balance 3. Cutting Board7. Filter paper10. Customized Bending Jig 4. Tongs Materials to purchase: $59.951Fisher Scientific: S34566Utility Funnel (Pk/12) $ Fresh GrocerChicken Leg (lb) $ Fisher Scientific: S mL Beaker (Pk/10) 6 14 Qty. H 3 PO 4, 85% (8.67 M)(1 L) RDF (1 Gal) Product Fisher Scientific: S93326 Statlab: D Manufacturer: Catalog # $ $ Total Price $