Tissue Bioreactor by Rachel Mosher, Joel Gaston, Kara Barnhart Client: Susan Thibeault Advisor: Brenda Ogle (October 19, 2007)

Outline Stimulating Vocal Fold Environment Vocal Folds Bioreactor Background Vibratory and Operational Requirements Rotation Problem Solution Ideas Assembly, Cell Culture, & Testing Conclusion

Problem Statement Realistic simulation of vocal fold environment Improve Previous Design: T-flask needs to be leak-free Motors need to be programmable Multiple stimuli required Tecoflex substitute

Background – Vocal Folds 2 mucous membranes Extracellular matrix Cartilage Horizontally stretched across larynx Vibration ranging 0-400Hz Modulate airflow from lungs during phonation

Background – Vocal folds

Bioreactor Background Supports/Mimics a biological system Similar to in vivo environment Fibroblasts cultured on cellular substrate Fluid provides nutrition Research on healthy and injured vocal fold tissue

Evolution of the Bioreactor Built by Hitchcock/Titze Vibration and tensile stress Cell culturing/seeded Tecoflex strips Relatively simple design

Evolution of the Bioreactor BME design Spring 2007 Vibration Problems - Leakage - New substrate - No support for vibration bar

Evolution of the bioreactor Work over the summer Address design issues/flaws, client requirements Research Design Parts Ordering Machining Much more work to be done

Evolution of the Bioreactor Current design Quality materials Vibration, tension, rotation between angles New and improved cellular substrate

Client Requirements Concerted bar vibration (50-400Hz frequency) Contact between strips during vibration Easy to sterilize and/or having disposable parts Tecoflex substrate alternative

Design Ideas Moment reaction due to motion of actuator Pneumatic System Bearing/Wheel Magnetic Repulsion Suspension by String/Wire

Pneumatic System Pros No Friction Cons Brings outside material into system, disturbing stability Difficult to construct and implement Not cost effective

Bearing/Wheel Pros Cost Effective Simplistic Easy to construct and apply Cons Some friction Induces wear and tear on the system Actuator support Bearings Polypropylene Tubing

Magnetic Repulsion Pros Frictionless Highly cost effective Fairly easy to construct and implement Cons Magnetic fields will affect electronics Magnetic fields may affect cells Magnets Actuator Support Polystyrene Tubing Side View Back View

Suspension System Pros Simple Highly cost effective Minimal effect on the rest of the system Easy to construct Cons Produces friction Unknown problems may arise; could interfere with vibrations Copper Tubing Polypropylene Tubing Suspension Wire

Design Matrix Least Amount of Friction (1-20) Cost Effectiveness (1-5) Simplicity (1-15) Effect on Rest of System (1-20) Ease of Construction (1-20) Total (80) Pneumatic System Bearing/ Wheel Magnetic Repulsion Suspension by String/Wire

Future Work Ordering custom parts Fabricating needed parts Assembling the bioreactor Culturing vocal cord cells Glycosan material Testing and Analysis Redesigning

Conclusion Research vocal folds Proper stimuli essential Suspension of moving parts to prevent undesirable rotation Parts need ordering and fabrication Testing with cells

Credits Brenda Ogle Susan Thibeault Stephanie Bartley Glenn Prestwich