title: Cell viability viscoelastic measurement in a rheometer used to stress and engineer tissues at low sonic frequencies.
abstract: Effects of vibration on human vocal fold extracellular matrix composition and the resultant tissue viscoelastic properties are difficult to study in vivo. Therefore, an in vitro bioreactor, simulating the in vivo physiological environment, was explored. A stress-controlled commercial rheometer was used to administer shear vibrations to living tissues at stresses and frequencies corresponding to male phonation, while simultaneously measuring tissue viscoelastic properties. Tissue environment was evaluated and adjustments made in order to sustain cell life for short term experimentation up to 6 h. Cell nutrient medium evaporation, osmolality, pH, and cell viability of cells cultured in three-dimensional synthetic scaffolds were quantified under comparably challenging environments to the rheometer bioreactor for 4 or 6 h. The functionality of the rheometer bioreactor was demonstrated by applying three vibration regimes to cell-seeded three-dimensional substrates for 2 h. Resulting strain was quantified throughout the test period. Rheologic data and cell viability are reported for each condition, and future improvements are discussed.
authors.affiliation: National Center for Voice and Speech at the Department of Communication Sciences and Disorders, The University of Iowa, Iowa City, Iowa 52242, USA. sarah-klemuk@uiowa.edu
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Klemuk
authors.forename: Sanyukta
authors.initials: S
authors.lastname: Jaiswal
authors.forename: Ingo R
authors.initials: IR
authors.lastname: Titze
mesh_terms: D019149:Bioreactors; D002460:Cell Line; D002470:Cell Survival; D004548:Elasticity; D005109:Extracellular Matrix / Q000502:physiology*; D005347:Fibroblasts / Q000502:physiology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008954:Models, Biological; D009994:Osmolar Concentration; D010699:Phonation; D013314:Stress, Mechanical; D013997:Time Factors; D054457:Tissue Scaffolds; D019415:Torque; D014465:Ultrasonics; D014732:Vibration; D014783:Viscosity; D014827:Vocal Cords / Q000502:physiology*