Rheology of the vitreous gel: effects of macromolecule organization on the viscoelastic properties.
The macromolecular organization of vitreous gel is responsible for its viscoelastic properties. Knowledge of this correlation enables us to relate the physical properties of vitreous to its pathology, as well as optimize surgical procedures such as vitrectomy. Herein, we studied the rheological properties (e.g. dynamic deformation, shear stress-strain flow, and creep compliance) of porcine vitreous humor using a stressed-control shear rheometer. All experiments were performed in a closed environment with the temperature set to that of the human body (i.e. 37°C) to mimic in-vivo conditions. We modeled the creep deformation using the two-element retardation spectrum model. By associating each element of the model to an individual biopolymeric system in the vitreous gel, a distinct response to the applied stress was observed from each component. We hypothesized that the first viscoelastic response with the short time scale (~1 s) is associated with the collagen structure, while the second viscoelastic response with longer time scale (~100 s) is related to the microfibrilis and hyaluronan network. Consequently, we were able to differentiate the role of each main component from the overall viscoelastic properties.
Department of Mechanical & Aerospace Engineering, University of California, Los Angeles, 420 Westwood Plaza, Los Angeles, CA 90095, USA. pskashani@ucla.edu
Pooria
P
Sharif-Kashani
Jean-Pierre
JP
Hubschman
Daniel
D
Sassoon
H Pirouz
HP
Kavehpour
D000818:Animals; D003094:Collagen / Q000502:physiology*; D004548:Elasticity / Q000502:physiology*; D005109:Extracellular Matrix / Q000502:physiology; D012212:Rheology / Q000379:methods*; D013314:Stress, Mechanical; D013552:Swine; D014783:Viscosity; D014822:Vitreous Body / Q000502:physiology*
D003094:Collagen