Resumo (PT):
Abstract (EN):
We utilize a recently developed microfluidic device, the Optimized Shape Crossslot Extensional Rheometer (OSCER), to study the elongational flow behavior and
rheological properties of hyaluronic acid (HA) solutions representative of the
synovial fluid (SF) found in the knee joint. The OSCER geometry is a stagnation
point device that imposes a planar extensional flow with a homogenous extension
rate over a significant length of the inlet and outlet channel axes. Due to the
compressive nature of the flow generated along the inlet channels, and the planar
elongational flow along the outlet channels, the flow field in the OSCER device
can also be considered as representative of the flow field that arises between
compressing articular cartilage layers of the knee joints during running or jumping
movements. Full-field birefringence microscopy measurements demonstrate a high
degree of localized macromolecular orientation along streamlines passing close to
the stagnation point of the OSCER device, while micro-particle image
velocimetry is used to quantify the flow kinematics. The stress-optical rule is used
to assess the local extensional viscosity in the elongating fluid elements as a
function of the measured deformation rate. The large limiting values of the
dimensionless Trouton ratio, Tr O(50), demonstrate that these fluids are highly
extensional-thickening, providing a clear mechanism for the load-dampening
properties of SF. The results also indicate the potential for utilizing the OSCER
in screening of physiological SF samples, which will lead to improved
understanding of, and therapies for, disease progression in arthritis sufferers
Idioma:
Inglês
Tipo (Avaliação Docente):
Científica
Nº de páginas:
14