posted on 2024-01-04, 08:30authored byKristin
N. Calahan, Karl G. Johannes, Xingwei Yang, Rong Long, Mark E. Rentschler
Micropatterned surfaces have the potential to greatly
enhance anchoring,
or traction, performance between medical devices such as stents or
catheters and tissue. There are numerous geometric parameters (e.g.,
cross-sectional shape, diameter, height, array density), loading conditions
(e.g., pressure or indentation depth), and material properties that
influence micropattern contact properties, thereby creating a vast
design space. Previously, our group identified that contact between
the lateral surface of an individual pillar in a micropillar array
and a soft hydrogel substrate acts as the governing mechanism for
enhanced shear traction under a given shear displacement. Here, we
explore the influence of the array density on the global shear traction
via changes in lateral contact. The experimental and simulation results
provide evidence that the array density directly influences the amount
of substrate deformation between neighboring pillars for a given indentation
depth. Ultimately, the substrate deformation, or deflection, leads
to sufficient lateral contact that is required for an increased shear
response. Finally, the simulation results show that the total shear
traction of a pillar is dominated by the lateral contact pressure
when sufficient lateral contact is engaged and by interfacial friction
otherwise.