posted on 2018-09-25, 00:00authored byYusheng
J. He, Daniel A. Young, Merjem Mededovic, Kevin Li, Chengyue Li, Kenneth Tichauer, David Venerus, Georgia Papavasiliou
Biomaterial strategies
focused on designing scaffolds with physiologically
relevant gradients provide a promising means for elucidating 3D vascular
cell responses to spatial and temporal variations in matrix properties.
In this study, we present a photopolymerization approach, ascending
photofrontal free-radical polymerization, to generate proteolytically
degradable hydrogel scaffolds of poly(ethylene) glycol with tunable
continuous gradients of (1) elastic modulus (slope of 80 Pa/mm) and
uniform immobilized RGD concentration (2.06 ± 0.12 mM) and (2)
immobilized concentration of the RGD cell-adhesion peptide ligand
(slope of 58.8 μM/mm) and uniform elastic modulus (597 ±
22 Pa). Using a coculture model of vascular sprouting, scaffolds embedded
with gradients of elastic modulus induced increases in the number
of vascular sprouts in the opposing gradient direction, whereas RGD
gradient scaffolds promoted increases in the length of vascular sprouts
toward the gradient. Furthermore, increases in vascular sprout length
were found to be prominent in regions containing higher immobilized
RGD concentration.