112 research outputs found
Three-dimensional photolithographic micropatterning: a novel tool to probe the complexities of cell migration
In order to independently study the numerous variables that influence cell movement, it will be
necessary to employ novel tools and materials that allow for exquisite control of the cellular
microenvironment. In this work, we have applied advanced 3D micropatterning technology, known as
two-photon laser scanning lithography (TP-LSL), to poly(ethylene glycol) (PEG) hydrogels modified with
bioactive peptides in order to fabricate precisely designed microenvironments to guide and
quantitatively investigate cell migration. Specifically, TP-LSL was used to fabricate cell adhesive PEGRGDS
micropatterns on the surface of non-degradable PEG-based hydrogels (2D) and in the interior of
proteolytically degradable PEG-based hydrogels (3D). HT1080 cell migration was guided down these
adhesive micropatterns in both 2D and 3D, as observed via time-lapse microscopy. Differences in cell
speed, cell persistence, and cell shape were observed based on variation of adhesive ligand, hydrogel
composition, and patterned area for both 2D and 3D migration. Results indicated that HT1080s migrate
faster and with lower persistence on 2D surfaces, while HT1080s migrating in 3D were smaller and
more elongated. Further, cell migration was shown to have a biphasic dependence on PEG-RGDS
concentration and cells moving within PEG-RGDS micropatterns were seen to move faster and with
more persistence over time. Importantly, the work presented here begins to elucidate the multiple
complex factors involved in cell migration, with typical confounding factors being independently
controlled. The development of this unique platform will allow researchers to probe how cells behave
within increasingly complex 3D microenvironments that begin to mimic specifically chosen aspects of
the in vivo landscape
Micron-Scale Spatially Patterned, Covalently Immobilized Vascular Endothelial Growth Factor on Hydrogels Accelerates Endothelial Tubulogenesis and Increases Cellular Angiogenic Responses
Spontaneous formation of endothelial tubules was restricted to patterned micron-scale regions presenting cell adhesion ligands and angiogenic signaling protein on poly(ethylene glycol) hydrogels. Arginine-glycine-aspartic acid-serine (RGDS), an integrin ligand, and vascular endothelial growth factor (VEGF), a rate-limiting signaling protein involved in angiogenesis, were covalently bound through photopolymerization via laser scanning lithography to the surface of poly(ethylene glycol) hydrogels in patterned micron-scale regions. Endothelial cells cultured in this restricted environment underwent accelerated tubulogenesis, forming endothelial tubes within 2 days, whereas cells cultured on larger patterned areas remained spread and did not form tubules by day 2. Tubules formed in 2 days on RGDS and VEGF patterns were observed to possess lumens; however, tubule-like structures formed in 2 days on RGDS-only control patterns did not have observable lumens. Additionally, tubules that formed on restricted areas of RGDS and VEGF expressed more VEGF receptor 1, VEGF receptor 2, and ephA7 surface markers, in addition to higher expression of laminin, than cells remaining spread on wide patterned lines. This work reports spatial control and acceleration of endothelial tubule formation using biocompatible hydrogel materials to allow the formation of highly organized vascularized tissues
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