title: Variably elastic hydrogel patterned via capillary action in microchannels.
abstract: Agarose hydrogels of varied elastic modulus can be patterned into 100-microm-wide channels with wall heights of 60 microm. After modifying the hydrogels with chloroacetic acid (acid gels), they are amenable to modification with amine-containing ligands using EDC-NHS chemistry. Using both rheometry and atomic force microscopy (AFM) nanoindentation measurements, the elastic modulus of unmodified hydrogels increases linearly from 3.6 +/- 0.5 kPa to 45.2 +/- 5.5 kPa for 0.5 to 2.0 wt/vol % hydrogel, respectively. The elastic modulus of acid gels is 2.2 +/- 0.3 kPa to 16.2 +/- 1.6 kPa for 0.5 to 2.0 wt/vol %, respectively. No further changes were measured after further modifying the acid gels with fibronectin. Confocal images of rhodamine-modified acid gels show that the optimal filling viscosity of the agarose solutions is between 1 and 4 cP. This new method of patterning allows for the creation of substrates that take advantage of both micron-scale patterns and variably elastic hydrogels.
authors.affiliation: Department of Chemistry, Institute for Genomic Biology, University of Illinois, Urbana-Champaign, IL 61801, USA.
authors.forename: Rui
authors.initials: R
authors.lastname: Dong
authors.forename: Tor W
authors.initials: TW
authors.lastname: Jensen
authors.forename: Kristin
authors.initials: K
authors.lastname: Engberg
authors.forename: Ralph G
authors.initials: RG
authors.lastname: Nuzzo
authors.forename: Deborah E
authors.initials: DE
authors.lastname: Leckband
mesh_terms: D000085:Acetates; D004548:Elasticity; D005353:Fibronectins; D020100:Hydrogels; D018625:Microscopy, Atomic Force; D012235:Rhodamines; D012685:Sepharose; D014783:Viscosity
chemical_list: D000085:Acetates; D005353:Fibronectins; D020100:Hydrogels; D012235:Rhodamines; C006972:chloroacetic acid; D012685:Sepharose