TY - JOUR
T1 - Micro- and nano-patterned elastin-like polypeptide hydrogels for stem cell culture
AU - Paul, A.
AU - Stührenberg, M.
AU - Chen, S.
AU - Rhee, D.
AU - Lee, W. K.
AU - Odom, T. W.
AU - Heilshorn, S. C.
AU - Enejder, A.
N1 - Funding Information:
We would like to thank Cecilia Brännmark and Charlotta Olofsson, Gothenburg University, for the kind donation of the rat adipose-derived stem cells; Rebecca DiMarco for AFM mechanical measurements of ELP substrates; and Pernilla Wittung-Stafshede, Chalmers University of Technology, for fruitful discussions. The research leading to these results has received funding from the European Union Seventh Framework Program ([FP7/2007–2013]) under grant agreement no. [607842] and the Swedish Research Council. D. R., W.-K. L. and T. W. O. acknowledge the National Science Foundation (CMMI-1462633) and the Office of Naval Research (N00014-13-1-0172) for funding. S. C. and S. C. H. acknowledge funding from the Stanford ChEM-H Institute (SICB-112878), National Science Foundation (DMR 1508006), and National Institutes of Health (U19-AI116484).
PY - 2017
Y1 - 2017
N2 - We show that submicron-sized patterns can be imprinted into soft, recombinant-engineered protein hydrogels (here elastin-like proteins, ELP) by transferring wavy patterns from polydimethylsiloxane (PDMS) molds. The high-precision topographical tunability of the relatively stiff PDMS is translated to a bio-responsive, soft material, enabling topographical cell response studies at elastic moduli matching those of tissues. Aligned and unaligned wavy patterns with mold periodicities of 0.24-4.54 μm were imprinted and characterized by coherent anti-Stokes Raman scattering and atomic force microscopy. The pattern was successfully transferred down to 0.37 μm periodicity (width in ELP: 250 ± 50 nm, height: 70 ± 40 nm). The limit was set by inherent protein assemblies (diameter: 124-180 nm) that formed due to lower critical solution temperature behavior of the ELP during molding. The width/height of the ELP ridges depended on the degree of hydration; from complete dehydration to full hydration, ELP ridge width ranged from 79 ± 9% to 150 ± 40% of the mold width. The surface of the ridged ELP featured densely packed protein aggregates that were larger in size than those observed in bulk/flat ELP. Adipose-derived stem cells (ADSCs) oriented along hydrated aligned patterns with periodicities ≥0.60 μm (height ≥170 ± 100 nm), while random orientation was observed for smaller distances/amplitudes, as well as flat and unaligned wavy ELP surfaces. Hence, micro-molding of ELP is a promising approach to create tissue-mimicking, hierarchical architectures composed of tunable micron-sized structures with nano-sized protein aggregates, which opens the way for orthogonal screening of cell responses to topography and cell-adhesion ligands at relevant elastic moduli.
AB - We show that submicron-sized patterns can be imprinted into soft, recombinant-engineered protein hydrogels (here elastin-like proteins, ELP) by transferring wavy patterns from polydimethylsiloxane (PDMS) molds. The high-precision topographical tunability of the relatively stiff PDMS is translated to a bio-responsive, soft material, enabling topographical cell response studies at elastic moduli matching those of tissues. Aligned and unaligned wavy patterns with mold periodicities of 0.24-4.54 μm were imprinted and characterized by coherent anti-Stokes Raman scattering and atomic force microscopy. The pattern was successfully transferred down to 0.37 μm periodicity (width in ELP: 250 ± 50 nm, height: 70 ± 40 nm). The limit was set by inherent protein assemblies (diameter: 124-180 nm) that formed due to lower critical solution temperature behavior of the ELP during molding. The width/height of the ELP ridges depended on the degree of hydration; from complete dehydration to full hydration, ELP ridge width ranged from 79 ± 9% to 150 ± 40% of the mold width. The surface of the ridged ELP featured densely packed protein aggregates that were larger in size than those observed in bulk/flat ELP. Adipose-derived stem cells (ADSCs) oriented along hydrated aligned patterns with periodicities ≥0.60 μm (height ≥170 ± 100 nm), while random orientation was observed for smaller distances/amplitudes, as well as flat and unaligned wavy ELP surfaces. Hence, micro-molding of ELP is a promising approach to create tissue-mimicking, hierarchical architectures composed of tunable micron-sized structures with nano-sized protein aggregates, which opens the way for orthogonal screening of cell responses to topography and cell-adhesion ligands at relevant elastic moduli.
UR - http://www.scopus.com/inward/record.url?scp=85028757717&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85028757717&partnerID=8YFLogxK
U2 - 10.1039/c7sm00487g
DO - 10.1039/c7sm00487g
M3 - Article
C2 - 28737182
AN - SCOPUS:85028757717
VL - 13
SP - 5665
EP - 5675
JO - Soft Matter
JF - Soft Matter
SN - 1744-683X
IS - 34
ER -