Figure 27.

Independent control over biomimetic material properties. (A) Microfabrication. By varying the height of PDMS microposts but keeping the diameter the same, the effective stiffness (or spring constant) of the microposts is tuned independent of adhesion-ligand density and surface chemical properties. Reprinted with permission from ref 978. Copyright 2010 Nature Publishing Group. (B) Chemical modification. Cysteine-containing peptides are incorporated into PEG-based hydrogels via a thiol–ene click reaction with independent control over the stiffness and adhesion-ligand density. Reprinted with permission from ref 458. Copyright 2010 American Chemical Society. (C) Composition change. PA hydrogels are fabricated with independently controlled stiffness and pore size (or porosity) by adjusting the acrylamide/bis-acrylamide ratio. Scale bars: 50 μm. Reprinted with permission from ref 30. Copyright 2014 Nature Publishing Group. (D) Cross-linking regulation. The stiffness of IPN hydrogels made from a reconstituted basement membrane matrix and alginate is tuned by simply increasing the Ca2+ concentration used for cross-linking alginate independent of the pore structure and adhesion-ligand density. Reprinted with permission from ref 378. Copyright 2014 Nature Publishing Group.