Reversible Control of Gelatin Hydrogel Stiffness by Using DNA Crosslinkers**

• DOI: 10.1002/cbic.202100030
• Publication Date: 2021-01-23T18:14:11Z
• Authors: Alex Buchberger; Harpinder Saini; Kiarash Rahmani E...; Azadeh Zare; Ryan Merkley; Yang Xu; Julio Bernal; Robert Ros; Mehdi Nikkhah; Nicholas Stephano...
• Keywords: 0301 basic medicine; Cell Survival; Ultraviolet Rays; Biocompatible Materials; Hydrogels; DNA; Elasticity; 3. Good health; 03 medical and health sciences; Cross-Linking Reagents; Gelatin; Humans; Methacrylates

AbstractBiomaterials with dynamically tunable properties are critical for a range of applications in regenerative medicine and basic biology. In this work, we show the reversible control of gelatin methacrylate (GelMA) hydrogel stiffness through the use of DNA crosslinkers. We replaced some of the inter‐GelMA crosslinks with double‐stranded DNA, allowing for their removal through toehold‐mediated strand displacement. The crosslinks could be restored by adding fresh dsDNA with complementary handles to those on the hydrogel. The elastic modulus (G’) of the hydrogels could be tuned between 500 and 1000 Pa, reversibly, over two cycles without degradation of performance. By functionalizing the gels with a second DNA strand, it was possible to control the crosslink density and a model ligand in an orthogonal fashion with two different displacement strands. Our results demonstrate the potential for DNA to reversibly control both stiffness and ligand presentation in a protein‐based hydrogel, and will be useful for teasing apart the spatiotemporal behavior of encapsulated cells.