Chemically reversible hydrogels

Dynamic Materials![Figure][1] Illustration of triggered superstructure changes CREDIT: MARK SENIW, SIMPSON QUERREY INSTITUTE, NORTHWESTERN UNIVERSITY The dynamic reorganization of some cellular biopolymers in response to signals has inspired efforts to create artificial materials with similar properties. Freeman et al. created hydrogels based on peptide amphiphiles that can bear DNA strands that assemble into superstructures and that disassemble in response to chemical triggers. The addition of DNA conjugates induced transitions from micelles to fibers and bundles of fibers. The resulting hydrogels were used as an extracellular matrix mimic for cultured cells. Switching the hydrogel between states also switched astrocytes between their reactive and naive phenotypes. Science , this issue p. [808][2] [1]: pending:yes [2]: /lookup/doi/10.1126/science.aat6141