Viscosity Sensitivity in a Reversible Polyacrylamide Gel with DNA Crosslinks

A polyacrylamide hydrogel in which double-stranded DNA replaces bis(acrylamide) as the crosslinker has been developed. The gel has the unique property of being reversible without heat; the addition of a removal DNA strand returns the gel to a liquid state by eliminating the crosslinks. Below a threshold concentration of crosslinks, the material behaves as a viscous liquid with a distinct melting temperature, above which viscosity decreases to a lower limit. At the threshold concentration of crosslinks, a solid gel forms at room temperature. Viscosity of the material is sensitive to both temperature and crosslinker density. This system possesses a large design space in comparison to conventional hydrogels due to the parameters introduced by the use of DNA crosslinks. Further characterization of the properties of the system is necessary to determine potential applications in drug delivery and tissue engineering.