Hyaluronic Acid Hydrogel Crosslinked with Complementary DNAs

Hyaluronic acid (HA), a polysaccharide presents widely in the extracellular matrix of various animals, is used as an injectable gel material for regenerative medicine due to its biocompatibility. HA hydrogel can be produced from HA molecules via crosslinking. Physical crosslinking by noncovalent bonds is preferable rather than chemical crosslinking using a crosslinking agent to prevent unintended interactions in a biological environment and reduce inflammation caused by reaction by-products. In this study, HA was modified with two types of complementary single-stranded DNA obtained by digestion of pUC118 vector with the restriction enzyme Bsp1286I. When both of HA-DNAs were mixed, hybridized complementary strands acted as crosslinking points to form hydrogels. Shearing stress was applied to mix these DNA-conjugated HA solutions. As a result, a stiff hydrogel with an elastic modulus of about 100 Pa was obtained. The gel thus obtained would be facile to handle as an injectable gel that gains its structural properties from the shear stress applied through injection with a needle. In addition, DNA crosslinking points can be used for hybridization of the hydrogels with other biopolymers, cleavage with restriction enzymes and dissociation by thermal denaturation