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A Self-Healing, Viscoelastic Hydrogel Promotes Healing of Brain Lesions

Brain lesions can arise from traumatic brain injury, infection, and craniotomy. Although injectable hydrogels show promise for promoting healing of lesions and health of surrounding tissue, enabling cellular ingrowth and restoring neural tissue continue to be challenging. We hypothesized that these challenges arise in part from viscoelastic mismatch between the hydrogel and the brain parenchyma, and tested this hypothesis by developing and evaluating a self-healing hydrogel that mimicked both the composition and viscoelasticity of native brain parenchyma. The hydrogel was crosslinked by dynamic boronate ester bonds between phenylboronic acid grafted hyaluronic acid (HA-PBA) and dopamine grafted gelatin (Gel-Dopa). This HA-PBA/Gel-Dopa hydrogel could be injected into a lesion cavity in a shear-thinning manner with rapid hemostasis, high tissue adhesion and efficient self-healing. We tested this in an in vivo mouse model of brain lesions and found the hydrogel to support neural cell infiltration, decrease astrogliosis and glial scars, and close the lesions. The results suggest a role for viscoelasticity in brain lesion healing, and motivate additional experimentation in larger animals as the technology progresses towards potential application in humans.