Chitosan-based adhesive patch with anti-inflammatory, pro-healing, and immunomodulatory properties for dural defect repair

Dural defects and subsequent cerebrospinal fluid (CSF) leakage are common complications in spinal and cranial surgeries. However, current clinical patches often fail to achieve long-term adhesion and effective sealing, as the presence of CSF can weaken interfacial bonding and ultimately result in adhesion failure. Herein, a new class of chitosan-based adhesive patch (PLLA/CP) is designed by constructing an adhesive hydrogel layer containing chitosan-dopamine (CS-DA) on the surface of fibrous poly(L-lactic acid) (PLLA) layer. Benefitting from electrostatic crosslinking within the hydrogel layer and the mechanical reinforcement of PLLA layer, our patch exhibits a low swelling ratio (3.8 %) without compromising wet adhesion (87.1 kPa). The interfacial mechanical interlocking between the adhesive hydrogel and fibrous dissipative layer contributes to its high burst pressure tolerance (327.7 mmHg). Moreover, the catechol groups in CS-DA endow PLLA/CP patch with the ability to scavenge intracellular reactive oxygen species and suppress inflammation. Furthermore, our PLLA/CP patch achieves long-term adhesion, prevents CSF leakage, and promotes defect repair through anti-inflammatory and immunomodulatory effects in a rabbit dural defect model, while also demonstrating effective hemostasis in a liver injury model. By integrating excellent anti-inflammatory, pro-healing, and immunomodulatory properties, this work presents a promising strategy for wet tissue repair.