A conductive network enhances nerve cell response

Nerve guidance conduits with favorable electrical conductivity were highly desired in peripheral nerve repair since nerve was natural electro-active tissue. MXene was an appealing candidate in endowing polymeric guidance conduits with electrical conductivity, yet its superiority was extremely constrained by its discrete distribution, incapable forming contiguous conduction channels in matrix. Herein, an efficient conductive nerve guidance conduit with three-dimensional continuous conductive network structure was constructed by prior powder design and laser additive manufacturing. Specifically, MXene was coated on poly- L -lactic acid (PLLA) particle surface by ultrasonic-assisted solution mixing and thus MXene was enriched at interfacial regions among adjacent polymer particles to form continuous MXene conductive network. More ingeniously, benefiting from the unique shearing-free and confined-flowing forming characteristic of laser additive manufacturing, not only network structure was retained as well as MXene contact became more tightly, which provided a continuous channel for rapid charge transfer. Results demonstrated that the conduits with 3.5 vol% MXene exhibited a continuous conductive network structure, resulting in an excellent electrical conductivity of 4.53 S/m, which was in appropriate conductive range of nerve growth (1–10 S/m). Cell evaluation confirmed the conduits significantly promoted cell proliferation, differential and neurite outgrowth. Therefore, this work not only illustrated the feasibility of additive manufacturing in constructing conduits with three-dimensional continuous conductive network structure, but also created a powerful strategy for fabricating desirable conductive nerve guidance conduits.