Integrating Near-Field Direct-Writing 3D Printing and Layer-By-Layer Self-Assembly to Construct Electroactive...

All current clinical treatments for peripheral nerve injury (PNI), including end-to-end suturing, allografts, non-surgical management, and autografts, suffer from inherent limitations that prevent adequate functional recovery. To address this challenge, we fabricated anisotropic polycaprolactone (PCL) mesh scaffolds via near-field direct-writing (NFDW) 3D printing for neural tissue engineering. To endow the scaffolds with electroactivity, a layer-by-layer (LbL) self-assembly technique was employed to coat polyethylenimine/graphene oxide (PEI/GO), followed by in situ reduction to form conductive reduced graphene oxide/PCL (RGO/PCL) composite scaffolds. Systematic characterization demonstrated that scaffolds coated with 10 LbL cycles achieved an optimal balance, maintaining a favorable topological structure while exhibiting significantly enhanced electrical conductivity, mechanical properties, and hydrophilicity. Biological evaluations confirmed the excellent biocompatibility of the composite scaffolds, which effectively promoted the adhesion, spreading, and neural differentiation of PC12-L cells. Notably, scaffolds with 10 and 15 coating cycles upregulated β-tubulin III expression and facilitated the formation of axon-like structures. Furthermore, the composite scaffold was successfully fashioned into a nerve conduit, highlighting its potential for peripheral nerve repair. This work offers a promising strategy for constructing electroactive, biomimetic scaffolds to enhance neural regeneration.