Nerve guidance conduits (NGCs) are an essential solution for peripheral nerve repair and regeneration in tissue engineering and medicine. However, the ability of current NGCs is limited to repairing longer nerve gap (i.e., >20 mm) because it cannot meet the following two conditions simultaneously: (1) directional guidance of the axial high-density channels and (2) regenerative stimulation of the extracellular matrix secreted by Schwann cells (SCs). Therefore, we propose a multi-material 3D bioprinting process to fabricate multi-channel nerve guide conduits (MNGCs) containing SCs. In the article, cell-laden methacrylate gelatin (GelMA) was used as the bulk material of MNGCs. To improve the printing accuracy of the axial channels and the survival rate of SCs, we systematically optimized the printing temperature parameter based on hydrogel printability analysis. The multi-material bioprinting technology was used to realize the alternate printing of supporting gelatin and cell-laden GelMA. Then, the high-accuracy channels were fabricated through the UV cross-linking of GelMA and the dissolving technique of gelatin. The SCs distributed around the channels with a high survival rate, and the cell survival rate maintained above 90%. In general, the study on multi-material 3D printing was carried out from the fabricating technology and material analysis, which will provide a potential solution for the fabrication of MNGCs containing SCs.

In industrial trajectory planning and real-time motion control, quintic B-splines are widely used for corner smoothing owing to their local support and high-order continuity. However, existing evaluation methods mainly rely on basis-function recursion or the de Boor algorithm, with limited attention paid to the analytical properties of fixed-topology continuity-constrained structures. This study reveals that, under geometric symmetry and C³ continuity constraints at the junction points, higher-order derivative control-point structures undergo progressive geometric degeneration, whereby second- and third-order derivatives reduce to one-dimensional forms governed by a single direction. Based on this degeneration property, a closed-form reconstruction method for fixed-topology quintic B-spline corner smoothing is developed, yielding unified closed-form expressions for curve position and first- to third-order derivatives. Mathematical analysis proves equivalence between the proposed reconstruction and the original quintic B-spline representation. Numerical validation and efficiency evaluation demonstrate machine-precision consistency with conventional B-spline evaluation while achieving an approximately 3–7-fold speedup in curve and derivative evaluation. System-level trajectory-planning simulations further confirm reduced geometric computation load. The proposed method provides an efficient analytical evaluation framework for real-time trajectory planning and demonstrates how continuity constraints can be exploited to derive efficient analytical spline representations.

Heterogeneous interfaces between hydrophobic elastomers and hydrophilic hydrogels suffer from poor interfacial compatibility and modulus mismatch, leading to delamination under dynamic mechanical loading and ineffective strain transmission at the cellular level. Here we report a synergistic strategy combining wettability modification with macroscopic mechanical interlocking to engineer robust heterogeneous interfaces capable of sustaining cyclic stretching while guiding cell alignment. A photo-crosslinkable silicone composite ink (PSCI) was formulated via thiol–ene click chemistry and reinforced with fumed silica nanoparticles (FSNPs) to tune printability and elasticity. Dithiol-terminated polyethylene glycol (HS-PEG-SH) was introduced as an interfacial wettability modifier, reducing the interfacial energy of PSCI and enabling complete infiltration of hydrophilic GelMA ink into 3D-printed mechanical interlocking structures (MIS). This synergy enhanced interfacial shear strength by over 7-fold and fracture energy by 5.6-fold compared with unmodified planar interfaces, maintaining structural integrity over 105 loading cycles. Heterogeneous integrated bioscaffolds (HIB) laden with C2C12 myoblasts were fabricated and subjected to cyclic uniform stretching in a custom-built dynamic culture system. The HIB exhibited cytocompatibility and induced robust myoblast alignment under dynamic stimulation (orientation index R = 0.85). This work establishes an interfacial engineering paradigm integrating wettability regulation with geometric interlocking, offering a viable route for fabricating tissue scaffolds that withstand dynamic mechanical loads.