• Propose an innovative nonlinear MEW toolpath strategy guided by user-defined bivariate functions, establishing for the first time a clear link between prescribed microarchitectural variations and the resulting nonlinear toolpaths. • Develop a Principal Component Analysis (PCA)-based algorithm and detailed computational procedure to quantitatively evaluate the fidelity of the proposed toolpath design • Systematically investigate and explain how guiding function characteristics and reference-line spacing affect MEW scaffold design fidelity, offering practical guidelines for optimizing nonlinear toolpath parameters. Adoption of nonlinear toolpaths has emerged as a promising strategy to enhance the biomimicry of scaffolds fabricated by melt electrowriting (MEW). However, a critical methodological gap remains: how to design a nonlinear toolpath that precisely conforms to user-defined, spatially varying microarchitectures. To address this, we propose a novel, function-driven framework governed by two arbitrary bivariate functions dictating the spatial distributions of pore length and width, respectively. The framework begins by partitioning the XY plane into a grid defined by two orthogonal sets of reference lines. A straightforward geometric method is then used to locate the intersection points between the target toolpath and these reference lines. Connecting these points sequentially generates a qualified nonlinear toolpath. The efficacy of the framework was validated using various bivariate functions, with the fabricated scaffolds closely replicating the prescribed pore parameters in all cases. Further analysis revealed that smaller reference-line spacings, lower function magnitudes, and reduced oscillation strength improve design fidelity. Finally, we demonstrate the framework’s versatility by translating the grayscale variation of Lena’s image into a scaffold microstructure. This work presents the first function-driven framework for designing MEW nonlinear toolpaths, establishing a new paradigm for tailoring scaffold microarchitecture to meet complex tissue-regeneration requirements.
Li et al. (Wed,) studied this question.