Fracture behavior of multilayer fibrous scaffolds featuring microstructural gradients

• Published in: Materials & design Vol. 184; p. 108184
• Main Authors: Khoo, W, Chung, SM, Lim, Shing Chee, Low, Cheng Yee, Shapiro, Jenna M., Koh, Ching Theng
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15-12-2019; Elsevier
• Subjects: Electrospinning; Finite element analysis; Functionally graded materials; Mechanical properties; Multilayer fibrous scaffolds; Tissue engineering; Electrospinning; Mechanical properties; Finite element analysis; Functionally graded materials; Tissue engineering; Multilayer fibrous scaffolds
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2019.108184

Multilayer nanofibrous scaffolds that mimic the microstructure gradient of connective tissues have shown promising results in tissue regeneration, but the effect of these gradients on the mechanical performance of fiber meshes is poorly understood. In this study, trilayer nanofibrous gelatin scaffolds with gradually increasing fiber diameters (227–679 nm) and pore sizes (1.14–4.93 μm2) were fabricated using a sequential electrospinning process, producing a fiber density gradient over the scaffold thickness. The mechanical properties of the fibrous scaffolds were evaluated using uniaxial tensile and fracture tests. Deformation of microscopic crack tip openings was simulated using finite element analysis. Results from uniaxial and fracture tensile tests showed that the mechanical properties of fibrous scaffolds were governed by network architectures. The microstructure gradient yielded corresponding changes of material properties over the scaffold thickness. Simulation results showed different stress distribution and energy dissipation at each layer of the graded scaffolds. Finite element analysis also revealed that a combination of network density and alignment gradients can improve fracture toughness of graded scaffolds. This study provides guidelines and methodologies for designing tailored gradient fibrous scaffolds to more closely mimic the structural and mechanical properties of native interfacial tissues.
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•Bioinspired nanofibrous gelatin scaffolds featuring fiber density gradients were fabricated via an electrospinning process.•A finite element model was developed to examine inhomogeneous stress distribution of graded fibrous networks at a notch root.•Microstructural gradients resulted in corresponding gradual changes of properties over the thickness of the scaffold.•Gradients in both network density and fiber alignment increased the toughness of the graded fibrous scaffolds in simulations.