An innovative 4D printing approach for fabrication of anisotropic collagen scaffolds.

Biofabrication

Department of Biomedical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL 32901, United States of America.

Published: October 2024

AI Article Synopsis

  • Collagen anisotropy provides important structural cues that influence how cells behave in tissue engineering, but traditional 3D printing methods often fail to create scaffolds with this property.
  • This study introduced a 4D printing technique combining extrusion-based printing with magnetic alignment to create collagen scaffolds that have a high degree of anisotropy.
  • Results showed that while adjusting materials and printing conditions improved collagen alignment, it sometimes compromised print fidelity; nevertheless, scaffolds successfully guided human mesenchymal stem cells towards tendon or ligament-like differentiation, highlighting their potential in musculoskeletal tissue engineering.

Article Abstract

Collagen anisotropy is known to provide the essential topographical cues to guide tissue-specific cell function. Recent work has shown that extrusion-based printing using collagenous inks yield 3D scaffolds with high geometric precision and print fidelity. However, these scaffolds lack collagen anisotropy. In this study, extrusion-based 3D printing was combined with a magnetic alignment approach in an innovative 4D printing scheme to generate 3D collagen scaffolds with high degree of collagen anisotropy. Specifically, the 4D printing process parameters-collagen (Col):xanthan gum (XG) ratio (Col:XG; 1:1, 4:1, 9:1 v/v), streptavidin-coated magnetic particle concentration (SMP; 0, 0.2, 0.4 mg ml), and print flow speed (2, 3 mm s)-were modulated and the effects of these parameters on rheological properties, print fidelity, and collagen alignment were assessed. Further, the effects of collagen anisotropy on human mesenchymal stem cell (hMSC) morphology, orientation, metabolic activity, and ligamentous differentiation were investigated. Results showed that increasing the XG composition (Col:XG 1:1) enhanced ink viscosity and yielded scaffolds with good print fidelity but poor collagen alignment. On the other hand, use of inks with lower XG composition (Col:XG 4:1 and 9:1) together with 0.4 mg mlSMP concentration yielded scaffolds with high degree of collagen alignment albeit with suboptimal print fidelity. Modulating the print flow speed conditions (2 mm s) with 4:1 Col:XG inks and 0.4 mg mlSMP resulted in improved print fidelity of the collagen scaffolds while retaining high level of collagen anisotropy. Cell studies revealed hMSCs orient uniformly on aligned collagen scaffolds. More importantly, collagen anisotropy was found to trigger tendon or ligament-like differentiation of hMSCs. Together, these results suggest that 4D printing is a viable strategy to generate anisotropic collagen scaffolds with significant potential for use in tendon and ligament tissue engineering applications.

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Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC11499585PMC
http://dx.doi.org/10.1088/1758-5090/ad7f8fDOI Listing

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