3D‐Printed Anisotropic Nanofiber Composites with Gradual Mechanical Properties

Abstract

3D printing of bio‐based nanomaterials into complex structures with design flexibility, structural anisotropy, and long‐term stability is a key issue for biomedical applications. Herein, 3D‐printed and ionically crosslinked structures with anisotropic, water‐proof, and tunable mechanical properties are fabricated using a polysaccharide ink composed of nanocellulose, alginate, and CaCO3 nanoparticles. The excellent shear thinning properties of the ink, combined with double or even triple extrusion, allow printing of complex structures (tubes, buckets, ears, and boat models) with high shape fidelity even after crosslinking. The anisotropically printed and crosslinked structures can be mechanically tuned by controlling the fiber orientation via the printing path, the amount of crosslinker, the type of acid used for crosslinking (weak to strong), and the storage medium. This allows for tailored flexibility and a tensile modulus of the materials in wet state ranging from 1 to 30 MPa. Application of hydrostatic pressure of 160–600 mmHg for 24 h with a physiological fluid to a tubular structure, a model for the cardiovascular system, shows no leakage or rupture in the tube. The great design freedom offered by 3D printing and spatially controlled structural anisotropy enable the production of tailored materials for soft robotics or biomedical applications.

3D-Printed Collagen–Nanocellulose Hybrid Bioscaffolds with Tailored Properties for Tissue Engineering Applications

“…On the other hand, CMC is water-soluble, structurally similar to NFC, and has an intrinsic affinity to NFC through interfacial adhesion. Therefore, it can impart flexibility, strength, and dimensional stability to printed bioscaffolds, similar to what has been observed with alginate. , …”

“…Therefore, it can impart flexibility, strength, and dimensional stability to printed bioscaffolds, similar to what has been observed with alginate. 12,13 Direct-ink-writing (DIW) 3D printing, a particular extrusion-based technique, enables the controlled deposition of inks to create multifunctional bioscaffolds from various natural or synthetic hydrogels. 10,14,15 However, DIW of Coll alone can be challenging regarding viscosity, layer adhesion, structural integrity, shape fidelity, and mechanical stability.…”

4‐Axis 3D‐Printed Tubular Biomaterials Imitating the Anisotropic Nanofiber Orientation of Porcine Aortae

“…Fiber orientation has a strong influence on the mechanical response of flat objects. [ 19,21a,c ] To compare the tensile strength and modulus of porcine aortic tissue with the printed tubes, dog‐bone‐shaped tensile test specimens were cut from the printed tubes and porcine aortae along the axial and radial directions of the blood flow axis (Figure 3F). The ultimate tensile strength and moduli of the materials reflect the fiber orientation in the tubes, and the cut direction of the tensile test specimen (Figure S2, Supporting Information).…”

“…The leached amount of calcium in the solution as well as in the scaffold analyzed by volumetric titration using Na 2 EDTA and an already established protocol from a previous work. [19] Mechanical Testing: Dog bone-shaped tensile test specimens were punched out from 3D printed scaffolds and porcine aortae (50 × 8.5 × 1.00-2.50 mm 3 ) according to DIN 53504 S3A. A Shimanzu AGS-X (Japan) tensile testing machine equipped with a 5 KN load cell was used to perform tensile and cycle tests at speeds between 10 and 200 mm s −1 .…”

Hierarchical Generative Network: A Hierarchical Multitask Learning Approach for Accelerated Composite Material Design and Discovery

“…[1][2][3] Advances in additive manufacturing techniques, such as 3D printing, have enabled the fabrication of composite materials with exceptional geometrical freedom and precise control over constituent material arrangements. [4][5][6] Nevertheless, traditional experimental approaches can be costly and time consuming when exploring the vast design space of numerous combinations.…”