3D fiber deposited polymeric scaffolds for external auditory canal wall

Abstract

The external auditory canal (EAC) is an osseocartilaginous structure extending from the auricle to the eardrum, which can be affected by congenital, inflammatory, and neoplastic diseases, thus reconstructive materials are needed. Current biomaterial-based approaches for the surgical reconstruction of EAC posterior wall still suffer from resorption (biological) and extrusion (synthetic). In this study, 3D fiber deposited scaffolds based on poly(ethylene oxide terephthalate)/poly(butylene terephthalate) were designed and fabricated to replace the EAC wall. Fiber diameter and scaffold porosity were optimized, leading to 200 ± 33 µm and 55% ± 5%, respectively. The mechanical properties were evaluated, resulting in a Young's modulus of 25.1 ± 7.0 MPa. Finally, the EAC scaffolds were tested in vitro with osteo-differentiated human mesenchymal stromal cells (hMSCs) with different seeding methods to produce homogeneously colonized replacements of interest for otologic surgery. This study demonstrated the fabrication feasibility of EAC wall scaffolds aimed to match several important requirements for biomaterial application to the ear under the Tissue Engineering paradigm, including shape, porosity, surface area, mechanical properties and favorable in vitro interaction with osteoinduced hMSCs. This study demonstrated the fabrication feasibility of outer ear canal wall scaffolds via additive manufacturing. Aimed to match several important requirements for biomaterial application to ear replacements under the Tissue Engineering paradigm, including shape, porosity and pore size, surface area, mechanical properties and favorable in vitro interaction with osteo-differentiated mesenchymal stromal cells.

Additive Manufacturing Approaches for Hydroxyapatite‐Reinforced Composites

“…Composites for TE are usually composed of a matrix, a reinforced part (i.e., particles, fibrils, and flakes), and, possibly, cellular tissues. Composites used for AM purposes (i.e., biomaterial inks or bioinks) can be classified in two groups: hard and soft materials, depending on the matrix used for each specific application . The first class includes materials with matrices possessing mechanical properties that assure stability after the printing (e.g., metals, ceramics, and many thermoplastic polymers).…”

Mimicking the Human Tympanic Membrane: the Significance of Geometry

“…Subsequently, hierarchical constructs were manufactured by applying the optimized FDM parameters. The 3D deposition of filaments with a diameter of 50.22 ± 6.06 μm is a four-fold increment with respect to the previously reported resolution for PEOT/PBT copolymer [23, 59, 60]. The human eardrum has been calculated to have a diameter of 7-8 mm with a thickness of roughly 70 μm [19].…”

Molecular origin of viscoelasticity in mineralized collagen fibrils

“…Furthermore, the results on mineralized fibrils help understanding the viscoelastic mechanisms of the ossicular chain and the temporal bone that, with different mechanisms, provide conductive hearing 2,3 . A deeper knowledge of healthy collagen-based structures can also pave the way to new bioinspired materials to replace and treat native tissues after traumas of pathologies 51,[63][64][65] . With the advent of additive manufacturing and Machine Learning, new generation of optimized prostheses and structures can take advantage of this study to mimic, and even improve, the behavior of native tissues to the eventual benefit of patients suffering different bone-related diseases (e.g., osteogenesis imperfecta, osteoporosis) or injuries [66][67][68][69] .…”