Properties and applications of additively manufactured metallic cellular materials: A review

Tissue regeneration is an auto-healing mechanism, initiating immediately following tissue damage to restore normal tissue structure and function. This falls in line with survival instinct being the most dominant instinct for any living organism. Nevertheless, the process is slow and not feasible in all tissues, which led to the emergence of tissue engineering (TE). TE aims at replacing damaged tissues with new ones. To do so, either new tissue is being cultured in vitro and then implanted, or stimulants are implanted into the target site to enhance endogenous tissue formation. Whichever approach is used, a matrix is used to support tissue growth, known as ‘scaffold’. In this review, an overall look at scaffolds fabrication is discussed, starting with design considerations and different biomaterials used. Following, highlights of conventional and advanced fabrication techniques are attentively presented. The future of scaffolds in TE is ever promising, with the likes of nanotechnology being investigated for scaffold integration. The constant evolvement of organoids and biofluidics with the eventual inclusion of organ-on-a-chip in TE has shown a promising prospect of what the technology might lead to. Perhaps the closest technology to market is 4D scaffolds following the successful implementation of 4D printing in other fields.

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Conventional and Recent Trends of Scaffolds Fabrication: A Superior Mode for Tissue Engineering

The RNA-binding protein SND1 promotes the degradation of GPX4 by destabilizing the HSPA5 mRNA and suppressing HSPA5 expression, promoting ferroptosis in osteoarthritis chondrocytes

Porosity is considered to be one of the key factors affecting the structural properties of porous lattices, but in fact, pore size also plays an important role, and it has great potential to adjust pore size and porosity independently to improve structural properties. In this work, by adjusting the sheet thickness of the triply periodic minimal surface (TPMS) lattice structures and adjusting the height of the single row structure according to linear and constant laws, the TPMS lattice structures with given porosity and adjustable pore size are designed, and the mechanical response is investigated. Based on preparing samples by Ti6Al4V laser powder bed fusion, the results of the tests show that the elastic modulus ranges of linear change TPMS (LC-TPMS) and constant TPMS (C-TPMS) lattice structures are 3625.6 MPa–4575.1 MPa and 3820.0 MPa–4509.1 MPa, respectively. In the plateau stage, the LC-TPMS lattice structures have a longer and more stable plateau stage, higher yield stress and better energy absorption capacity than the C-TPMS lattice structures. The maximum energy absorption difference is 62.7 MJ/mm 3 and the maximum energy absorption efficiency difference is 0.12. The LC-TPMS lattice structures can also obtain a larger damping ratio under larger compressive strain. 

Design and mechanical testing of porous lattice structure with independent adjustment of pore size and porosity for bone implant

Tissue engineering, whose aim is to repair or replace damaged tissues by combining the principle of biomaterials and cell transplantation, is one of the most important and interdisciplinary fields of regenerative medicine. Despite remarkable progress, there are still some limitations in the tissue engineering field, among which designing and manufacturing suitable scaffolds. With the advent of additive manufacturing (AM), a breakthrough happened in the production of complex geometries. In this vein, AM has enhanced the field of bioprinting in generating biomimicking organs or artificial tissues possessing the required porous graded structure. In this study, triply periodic minimal surface structures, suitable to manufacture scaffolds mimicking bone’s heterogeneous nature, have been studied experimentally and numerically; the influence of the printing direction and printing material has been investigated. Various multi-morphology scaffolds, including gyroid, diamond, and I-graph and wrapped package graph (I-WP), with different transitional zone, have been three-dimensional (3D) printed and tested under compression. Further, a micro-computed tomography (μCT) analysis has been employed to obtain the real geometry of printed scaffolds. Finite element analyses have been also performed and compared with experimental results. Finally, the scaffolds’ behavior under complex loading has been investigated based on the combination of μCT and finite element modeling.

Additively Manufactured Multi-Morphology Bone-like Porous Scaffolds: Experiments and Micro-Computed Tomography-Based Finite Element Modeling Approaches

Design an implant similar to the human bone is one of the critical problems in bone tissue engineering Metal porous scaffolds have good prospects in bone tissue replacement due to their matching elastic modulus, better strength, and biocompatibility However, traditional processing methods are challenging to fabricate scaffolds with a porous structure, limiting the development of porous scaffolds With the advancement of additive manufacturing (AM) and computer-aided technologies, the development of porous metal scaffolds also ushers in unprecedented opportunities In recent years, many new metal materials and innovative design methods are used to fabricate porous scaffolds with excellent mechanical properties and biocompatibility This article reviews the research progress of porous metal scaffolds, and introduces the AM technologies used in porous metal scaffolds Then the applications of different metal materials in bone scaffolds are summarized, and the advantages and limitations of various scaffold design methods are discussed Finally, we look forward to the development prospects of AM in porous metal scaffolds

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Changgong Lan

Papers

Metal Material, Properties and Design Methods of Porous Biomedical Scaffolds for Additive Manufacturing: A Review.

Carfilzomib alleviated osteoporosis by targeting PSME1/2 to activate Wnt/β-catenin signaling.

HA15 alleviates bone loss in ovariectomy-induced osteoporosis by targeting HSPA5.