Three-Dimensional Bioprinting Applications for Bone Tissue Engineering

Computer-aided design and 3D printing for a stable construction of segmental bone defect model in Beagles: a short term observation

OBJECTIVE

Segmental bone defect animal studies require stable fixation which is a continuous experimental challenge. Large animal models are comparable to the human bone, but with obvious drawbacks of housing and costs. Our study aims to utilize CAD and 3D printing in the construction of a stable and reproducible segmental bone defect animal mode.

METHODS

CAD-aided 3D printed surgical instruments were incorporated into the construction of the animal model through preoperative surgical emulation. 20 3D printed femurs were divided into either experimental group using 3D surgical instruments or control group. In Vitro surgical time and accuracy of fixation were analysed and compared between the two groups. A mature surgical plan using the surgical instruments was then utilized in the construction of 3 segmental bone defect Beagle models in vivo. The Beagles were postoperatively assessed through limb function and imaging at 1, 2 and 3 months postoperatively.

RESULTS

In vitro experiments showed a significant reduction in surgical time from 40.6 ± 14.1 (23-68 min) to 26 ± 4.6 (19-36 min) (n = 10, p < 0.05) and the accuracy of intramedullary fixation placement increased from 71.6 ± 23.6 (33.3-100) % to 98.3 ± 5.37 (83-100) %, (n = 30, p < 0.05) with the use of CAD and 3D printed instruments. All Beagles were load-bearing within 1 week, and postoperative radiographs showed no evidence of implant failure.

CONCLUSION

Incorporation of CAD and 3D printing significantly increases stability, while reducing the surgical time in the construction of the animal model, significantly affecting the success of the segmental bone defect model in Beagles.

Advancing bone regeneration: Unveiling the potential of 3D cell models in the evaluation of bone regenerative materials

Bone, a rigid yet regenerative tissue, has garnered extensive attention for its impressive healing abilities. Despite advancements in understanding bone repair and creating treatments for bone injuries, handling nonunions and large defects remains a major challenge in orthopedics. The rise of bone regenerative materials is transforming the approach to bone repair, offering innovative solutions for nonunions and significant defects, and thus reshaping orthopedic care. Evaluating these materials effectively is key to advancing bone tissue regeneration, especially in difficult healing scenarios, making it a critical research area. Traditional evaluation methods, including two-dimensional cell models and animal models, have limitations in predicting accurately. This has led to exploring alternative methods, like 3D cell models, which provide fresh perspectives for assessing bone materials' regenerative potential. This paper discusses various techniques for constructing 3D cell models, their pros and cons, and crucial factors to consider when using these models to evaluate bone regenerative materials. We also highlight the significance of 3D cell models in the in vitro assessments of these materials, discuss their current drawbacks and limitations, and suggest future research directions. STATEMENT OF SIGNIFICANCE: This work addresses the challenge of evaluating bone regenerative materials (BRMs) crucial for bone tissue engineering. It explores the emerging role of 3D cell models as superior alternatives to traditional methods for assessing these materials. By dissecting the construction, key factors of evaluating, advantages, limitations, and practical considerations of 3D cell models, the paper elucidates their significance in overcoming current evaluation method shortcomings. It highlights how these models offer a more physiologically relevant and ethically preferable platform for the precise assessment of BRMs. This contribution is particularly significant for "Acta Biomaterialia" readership, as it not only synthesizes current knowledge but also propels the discourse forward in the search for advanced solutions in bone tissue engineering and regeneration.

Construction Form and Application of Three-Dimensional Bioprinting Ink Containing Hydroxyapatite

With the increasing prevalence of bone tissue diseases, three-dimensional (3D) bioprinting applied to bone tissue engineering for treatment has received a lot of interests in recent years. The research and popularization of 3D bioprinting in bone tissue engineering require bioinks with good performance, which is closely related to ideal material and appropriate construction form. Hydroxyapatite (HAp) is the inorganic component of natural bone and has been widely used in bone tissue engineering and other fields due to its good biological and physicochemical properties. Previous studies have prepared different bioinks containing HAp and evaluated their properties in various aspects. Most bioinks showed significant improvement in terms of rheology and biocompatibility; however, not all of them had sufficiently favorable mechanical properties and antimicrobial activity. The deficiencies in properties of bioink and 3D bioprinting technology limited the applications of bioinks containing HAp in clinical trials. This review article summarizes the construction forms of bioinks containing HAp and its modifications in previous studies, as well as the 3D bioprinting techniques adopted to print bioink containing HAp. In addition, this article summarizes the advantages and underlying mechanisms of bioink containing HAp, as well as its limitations, and suggests possible improvement to facilitate the development of bone tissue engineering bioinks containing HAp in the future.

Investigation of Liquid Collagen Ink for Three-Dimensional Printing

Three-dimensional printing provides more versatility in the fabrication of scaffold materials for hard and soft tissue replacement, but a critical component is the ink. The ink solution should be biocompatible, stable, and able to maintain scaffold shape, size, and function once printed. This paper describes the development of a collagen ink that remains in a liquid pre-fibrillized state prior to printing. The liquid stability occurs due to the incorporation of ethylenediaminetetraacetic acid (EDTA) during dialysis of the collagen. Collagen inks were 3D-printed using two different printers. The resulting scaffolds were further processed using two different chemical crosslinkers, 1-Ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride)/N-hydroxysuccinimide (EDC/NHS) and genipin; gold nanoparticles were conjugated to the scaffolds. The 3D-printed scaffolds were characterized to determine their extrudability, stability, amount of AuNP conjugated, and overall biocompatibility via cell culture studies using fibroblast cells and stroma cells. The results demonstrated that the liquid collagen ink was amendable to 3D printing and was able to maintain its 3D shape. The scaffolds could be conjugated with gold nanoparticles and demonstrated enhanced biocompatibility. It was concluded that the liquid collagen ink is a good candidate material for the 3D printing of tissue scaffolds.

Design of bone scaffolds with calcium phosphate and its derivatives by 3D printing: A review

Tissue engineering is a fascinating field that combines biology, engineering, and medicine to create artificial tissues and organs. It involves using living cells, biomaterials, and bioengineering techniques to develop functional tissues that can be used to replace or repair damaged or diseased organs in the human body. The process typically starts by obtaining cells from the patient or a donor. These cells are then cultured and grown in a laboratory under controlled conditions. Scaffold materials, such as biodegradable polymers or natural extracellular matrices, are used to provide support and structure for the growing cells. 3D bone scaffolds are a fascinating application within the field of tissue engineering. These scaffolds are designed to mimic the structure and properties of natural bone tissue and serve as a temporary framework for new bone growth. The main purpose of a 3D bone scaffold is to provide mechanical support to the surrounding cells and guide their growth in a specific direction. It acts as a template, encouraging the formation of new bone tissue by providing a framework for cells to attach, proliferate, and differentiate. These scaffolds are typically fabricated using biocompatible materials like ceramics, polymers, or a combination of both. The choice of material depends on factors such as strength, biodegradability, and the ability to facilitate cell adhesion and growth. Advanced techniques like 3D printing have revolutionized the fabrication process of these scaffolds. Using precise layer-by-layer deposition, it allows for the creation of complex, patient-specific geometries, mimicking the intricacies of natural bone structure. This article offers a brief overview of the latest developments in the research and development of 3D printing techniques for creating scaffolds used in bone tissue engineering.

Additively manufactured porous scaffolds by design for treatment of bone defects

There has been increasing attention to produce porous scaffolds that mimic human bone properties for enhancement of tissue ingrowth, regeneration, and integration. Additive manufacturing (AM) technologies, i.e., three dimensional (3D) printing, have played a substantial role in engineering porous scaffolds for clinical applications owing to their high level of design and fabrication flexibility. To this end, this review article attempts to provide a detailed overview on the main design considerations of porous scaffolds such as permeability, adhesion, vascularisation, and interfacial features and their interplay to affect bone regeneration and osseointegration. Physiology of bone regeneration was initially explained that was followed by analysing the impacts of porosity, pore size, permeability and surface chemistry of porous scaffolds on bone regeneration in defects. Importantly, major 3D printing methods employed for fabrication of porous bone substitutes were also discussed. Advancements of MA technologies have allowed for the production of bone scaffolds with complex geometries in polymers, composites and metals with well-tailored architectural, mechanical, and mass transport features. In this way, a particular attention was devoted to reviewing 3D printed scaffolds with triply periodic minimal surface (TPMS) geometries that mimic the hierarchical structure of human bones. In overall, this review enlighten a design pathway to produce patient-specific 3D-printed bone substitutions with high regeneration and osseointegration capacity for repairing large bone defects.

Chitosan nanocomposite for tissue engineering and regenerative medicine: A review

Regenerative medicine and tissue engineering have emerged as a multidisciplinary promising field in the quest to address the limitations of traditional medical approaches. One of the key aspects of these fields is the development of such types of biomaterials that can mimic the extracellular matrix and provide a conducive environment for tissue regeneration. In this regard, chitosan has played a vital role which is a naturally derived linear bi-poly-aminosaccharide, and has gained significant attention due to its biocompatibility and unique properties. Chitosan possesses many unique physicochemical properties, making it a significant polysaccharide for different applications such as agriculture, nutraceutical, biomedical, food, nutraceutical, packaging, etc. as well as significant material for developing next-generation hydrogel and bio-scaffolds for regenerative medicinal applications. Moreover, chitosan can be easily modified to incorporate desirable properties, such as improved mechanical strength, enhanced biodegradability, and controlled release of bioactive molecules. Blending chitosan with other polymers or incorporating nanoparticles into its matrix further expands its potential in tissue engineering applications. This review summarizes the most recent studies of the last 10 years based on chitosan, blends, and nanocomposites and their application in bone tissue engineering, hard tissue engineering, dental implants, dental tissue engineering, dental fillers, and cartilage tissue engineering.

Nanotechnology development in surgical applications: recent trends and developments

This paper gives a detailed analysis of nanotechnology's rising involvement in numerous surgical fields. We investigate the use of nanotechnology in orthopedic surgery, neurosurgery, plastic surgery, surgical oncology, heart surgery, vascular surgery, ophthalmic surgery, thoracic surgery, and minimally invasive surgery. The paper details how nanotechnology helps with arthroplasty, chondrogenesis, tissue regeneration, wound healing, and more. It also discusses the employment of nanomaterials in implant surfaces, bone grafting, and breast implants, among other things. The article also explores various nanotechnology uses, including stem cell-incorporated nano scaffolds, nano-surgery, hemostasis, nerve healing, nanorobots, and diagnostic applications. The ethical and safety implications of using nanotechnology in surgery are also addressed. The future possibilities of nanotechnology are investigated, pointing to a possible route for improved patient outcomes. The essay finishes with a comment on nanotechnology's transformational influence in surgical applications and its promise for future breakthroughs.

Tissue Engineering Strategies Applied in Bone Regeneration and Bone Repair

Bone regeneration and repair present significant challenges in the field of regenerative medicine [...].