Background With three-dimensional (3D) bioprinting emerging as the ultimate pinnacle of personalised treatment for achieving predictable regenerative outcomes, the search for tissue-specific bioinks is on. Decellularised extracellular matrix (DECM), which provides the inherent biomimetic cues, has gained considerable attention. The objective of the present study was to compare the efficacy of three different demineralisation protocols to obtain DECM for bone tissue engineering applications.  Methodology Goat femurs were treated using three demineralisation protocols to obtain DECM. Group A was treated with demineralisation solution at 40 rpm for 14 days, Group B with freeze-thaw cycles and 0.05M hydrochloric acid (HCl) and 2.4 mM ethylenediamine tetra-acetic acid (EDTA) at 40 rpm for 60 days, and Group C with 0.1M HCl at 40 rpm for three days. After washing, neutralization, 0.05% trypsin-EDTA treatment for 24 hours, and lyophilisation, DECM was obtained. Assessments included scanning electron microscope (SEM) analysis, energy dispersive X-ray (EDX) analysis, hematoxylin and eosin (H&E) staining, and biocompatibility analysis.  Results On comparative analysis, the protocol followed by Group C revealed good surface properties with patent and well interconnected pores with an average pore size of 218.87µm. Group C also revealed carbon and oxygen as predominant components with trace amounts of calcium, proving adequate demineralisation. Group C further revealed optimal demineralisation and decellularisation under histological analysis while maintaining biocompatibility. DECM obtained in Group C should be further processed for bioprinting applications.  Conclusion The three protocols explored in this study hold potential, with Group C\'s protocol demonstrating the most promise for DECM-based bioink applications. Further research is needed to evaluate the suitability of the obtained DECM for preparing tissue-specific bioinks for 3D bioprinting.

Hyalocytes, which are considered to originate from the monocyte/macrophage lineage, play active roles in vitreous collagen and hyaluronic acid synthesis. Obtaining a hyalocyte-compatible bioink during the 3D bioprinting of eye models is challenging. In this study, we investigated the suitability of a cartilage-decellularized extracellular matrix (dECM)-based bioink for printing a vitreous body model. Given that achieving a 3D structure and environment identical to those of the vitreous body necessitates good printability and biocompatibility, we examined the mechanical and biological properties of the developed dECM-based bioink. Furthermore, we proposed a 3D bioprinting strategy for volumetric vitreous body fabrication that supports cell viability, transparency, and self-sustainability. The construction of a 3D structure composed of bioink microfibers resulted in improved transparency and hyalocyte-like macrophage activity in volumetric vitreous mimetics, mimicking real vitreous bodies. The results indicate that our 3D structure could serve as a platform for drug testing in disease models and demonstrate that the proposed printing technology, utilizing a dECM-based bioink and volumetric vitreous body, has the potential to facilitate the development of advanced eye models for future studies on floater formation and visual disorders.

Three-dimensional bioprinting has revolutionized tissue engineering by enabling the fabrication of complex and functional human tissues and organs. An essential component of successful 3D bioprinting is the selection of an appropriate bioink capable of supporting cell proliferation and viability. Plant-derived biomaterials, because of their abundance, biocompatibility, and tunable properties, hold promise as bioink sources, thus offering advantages over animal-derived biomaterials, which carry immunogenic concerns. This comprehensive review explores and analyzes the potential of plant-derived biomaterials as bioinks for 3D bioprinting of human tissues. Modification and optimization of these materials to enhance printability and biological functionality are discussed. Furthermore, cancer research and drug testing applications of the use of plant-based biomaterials in bioprinting various human tissues such as bone, cartilage, skin, and vascular tissues are described. Challenges and limitations, including mechanical integrity, cell viability, resolution, and regulatory concerns, along with potential strategies to overcome them, are discussed. Additionally, this review provides insights into the potential use of plant-based dECM as bioinks, future prospects, and emerging trends in the use of plant-derived biomaterials for 3D bioprinting applications. The potential of plant-derived biomaterials as bioinks for 3D bioprinting of human tissues is highlighted herein. However, further research is necessary to optimize their processing, standardize their properties, and evaluate their long-term in vivo performance. Continued advancements in plant-derived biomaterials have the potential to revolutionize tissue engineering and facilitate the development of functional and regenerative therapies for diverse clinical applications.

Articular cartilage is an avascular tissue with very limited capacity of self-regeneration. Trauma or injury-related defects, inflammation, or aging in articular cartilage can induce progressive degenerative joint diseases such as osteoarthritis. There are significant clinical demands for the development of effective therapeutic approaches to promote articular cartilage repair or regeneration. The current treatment modalities used for the repair of cartilage lesions mainly include cell-based therapy, small molecules, surgical approaches, and tissue engineering. However, these approaches remain unsatisfactory. With the advent of three-dimensional (3D) bioprinting technology, tissue engineering provides an opportunity to repair articular cartilage defects or degeneration through the construction of organized, living structures composed of biomaterials, chondrogenic cells, and bioactive factors. The bioprinted cartilage-like structures can mimic native articular cartilage, as opposed to traditional approaches, by allowing excellent control of chondrogenic cell distribution and the modulation of biomechanical and biochemical properties with high precision. This review focuses on various hydrogels, including natural and synthetic hydrogels, and their current developments as bioinks in 3D bioprinting for cartilage tissue engineering. In addition, the challenges and prospects of these hydrogels in cartilage tissue engineering applications are also discussed.

Conducting/insulating inks have received significant attention for the fabrication of a wide range of additive manufacturing technology. However, current inks often demonstrate poor biocompatibility and face trade-offs between conductivity and mechanical stiffness under physiological conditions. Here, conductive/insulating bioinks based on two-dimensional materials are proposed. The conductive bioink, graphene (GR)-poly(lactic-co-glycolic acid) (PLGA), is prepared by introducing conductive GR into a degradable polymer matrix, PLGA, while the insulating bioink, boron nitride (BN)-PLGA, is synthesized by adding insulating BN. By optimizing the material ratios, this work achieves precise control of the electromechanical properties of the bioinks, thereby enabling the flexible construction of conductive networks according to specific requirements. Furthermore, these bioinks are compatible with a variety of manufacturing technologies such as 3D printing, electrospinning, spin coating, and injection molding, expanding their application range in the biomedical field. Overall, the results suggest that these conducting/insulating bioinks offer improved mechanical, electronic, and biological properties for various emerging biomedical applications.

3D printing can revolutionize personalized medicine by allowing cost-effective, customized tissue-engineering constructs. However, the limited availability and diversity of biopolymeric hydrogels restrict the variety and applications of bioinks. In this study, we introduce a composite bioink for 3D bioprinting, combining a photo-cross-linkable derivative of Mucin (Mu) called Methacrylated Mucin (MuMA) and Hyaluronic acid (HA). The less explored Mucin is responsible for the hydrogel nature of mucus and holds the potential to be used as a bioink material because of its plethora of features. HA, a crucial extracellular matrix component, is mucoadhesive and enhances ink viscosity and printability. Photo-cross-linking with 405 nm light stabilizes the printed scaffolds without damaging cells. Rheological tests reveal shear-thinning behavior, aiding cell protection during printing and improved MuMA bioink viscosity by adding HA. The printed structures exhibited porous behavior conducive to nutrient transport and cell migration. After 4 weeks in phosphate-buffered saline, the scaffolds retain 70% of their mass, highlighting stability. Biocompatibility tests with lung epithelial cells (L-132) confirm cell attachment and growth, suggesting suitability for lung tissue engineering. It is envisioned that the versatility of bioink could lead to significant advancements in lung tissue engineering and various other biomedical applications.

Due to the limitations of the current skin wound treatments, it is highly valuable to have a wound healing formulation that mimics the extracellular matrix (ECM) and mechanical properties of natural skin tissue. Here, a novel biomimetic hydrogel formulation has been developed based on a mixture of Agarose-Collagen Type I (AC) combined with skin ECM-related components: Dermatan sulfate (DS), Hyaluronic acid (HA), and Elastin (EL) for its application in skin tissue engineering (TE). Different formulations were designed by combining AC hydrogels with DS, HA, and EL. Cell viability, hemocompatibility, physicochemical, mechanical, and wound healing properties were investigated. Finally, a bilayered hydrogel loaded with fibroblasts and mesenchymal stromal cells was developed using the Ag-Col I-DS-HA-EL (ACDHE) formulation. The ACDHE hydrogel displayed the best in vitro results and acceptable physicochemical properties. Also, it behaved mechanically close to human native skin and exhibited good cytocompatibility. Environmental scanning electron microscopy (ESEM) analysis revealed a porous microstructure that allows the maintenance of cell growth and ECM-like structure production. These findings demonstrate the potential of the ACDHE hydrogel formulation for applications such as an injectable hydrogel or a bioink to create cell-laden structures for skin TE.

The development of therapeutic drugs and methods has been greatly facilitated by the emergence of tumor models. However, due to their inherent complexity, establishing a model that can fully replicate the tumor tissue situation remains extremely challenging. With the development of tissue engineering, the advancement of bioprinting technology has facilitated the upgrading of tumor models. This article focuses on the latest advancements in bioprinting, specifically highlighting the construction of 3D tumor models, and underscores the integration of these two technologies. Furthermore, it discusses the challenges and future directions of related techniques, while also emphasizing the effective recreation of the tumor microenvironment through the emergence of 3D tumor models that resemble in vitro organs, thereby accelerating the development of new anticancer therapies.

UNASSIGNED: To review the research progress on the application of three-dimensional (3D) bioprinting technology in auricle repair and reconstruction.
UNASSIGNED: The recent domestic and international research literature on 3D printing and auricle repair and reconstruction was extensively reviewed, and the concept of 3D bioprinting technology and research progress in auricle repair and reconstruction were summarized.
UNASSIGNED: The auricle possesses intricate anatomical structure and functionality, necessitating precise tissue reconstruction and morphological replication. Hence, 3D printing technology holds immense potential in auricle reconstruction. In contrast to conventional 3D printing technology, 3D bioprinting technology not only enables the simulation of auricular outer shape but also facilitates the precise distribution of cells within the scaffold during fabrication by incorporating cells into bioink. This approach mimics the composition and structure of natural tissues, thereby favoring the construction of biologically active auricular tissues and enhancing tissue repair outcomes.
UNASSIGNED: 3D bioprinting technology enables the reconstruction of auricular tissues, avoiding potential complications associated with traditional autologous cartilage grafting. The primary challenge in current research lies in identifying bioinks that meet both the mechanical requirements of complex tissues and biological criteria.
UNASSIGNED: 对3D生物打印技术在耳廓修复重建方面的应用研究进展作一综述。.
UNASSIGNED: 广泛查阅近年来国内外3D打印与耳廓修复重建相关研究文献，对3D生物打印技术概念及其在耳廓修复重建中的应用研究进展进行总结。.
UNASSIGNED: 耳廓具有复杂解剖结构和功能，需要精确的组织重建和形态复制，因此 3D打印技术在耳廓修复重建方面具有巨大应用潜力。与传统3D打印技术相比，3D生物打印技术不仅能模拟耳廓外形结构，还能将细胞与材料混合打印，在支架成型过程中实现细胞在支架内部精准分布，模拟天然组织组成及结构，更有利于构建具有生物活性功能的耳廓组织，从而提高修复效果。.
UNASSIGNED: 3D生物打印技术可以重建耳廓组织，能避免传统自体软骨移植相关并发症，寻找既符合耳廓组织机械性要求，又符合生物要求的生物墨水是目前研究的主要挑战。.

In the context of tissue engineering, biofabrication techniques are employed to process cells in hydrogel-based matrices, known as bioinks, into complex 3D structures. The aim is the production of functional tissue models or even entire organs. The regenerative production of biological tissues adheres to a multitude of criteria that ultimately determine the maturation of a functional tissue. These criteria are of biological nature, such as the biomimetic spatial positioning of different cell types within a physiologically and mechanically suitable matrix, which enables tissue maturation. Furthermore, the processing, a combination of technical procedures and biological materials, has proven highly challenging since cells are sensitive to stress, for example from shear and tensile forces, which may affect their vitality. On the other hand, high resolutions are pursued to create optimal conditions for subsequent tissue maturation. From an analytical perspective, it is prudent to first investigate the printing behavior of bioinks before undertaking complex biological tests. According to our findings, conventional shear rheological tests are insufficient to fully characterize the printing behavior of a bioink. For this reason, we have developed optical methods that, complementarily to the already developed tests, allow for quantification of printing quality and further viscoelastic modeling of bioinks.