Microalgae-Based 3D Bioprinting: Recent Advances, Applications and Perspectives

Biomaterial-based 3D bioprinting strategy for orthopedic tissue engineering.

Current Progress of 3D bioprinting in oral and craniomaxillofacial tissue regeneration: A systematic review.

An insight on advances and applications of 3d bioprinting: A review

In the era of personalised medicine, novel therapeutic approaches raise increasing hopes to address currently unmet medical needs by developing patient-customised treatments. Three-dimensional (3D) bioprinting is rapidly evolving and has the potential to obtain personalised tissue constructs and overcome some limitations of standard tissue engineering approaches. Bioprinting could support a wide range of biomedical applications, such as drug testing, tissue repair or organ transplantation. There is a growing interest for 3D bioprinting in the orthopaedic field, with remarkable scientific and technical advances. However, the full exploitation of 3D bioprinting in medical applications still requires efforts to anticipate the upcoming challenges in translating bioprinted products from bench to bedside. In this review we summarised current trends, advances and challenges in the application of 3D bioprinting for bone and cartilage tissue engineering. Moreover, we provided a detailed analysis of the applicable regulations through the 3D bioprinting process and an overview of available standards covering bioprinting and additive manufacturing.

Advances in 3D bioprinting technology for cardiac tissue engineering and regeneration

Three-dimensional (3D) bioprinting is a promising technology which utilises additive manufacturing technologies to produce functional tissues and organs. A bioink is the term used to describe any biomaterial, containing cells or other biologics, which is compatible with 3D bioprinting processes. The ideal bioink is one which is biocompatible, biodegradable, can achieve high shape fidelity during and after the bioprinting process and can provide a microenvironment which can accommodate the formation of a functional biological tissue. This chapter will discuss the composition of multiple naturally derived bioinks and synthetic bioinks which are commonly used in 3D bioprinting. It will also discuss how bioink stiffness and composition can influence and direct cell fate. Finally, this chapter will demonstrate how bioinks have advanced the field of tissue engineering by highlighting some key strategies involving the 3D bioprinting of tissues such as bone, vascular tissue and liver.

3D bioprinted functional and contractile cardiac tissue constructs

Bone defect repairing and reconstruction has been a hot research topic in orthopedics for a long time. Tissue engineering and stem cell technology have made a series of important achievements in promoting bone regeneration to treat bone defect. In recent years, 3D bio-printing, which combining with 3D printing, tissue engineering and stem cell technology, has significant advantages in optimizing the geometry, mechanical properties and biological functions of repairing tissue for bone defect by accurately controlling the shape and internal structure of scaffolds, and printing biomaterials, stem cells and (or) cells into three-dimensional biological functional structures. A series of important progress has been achieved. The common printing methods for bio-printing related to orthopedic include: Inkjet 3D bioprinting; microextrusion 3D bioprinting; laser-assisted 3D bioprinting; stereolithography; microvalve based 3D bioprinting. Various printing methods and principles are not the same, and each has advantages and disadvantages, and the applicable bio ink is also different. The key technologies of orthopedic bio-3D printing include: the methods of image data acquisition and 3D structure design; development and application of composite bio-scaffold materials suitable for 3D printing, tissue engineering and bone-enhancing effect; stem cell selection for ensuring graft biological performance and induced pluripotent stem cell technology; in vitro bioreactor technology for improving the maturity and biocharacterization of bioprinted tissues. The literature published in the field of biological 3D printing research has continued to grow at a high rate since 2008. Using the bibliometric analysis software VOSviewer to create a co-word matrix for high-frequency keywords and to draw a keyword co-occurrence network map analysis, biological 3D printing research hotspots are the use of tissue engineering methods to 3D printed tissue scaffolds, while studying cell survival and drug effects. The instruments and methods of bio-3D printing are also one of the research hotspots.

Classification, processing, and applications of bioink and 3D bioprinting: A detailed review

Corneal transplantation remains gold standard for the treatment of severe cornea diseases, however, scarcity of donor cornea is a serious bottleneck. 3D bioprinting holds tremendous potential for cornea tissue engineering (TE). One of the key technological challenges is to design bioink compositions with ideal printability and cytocompatibility. Photo-crosslinking and ionic crosslinking are often used for the stabilization of 3D bioprinted structures, which can possess limitations on biological functionality of the printed cells. Here, we developed a hyaluronic acid-based dopamine containing bioink using hydrazone crosslinking chemistry for the 3D bioprinting of corneal equivalents. First, the shear thinning property, viscosity, and mechanical stability of the bioink were optimized before extrusion-based 3D bioprinting for the shape fidelity and self-healing property characterizations. Subsequently, human adipose stem cells (hASCs) and hASC-derived corneal stromal keratocytes were used for bioprinting corneal stroma structures and their cell viability, proliferation, microstructure and expression of key proteins (lumican, vimentin, connexin 43, α-smooth muscle actin) were evaluated. Moreover, 3D bioprinted stromal structures were implanted into ex vivo porcine cornea to explore tissue integration. Finally, human pluripotent stem cell derived neurons (hPSC-neurons), were 3D bioprinted to the periphery of the corneal structures to analyze innervation. The bioink showed excellent shear thinning property, viscosity, printability, shape fidelity and self-healing properties with high cytocompatibility. Cells in the printed structures displayed good tissue formation and 3D bioprinted cornea structures demonstrated excellent ex vivo integration to host tissue as well as in vitro innervation. The developed bioink and the printed cornea stromal equivalents hold great potential for cornea TE applications.

Silk fibroin (SF) is an attractive material for composing bioinks suitable for three-dimensional (3D) bioprinting. However, the low viscosity of SF solutions obtained through common dissolution methods limits 3D-bioprinting applications without the addition of thickeners or partial gelation beforehand. Here, we report a method of 3D bioprinting low-viscosity SF solutions without additives. We combined a method of freeform reversible embedding of suspended hydrogels, known as the FRESH method, with horseradish peroxidase-catalyzed cross-linking. Using this method, we successfully fabricated 3D SF hydrogel constructs from low-viscosity SF ink (10% w/w, 50 mPa s at 1 s-1 shear rate), which does not yield 3D constructs when printed onto a plate in air. Studies using mouse fibroblasts confirmed that the printing process was cell-friendly. Additionally, cells enclosed in printed SF hydrogel constructs maintained > 90% viability for 11 days of culture. These results demonstrate that the 3D bioprinting technique developed in this study enables new 3D bioprinting applications using SF inks and thus has a great potential to contribute to tissue engineering and regenerative medicine.

Three-dimensional bioprinting adipose tissue and mammary Organoids feasible for artificial breast structure regeneration

Introduction: The promise of bioprinting tissue constructs that could potentially serve the same function in the human body as native tissues has taken the world of regenerative medicine by storm. The current review describes system-wide clinical applications of three-dimensional (3D) bioprinting and aims to address ethical and social considerations, while also discussing the scope of this technology in the near future. Discussion: 3D bioprinting is believed to present new approaches to conventional treatment, offering the advantage of customization and on-time availability. It facilitates simultaneous deposition of appropriate bioinks and biomaterials onto scaffolds which can then be employed to develop tissue fabricates that can potentially mimic native tissues in both structure and functionality. It has been extensively employed to regenerate viable tissue constructs of skin, bone, cartilage, vasculature, myocardial tissue and heart valves, nervous tissue, lung and tracheal tissue, liver, pancreatic, and corneal tissue. Conclusion: To obviate the current restrictions associated with this technology, it is imperative to understand where we currently stand in terms of current clinical applications of 3D bioprinting. This technology is anticipated to contribute significantly to the fields of tissue engineering and regenerative medicine (TERM), where it can be employed to fabricate functional tissues that can simulate their counterparts in the human body. Relevance: The increasing disparity between organ demand and supply as well as the shortcomings associated with antiquated approaches to treatment call for utilizing 3D bioprinting to develop viable tissue constructs.

Development of photocrosslinkable bioinks with improved electromechanical properties for 3D bioprinting of cardiac BioRings

Insights into cellulose nanocrystals-based bioinks for 3D bioprinting in regenerative medicine and tissue engineering: A review.