Bioprinting cells with an electrically conductive bioink provides an opportunity to produce three-dimensional (3D) cell-laden constructs with the option of electrically stimulating cells in situ during and after tissue development. We and others have demonstrated the use of electrical stimulation (ES) to influence cell behavior and function for a more biomimetic approach to tissue engineering. Here, we detail a previously published method for 3D printing an electrically conductive bioink with human neural stem cells (hNSCs) that are subsequently differentiated. The differentiated tissue constructs comprise functional neurons and supporting neuroglia and are amenable to ES for the purposeful modulation of neural activity. Importantly, the method could be adapted to fabricate and stimulate neural and nonneural tissues from other cell types, with the potential to be applied for both research- and clinical-product development.Three-dimensional (3D) bioprinting is driving major innovations in the area of cartilage tissue engineering. As an alternative to computer-aided 3D printing, in situ additive manufacturing has the advantage of matching the geometry of the defect to be repaired without specific preliminary image analysis, shaping the bioscaffold within the defect, and achieving the best possible contact between the bioscaffold and the host tissue. Here, we describe an in situ approach that allows 3D bioprinting of human adipose-derived stem cells (hADSCs) laden in 10%GelMa/2%HAMa (GelMa/HAMa) hydrogel. We use coaxial extrusion to obtain a core/shell bioscaffold with high cell viability, as well as adequate mechanical properties for articular cartilage regeneration and repair.Bioprinting is a novel technological approach that has the potential to solve unmet questions in the field of tissue engineering. Laser-assisted bioprinting (LAB), due to its unprecedented cell printing resolution and precision, is an attractive tool for the in situ printing of a bone substitute. Here, we describe the protocol for LAB and its use for the in situ bioprinting of mesenchymal stromal cells, associated with collagen and nanohydroxyapatite, in order to favor bone regeneration in a calvaria defect model in mice.In recent years, new technologies based on 3D bioprinting have emerged as ideal tools with which to arrange cells and biomaterials in three dimensions and so achieve tissue engineering's original goals. The simplest and most widely used form of bioprinting is based on pneumatic extrusion, where 3D structures are built up by drawing patterns of cell-laden or non-cell-laden material through a robotically manipulated syringe. Developing and characterizing new biomaterials for 3D bioprinting (i.e., bioinks) is critical for the progress of the field. This chapter describes a series of protocols for developing, optimizing, and testing new bioinks for extrusion-based 3D bioprinting.Stereolithography (SLA) 3D bioprinting has emerged as a prominent bioprinting method addressing the requirements of complex tissue fabrication. This chapter addresses the advancement in SLA 3D bioprinting in concurrent with the development of novel photocrosslinkable biomaterials with enhanced physical and chemical properties. We discuss the cytocompatible photoinitiators operating in the wide spectrum of the ultraviolet (UV) and the visible light and high-resolution dynamic mask projection systems with a suitable illumination source. The potential of SLA 3D bioprinting has been explored in various themes, like bone and neural tissue engineering and in the development of controlled microenvironments to study cell behavior. The flexible design and versatility of SLA bioprinting makes it an attractive bioprinting process with myriad possibilities and clinical applications.The field of bioengineering has long pursued the goal of fabricating large-scale tissue constructs for use both in vitro and in vivo. Recent technological advances have indicated that bioprinting will be a key technique in manufacturing these specimens. This chapter aims to provide an overview of what has been achieved to date through the use of microextrusion bioprinters and what major challenges still impede progress. Microextrusion printer configurations will be addressed along with critical design characteristics including nozzle specifications and bioink modifications. Significant challenges within the field with regard to achieving long-term cell viability and vascularization, and current research that shows promise in mitigating these challenges in the near future are discussed. While microextrusion is a broad field with many applications, this chapter aims to provide an overview of the field with a focus on its applications toward human-sized tissue constructs.3D bioprinting involves engineering live cells into a 3D structure, using a 3D printer to print cells, often together with a compatible 3D scaffold. 3D-printed cells and tissues may be used for a range of purposes including medical research, in vitro drug testing, and in vivo transplantation. The inclusion of living cells and biomaterials in the 3D printing process raises ethical, policy, and regulatory issues at each stage of the bioprinting process that include the source of cells and materials, stability and biocompatibility of cells and materials, disposal of 3D-printed materials, intended use, and long-term effects. This chapter focuses on the ethical issues that arise from 3D bioprinting in the lab-from consideration of the source of cells and materials, ensuring their quality and safety, through to testing of bioprinted materials in animal and human trials. It also provides guidance on where to seek information concerning appropriate regulatory frameworks and guidelines, including on classification and patenting of 3D-bioprinted materials, and identifies regulatory gaps that deserve attention.Three-dimensional (3D) printing of human tissues and organs has been an exciting area of research for almost three decades [Bonassar and Vacanti. J Cell Biochem. 72(Suppl 30-31)297-303 (1998)]. The primary goal of bioprinting, presently, is achieving printed constructs with the overarching aim toward fully functional tissues and organs. Technology, in hand with the development of bioinks, has been identified as the key to this success. As a result, the place of computer-aided systems (design and manufacturing-CAD/CAM) cannot be underestimated and plays a significant role in this area. Unlike many reviews in this field, this chapter focuses on the technology required for 3D bioprinting from an initial background followed by the exciting area of medical imaging and how it plays a role in bioprinting.  https://www.selleckchem.com/products/puromycin-aminonucleoside.html  Extraction and classification of tissue types from 3D scans is discussed in addition to modeling and simulation capabilities of scanned systems. After that, the necessary area of transferring the 3D model to the printer is explored.