Synergistic interplay between human MSCs and HUVECs in 3D spheroids laden in collagen/fibrin hydrogels for bone tissue engineering.

Stem cell encapsulation in hydrogels has been widely employed in tissue engineering, regenerative medicine, organ-on-a-chip devices and gene delivery; however, fabrication of native-like bone tissue using such a strategy has been a challenge, particularly in vitro, due to the limited cell loading densities resulting in weaker cell-cell interactions and lesser extra-cellular matrix deposition. In particular, scalable bone tissue constructs require vascular network to provide enough oxygen and nutrient supplies to encapsulated cells. To enhance stem cell function and generate pre-vascularized network, we here employed collagen/fibrin hydrogel as an encapsulation matrix for the incorporation of human mesenchymal stem cell/human umbilical vein endothelial cell (MSC/HUVEC) spheroids, and investigated their cellular behavior (including cell viability, morphology, proliferation, and gene expression profile) and compared to that of cell suspension- or MSC spheroids-laden hydrogels.

Porous tissue strands: avascular building blocks for scalable tissue fabrication.

The scalability of cell aggregates such as spheroids, strands, and rings has been restricted by diffusion of nutrient and oxygen into their core. In this study, we introduce a novel concept in generating tissue building blocks with micropores, which represents an alternative solution for vascularization. Sodium alginate porogens were mixed with human adipose-derived stem cells, and loaded into tubular alginate capsules, followed by de-crosslinking of the capsules.

Squid Ring Teeth-coated Mesh Improves Abdominal Wall Repair.

Background: Hernia repair is a common surgical procedure with polypropylene (PP) mesh being the standard material for correction because of its durability. However, complications such as seroma and pain are common, and repair failures still approach 15% secondary to poor tissue integration. In an effort to enhance mesh integration, we evaluated the applicability of a squid ring teeth (SRT) protein coating for soft-tissue repair in an abdominal wall defect model.

Sprouting angiogenesis in engineered pseudo islets.

Despite the recent achievements in cell-based therapies for curing type-1 diabetes (T1D), capillarization in beta (β)-cell clusters is still a major roadblock as it is essential for long-term viability and function of β-cells in vivo. In this research, we report sprouting angiogenesis in engineered pseudo islets (EPIs) made of mouse insulinoma βTC3 cells and rat heart microvascular endothelial cells (RHMVECs). Upon culturing in three-dimensional (3D) constructs under angiogenic conditions, EPIs sprouted extensive capillaries into the surrounding matrix.

Transplantation of Bioprinted Tissues and Organs: Technical and Clinical Challenges and Future Perspectives.

: Three-dimensional (3D) bioprinting is a revolutionary technology in building living tissues and organs with precise anatomic control and cellular composition. Despite the great progress in bioprinting research, there has yet to be any clinical translation due to current limitations in building human-scale constructs, which are vascularized and readily implantable. In this article, we review the current limitations and challenges in 3D bioprinting, including in situ techniques, which are one of several clinical translational models to facilitate the application of this technology from bench to bedside.

The bioink: A comprehensive review on bioprintable materials.

This paper discusses "bioink", bioprintable materials used in three dimensional (3D) bioprinting processes, where cells and other biologics are deposited in a spatially controlled pattern to fabricate living tissues and organs. It presents the first comprehensive review of existing bioink types including hydrogels, cell aggregates, microcarriers and decellularized matrix components used in extrusion-, droplet- and laser-based bioprinting processes. A detailed comparison of these bioink materials is conducted in terms of supporting bioprinting modalities and bioprintability, cell viability and proliferation, biomimicry, resolution, affordability, scalability, practicality, mechanical and structural integrity, bioprinting and post-bioprinting maturation times, tissue fusion and formation post-implantation, degradation characteristics, commercial availability, immune-compatibility, and application areas.

Current advances and future perspectives in extrusion-based bioprinting.

Extrusion-based bioprinting (EBB) is a rapidly growing technology that has made substantial progress during the last decade. It has great versatility in printing various biologics, including cells, tissues, tissue constructs, organ modules and microfluidic devices, in applications from basic research and pharmaceutics to clinics. Despite the great benefits and flexibility in printing a wide range of bioinks, including tissue spheroids, tissue strands, cell pellets, decellularized matrix components, micro-carriers and cell-laden hydrogels, the technology currently faces several limitations and challenges.