Tissue engineering is limited by our inability to adequately vascularize tissues post implantation because all tissue-engineered substitutes (with the exception of cornea and cartilage) require a vascular network to provide the nutrient and oxygen supply needed for their survival. This review gives a brief overview of the processes and factors involved in the vascularization and angiogenesis and summarizes the different strategies to overcome the issue of slow vascularization and angiogenesis in a range of tissue-engineered substitutes. Moreover, we will announce some potential future plans.
Cornea ; Methods* ; Oxygen ; Tissue Engineering

For the damage and loss of tissues and organs caused by urinary system diseases, the current clinical treatment methods have limitations. Tissue engineering provides a therapeutic method that can replace or regenerate damaged tissues and organs through the research of cells, biological scaffolds and biologically related molecules. As an emerging manufacturing technology, three-dimensional (3D) bioprinting technology can accurately control the biological materials carrying cells, which further promotes the development of tissue engineering. This article reviews the research progress and application of 3D bioprinting technology in tissue engineering of kidney, ureter, bladder, and urethra. Finally, the main current challenges and future prospects are discussed.
Bioprinting ; Regeneration ; Technology ; Tissue Engineering/methods*

OBJECTIVE: To review the research progress in the construction strategy and application of bone/cartilage immunomodulating hydrogels. METHODS: The literature related to bone/cartilage immunomodulating hydrogels at home and abroad in recent years was reviewed and summarized from the immune response mechanism of different immune cells, the construction strategy of immunomodulating hydrogels, and their practical applications. RESULTS: According to the immune response mechanism of different immune cells, the biological materials with immunoregulatory effect is designed, which can regulate the immune response of the body and thus promote the regeneration of bone/cartilage tissue. Immunomodulating hydrogels have good biocompatibility, adjustability, and multifunctionality. By regulating the physical and chemical properties of hydrogel and loading factors or cells, the immune system of the body can be purposively regulated, thus forming an immune microenvironment conducive to osteochondral regeneration. CONCLUSION Immunomodulating hydrogels can promote osteochondral repair by affecting the immunomodulation process of host organs or cells. It has shown a wide application prospect in the repair of osteochondral defects. However, more data support from basic and clinical experiments is needed for this material to further advance its clinical translation process.
Hydrogels ; Cartilage ; Bone and Bones ; Tissue Engineering/methods*

An ideal biologically derived that tissue engineering material of tendon has biological activities and functions, so that it may lead to a perfect effect in histological reparation and reconstruction. In addition, the tissue engineering material can avoid disease transmission, be provided from variety of sources and be weak in immune responses. Generally, there are two kinds biologically derived material, i. e. natural biomaterials and purified biomaterials. In this review, researches about the effect, capability and relevant preparation methods, enhancing strategies and the development in the future are discussed.
Biocompatible Materials ; Humans ; Tendons ; Tissue Engineering ; methods ; Tissue Scaffolds

OBJECTIVE: To summarize the influence of microstructure on performance of triply-periodic minimal surface (TPMS) bone scaffolds. METHODS: The relevant literature on the microstructure of TPMS bone scaffolds both domestically and internationally in recent years was widely reviewed, and the research progress in the imfluence of microstructure on the performance of bone scaffolds was summarized. RESULTS: The microstructure characteristics of TPMS bone scaffolds, such as pore shape, porosity, pore size, curvature, specific surface area, and tortuosity, exert a profound influence on bone scaffold performance. By finely adjusting the above parameters, it becomes feasible to substantially optimize the structural mechanical characteristics of the scaffold, thereby effectively preempting the occurrence of stress shielding phenomena. Concurrently, the manipulation of these parameters can also optimize the scaffold's biological performance, facilitating cell adhesion, proliferation, and growth, while facilitating the ingrowth and permeation of bone tissue. Ultimately, the ideal bone fusion results will obtain. CONCLUSION The microstructure significantly and substantially influences the performance of TPMS bone scaffolds. By deeply exploring the characteristics of these microstructure effects on the performance of bone scaffolds, the design of bone scaffolds can be further optimized to better match specific implantation regions.
Tissue Scaffolds/chemistry* ; Tissue Engineering/methods* ; Bone and Bones ; Porosity

Droplet microfluidics technology offers refined control over the flows of multiple fluids in micro/nano-scale, enabling fabrication of micro/nano-droplets with precisely adjustable structures and compositions in a high-throughput manner. With the combination of proper hydrogel materials and preparation methods, single or multiple cells can be efficiently encapsulated into hydrogels to produce cell-loaded hydrogel microspheres. The cell-loaded hydrogel microspheres can provide a three-dimensional, relatively independent and controllable microenvironment for cell proliferation and differentiation, which is of great value for three-dimensional cell culture, tissue engineering and regenerative medicine, stem cell research, single cell study and many other biological science fields. In this review, the preparation methods of cell-loaded hydrogel microspheres based on droplet microfluidics and its applications in biomedical field are summarized and future prospects are proposed.
Hydrogels/chemistry* ; Microfluidics/methods* ; Microspheres ; Regenerative Medicine ; Tissue Engineering/methods*

Articular osteocartilage injury caused by trauma or bone disease is very common in clinical practices,the proportion of cartilage defects reached 40.31%. As the low self healing abilities of articular cartilage, the technology of tissue engineering becomes a new method to treat articular cartilage injuries with regenerative medicine. Scaffolds can be divided into preformed and hydrogel scaffolds according to properties. The traditional graft of pre-formed scaffold will bring the secondary injury to the cartilage around the defect, and the loose graft intergration with the defect surface is still a problem. Repairing irregular articular cartilage defects with ideal biomimic materials on the basis of avoiding secondary damage will become a main issue. The method of minimally invasive injecting, biomimics, and in situ remodeling brings hope to articular cartilage repairing. Below is a summary of the international and domestics reference data of recent years on collagen hydrogel in cartilage tissue engineering.
Collagen ; Humans ; Hydrogel, Polyethylene Glycol Dimethacrylate ; Tissue Engineering ; methods

OBJECTIVETo study the feasibility of ectopic bone formation for engineered bone constructs with bone marrow stromal cells (BMSCs).

METHODSBMSCs were obtained from 3-month female New-Zealand rabbits with weight of 3 kg, induced to osteogenitor cell, were expanded by culture and then seeded into the porous beta-tricalcium phosphate (beta-TCP) particles. Engineered bone constructs were implanted under the periostem of rabbit femur. Samples were retrieved and examed after 3 months. Blood vessels and osteoblast were examined through optical microscope.

RESULTSTwelve implanted engineered bone particles of 16 samples were fixed well under periosteum and rounded by periosteum. There were a lot of vessels and new bone in engineered bone. The structure of bone was disorder; the vessels arranged equally. Four cases found implanted bone freed outside of periosteum,lots of implanted material were absorbed,the volume of residual was less than osteogenesis, and lack of blood vessel. 80% engineered bone constructs attached to the femur under the periostem very well,osteogenesis was fine and vessels were growed into new bone.

CONCLUSIONEngineered bone can obtained good ectopic bone under the periostem.

Heart Failure ; therapy ; Humans ; Myocardium ; Tissue Engineering ; methods ; trends

In this article, based on the relative references in the latest 8 years, we introduce briefly the origin, preparation and application of various injectable and absorbable gelling scaffold materials, and outline their advantages and disadvantages as localized gelling scaffold systems.
Absorbable Implants ; Biocompatible Materials ; Gels ; chemistry ; Injections ; Tissue Engineering ; methods