ObjectiveTo review the application and research progress of in vivo bioreactor as vascularization strategies in bone tissue engineering. MethodsThe original articles about in vivo bioreactor that can enhance vascularization of tissue engineered bone were extensively reviewed and analyzed. ResultsThe in vivo bioreactor can be created by periosteum, muscle, muscularis membrane, and fascia flap as well as biomaterials. Using in vivo bioreactor can effectively promote the establishment of a microcirculation in the tissue engineered bones, especially for large bone defects. However, main correlative researches, currently, are focused on animal experiments, more clinical trials will be carried out in the future. ConclusionWith the rapid development of related technologies of bone tissue engineering, the use of in vivo bioreactor will to a large extent solve the bottleneck limitations and has the potential values for clinical application.
In vivo transplantation of tracheal grafts utilizes natural environment in vivo to improve cell adhesion, growth and scaffold properties, which can not only promote graft revascularization, but also induce immune tolerance and increase postoperative survival rate. Decellularized trachea with stem cells covering the outside layer and airway epithelial cells covering the inside layer can achieve complete mucosa re-epithelialization, cartilage cell growth and revascularization, using own body as a natural bioreactor to boost the maturity of tissue engineered trachea. Then transplantation at a normotopic in situ positioning is performed. This transplantation strategy provides a promising approach for the treatment of long-segment tracheal defects. This review focuses on the significance and research progress of constructing tissue engineered trachea in vivo.
Bioartificial liver support system (BALSS) provides a new way to treat liver failure and leaves more time for patients who are waiting for liver transplantation. It has detoxification function as well as the human liver, at the same time it can provide nutrition and improve the internal environment inside human body. Bioreactors and hepatocytes with good biological activity are the cores of BALSS which determine the treatment effect. However, in the course of prolonged treatment, the function and activity of hepatocytes might be greatly changed which could influence the efficacy. Therefore, it is very important to detect the status of the hepatocytes in BALSS. This paper presents some common indicators of cell activity, detoxification and synthetic functions, and also introduces the commonly detection methods corresponding to each indicator. Finally, we summarize the application of detection methods of the hepatocyte status in BALSS and discuss its development trend.
Bone tissue engineering is considered as one of the most promising way to treat large segmental bone defect. When constructing bone tissue engineering graft in vitro, suitable bioreactor is usually used to incubate cell-scaffold complex under perfusion to obtain bone tissue engineering graft with good repair efficiency. However, the theoretical model for growth rate of single cell (especially for stem cell) during this process still has many defects. The difference between stem cells and terminally differentiated cells is always ignored. Based on our previous studies, this study used self-made perfusion apparatus to apply different modes and strengths of fluid shear stress (FSS) to the cells seeded on scaffolds. The effects of FSS on the proliferation and osteogenic differentiation of mesenchymal stem cells (MSCs) were investigated. The regression analysis model of the effect of FSS on the single-cell growth rate of MSCs was further established. The results showed that 0.022 5 Pa oscillatory shear stress had stronger ability to promote proliferation and osteogenic differentiation of MSCs, and the growth rate of a single MSC cell under FSS was modified. This study is expected to provide theoretical guidance for optimizing the perfusion culture condition of bone tissue engineering grafts in vitro.
ObjectiveTo review the advances in the computational fluid dynamics (CFD) in tissue engineering.MethodsThe latest research of CFD applied to tissue engineering were extensively retrieved and analyzed, the optimization of bioreactor design and the simulation of fluid dynamics and cell growth kinetics during tissue regeneration in vitro were mainly reviewed.ResultsThe simulation and predictive capabilities of CFD can provide important guidance for the optimization of bioreactor design, and the cultivation of engineering tissue. The accuracy of model prediction results can be further improved by combining with experimental research.ConclusionAs a new and effective research tool, CFD has its unique advantages in the application of tissue engineering. However, a more comprehensive and accurate simulation of the whole process of tissue regeneration still needs further studies.
ObjectiveTo review the research progress of in vivo bioreactor (IVB) for bone tissue engineering in order to provide reference for its future research direction.MethodsThe literature related to IVB used in bone tissue engineering in recent years was reviewed, and the principles of IVB construction, tissue types, sites, and methods of IVB construction, as well as the advantages of IVB used in bone tissue engineering were summarized.ResultsIVB takes advantage of the body’s ability to regenerate itself, using the body as a bioreactor to regenerate new tissues or organs at injured sites or at ectopic sites that can support the regeneration of new tissues. IVB can be constructed by tissue flap (subcutaneous pocket, muscle flap/pocket, fascia flap, periosteum flap, omentum flap/abdominal cavity) and axial vascular pedicle (axial vascular bundle, arteriovenous loop) alone or jointly. IVB is used to prefabricate vascularized tissue engineered bone that matched the shape and size of the defect. The prefabricated vascularized tissue engineered bone can be used as bone graft, pedicled bone flap, or free bone flap to repair bone defect. IVB solves the problem of insufficient vascularization in traditional bone tissue engineering to a certain extent.ConclusionIVB is a promising method for vascularized tissue engineered bone prefabrication and subsequent bone defect reconstruction, with unique advantages in the repair of large complex bone defects. However, the complexity of IVB construction and surgical complications hinder the clinical application of IVB. Researchers should aim to develop a simple, safe, and efficient IVB.