ABSTRACT
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.
Subject(s)
Bioprinting , Regeneration , Technology , Tissue Engineering/methodsABSTRACT
Three dimensional (3D) bioprinting is a new biological tissue engineering technology in recent years. The development of 3D bioprinting is conducive to solving the current problems of clinical tissue and organ repairing. This article provides a review about the clinical and research status of 3D bioprinting and urinary system reconstruction. Furthermore, the feasibility and clinical value of 3D bioprinting in urinary system reconstruction will be also discussed.
Subject(s)
Humans , Bioprinting , Printing, Three-Dimensional , Tissue Engineering , Urinary TractABSTRACT
BACKGROUND: It is very difficult for urologists to choose what kind of substitute and how to reconstruct the long ureteral injuries to restore the integrity and function of the ureter. OBJECTIVE: To review recent progress and the evolution trends in the reconstruction methods of long ureteral injuries. METHODS: Relevant articles published from 1950 to 2019 were searched in PubMed, Web of Science, MEDLINE, and WanFang databases. The keywords were “ureteral injuries, ureteral replacement, biomaterial, tissue engineering, 3D bioprinting” in English and Chinese, respectively. The articles addressing ureteral replacement materials and reconstruction of ureteral injuries were selected. RESULTS AND CONCLUSION: In the reconstruction of long ureteral injury, the earliest repair method is to use autologous tissues, such as ileal, bladder muscle flap (Boari flap), and buccal mucosa graft. But such operations are difficult to avoid the damage to the surrounding tissues and organs. After that, various non-biomaterials were produced for ureteral replacement, but failed due to immune rejection and lack of peristalsis. With the development of cytology, biology and materials, the damaged tissues and organs have been regenerated by using autologous cells. Due to the development of regenerative medicine and three-dimensional printing technology, complex multi-component and multi-layered hollow tube structures that similar to their internal counterparts can be generated with three-dimensional bioprinting. But three-dimensional bioprinting cannot reconstruct the ureter and bladder with normal peristalsis and contraction function.
ABSTRACT
BACKGROUND: Cells cannot survive in the area 200 µm away from nutrients in vitro. Vascular network construction is crucial for thick tissue and organ regeneration in tissue engineering. Coaxial cell printing provides a new way to construct vascular-like channels in vitro. OBJECTIVE: To optimize the coaxial cell printing performance of bioink and to build the tissue-engineered scaffolds with vascular-like structure. METHODS: The aseptic sodium alginate solution was prepared by intermittent pasteurization and then frozen. Freeze-dried powder of aseptic silk fibroin was prepared from degummed silk and sealed. The thawed sodium alginate solution was added to the silk fibroin protein freeze-dried powder and human umbilical vein endothelial cells were added to prepare the bioink. The outer axis of the biological three-dimensional printer was connected with the bioink, and the inner axis was connected with the crosslinking agent. The scaffolds were prepared by coaxial printing, and performed by optical coherence tomography, scanning electron microscopy observation and tensile test. Coaxial scaffolds were made by freeze-preserved sodium alginate solution for 7 days with human umbilical vein endothelial cells. Coaxial scaffolds were also made by freeze-dried sodium alginate solution for 7 days with human umbilical vein endothelial cells and silk fibroin protein sealed for 6 months. The cell survival rate was detected by dead and alive staining after 24 hours of culture in vitro. Vascular-like scaffolds with series and parallel structures were designed and printed. The cell proliferation was detected after 1, 3, 7, 10, and 14 days of culture. RESULTS AND CONCLUSIONS: (1) The optical coherence tomography showed that the maximum printing height of the bioink was 9 layers and the overall thickness was about 4.4 mm. Scanning electron microscopy showed that the outer wall of hollow fiber-filament of vascular-like scaffolds presented irregular strip-shaped crimp with micron-scale internal connected pore structure, while the inner wall of hollow fiber-filament had denser pore structure. (2) The elastic modulus of silk protein freeze-dried scaffold was higher than that of sodium alginate solution (P < 0.05). (3) The cell survival rate of scaffolds treated with sodium alginate solution for 7 days was (86.7±3.4)%, and that of scaffolds treated with silk protein freeze-dried powder for 7 days was (98.1±1.2)%, indicating that the sodium alginate solution freeze- preserved for 7 days was free of bacteria and the shelf-life of silk protein could be up to 6 months. (4) The proliferation activity of cells cultured with parallel structure for 7, 10, and 14 days was higher than that with series structure (P < 0.05). (5) These results imply that the scaffolds have good biocompatibility and mechanical properties.
ABSTRACT
As a temporary skin substitute, the dressings can protect the wound, stop bleeding, prevent infection and contribute to wound healing. According to the characteristics of the materials, wound dressings can be classified into traditional wound dressings, interactive dressings, bioactive dressings, tissue engineering dressings and smart dressings, etc. Different dressings have different characteristics, and some products have been widely used in clinic. Recently nanomaterials and three-dimensional bio-printing technology have significantly improved the performance of wound dressings. Future dressings will be developed from single function to multi-function composite, and integrated into an intelligent one. This paper reviews the current research progress and future development prospects of wound dressings.
Subject(s)
Bandages , Skin, Artificial , Tissue Engineering , Wound HealingABSTRACT
Deep skin wounds require skin grafts for coverage. Current treatments such as tissue engineered skin or skin substitutes can not meet the needs of clinical application due to the technical problems involving preservation, transportation, and a lengthy preparation process. In comparison with traditional methods such as freeze-drying, three-dimensional bioprinting can precisely dispense living cells, nucleic acid, growth factor, and phase-changing hydrogels according to the wound form, while maintaining high cell viability. Besides, it has excellent performance in high resolution, flexibility, reproducibility, and high throughput, showing great potential in the fabrication of tissue engineered skin. This review mainly introduces the common techniques of three-dimensional bioprinting, and their application in skin tissue engineering, focusing on the latest research progress, and summarizes the current challenges and future development of three-dimensional skin printing.
ABSTRACT
Three-dimensional (3D) printing is a low-cost, high-efficiency production method, which can reduce the current cost and increase the profitability of skin repair material industry nowadays, and develop products with better performance. The 3D printing technology commonly used in the preparation of skin repair materials includes fused deposition molding technology and 3D bioprinting technology. Fused deposition molding technology has the advantages of simple and light equipment, but insufficient material selection. 3D bioprinting technology has more materials to choose from, but the equipment is cumbersome and expensive. In recent years, research on both technologies has focused on the development and application of materials. This article details the principles of fused deposition modeling and 3D bioprinting, research advances in wound dressings and tissue engineering skin production, and future developments in 3D printing on skin tissue repair, including cosmetic restoration and biomimetic tissue engineering. Also, this review prospects the development of 3D printing technology in skin tissue repairment.
ABSTRACT
Three-dimensional bioprinting is one of the latest and fastest growing technologies in the medical field. It has been implemented to print part of the transplantable tissues and organs, such as skin, ear, and bone. This paper introduces the application status, challenges, and application prospect of three-dimensional bioprinting in burn and plastic surgery field.
ABSTRACT
Sweat glands are abundant in the body surface and essential for thermoregulation. Sweat glands fail to conduct self-repair in patients with large area of burn and trauma, and the body temperature of patients increases in hot climate, which may cause shock or even death. Now, co-culture system, reprogramming, and tissue engineering have made progresses in inducing sweat gland regeneration, but the inductive efficiency and duration need to be improved. Cellular microenvironment can regulate cell biological behavior, including cell migration and cell differentiation. This article reviews the studies of establishment of microenvironment in vitro by three-dimensional bioprinting technology to induce sweat gland regeneration.
ABSTRACT
The need for organ and tissue regeneration in patients continues to increase because of a scarcity of donors, as well as biocompatibility issues in transplant immune rejection. To address this, scientists have investigated artificial tissues as an alternative to transplantation. Three-dimensional (3D) bioprinting technology is an additive manufacturing method that can be used for the fabrication of 3D functional tissues or organs. This technology promises to replicate the complex architecture of structures in natural tissue. To date, 3D bioprinting strategies have confirmed their potential practice in regenerative medicine to fabricate the transplantable hard tissues, including cartilage and bone. However, 3D bioprinting approaches still have unsolved challenges to realize 3D hard tissues. In this manuscript, the current technical development, challenges, and future prospects of 3D bioprinting for engineering hard tissues are reviewed.
Subject(s)
Humans , Bioprinting , Cartilage , Methods , Regeneration , Regenerative Medicine , Tissue Donors , Tissue EngineeringABSTRACT
Recently, three-dimensional (3D) printing technologies have become an attractive manufacturing process, which is called additive manufacturing or rapid prototyping. A 3D printing system can design and fabricate 3D shapes and geometries resulting in custom 3D scaffolds in tissue engineering. In tissue regeneration and replacement, 3D printing systems have been frequently used with various biomaterials such as natural and synthetic polymers. In tissue engineering, soft tissue regeneration is very difficult because soft tissue has the properties of high elasticity, flexibility and viscosity which act as an obstacle when creating a 3D structure by stacking layer after layer of biomaterials compared to hard tissue regeneration. To overcome these limitations, many studies are trying to fabricate constructs with a very similar native micro-environmental property for a complex biofunctional scaffold with suitable biological and mechanical parameters by optimizing the biomaterials, for example, control the concentration and diversification of materials. In this review, we describe the characteristics of printing biomaterials such as hydrogel, synthetic polymer and composite type as well as recent advances in soft tissue regeneration. It is expected that 3D printed constructs will be able to replace as well as regenerate defective tissues or injured functional tissues and organs.