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Reliable prosthetic or tissue graft of trachea has not been developed yet for reconstruction of large, circumferential tracheal defect. Major limitation was anastomotic dehiscence and stenosis, which was attributed to the poor epithelinization and vascularization of the prosthetic graft. We developed the new tracheal prosthesis that has well-vascularized and viable mucosa. The prosthesis consists of Prolene mesh reinforced with polypropylene rings, and coated with gelatin. And we lined the luminal surface of the prosthesis with transplanted autogenous oral mucosa and wrapped the prosthesis with greater omentum and placed in peritoneal cavity for 2 weeks. Then, complete surgical resection and replacement of a segment of the thoracic trachea was performed in 9 adult mongrel dogs. Complete surgical resection and replacement of a thoracic trachea were performed in 2 dogs, and they survive well with normal activity. The transplanted mucosa and wrapped greater omentum was tightly adhered to the prosthesis to make a single unit within two weeks. The mucosa was well survived, well vascularized from new vessels from greater omentum and showed normal histology. We concluded that this highly biocompatible tracheal prosthesis could be very useful for staged reconstruction of tracheal defects.
During the past several years there has been a major advance in the development of biomedical materials and this has been progressed in the innovation of ceramic materials for skeletal repair and reconstruction. The materials within this class of medical implant are often referred to as “Bioceramics” and the expansion in their range of biomedical applications has been characterized by a significant increase in the number of patents and publications in the field and an ever increasing number of major international conferences and symposia. The present paper is giving the global trends of technology and markets for bioceramics, through analyzing the patents released during past 10 years. The perspective of bioceramics for the future will be also proposed on the development of biomaterials for biomedical application.
Since middle of 20 century, so many efforts have been conducted to make excellent biocompatible biomaterials especially for quick and firm osseointegration. SiO2-CaO-NaO-P2O5 system was proposed with the name of 멊ioglass? Bioglasses provide the convenient surface for hydroxyapatite formation when they are immersed in the body fluids. Bioglasses are the first artificial materials which can make direct bonding to the bone. Alkali treatment to metals and zeta-potential experiment are reviewed to investigate the essential component for the hydroxyapatite formation. It is uncovered that the essential component is not Si, Ca nor P but hydroxyl group.
Infusion tube set made from PVC contains DEHP as plasticizer in order to provide elastic property. But the release of this DEHP from PVC tube occurs various clinical undesired effects in living body. In this study, we tried to develop non-PVC infusion tube using polybutadiene based polymer and styrene based copolymer. After processing 2 kinds of tube using above material, the biological safety was confirmed. As control, commercialized tubes(made by Hanaco(China) and JMS(Japan)) was adapted. From the results of safety test, we concluded that developed materials showed very weak cytotoxicity, good blood compatibility and excellent biological safety comparing to control group.
Total joint replacement (TJR) has been used for treating joint diseases since 1960s to restore function and mobility without pain that result of osteoarthritis, rheumatoid arthritis and femoral neck fractures. Co-Cr alloy and ultra-high molecular polyethylene (UHMWPE) are widely used for articulating bearing component with its biocompatibility and excellent mechanical properties. In this study, we evaluated frictional characteristics of three kinds of the most representative UHMWPEs against Co-Cr alloy under a contact pressure of 5MPa in two different kinematic motions with a Pin-on-Disk type tribo-tester. Conventional gamma-irradiated UHMWPE (GIPE) specimens were machined from ramextruded Chirulen® 1020 rod and then gamma-irradiated with a dose of 4.0Mrad. Remelted highly cross-linked UHMWPE (RXLPE) were machined from hip liner of ZimmerTM product. Sequentially irradiated and annealed highly cross-linked UHMWPE (AXLPE) were machined from knee liner of StrikerTM product. To evaluate the effect of kinematic motion on the coefficients of friction (COF) between UHMWPE cylindrical pin specimens and orthopaedic grade Co-Cr alloy disk specimens, a repeat passed rotational motion and a linear reciprocal sliding motion tests were conducted and their COF were compared. As a result, the mean COF of all kinds of UHMWPEs in a reciprocal motion were significantly higher than in a rotational motion. Mean COF of GIPE were higher than two kinds of highly crosslinked UHMWPEs in both kinematic motions. Consequently, based on this comparative analyses in this study, kinematic motion gave a significant influence on the frictional property of tested all kinds of UHMWPEs.
Hyaluronic acid hydrogels (HAHs) were synthesized by immersing the micro-beads cross linked by divinyl sulfone in phosphate buffered saline solution to examine short-term biocompatibility of the gels with means of the L929 cyto-toxicity test and the acute toxicity test. Neither dead animals nor significant changes in body weights were observed for the ICR mouses after injection. In addition, no lesions were detected during the acute toxicity test. Both the reagent control and the negative control showed no cytotoxicity, while the positive control showed cytotoxicity in more than 75% cells as anticipated. The test medium was determined to be similar to the reagent and the negative control medium after 48 h. It is suggested that the HAHs are safe and effective.
Rupture of tendon and ligament has been frequently occurred in chronic disease or sports injury and result in a significant decrease in quality of patient's life. Many studies about tendon reconstruction were performed to propose treatment technique or mechanism. However, there is often fail to fully restore mechanical property. To overcome this limitation, bioreactor system to offer mechanical stimulation can be a good candidate solution. Recently, we have developed novel bioreactor system, which is composed with the driving system to offer mechanical stimulation, the reactor motion control system to control mechanical stimulation and the vessel chamber to supply saline buffer solution. As this bioreactor system can provide mechanical stimulation to tibialis tendon, we tested that this bioreactor system can be applied as the improvement of mechanical strength for tibialis tendon. The morphology of tibialis tendon was observed using scanning electron microscopy. We used a custom bioreactor to apply cyclic mechanical loading onto tibialis tendon to study ultimate tensile strength (UTS). Each tibialis tendon was implanted into the vessel chamber of bioreactor system and loaded under a tension stress of 10%, torsion stress of 90o and frequency of 1Hz for 1, 4and 7 days. Tibialis tendon exposed to bioreactor loading for 7days had a significantly higher UTS (818.1 N) compared to nonloaded control (354.9 N). In this study, we have developed a bioreactor system. We can conclude that bioreactor system could be useful device to improve UTS of tibialis tendon.
Bone graft is a healing method to repair and reinforce between and around fractured bones. It mainly divided into four kinds of bond graft; autograft, allograft, xenograft and alloplast. Bone grafts have several drawbacks including the need of medical operation for collection, limited supply of tissues, the disease infection and inflammatory response of other people/animal, ethical problem and osteogenic deficiency. Alloplast has been recently proposed as an alternative for bone graft. This article reviews the recent and relevant reports of a synthetic bone graft substitute fabricated with beta-tricalcium phosphate (β-TCP) and hydroxyapatite (HAp).
The scaffolds with an open porous structure are one of the most important components for successful tissue regeneration, which can provide 3-dimensional space and biocompatible surfaces for favorable bone ingrowth. Fundamentally, the mechanical properties and biological functions of these porous scaffolds are strongly affected by their porous structure, such as porosity, pore size, interconnections between the pores. Thus, considerable effort has been made to develop new techniques for the production of porous scaffolds with a controlled porous structure, including sponge replication, freeze casting, direct foaming techniques, vacuum-assisted foaming of a ceramic suspension and solid freeform fabrications (SFFs). This paper reviews the operation principle and application of various state-of-the art SFFs, which can create porous scaffolds with an arbitrary geometry, as well as a tightly controlled porous structure.