• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.1
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• pp.7-12
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• 2009

Purpose: Gelatin-hydroxyapatite nanocomposite is similar to inorganic nanostructure of bone. To make a scaffold with osteoinductivity, bone marrow derived stem cells from rabbit femur were impinged into the nanocomposite. This vitro study was to test osteogenic differentiation of the stem cells in the nanocomposite, which was made by authors. Material & Methods: Gel-HA nanocomposite with 10g of HA, 3 g of Gel has been made by co-precipitation process. Bone marrow was obtained from femur of New Zealand White rabbits and osteogenic differentiation was induced by culturing of the BMSCs in an osteogenic medium. The BMSCs were seeded into the Gel-HA nanocomposite scaffold using a stirring seeding method. The scaffolds with the cells were examined by scanning electron microscopy (SEM), colorimetry assay, biochemical assay with alkaline phosphatase (ALP) diagnostic kit, osteocalcin ELISA kit. Results: Gel-HA nanocomposite scaffolds were fabricated with relatively homogenous microscale pores ($20-40{\mu}m$). The BMSCs were obtained from bone marrow of rabbit femurs and confirmed with flow cytometry, Alizarin red staining. Attachment and proliferation of BMSCs in Gel-HA nanocomposite scaffold could be identified by SEM, ALP activity and osteocalcin content of BMSCs. Conclusion: The Gel-HA nanocomposite scaffold with micropores could be fabricated and could support BMSCs seeding, osteogenic differentiation.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.56.2-56.2
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• 2012

Clinically-favored materials for bone regeneration are mainly based on bioceramics due to their chemical similarity to the mineral phase of bone. A successful scaffold in bone regeneration should have a 3D interconnected pore structure with the proper biodegradability, biocompatibility, bioactivity, and mechanical property. The pore architecture and mechanical properties mainly dependent on the fabrication process. Bioceramics scaffolds are fabricated by polymer sponge method, freeze drying, and melt molding process in general. However, these typical processes have some shortcomings in both the structure and interconnectivity of pores and in controlling the mechanical stability. To overcome this limitation, the rapid prototyping (RP) technique have newly proposed. Researchers have suggested RP system in fabricating bioceramics scaffolds for bone tissue regeneration using selective laser sintering, powder printing with an organic binder to form green bodies prior to sintering. Meanwhile, sintering process in high temperature leads to bad cost performance, unexpected crystallization, unstable mechanical property, and low bio-functional performance. The development of RP process without high thermal treatment is especially important to enhance biofunctional performance of scaffold. The purpose of this study is development of new process to fabricate ceramic scaffold at room temperature. The structural properties of the scaffolds were analyzed by XRD, FE-SEM and TEM studies. The biological performance of the scaffolds was also evaluated by monitoring the cellular activity.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.5
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• pp.311-325
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• 2001

Tissue engineering scaffolds play a critical role in regulating the reconstructed human tissue development. Various types of scaffolds have been developed in recent years, including fibrous matrix and foam-like scaffolds. The design of scaffold materials has been investigated extensively. However, the design of physical structure of the scaffold, especially fibrous matrices, has not received much attention. This paper compares the different characteristics of fibrous and foam-like scaffolds, and reviews regulatory roles of important scaffold properties, including surface geometry, scaffold configuration, pore structure, mechanical property and bioactivity. Tissue regeneration, cell organization, proliferation and differentiation under different microstructures were evaluated. The importance of proper scaffold selection and design is further discussed with the examples of bone tissue engineering and stem cell tissue engineering. This review addresses the importance of scaffold microstructure and provides insights in designing appropriate scaffold structure for different applications of tissue engineering.

• Journal of the Korean Society of Radiology
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• v.15 no.4
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• pp.539-545
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• 2021

Radiation therapy is accompanied by adverse radiation effective. In particular, it is accompanied by disorders of the vascular system. Therefore, oxygen and nutrient deficiency occurs in the regeneration area. Eventually, osteoradionecrosis is formed in this cellular environment. According to a precedent study, bone morphogenetic protein-2 is used to overcome osteoradionecrosis. The purpose of this study was to investigate the regeneration ability of osteoradionecrosis by treating bone-forming protein-2 on a fibrinogen scaffold which is a biomaterial that is frequently used for bone regeneration after irradiation of the rat head. In addition, the purpose of this study was to verify the bone regeneration effect from the eight weeks. According to the experimental results, in the calvarial defected model of the irradiated mouse, making bone-formation was obtained after 8 weeks rather than bone-formation period in the early 4 weeks. moreover, it was found that the regenerated bone formation of the fibrinogen scaffold is formed from the inside of the bone of the defect area.

• Polymer(Korea)
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• v.31 no.1
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• pp.14-19
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• 2007

Demineralized bone particle (DBP) has been used as one of the powerful inducers of bone and cartilage tissue specialization. In this study, we fabricated DBP/PLGA scaffold for tissue engineered disc regeneration. We manufactured dual-structured scaffold to compose inner cylinder and outer doughnut similar to nature disc tissue. The DBP/PLGA scaffold was characterized by porosity, wettability, and water uptake ability. We isolated and cultured nucleus pulposus (NP) and annulus fibrosus (AF) cells from rabbit intervertebral disc. We seeded NP cells into the inner core of the hybrid scaffold and AF cells into the outer portion of it. Cellular viability and proliferation were assayed by 3-(4,5-dimethylthiazole-2-yl) -2,5- diphenyltetrazolium -bromide (MTT) test. PLGA and PLGA/DBP scaffolds were implanted in subcutaneous of athymic nude mouse to observe the formation of disc-like tissue in vivo. And then we observed change of morphology and hematoxylin and eosin (H&E). Formation of disc-like tissue was better DBP/PLGA hybrid scaffold than control. Specially, we confirmed that scaffold impregnated 20 and 40% DBP affected to proliferation of disc cell and formation of disc-like tissue.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.1
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• pp.9-15
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• 2010

Aim of the study: As an injectable scaffold, MPEG-PCL diblock copolymer was applied in bone tissue engineering. In vivo bone formation was evaluated by soft X-ray, histology based on the rat calvarial critical size defect model. Materials and Methods: New bone formation was evaluated with MPEG-PCL diblock copolymer in rat calvarial critical size bone defect. No graft was served as control. 4, 8 weeks after implantation, gross evidence of bone regeneration was evaluated by histology and soft X-ray analysis. Results: The improved and effective bone regeneration was achieved with the BMP-2 and osteoblasts loaded MPEG-PCL diblock copolymer. Conclusion: It was confirmed that MPEG-PCL temperature sensitive hydrogels was useful as an injectable scaffold in bone regeneration.

• Archives of Plastic Surgery
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• v.34 no.2
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• pp.141-148
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• 2007

Purpose: The object of this study was to evaluate the development of continuous osteogenic differentiation and bone formation after the subcutaneous implantation of the tissue-engineered bone, in vitro. Methods: Human adipose-derived stem cells were obtained by proteolytic digestion of liposuction aspirates. Adipose-derived stem cells were seeded in PLGA scaffolds after being labeled with PKH26 and cultured in osteogenic differentiation media for 1 month. The PLGA scaffolds with osteogenic stimulated adipose-derived stem cells were implanted in subcutaneous layer of four nude mice. Osteogenesis was assessed by RT-PCR for mRNA of osteopontin and bone sialoprotein(BSP), and immunohistochemistry for osteocalcin, and von Kossa staining for calcification of extracellular matrix at 1 and 2 months. Results: Implanted PLGA scaffold with adipose-derived stem cells were well vascularized, and PLGA scaffolds degraded and were substituted by host tissues. The mRNA of osteopontin and BSP was detected by RT-PCR in both osteogenic stimulation group and also osteocalcin was detected by immunohistochemistry at osteogenic stimulation 1 and 2 months, but no calcified extracellular deposit in von Kossa stain was found in all groups. Conclusion: In vivo, it could also maintain the characteristics of osteogenic differentiation that adipose-derived stem cells within PLGA scaffold after stimulation of osteogenic differentiation in vitro, but there were not normal bone formation in subcutaneous area. Another important factor to consider is in vivo, heterologous environment would have negative effect on bone formation as.[p1]

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.12
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• pp.1229-1235
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• 2015

Scaffold fabrication technology using a 3D printer was developed for damaged bone tissue regeneration. A scaffold for bone tissue regeneration application should be biocompatible, biodegradable, and have an adequate mechanical strength. Moreover, the scaffold should have pores of satisfactory quantity and interconnection. In this study, we used the polymer deposition system (PDS) based on fused deposition modeling (FDM) to fabricate a 3D scaffold. The materials used were polycaprolactone (PCL) and alginic acid sodium salt (sodium alginate, SA). The salt-leaching method was used to fabricate dual pores on the 3D scaffold. The 3D scaffold with dual pores was observed using SEM-EDS (scanning electron microscope-energy dispersive spectroscopy) and evaluated through in-vitro tests using MG63 cells.

• Korean Journal of Materials Research
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• v.24 no.6
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• pp.310-318
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• 2014

In this experiment, a highly porous scaffold of biphasic calcium phosphate (BCP) was prepared using the spongereplica method. The BCP scaffold was coated with 58S bioactive glass (BG) and sintered for a second time. The resulting scaffold was coated with gelatin (Gel) and cross-linked with [3-(3-dimethyl aminopropyl) carbodiimide] and N-Hydroxysuccinamide (EDC-NHS). The initial average pore size of the scaffold ranged from 300 to $700{\mu}m$, with more than 85 % porosity. The coating of BG and Gel had a significant effect on the scaffold-pore size, decreasing scaffold porosity while increasing mechanical strength. The material and surface properties were evaluated by means of several experiments involving scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) and X-ray diffraction (XRD). Cytotoxicity was evaluated using MTT assay and confocal imaging of MC3T3-E1 pre-osteoblast cells cultured in vitro. Three types of scaffold (BCP, BCP-BG and BCP-BG-Gel) were implanted in a rat skull for in vivo evaluation. After 8 weeks of implantation, bone regeneration occurred in all three types of sample. Interestingly, regeneration was found to be greater (geometrically and physiologically) for neat BCP scaffolds than for two other kinds of composite scaffolds. However, the other two types of scaffolds were still better than the control (i.e., defect without treatment).

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.42.2-42.2
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• 2010

Recently, highly porous bone substitutes, which have interconnected open pore structure, have been focused on improving their mechanical properties and modifying their functions. Especially, it is highly required to develop functional gradient structured bone substitute which is available for controlling their material properties such as bioresorption rate and elastic modulus. Porous $ZrO_2$ scaffold was fabricated by the sponge replica method using PU sponge. After 3 times of dip coating and the subsequent oven drying, burning out and microwave sintering were carried out. Various $ZrO_2$-BCP powder mixtures were prepared depending on the ratio and coated on the $ZrO_2$ scaffold by dip coating process. X-ray diffraction analysis was performed to characterize the phase identification of the scaffolds. Microstructures of the bone substitutes were observed using scanning electron microscopy.