• 반도체디스플레이기술학회지
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• 제17권4호
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• pp.70-75
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• 2018

In this paper, we have studied the deformation problem of the scaffold caused by the FDM type 3D printer. The DOE (Design of experiment) and 3SC was used to solve the deformation problem of the scaffold generated from the adhesion surface between the scaffold and the bed. The methodology was used to derive the solution and the experiment was conducted on the derived solution. As a result of evaluating the experimental results obtained for the solution, it was found that the deformation of the scaffold was much improved. By using the DOE, We were possible to derive the output condition of scaffold.

• Reproductive and Developmental Biology
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• 제37권2호
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• pp.79-83
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• 2013

Matrix metalloproteinases (MMPs) have been known to affect to cell migration, proliferation, morphogenesis and apoptosis by degrading the extracellular matrix. In the previous studies, undifferentiated mouse embryonic stem cells (ESCs) were successfully proliferated inside the extracellular matrix (ECM) analog-conjugated three-dimensional (3D) poly ethylene glycol (PEG)-based hydrogel. However, there is no report about MMP secretion in ESCs, which makes it difficult to understand and explain how ESCs enlarge space and proliferate inside 3D PEG-based hydrogel constructed by crosslinkers containing MMP-specific cleavage peptide sequence. Therefore, we investigated what types of MMPs are released from undifferentiated ESCs and how extracellular signals derived from various niche conditions affect MMP expression of ESCs at the transcriptional level. Results showed that undifferentiated ESCs expressed specifically MMP2 and MMP3 mRNAs. Transcriptional up-regulation of MMP2 was caused by the 3D scaffold, and activation of integrin inside the 3D scaffold upregulated MMP2 mRNAs synergistically. Moreover, mouse embryonic fibroblasts (MEFs) on 2D matrix and 3D scaffold induced upregulation of MMP3 mRNAs, and activation of integrins through conjugation of extracellular matrix (ECM) analogs with 3D scaffold upregulated MMP3 mRNAs synergistically. These results suggest that successful proliferation of ESCs inside the 3D PEG-based hydrogel may be caused by increase of MMP2 and MMP3 expression resulting from 3D scaffold itself as well as activation of integrins inside the 3D PEG-based scaffold.

• 한국기계가공학회지
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• 제15권5호
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• pp.86-92
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• 2016

In this study, we used a polymer deposition system, based on fused deposition modeling, to fabricate the 3D scaffold and then fabricated micro-pores on a 3D scaffold using a salt leaching method. Materials included polycaprolactone (PCL) and sodium chloride (NaCl). The 3D porous scaffolds were fabricated according to blending ratio such as PCL (70 wt%)/NaCl (30 wt%) and PCL (50 wt%)/NaCl (50 wt%). The 3D porous scaffolds were observed by scanning electron microscopy. The results showed that 3D porous scaffolds had a deposition width of $500{\mu}m$, contained a pore size of $500{\mu}m$ and below $100{\mu}m$. To evaluate the 3D porous scaffolds for bone tissue engineering, we carried out the cell proliferation experiment using a CCK-8 and a mechanical strength test using a universal testing machine. In summary, the 3D porous scaffold was found to be suitable for cancellous bone of human in accordance with the result of in-vitro cell proliferation and mechanical strength. Thus, a 3D porous scaffold could be a promising approach for effective bone regeneration.

• 폴리머
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• 제32권2호
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• pp.163-168
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• 2008

생체 친화적이며 생분해성 고분자 소재인 poly($\varepsilon$-caprolactone)(PCL)을 rapid prototyping(RP) 공정인 바이오플로팅 시스템을 통해 세포 재생용 지지체(scaffold)를 제작하였다. 제작된 PCL 지지체는 DMA(dynamic mechanical analyzer)를 통해 동일한 재료로 제작된 기존 염침출법(salt-leaching)에 의한 지지체보다 월등히 향상된 기계적 강도를 갖고 있음을 확인하였고, 이는 기존 전통적인 세포지지체 제작에서 문제점중의 하나인 기계적인 강도적인 측면을 보완하여, 뼈조직 재생에 유용하게 활용될 수 있을 것으로 예상된다. 지지체 내부의 구조는 세포의 증식과 이동 및 영양분의 공급이 지속될 수 있도록 전체적으로 연결된 통로로 구성되어 있고, 다양한 세포의 증식이 가능하도록 지지체의 공극 크기와 strand의 굵기 등을 조절할 수 있으며, 이를 이용하여 대체하고자 하는 생체조직의 특성에 맞도록 기계적 강도를 조정할 수 있음을 확인하였다. 제조된 PCL지지체는 연골세포를 통하여 셀 컬쳐링 되었고, 3차원 세포 지지체로서의 충분한 가능성을 보여주었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.159-160
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• 2006

A novel approach to the manufacture of biocompatible ceramic scaffold for tissue engineering using micro-stereolithography system is introduced. Micro-stereolithography is a newly proposed technology that enables to make a 3D micro structure. The 3D micro structures made by this technology can have accurate and complex shape within a few micron error. Therefore, the application based on this technology can vary greatly in nano-bio fields. Recently, tissue-engineering techniques have been regarded as alternative candidate to treat patients with serious bone defects. So many techniques to design and fabricate 3D scaffolds have been developed. But the imperfection of scaffold such as random pore size and porosity causes a limitation in developing optimum scaffold. So scaffold development with controllable pore size and fully interconnected shape have been needed for a more progress in tissue engineering. In this paper, bone scaffold was developed by applying the micro-stereolithography to the mold technology. The scaffold material used was HA(Hydroxyapatite) nano powder. HA is a type of calcium phosphate ceramic with similar characteristic to human inorganic bone component. The bone scaffold made by HA is expected, in the near future, to be an efficient therapy for bone defect.

• 한국정밀공학회지
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• 제28권7호
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• pp.834-850
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• 2011

In this paper, a novel tissue engineering scaffold design method based on triply periodic minimal surface (TPMS) is proposed. After generating the hexahedral elements for a 3D anatomical shape using the distance field algorithm, the unit cell libraries composed of triply periodic minimal surfaces are mapped into the subdivided hexahedral elements using the shape function widely used in the finite element method. In addition, a heterogeneous implicit solid representation method is introduced to design a 3D (Three-dimensional) bio-mimetic scaffold for tissue engineering from a sequence of computed tomography (CT) medical image data. CT image of a human spine bone is used as the case study for designing a 3D bio-mimetic scaffold model from CT image data.

• 대한두개안면성형외과학회지
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• 제19권3호
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• pp.181-189
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• 2018

Background: Autogenous bone grafts have several limitations including donor-site problems and insufficient bone volume. To address these limitations, research on bone regeneration is being conducted actively. In this study, we investigate the effects of a three-dimensionally (3D) printed polycaprolactone (PCL)/tricalcium phosphate (TCP) scaffold on the osteogenic differentiation potential of adipose tissue-derived stem cells (ADSCs) and bone marrow-derived stem cells (BMSCs). Methods: We investigated the extent of osteogenic differentiation on the first and tenth day and fourth week after cell culture. Cytotoxicity of the 3D printed $PCL/{\beta}-TCP$ scaffold was evaluated by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay, prior to osteogenic differentiation analysis. ADSCs and BMSCs were divided into three groups: C, only cultured cells; M, cells cultured in the 3D printed $PCL/{\beta}-TCP$ scaffold; D, cells cultured in the 3D printed $PCL/{\beta}-TCP$ scaffold with a bone differentiation medium. Alkaline phosphatase (ALP) activity assay, von Kossa staining, reverse transcription-polymerase chain reaction (RT-PCR), and Western blotting were performed for comparative analysis. Results: ALP assay and von Kossa staining revealed that group M had higher levels of osteogenic differentiation compared to group C. RT-PCR showed that gene expression was higher in group M than in group C, indicating that, compared to group C, osteogenic differentiation was more extensive in group M. Expression levels of proteins involved in ossification were higher in group M, as per the Western blotting results. Conclusion: Osteogenic differentiation was increased in mesenchymal stromal cells (MSCs) cultured in the 3D printed PCL/TCP scaffold compared to the control group. Osteogenic differentiation activity of MSCs cultured in the 3D printed PCL/TCP scaffold was lower than that of cells cultured on the scaffold in bone differentiation medium. Collectively, these results indicate that the 3D printed PCL/TCP scaffold promoted osteogenic differentiation of MSCs and may be widely used for bone tissue engineering.

• 반도체디스플레이기술학회지
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• 제19권3호
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• pp.77-81
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• 2020

In this paper, we create scaffold defect classification models using machine learning based data. We extract the characteristic from collected scaffold external images using USB camera. SVM, KNN, MLP algorithm of machine learning was using extracted features. Classification models of three type learned using train dataset. We created scaffold defect classification models using test dataset. We quantified the performance of defect classification models. We have confirmed that the SVM accuracy is 95%. So the best performance model is using SVM.

• 대한의용생체공학회:의공학회지
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• 제39권1호
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• pp.22-29
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• 2018

Intervertebral disc(IVD) mainly consists of Annulus fibrosus(AF) and Nucleus pulposus(NP), playing a role of distributing a mechanical load on vertebral body. IVD tissue engineering has been developed the methods to achieve anatomic morphology and restoration of biological function. The goal of present study is to identify the possibilities for creating a substitute of IVD the morphology and biological functions are the same as undamaged complete IVD. To fabricate the AF and NP combine biphasic IVD tissue, AF tissue scaffolds have been printed by 3D bio-printing system with natural biomaterials and NP tissues have been prepared by scaffold-free culture system. We evaluated whether the combined structure of 3D printed AF scaffold and scaffold-free NP tissue construct could support the architecture and cell functions as IVD tissue. 3D printed AF scaffolds were printed with 60 degree angle stripe patterned lamella structure(the inner-diameter is 5mm, outer-diameter is 10 mm and height is 3 mm). In the cytotoxicity test, the 3D printed AF scaffold showed good cell compatibility. The results of histological and immunohistochemical staining also showed the newly synthesized collagens and glycosaminoglycans, which are specific makers of AF tissue. And scaffold-free NP tissue actively synthesized glycosaminoglycans and type 2 collagen, which are the major components of NP tissue. When we combined two engineered tissues to realize the IVD, combined biphasic tissues showed a good integration between the two tissues. In conclusion, this study describes the fabrication of Engineered biphasic IVD tissue by using enable techniques of tissue engineering. This fabricated biphasic tissue would be used as a model system for the study of the native IVD tissue. In the future, it may have the potential to replace the damaged IVD in the future.

• 한국정밀공학회지
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• 제31권12호
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• pp.1067-1076
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• 2014

To date, biomedical application of three-dimensional (3D) printing technology remains one of the most important research topics and business targets. A wide range of approaches have been attempted using various 3D printing systems with general materials and specific biomaterials. In this review, we provide a brief overview of the biomedical applications using 3D printing techniques, such as surgical tool, medical device, prosthesis, and tissue engineering scaffold. Compared to the other applications of 3D printed products, the scaffold fabrication should be performed with careful selection of bio-functional materials. In particular, we describe how the biomaterials can be processed into 3D printed scaffold and applied to tissue engineering area.