• 대한의용생체공학회:의공학회지
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• 제36권6호
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• pp.271-275
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• 2015

The aim of this study was to develop a multi-nozzle based bioprinting system for fabrication of three-dimensional (3D) biological structure. In this study, a thermoplastic biomaterial that has relatively high mechanical stability, polycaprolactone (PCL) was used to make the 3D structure. A multi-nozzle bioprinting system was designed to dispense thermoplastic biomaterial and hydrogel simultaneously. The system that consists of 3-axes of x-y-z motion control stage and a compartment for injection syringe control mounted on the stage has been developed. Also, it has 1-axis actuator for position change of nozzle. The controllability of the printed line width with PCL was tested as a representative performance index.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2017년도 춘계학술대회 논문집
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• pp.3-23
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• 2017

The achievement of tissue engineering can be highly depending on the capability to generate complicated, cell seeded three dimensional (3D) micro/nano-structures. So, various fabrication techniques that can be used to precisely design the architecture and topography of scaffolding materials will signify a key aspect of multi-functional tissue engineering. Previous methods for obtaining scaffolds based on top-down are often not satisfactory to produce complex micro/nano-structures due to the lack of control on scaffold architecture, porosity, and cellular interactions. However, a bioprinting method can be used to design sophisticated 3D tissue scaffolds that can be engineered to mimic the tissue architecture using computer aided approach. Also, in recent, the method has been modified and optimized to fabricate scaffolds using various natural biopolymers (collagen, alginate, and chitosan etc.). Variation of the topological structure and polymer concentration allowed tailoring the physical and biological properties of the scaffolds. In this presentation, the 3D bioprinting supplemented with a newly designed plasma treatment for attaining highly bioactive and functional scaffolds for tissue engineering applications will be introduced. Moreover, various in vivo and in vitro results will show that the fabricated scaffolds can carry out their structural and biological functionality.

• 한국수정란이식학회지
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• 제28권3호
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• pp.273-280
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• 2013

The aim of this study was to establish a three dimensional (3D) culture system of endometrial cells and to examine the plasminogen activators (PAs) activity in porcine uterine. The 3D culture system in porcine endometrial cells was composed to mixture 3D gel, stromal cells and epithelial cells. The 3D culture system was used to identify normal structure search as uterine tissue and PAs expression in this study. In results, porcine endometrium epithelial cells forming a top monolayer and endometrium stromal cells developed as fibroblast-like within 3D matrix scaffold. Expression of urokinase-type PA (uPA) and tissue-type PA (tPA) were observed during the 3D culture using immunofluorescence. PA activity in 3D-cultured endometrial cells was no significant difference between the tissue type, but 2D culture system were significantly lower than in 3D-cultured endometrial cells (P<0.05). Therefore, basic system and functional aspect of 3D culture could be established with similar system of endometrium tissue. We suggest that this study was assumed applicable as baseline data to investigate mechanism between porcine uterus cells in vitro.

• 한국기계가공학회지
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• 제20권10호
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• pp.38-43
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• 2021

Photocurable hydrogels are widely used as 3D printing materials in tissue engineering (e.g., scaffold fabrication) as well as optical fibers (or optical sensors) materials. Photocurable hydrogels can control optical and mechanical properties such as chemical or fabrication conditions. In previous research, we introduced a new 3D printing method to fabricate a freestanding overhanging hydrogel structure without supporting structure. This study was measured and analyzed the difference of the mechanical properties of the photocurable hydrogel according to the light intensity using a micro tensile tester. In practically, it was difficult to perform a direct tensile test on a micro (less than 1 mm) size fiber. In this study, the tensile test of the hydrogel fibers could be measured simply and repeatedly using a paper carrier.

• Bulletin of the Korean Chemical Society
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• 제33권7호
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• pp.2295-2298
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• 2012

We describe herein a three-dimensionally diverse micropatterning of poly(lactic acid), as a biopolymer, using 1-butyl-3-methylimidazolium-based room-temperature ionic liquids (bmim-based RTILs), [bmim]X (X = $SbF_6$, $PF_6$, $NTf_2$, Cl). Utilizing the hydrophobic bmim-based RTILs, [bmim]X (X = $SbF_6$, $PF_6$, $NTf_2$) and a phase separation technique, we were able to produce white and opaque membranes with a three-dimensional structure closely packed with particles ($10-50{\mu}m$ in diameter). The particlulate structure, made by the assistance of [bmim]$NTf_2$ and DCM, interestingly transformed to a fibrous structure by using a cosolvent, e.g., DCM/$CF_3CH_2OH$. When we used an increased amount of [bmim]$NTf_2$, the particles were effectively detached and macrosized ($100-500{\mu}m$ in diameter) and the oval-shaped beads were obtained in a powder form. By varying the counter-anion type of the imidazolium-based RTIL, for example from $NTf_2^-$ to $Cl^-$, the particulate 3D-morphology was once more transformed to a porous structure. These reserch results could be potentially useful, as a method to fabricate particulate scaffolds, fibrous or porous scaffolds, and beads as a biopolymer device in diverse fields including drug delivery, tissue regeneration, and biomedical engineering.

• 폴리머
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• 제35권3호
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• pp.189-195
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• 2011

조직 형성을 위한 생리학적 환경을 제공하는 새로운 생활성 지지체의 디자인은 생체재료 연구에서 중요한 분야이다. 본 연구에서는 3차원적 실크/PLGA 지지체의 물성평가를 위해 압축강도, 수분친화도, SEM 분석을 하였으며, 세포친화성 평가를 위해 RAW 264.7과 NIH/3T3의 부착, 증식 및 표현형유지와 염증반응에 미치는 영향을 조사하였다. 지지체는 용매 캐스팅/염 추출법으로 제조하였고, 압축강도, 수분친화도 면에서 실크 함량이 20 wt%에서 우수함 확인했으며, 표면의 거침도활 높여 세포부착에 긍정적인 구조임을 확인하였다. 세포친화성 분석 결과 실크함량이 20 wt%인 실크/PLGA 지지체에서 높은 초기부작도 및 증식률을 보였으며, 실크함량이 20 wt%에서 염증반응이 눈에 띄게 감소함을 확인하였다. 조직공학적 응용에 실크/PLGA 지지체가 유용할 것이라 판단하였다.

• Bulletin of the Korean Chemical Society
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• 제35권2호
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• pp.562-568
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• 2014

In this work, synthesis, characterization and antimicrobial activity of series of imidazolines-oxazolines scaffolds 5a-f and 10a-d have been investigated. All the imidazolines-oxazolines derivatives were prepared from acid derivatives 1 and 6a-c, and enantiomerically pure (S)-2-amino-3-methyl-1-butanol in four steps with excellent optical purity. The structures of all newly synthesized compounds have been elucidated by $^1H$, $^{13}C$ NMR, GCMS, and IR spectrometry. Their purity was confirmed using elemental analysis. Some newly synthesized compounds were examined to in-vitro antimicrobial activity. Among the prepared products 10d was found to exhibits the most active against all tested bacteria and fungi with minimal inhibitory concentration (MIC) ranged between 21.9 and $42.6{\mu}g/mL$.

• Bulletin of the Korean Chemical Society
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• 제34권4호
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• pp.1212-1220
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• 2013

The human coagulation factor XI (FXI) is a serine protease that plays a significant role in blocking of the blood coagulation cascade as an attractive antithrombotic target. Selective inhibition of FXIa (an activated form of factor XI) disrupts the intrinsic coagulation pathway without affecting the extrinsic pathway or other coagulation factors such as FXa, FIIa, FVIIa. Furthermore, targeting the FXIa might significantly reduce the bleeding side effects and improve the safety index. This paper reports on a docking-based three dimensional quantitative structure activity relationship (3D-QSAR) study of the potent FXIa inhibitors, the chloro-phenyl tetrazole scaffold series, using comparative molecular field analysis (CoMFA) and comparative molecular similarity analysis (CoMSIA) methods. Due to the characterization of FXIa binding site, we classified the alignment of the known FXIa inhibitors into two groups according to the docked pose: S1-S2-S4 and S1-S1'-S2'. Consequently, highly predictive 3D-QSAR models of our result will provide insight for designing new potent FXIa inhibitors.

• Steel and Composite Structures
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• 제43권1호
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• pp.91-106
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• 2022

This paper has focused on presenting a three dimensional theory of elasticity for free vibration of 3D-graphene foam reinforced polymer matrix composites (GrF-PMC) cylindrical panels resting on two-parameter elastic foundations. The elastic foundation is considered as a Pasternak model with adding a Shear layer to the Winkler model. The porous graphene foams possessing 3D scaffold structures have been introduced into polymers for enhancing the overall stiffness of the composite structure. Also, 3D graphene foams can distribute uniformly or non-uniformly in the shell thickness direction. The effective Young's modulus, mass density and Poisson's ratio are predicted by the rule of mixture. Three complicated equations of motion for the panel under consideration are semi-analytically solved by using 2-D differential quadrature method. The fast rate of convergence and accuracy of the method are investigated through the different solved examples. Because of using two-dimensional generalized differential quadrature method, the present approach makes possible vibration analysis of cylindrical panels with two opposite axial edges simply supported and arbitrary boundary at the curved edges. It is explicated that 3D-GrF skeleton type and weight fraction can significantly affect the vibrational characteristics of GrF-PMC panel resting on two-parameter elastic foundations.

• Journal of Periodontal and Implant Science
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• 제53권1호
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• pp.20-37
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• 2023

Purpose: Our pilot study showed that a 3-dimensional dual drug delivery scaffold (DDDS) loaded with Chinese herbs significantly increased the regenerated bone volume fraction. This study aimed to confirm the synergistic anti-inflammatory and osteogenic preclinical effects of this system. Methods: The targets and pathways of parthenolide and naringin were predicted. Three cell models were used to assess the anti-inflammatory effects of parthenolide and the osteogenic effects of naringin. First, the distance between the cementoenamel junction and alveolar bone crest (CEJ-ABC) and the bone mineral density (BMD) of surgical defects were measured in a rat model of periodontitis with periodontal fenestration defects. Additionally, the mRNA expression levels of matrix metallopeptidase 9 (MMP9) and alkaline phosphatase (ALP) were measured. Furthermore, the number of inflammatory cells and osteoclasts, as well as the protein expression levels of tumor necrosis factor-alpha (TNF-α) and levels of ALP were determined. Results: Target prediction suggested prostaglandin peroxidase synthase (PTGS2) as a potential target of parthenolide, while cytochrome P450 family 19 subfamily A1 (CYP19A1) and taste 2 receptor member 31 (TAS2R31) were potential targets of naringin. Parthenolide mainly targeted inflammation-related pathways, while naringin participated in steroid hormone synthesis and taste transduction. In vitro experiments revealed significant antiinflammatory effects of parthenolide on RAW264.7 cells, and significant osteogenic effects of naringin on bone marrow mesenchymal stem cells and MC3T3-E1 cells. DDDS loaded with parthenolide and naringin decreased the CEJ-ABC distance and increased BMD and ALP levels in a time-dependent manner. Inflammation was significantly alleviated after 14 days of DDDS treatment. Additionally, after 56 days, the DDDS group exhibited the highest BMD and ALP levels. Conclusions: DDDS loaded with parthenolide and naringin in a rat model achieved significant synergistic anti-inflammatory and osteogenic effects, providing powerful preclinical evidence.