• 대한기계학회논문집B
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• 제37권7호
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• pp.669-674
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• 2013

최근 생체모사 융모는 검체검사 및 신약개발 등의 분야에서 비용 및 윤리적 문제를 해결하기 위한 대안으로 부각되고 있다. 본 연구는 생체모사 융모구조 3 차원 하이드로젤 지지체의 효과적인 제작을 위한 고분자 몰드의 가공에 관한 내용을 다루고 있다. 고분자 몰드 제작을 위하여 레이저 가공 및 마이크로 드릴링 가공 프로세스를 적용한 실험이 수행되었다. 가공 프로세스 최적화를 위하여 다양한 조건에서 레이저 가공 및 마이크로 드릴링 실험을 진행하였으며, 이 때 폴리카보네이트(poly-carbonate) 고분자 몰드가 사용되었다. 전자주사현미경 및 광학현미경 관측을 통하여 고분자 몰드 및 생체모사 융모 형상을 관측하였다. 실험결과 생체모사 융모는 레이저 가공 및 마이크로 드릴링을 적용한 경우 모두 적절한 형상을 보이는 것으로 확인되었다.

• 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.

• Archives of Plastic Surgery
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• 제44권3호
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• pp.194-201
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• 2017

Background Platelet-rich plasma (PRP) contains high concentrations of growth factors involved in wound healing. Hydrogel is a 3-dimensional, hydrophilic, high-molecular, reticular substance generally used as a dressing formulation to accelerate wound healing, and also used as a bio-applicable scaffold or vehicle. This study aimed to investigate the effects of PRP and hydrogel on wound healing, in combination and separately, in an animal wound model. Methods A total of 64 wounds, with 2 wounds on the back of each nude mouse, were classified into 4 groups: a control group, a hydrogel-only group, a PRP-only group, and a combined-treatment group. All mice were assessed for changes in wound size and photographed on scheduled dates. The number of blood vessels was measured in all specimens. Immunohistochemical staining was used for the analysis of vascular endothelial growth factor (VEGF) expression. Results Differences in the decrease and change in wound size in the combined-treatment group were more significant than those in the single-treatment groups on days 3, 5, 7, and 10. Analysis of the number of blood vessels through histological examination showed a pattern of increase over time that occurred in all groups, but the combined-treatment group exhibited the greatest increase on days 7 and 14. Immunohistochemical staining showed that VEGF expression in the combined-treatment group exhibited its highest value on day 7. Conclusions This experiment demonstrated improved wound healing using a PRP-hydrogel combined treatment compared to either treatment individually, resulting in a decrease in wound size and a shortening of the healing period.

• International Journal of Industrial Entomology and Biomaterials
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• 제23권2호
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• pp.193-199
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• 2011

Silk protein and agarose are widely known as biocompatible materials in the human body. A three-dimensional (3D) scaffold composed of agarose and low-molecular- weight silk fibroin (LSF) was fabricated and examined in terms of structural characteristics and cellular responses in bone tissue engineering. This study showed that mouse pluripotent precursor cells attached to and proliferated uniformly on and within the LSF-containing 3D scaffold. Interestingly, cell proliferation and attachment was shown to be higher in a 3D scaffold containing 0.02% LSF, as compared to other LSF concentrations. The results of this study suggest that agarose-LSF scaffolds may be useful materials for tissue engineering.

• 한국임상수의학회지
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• 제32권3호
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• pp.224-230
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• 2015

본 연구는 키토산 알지네이트 수화겔을 사용하여 제작된 연골세포의 3차원 구조를 유지하며 생물학적, 생리학적인 기능을 유지하는데 적합한 poly (L-Lactic-co-${\varepsilon}$-Caprolactone) (PLCL) 지지체의 효과에 대한 연구이다. 체내에서 수화겔은 단독으로 지지체 역할을 하기에는 부하를 견디기에 약하다. 이에 본 연구에서는 연골세포와 유사한 세포, 세포외 기질의 3차원적 구성을 만들기 위해 PLCL 지지체와 수화겔을 사용하여 합성 지지체를 제작하였다. 염화나트륨을 사용한 입자 침출 기법으로 85%의 다공성, $300-500{\mu}m$ 크기의 구멍을 가진 탄성력 높은 지지체를 제작하였다. 소의 연골세포와 키토산 알지네이트 겔 혼합물이 PLCL 지지체에 적용되었고 대조군의 알지네이트와 비교 연구하였다. 키토산 알지네이트 수화겔과 연골세포가 혼합된 경우에 알지네이트 단독 사용에 비해 세포 성숙, 증식, 세포외 기질의 합성, sGAG 생성과 II 형 콜라겐의 발현 등의 효과가 좋은 것으로 확인되었다. 본 연구 결과를 통해 PLCL 지지체에 연골세포와 키토산 알지네이트 겔 혼합물을 적용할 경우 세포 증식과 기질의 합성에 적합한 환경을 만들 수 있으며 연골의 복구와 재생에 효과적으로 사용될 수 있을 것으로 기대된다.

• Journal of Industrial and Engineering Chemistry
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• 제67권
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• pp.388-395
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• 2018

Significant efforts have been applied toward fabricating three-dimensional (3D) scaffolds using 3D-bioprinting tissue engineering techniques. Gelatin has been used in 3D-bioprinting to produce designed 3D scaffolds; however, gelatin has a poor printability and is not useful for fabricating desired 3D scaffolds using 3D-bioprinting. In this study, we fabricated pore size controlled 3D gelatin scaffolds with two step 3D-bioprinting approach: a low-temperature ($-10^{\circ}C$) freezing step and a crosslinking process. The scaffold was crosslinked with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS). The pore sizes of the produced 3D gelatin scaffolds were approximately 30% smaller than the sizes of the designed pore sizes. The surface morphologies and pore sizes of the 3D gelatin scaffolds were confirmed and measured using scanning electron microscopy (SEM). Human dermal fibroblasts (HDFs) were cultured on a 3D gelatin scaffold to evaluate the effect of the 3D gelatin scaffold pore size on the cell proliferation. After 14 days of culture, HDFs proliferation throughout the 3D gelatin scaffolds prepared with more than $580{\mu}m$ pore size was approximately 14% higher than proliferation throughout the 3D gelatin scaffold prepared with a $435{\mu}m$ pore size. These results suggested that control over the 3D gelatin scaffold pore size is important for tissue engineering scaffolds.

• 대한수의학회지
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• 제58권4호
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• pp.211-217
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• 2018

Mesenchymal stem cells (MSCs) are useful candidates for tissue engineering and cell therapy. Physiological cell environment not only connects cells to each other, but also connects cells to the extracellular matrix that provide mechanical support, thus exposing the entire cell surface and activating signaling pathways. Hydrogel is a polymeric material that swells in water and maintains a distinct 3-dimensional (3D) network structure by cross linking. In this study, we investigated the optimized cellular function for canine adipose tissue-derived MSCs (cAD-MSCs) using hydrogel. We observed that the expression levels of Ki67 and proliferating cell nuclear antigen, which are involved in cell proliferation and stemness, were increased in transwell-hydrogel (3D-TN) compared to the transwell-normal (TN). Also, transforming growth factor-${\beta}1$ and SOX9, which are typical bone morphogenesis-inducing factors, were increased in 3D-TN compared to the TN. Collagen type II alpha 1, which is a chondrocyte-specific marker, was increased in 3D-TN compared to the TN. Osteocalcin, which is a osteocyte-specific marker, was increased in 3D-TN compared to the TN. Collectively, preconditioning cAD-MSCs via 3D culture systems can enhance inherent secretory properties that may improve the potency and efficacy of MSCs-based therapies for bone regeneration process.

• 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.