• 대한의용생체공학회:의공학회지
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• 제36권6호
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• pp.251-263
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• 2015

Scaffolds play a crucial role in the tissue engineering. Biodegradable polymers with great processing flexibility and biocompatability are predominant scaffolding materials. New developments in biodegradable polymers and their nanocomposites for the tissue engineering are discussed. Recent development in the scaffold designs that mimic nano and micro features of the extracellular matrix (ECM) of bones, cartilages, and vascular vessels are presented as well.

• Journal of Microbiology and Biotechnology
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• 제14권4호
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• pp.707-714
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• 2004

How to improve the cell culture method on scaffolds is important in the tissue engineering fileld. In this study, we optimized seeding and culture methods to vascular smooth muscle cells (VSMCs) on biodegradable polymer scaffold. The primary culture of VSMCs obtained from canine external jugular vein was accomplished by applying the explant-derived method. The primary cultured VSMCs were seeded into scaffolds and then cultured by using various different methods; static or dynamic seeding, static or dynamic culture. The difference in proliferative response of VSMCs was analyzed with an alamar blue assay. Cell-polymer construct was examined by histochemical method and scanning electron microscopy. Mesh type scaffold ($10 \times 10 \times0.4 mm$) was made of polyglycolic acid (PGA) suture thread. The PGA mesh type scaffold was 45% in porosity, and 0.03 g in weight. The primary cultured VSMCs were confirmed with immunohistochemical staining using monoclonal anti-$\alpha$-smooth muscle actin. The density and distribution of proliferated VSMCs within the scaffold and cellular adherence on the surface of the scaffold showed better results in the static seeding condition than in the dynamic condition. Under the same condition of seeding method as the static condition, the dynamic culture condition showed enhanced proliferation rates of the VSMCs when compared to the static culture condition. In conclusion, to improve the VSMCs proliferation in vitro, static seeding is better than the dynamic condition. In the culture condition, however, culture under the dynamic status is better than the static condition. This was a pilot study to manufacture artificial vascular vessel by tissue engineering.

• 방사선산업학회지
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• 제9권4호
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• pp.171-180
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• 2015

Vascular tissue engineering has been accessed to mimic the natural composition of the blood vessel containing intima, media, and adventitia layers. We fabricated mechanically expanded PLLA/PLCL nanofibers using electrospinning and UTM. The pore size of the meshes was increased the gelatin immobilized AAc-PLLA/PLCL nanofibers ($203.30{\pm}49.62microns$) than PLLA/PLCL nanofibers ($59.99{\pm}8.66microns$) after mechanical expansion. To increase the cell adhesion and proliferation, we introduced carboxyl group, and gelatin was conjugated on them. The properties of the PLLA/PLCL nanofibers were analyzed with SEM, ATR-FTIR, TBO staining, and water contact angle measurement, general cell responses on the PLLA/PLCL nanofibers such as adhesion, proliferation, and infiltration were also investigated using smooth muscle cell (SMC). During the SMC culture, the initial viability of the cells was significantly increased on the gelatin immobilized AAc-PLLA/PLCL nanofibers, and infiltration of the cells was also enhanced on them. Therefore, gelatin immobilized AAc-PLLA/PLCL nanofibers and mechanically expanded meshes may be a good tool for vascular tissue engineering application.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.45-47
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• 2002

Although Dacron and ePTFE have most widely been used for artificial vascular grafts, these materials cannot be used for small-diameter grafts (l.D.<6mm) due to thrombotic occlusion. To overcome this limitation, a small-diameter vascular graft was developed with stem cell and tissue engineering method. Autologous bone marrow stem cells were cultured and seeded onto small-diameter (4mm) collagen tubular matrices. The matrices were anastomosed to carotid arteries in canine models. Prior to implantation, histological and electron microscopical examination revealed stem cell adhesion and growth on the matrices. Angiography indicated that the vascular grafts maintained patent for 8 weeks. Histological examination showed the regeneration of endothelium, media and adventitia in the grafts. This study may allow us to step forward to the development of tissue-engineered small-diameter vascular graft appropriate for clinical applications.

• International Journal of Stem Cells
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• 제17권1호
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• pp.15-29
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• 2024

The development and differentiation of endothelial cells (ECs) are fundamental processes with significant implications for both health and disease. ECs, which are found in all organs and blood vessels, play a crucial role in facilitating nutrient and waste exchange and maintaining proper vessel function. Understanding the intricate signaling pathways involved in EC development holds great promise for enhancing vascularization, tissue engineering, and vascular regeneration. Hematopoietic stem cells originating from hemogenic ECs, give rise to diverse immune cell populations, and the interaction between ECs and immune cells is vital for maintaining vascular integrity and regulating immune responses. Dysregulation of vascular development pathways can lead to various diseases, including cancer, where tumor-specific ECs promote tumor growth through angiogenesis. Recent advancements in single-cell genomics and in vivo genetic labeling have shed light on EC development, plasticity, and heterogeneity, uncovering tissue-specific gene expression and crucial signaling pathways. This review explores the potential of ECs in various applications, presenting novel opportunities for advancing vascular medicine and treatment strategies.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 1999년도 제3회 전자장의 생체영향에 관한 워크숍
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• pp.117-129
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• 1999

Acute effects of locally applied of static magnetic field (SMF) and extremely low frequency electromagnetic field(ELF-EMF) to the cutaneous tissue within a rabbit ear chamber (REC)were evaluated under conscious conditions. Rabbits with the REC were subjected to intravital microscopical investigation by use of microphotoelectric plethysmography(MPPG). There was no dose-response relationship between the extent of vasomotion changes and frequencies(0,20,50, 100Hz)or power levels (1, 5, 10, 25, 50, 100, 200 mT). Under low vascular tone the both fields induce vasodilatation. The effects of SMF (1 mT) on the cutaneous microcirculatory system induced the vasodilatation with enhanced vasomotion under nor-adrenaline-induced high vascular tone as well as the vasoconstriction with reduced vasomotion under acetylcholine-induced low vascular tone. This suggests that the SMF can modulate vascular tone due to the modification of vasomotion biphasically in the cutaneous tissue.

• 순환기질환의공학회:학술대회논문집
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• 순환기질환의공학회 2001년도 제1회 학술대회 초록집
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• pp.35-36
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• 2001

• International Journal of Vascular Biomedical Engineering
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• 제3권1호
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• pp.23-29
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• 2005

We developed a three dimensional cardiac tissue model based on human cardiac cell and mono-domain approximation for action potential propagation. The human myocyte model proposed by ten Tusscher et al. (TNNP model) (2004) for cell electrophysiology and a mono-domain method for electric wave propagation are used to simulate the cardiac tissue propagation mechanism using a finite element method. To delineate non-homogeneity across cardiac tissue layer, we used three types of cardiac cell models. Ansiotropic effect of action potential propagation is also considered in this study. In this 3D anisotropic cardiac tissue with three cell layers, we generated a reentrant wave using S1-S2 protocol. Computational results showed that the reentrant wave was affected by the anisotropic properties of the cells. To test the reentrant wave under pathological state, we simulated a hypertopic model with non-excitable fibroblasts in stochastic manner. Compared with normal tissue, the hypertropic tissue result showed another center of reentrant wave, indicating that the wave pattern can be more easily changed from regular with a concentric focus to irregular multi-focused reentrant waves in case of patients with hypertrophy.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.98-100
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• 2003

합성고분자(PET, ePTFE)로 제작된 기존의 혈관 패치는 혈전생성으로 인한 혈관 막힘 현상과 생체 비적합성으로 인한 석회화 현상 때문에 장기간 혈관 기능을 수행할 수 없다. 본 연구에서는 혈관조직을 형성하는 세포들로 분화가 가능한 중간엽줄기세포와 생체적합성 매트릭스를 이용하여 혈관용 패치를 개발하였다. 이식 후 3주에 관찰하였을 때 조직공학적으로 제조된 혈관 패치는 동물 임상시험에서 혈관막힘 현상 없이 혈관기능을 수행하였고 실제 혈관과 유사한 조직으로 재생되었다. 동물모델에서의 장기간 추가 보완 연구를 거친다면 본 연구에서 개발된 혈관 패치는 기존의 재료를 대체하여 많은 혈관질환 치료에 적용이 가능할 것으로 사료된다.

• International Journal of Vascular Biomedical Engineering
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• 제1권1호
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• pp.3-12
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• 2003

Ultrasonic pulsed Doppler velocimetry has become a standard international method of classifying carotid disease. Because the measured angle adjusted velocity increases as the Doppler angle increases, examinations should be performed at a convenient standard Doppler examination angle. An angle of 60 degrees is achievable throughout most examinations. Multiple Doppler viewing angles allow the acquisition of velocity vectors during the cardiac cycle, revealing the complex velocity patterns. Ultrasonic velocimetry (whether Doppler or time domain) is based on changes in the phase of the ultrasound echo. Other examinations can be done based on the echo phase. Slow motions of organs such as the brain can be used to monitor changes in edema. Measurements of tissue strain due to the pulsatile filling of the arterioles. This plethysmographic imaging method can display differences in tissue perfusion because of different tissue types and changes in autonomic activity.