• Journal of Microbiology and Biotechnology
• /
• v.14 no.4
• /
• pp.707-714
• /
• 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.

• Textile Coloration and Finishing
• /
• v.34 no.4
• /
• pp.284-301
• /
• 2022

The limitations of food production caused by global warming, consumption of soil fertility, and land shortage have demanded the development of alternative foods. Their market has been increasing, and in particular, there is an urgent need for an alternative meat. Among them, the non-slaughtered cell-cultured meat that can be manufactured in the laboratory, that is, cultured meat, is in the spotlight, which can solve the problem of meat consumption while including the advantages of meat. It is classified into minced cultured meat and structured one with a structure similar to that of real meat. The latter is currently facing limitations related scaffolds, cells, and the multiplicative problems, and many attempts are being made to solve them. The complex problem is related to secure texture and taste as well as structural similarity to actual meat. To solve the problems, it is necessary to lay emphasis on cells, there are fat cells and vascular cells, and the most fundamental cells, muscle cells. These are the main cells that control the texture and nutrients of meat, and unlike other cells, they grow in the form of fibers. A myofibril (also known as a muscle fibril) is a basic rod-like organelle of a muscle cell, which is a quantitatively major component of meat, and one of the tissues that maintain the appearance of the body and bones. In this review article, we focused on the growth of muscle cells into long, tubular cells known as muscle fibers using the fabricated fibrous scaffold, and reviewed not only research results for muscle tissue engineering but also various results in the related fields for the last five years.

• Journal of the Ergonomics Society of Korea
• /
• v.29 no.3
• /
• pp.347-356
• /
• 2010

The purpose of this study is to analyze the spine stability by comparing muscle activation in various scaffold working conditions. The independent working conditions were designed by two levels of working height, existence and absence of safety handrail, and the two levels of expertise. The corresponding activities of the agonist and antagonist muscles of spine were simultaneously recorded by using EMG. As results, novice worker showed increased muscle activity while doing the task on the 2nd floor, absence of handrail. And expert showed the increase of co-contraction while working on the 2nd floor without handrail. Such co-contraction was found to increase the spine stability when the working condition become risky. On the other hand, the co-contraction was prolonged, the spine muscle fatique and disc pressure could be increased, which would increase the risk of musculo-skeletal disorder. The results of co-contraction in this study indicates that the motor control system responds to maintain the stability of the spine particularly when workers cognitively recognize the danger of falling or imbalance. This study also quantitatively accounted for the biomechanical cause of LBP among workers who has to prevent themselves from falling. Therefore, if can be said that safe environment preventing falling can also prevent workers from MSDs as well. Such knowledge can be applied to design ergonomic workplace environment as well as movable scaffold.

• Polymer(Korea)
• /
• v.30 no.1
• /
• pp.14-21
• /
• 2006

Tissue engineering techniques require the use of a porous biodegradable/bioresorbable scaffold, which server as a three-dimensional template for initial cell attachment and subsequent tissue formation in both in vitro and in vivo. Small intestinal submucosa (SIS) has been investigated as a source of collagenous tissue with the potential to be used as biomaterials because of its inherent strength and biocompatibility. SIS-loaded poly(L-lactide-co-glicolide)(PLGA) scaffolds were prepared by solvent casting/particle leaching. Characterizations of SIS/PLGA scaffold were carried out by SEM, mercury porosimeter, and so on. Muscle-derived stem cells can be differentiated in culture into osteoblasts, chondrocytes, and even myoblasts by the controlling the culture environment. Cellular viability and proliferation were assayed by 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium-bromide(MTT) test. Osteogenic differential cells were analyzed by alkaline phosphatase(ALP) activity. SIS/PLGA scaffolds were implanted into the back of athymic nude mouse to observe the effect of SIS on the osteoinduction compared with controlled PLGA scaffolds. Thin sections were cut from paraffin embedded tissues and histological sections were conducted hematoxylin and eosin (H&E), Trichrome, and von Kossa. We observed that bone formatioin of SIS/PLGA hybrid scaffold as natural/synthetic scaffold was better thean that of only PLGA scaffold. It canb be explained that SIS contains various kinds of bioactive molecules for osteoinduction.

• Journal of Periodontal and Implant Science
• /
• v.28 no.4
• /
• pp.559-568
• /
• 1998

direct bone apposition during bone remodelling. To address these problem, we developed a new ceramic, calcium metaphosphate(CMP), and report herein the biologic response to CMP in subcutaneous tissue, muscle and bone. Porous CMP blocks were prepared by condensation of anhydrous $Ca(H_2PO_4)_2$ to form non-crystalline $Ca(PO_3)_2$. Macroporous scaffolds were made using a polyurethane sponge method. CMP block possesses a macroporous structure with approximate pore size range of 0.3-1mm. CMP blocks were implanted in 8mm sized calvarial defect, subcutaneous tissue and muscle of 6 Newzealand White rabbits and histologic observation were performed at 4 and 6 weeks later. CMP blocks in subcutaneous tissue and muscle were well adapted without any adverse tissue reaction and resorbed slowly and spontaneously. Histologic observation of calvarial defect at 4 and 6 weeks revealed that CMP matrix were mingled with and directly apposed to new bone without any intervention of fibrous connective tissue. CMP blocks didn't show any adverse tissue reaction and resorbed spontaneously also in calvarial defect. This result revealed that CMP had a high affinity for bone and was very biocompatible. From this preliminary result, it was suggested that CMP was a promising ceramic as a bone substitute and tissue engineering scaffold for bone formation.

• Journal of Biomedical Engineering Research
• /
• v.29 no.1
• /
• pp.52-58
• /
• 2008

The object of this study is to investigate the effects of intermittent cyclic stretching on the smooth muscle cells (SMCs) seeded onto aligned multi-layered fibrous scaffold. To make multi-layered fibrous scaffold, polyurethane (PU) and poly(ethylene oxide) (PEO) were electrospun alternatively, then were immersed into distilled water to extract PEO. Various types of scaffolds were fabricated depending on fiber directions, i.e., aligned or randomly oriented. The direction of stretching was either parallel or vertical to the fiber direction for the aligned scaffolds. The stretching was also applied to the randomly aligned scaffolds. The duration of stretching was 2 min with 15 min resting period. During the stretching, the maximum and minimum strain was adjusted to be 10 and 7%, respectively with the frequency of 1 Hz. The bioactivities of cells on the scaffolds were assessed by quantifying DNA, collagen, and glycosaminoglycan (GAG) levels. And the cell morphology was observed by staining F-actin. SMCs under parallel stretching to the fiber direction responded more positively than those in other conditions. From the results, we could explain the morphological effect of a substrate on cellular activities. In addition the synergistic effects of substrate and mechanical stimuli effects were confirmed.

• Journal of the Ergonomics Society of Korea
• /
• v.30 no.5
• /
• pp.671-681
• /
• 2011

Objective: The purpose of this study is to compare the workload level at each lower limbs posture and suggest the ergonomic workstation guideline for working period by evaluating the imbalanced lower limbs postures from the physiological and psychophysical points of view. Background: Many workers like welders are working in various imbalanced lower limbs postures either due to the narrow working conditions or other environmental conditions. Method: Ten male subjects participated in this experiment. Subjects were asked to maintain 3 different lower limbs postures(standing, squatting and bending) with 3 different working conditions(balanced floor with no scaffold, imbalanced floor with 10cm height of scaffold, and imbalanced floor with 20cm height of scaffold). EMG data for the 4 muscle groups(Retus Femoris, Vastus Lateralis, Tibialis Anterior, Gastrocnemius) from each lower limbs posture were collected for 20 seconds every 2 minutes during the 8 minutes sustaining task. Subjects were also asked to report their discomfort ratings of body parts such as waist, upper legs, lower legs, and ankle. Results: The ANOVA results showed that the EMG root mean square(RMS) values and the discomfort ratings(CR-10 Rating Scale) were significantly affected by lower limbs postures and working time(p<0.05). The correlation was analyzed between the EMG data and the discomfort ratings. Also, prediction models for the discomfort rating for each posture were developed using physical condition, working time, and scaffold height. Conclusion: We strongly recommend that one should not work more than 6 minutes in a standing or squatting postures and should not work more than 4 minutes in a bending posture. Application: The results of this study could be used to design and assess working environments and methods. Furthermore, these results could be used to suggest ergonomic guidelines for the lower limbs postures such as squatting and bending in the working fields in order to prevent fatigue and pain in the lower limbs body.

• 순환기질환의공학회:학술대회논문집
• /
• 2002.11a
• /
• pp.29-30
• /
• 2002

• Journal of Chest Surgery
• /
• v.41 no.2
• /
• pp.160-169
• /
• 2008

Bakcground: To treat anastomosis site stenosis and occlusion of the artificial vessels used in vascular surgery, tissue-engineered artificial vessels using autologous cells have been constructed. We developed artificial vessels using a polymer scaffold and autologous bone marrow cells and performed an in vivo evaluation. Material and Method: We manufactured a vascular scaffold using biodegradable PLCL (poly lactide-co-${\varepsilon}$-caprolactone) and PGA (poly glycolic acid) fibers. Then we seeded autologous bone marrow cells onto the scaffold. After implantation of the artificial vessel into the abdominal aorta, we performed an angiography 3 weeks after surgery. After the dogs were euthanized we retrieved the artificial vessels and performed histological analysis. Result: Among the six dogs, 2 dogs died of massive bleeding due to a crack in the vascular scaffold 10 days after the operation. The remaining four dogs lived for 3 weeks after the operation. In these dogs. the angiography revealed no stenosis or occlusion at 3 weeks after the operation. Gross examination revealed small thrombi on the inner surface of the vessels and the histological analysis showed three layers of vessel structure similar to the native vessel. Immunohistochemical analysis demonstrated regeneration of the endothelial and smooth muscle cell layers. Conclusion: A tissue engineered vascular graft was manufactured using a polymer scaffold and autologous bone marrow cells that had a structure similar to that of the native artery. Further research is needed to determine how to accommodate the aortic pressure.

• Journal of Biomedical Engineering Research
• /
• v.27 no.5
• /
• pp.224-228
• /
• 2006

The object of this study is to investigate the potential of dual-electrospun polymer based structure for vascular tissue engineering, especially for the medium or small sue blood vessels. Polyurethane(PU), which is known to be biocompatible in this area, was electrospun with poly(ethylene oxide) (PEO). Concentration of PU was fixed at 20wt%, while that of PEO was set from 15 to 35wt%. Morphological features were observed by SEM image and measurement of porosity and cellular responses were tested before and after extracting PEO from the hybrid scaffolds by immersing the scaffolds into distilled water. The diameter of PEO fibers were ranged from 200nm to 500nm. The lower concentration of PEO tended to show beads. The porosity of the scaffolds after extracting PEO was highly increased with higher concentration of PEO as expected. Also, higher proliferation rate of smooth muscle cells was observed at higher concentration of PEO than at the lower concentration and without PEO. As conclusions, this dual electrospinning technique combined with PU and PEO is expected to overcome the current barrier of cell penetration by providing more space for cells to proliferation.