• Journal of Biomedical Engineering Research
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• v.19 no.5
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• pp.441-448
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• 1998

Defined spatial localization of biomolecules on the polymer surface Is potentially powerful method to generate biocompatible surface. Photolithography and photochemistry can be used to immobilize peptides only al a given region of the surface. In this study, peptide RGDS, one of the endothelial cells recognition sites of fibronectin, was covalently immobilized on the polystyrene coated surface with micropattern. It was performed by photochemical reactivity of a synthesized N-hydroxysuccinimidyl phenyl azide. The micropatterning was confirmed by staining with fluorescent dye, aminoacetamido fluorescein. Endothelial cell adhesion was observed only on the RGDS immobilized areas.

• Proceeding of EDISON Challenge
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• 2017.03a
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• pp.703-707
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• 2017

배아줄기세포 유래 심근세포는 심근경색 등으로 심장이 제 기능을 다 하지 못할 때 치료적 목적으로 주사하여 환자의 심기능을 정상화 시키는 데에 쓰인다. 배아줄기세포 유래 심근세포는 페이스메이커 활동을 보이면서 막전압 고정상태에서도 주기적인 일과성 내향전류를 보이는 특징을 갖고 있다. 본 연구는 기존에 발표된 배아줄기세포 유래 심근세포의 시뮬레이션 모델을 이용하여 어떻게 하여 페이스메이커 활동이 나타나는지 그 기전을 밝히고자 하였다. 세포내 모든 이온을 고정하였을 때 모델 세포는 여전히 페이스메이커 활동을 보였다. 근장그물내 칼슘 이온을 고정하였을 때도 모델 세포는 페이스메이커 활동을 보였다. 그러나 Na-Ca 교환 전류를 차단하였을 때는 모델 세포의 페이스메이커 활동이 사라졌는데, 여기서 L-type $Ca^{2+}$ 전류의 칼슘 의존성 비활성화 기전을 제거하자 페이스메이커 활동이 지속되었다. 또한 Na-Ca 교환전류와 L-type $Ca^{2+}$ 전류만으로는 페이스메이커 활동이 보이지 않았으나 L-type $Ca^{2+}$ 전류의 크기를 3배로 증가시키자 페이스메이커 활동이 다시 나타남을 확인하였다. 따라서, 배아줄기세포 유래 심근세포의 페이스메이커 활동은 Na-Ca 교환전류와 L-type $Ca^{2+}$ 전류의 역할이 매우 중요하며, Na-Ca 교환전류는 L-type $Ca^{2+}$ 전류가 비활성화되지 않도록 칼슘 이온의 농도를 조절하는 데에 큰 역할을 하는 것으로 결론을 내렸다.

• Proceeding of EDISON Challenge
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• 2017.03a
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• pp.698-702
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• 2017

배아줄기세포 유래 심근세포는 심근경색 등으로 심장이 제 기능을 다 하지 못할 때 치료적 목적으로 주사하여 환자의 심기능을 정상화 시키는 데에 쓰인다. 배아줄기세포 유래 심근세포는 페이스메이커 활동을 보이면서 막전압 고정상태에서도 주기적인 일과성 내향전류를 보이는 특징을 갖고 있다. 본 연구는 기존에 발표된 배아줄기세포 유래 심근세포의 시뮬레이션 모델을 이용하여 어떻게 하여 페이스메이커 활동이 나타나는지 그 기전을 밝히고자 하였다. 세포내 모든 이온을 고정하였을 때 모델 세포는 여전히 페이스메이커 활동을 보였다. 근장그물내 칼슘 이온을 고정하였을 때도 모델 세포는 페이스메이커 활동을 보였다. 그러나 Na-Ca 교환 전류를 차단하였을 때는 모델 세포의 페이스메이커 활동이 사라졌는데, 여기서 L-type $Ca^{2+}$ 전류의 칼슘 의존성 비활성화 기전을 제거하자 페이스메이커 활동이 지속되었다. 또한 Na-Ca 교환전류와 L-type $Ca^{2+}$ 전류만으로는 페이스메이커 활동이 보이지 않았으나 L-type $Ca^{2+}$ 전류의 크기를 3배로 증가시키자 페이스메이커 활동이 다시 나타남을 확인하였다. 따라서, 배아줄기세포 유래 심근세포의 페이스메이커 활동은 Na-Ca 교환전류와 L-type $Ca^{2+}$ 전류의 역할이 매우 중요하며, Na-Ca 교환전류는 L-type $Ca^{2+}$ 전류가 비활성화되지 않도록 칼슘 이온의 농도를 조절하는 데에 큰 역할을 하는 것으로 결론을 내렸다.

• Microbiology and Biotechnology Letters
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• v.28 no.2
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• pp.117-123
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• 2000

The object of this work is to improve the maintenance of bioluminescence from stored Photobacterium phosphoreum in a view of developing continuous monitoring system for pollutants. The long-term experiments were performed to determine the effect of storage temperature and immobilization on the maintenance of bioluminescence and viability of P. phosphoreum. A naturally luminescent bacterium, P. phosphoreum was starved in 2.5% Nael solution at $20^{\circ}C$, $4^{\circ}C$, -$20^{\circ}C$ and -$70^{\circ}C$ for 30 days. In vivo luminescence was measured by luminometry, and total cell concentrations and concentrations of culturable and viable cells were determined by acridine orange staining, dilution plate counting, and direct viable counting, respectively. The bioluminescence emission from cells stored at 4De was maintained up to 10 days while those with starved cells at other temperature ranges decreased to background level within 3 days. In terms of viability of cells, concentrations of cells stored at $20^{\circ}C$ were rapidly decreased as a result of cell lysis, leading to a drop in culturable and viable counts while cells stored at $4^{\circ}C$ was shown viable but nonculturable state during starvation. With immobilized cells on strontium alginate, the bioluminescence showed higher maintenance than free cells and decreased with count number of nonculturable cells.

• Microbiology and Biotechnology Letters
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• v.28 no.3
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• pp.172-179
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• 2000

Bretlanomyces C!tstersii Hl-39 mutant was immobilized with various caniers. Immobilized mutant Hl-39 produced more ethanol and showed higher productivity and cell concentration than those of free 81-39 in 3.4% hydrolyzate of wood-chips at different temperatures ($37^{\circ}C$, $40^{\circ}C$ and $43^{\circ}C$). At $37^{\circ}C$, ethanol concentration produced by mutant H1-39 immobilized in Ca-alginate and ARG(l % Ca-alginate, 1.67% bentonite, 0.33% glutaraldehyde) bead were higher than those produced by the other earners (ACG ; 1 % CaHalginate. ] .67% celite R-634 , 0.33% glutaraldehyde, ABP ; 1 % Ca-alginate. 1.67% bentonite, 0.33% pectin. ACP: 1 % Ca-alginate, ] .67% celiLe R-634, 0.33% pecLin). The highest value of productivity(l.23 ) was obtained by using ABG beads. At $40^{\circ}C$, ethanol conccntration and productivity obtained by ABC beads ,>,"ere 15.2 glL and 0.84 gl L.h, respectively, which showed the highest value compared to other carriers. Particularly, productivity of ilmnobilized ceIl was increased up to 90% as compared to that offree cell. On the other hand, ABP(l % Ca-alginate+L67% bentonile+O.33% pectin) beads gave the best resulLs at $43^{\circ}C$ for production of ethanol and productivity, which were 13.8 g!l and 0.77 g/l h, respectively.ively.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.399-399
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• 2010

Polyethylene glycol(PEG)은 강력한 단백질 및 세포흡착 억제력을 가지고 있어 다양한 생물학적 연구에 사용되고 있으나, 기판과의 결합력이 무척 약해 기판 위에 박막을 형성하기가 매우 어렵다는 문제점이 있다. 이번 연구에서는 capacitively-coupled plasma chemical vapor deposition(CCP-CVD)를 이용하여 PEG를 유리 기판 위에 플라즈마 중합하여 plasma-polymerized PEG(PP-PEG) 기판을 만들었다. PP-PEG 박막은 FT-IR, XPS, ToF-SIMS 분석을 통하여 PEG와 매우 유사한 화학적 조성을 가지고 있음을 확인할 수 있었다. 또한 PP-PEG 기판은 photolithography 방법을 이용하여 표면에 photoresist를 패턴한 뒤 아민작용기를 가지는 plasma-polymerized ethylenediamine (PPEDA)를 증착하여 표면이 amine/PEG로 패턴화된 박막 기판을 만들었다. 패턴된 기판에 단백질 및 세포를 고정화하였을 때, 아민 작용기가 노출된 부분에만 고정화가 나타나고 PP-PEG 영역에는 단백질 및 세포의 흡착이 효율적으로 억제되는 것을 형광측정 및 ToF-SIMS chemical imaging 방법을 이용하여 확인하였다. 이러한 바이오칩 제작기술은 단백질 및 세포 칩을 포함한 여러 분야에서 폭넓게 응용될 수 있을 것으로 기대된다.

• Microbiology and Biotechnology Letters
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• v.32 no.2
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• pp.154-157
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• 2004

Immobilized cells of Aspergillus niger was employed to produce citric acid by fermentation of milk factory waste water. A. niger ATCC 9142 as a citric acid production strain was cultured for 3 days and was entrapped with Ca-alginate bead about 2.5∼3.5 mm. The optimal pH and temperature were estimated to be 3.0 and $30^{\circ}C$, respectively. Dilution rate for fermentation was calculated to be $0.025 h^{－1}$ . Maximum amount of citric acid was obtained at 4.5 g/$\ell$ with the optimized fermentation condition. The yield of citric acid produced by immobilized A. niger ATCC 9143 was 70.3%. The yield was increased by 20% with immobilized cell, compared to that of the shake flask culture. Hence, the milk factory waste water is worthy to be used for the substrate of citric acid fermentation.

• KSBB Journal
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• v.20 no.6
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• pp.447-452
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• 2005

The hydrogen production using immobilized cellsl was conducted using fruit wastewaters at various culture conditions. Three kinds of fruit wastewaters, melon, watermelon and pear were used. Sodium alginate was used as immobilization material. Among them, concentration of reducing sugar which was one of the main components in fruit was the highest at watermelon wastewater, and also hydrogen production was the highest as 2319.2 mL/L in it. Although hydrogen production was not much changed according to sodium alginate concentration, its production was the most at 3%(w/v). As bead size as small, hydrogen production was higher. With inspection of interior, it confirmed that the cell grew well in bead. But the addition of amino acids using as agent for metabolite production had almost no affected on hydrogen productivity. The effective range of $FeSO_4$ addition on hydrogen production were up to 1.2 g/L, and above the concentration, it inhibited the productivity. Organic acids produced during watermelon fermentation were mainly lactic acid, butyric acid, abd acetic acid; and a little of propionic acid.

• Korean Journal of Food Science and Technology
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• v.11 no.4
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• pp.249-257
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• 1979

Using the whole cell immobilized glucose isomerase which was prepared in the previous work (Korean J. Food Sci. & Technol., 11(3), 192 (1979), the specific activity of the immobilized enzyme was 48.1 units in the batch reaction system and 114 units in the continuous reaction system per g of matrix, respectively. In the continuous reactor the voidity was 0.36, which was suitable for the packed bed reactor. This immobilized enzyme showed a good operational stability of 115 days of half life which was sufficient for the continuous operation. The experimental result showed that 55 % of the substrate was converted to the product in the packed bed reactor. The productivity was dependent on the flow rate, column geometry, enzyme loading, and substrate concentration. An intrapaticle diffusion was observed by the effectiveness factor of 0.75 and interparticle diffusion by the decrease of Km' with increasing the superficial velocity.

• Microbiology and Biotechnology Letters
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• v.18 no.5
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• pp.525-529
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• 1990

Plant cell cultures of Lithospermum erythrorhizon were performed in stirred tank and packed-bed reactors with in situ extraction by n-hexadecane. The specific shikonin production and volumetric shikonin productivity of stirred tank reactor reached 1.5 mg shikoninlg cell and 400$\mu g$ shikonin/(L.day), respectively. In packed-bed reactor with calcium alginate-immobilized cells specific shikonin production and volumetric productivity reached 2.0 mg shikoninlg cell and 2857$\mu g$ shikonin/(L.day), which were 1.3 and 7.1 times higher than those of stirred tank reactor, respectively. The higher shikonin production and productivity of packed-bed reactor seemed to be due to high cell loading capacity of calcium alginate immobilized cells in packed-bed reactor and improved cell-cell contact.