• Journal of Microbiology and Biotechnology
• /
• 제22권12호
• /
• pp.1782-1789
• /
• 2012

We have developed a novel type of polymer nanogel loaded with anticancer drug based on bio-derived poly(${\gamma}$-glutamic acid) (${\gamma}$-PGA). ${\gamma}$-PGA is a highly anionic polymer that is synthesized naturally by microbial species, most prominently in various bacilli, and has been shown to have excellent biocompatibility. Thiolated ${\gamma}$-PGA was synthesized by covalent coupling between the carboxyl groups of ${\gamma}$-PGA and the primary amine group of cysteamine. Doxorubicin (Dox)-loaded ${\gamma}$-PGA nanogels were fabricated using the following steps: (1) an ionic nanocomplex was formed between thiolated ${\gamma}$-PGA as the negative charge component, and Dox as the positive charge component; (2) addition of poly(ethylene glycol) (PEG) induced hydrogen-bond interactions between thiol groups of thiolated ${\gamma}$-PGA and hydroxyl groups of PEG, resulting in the nanocomplex; and (3) disulfide crosslinked ${\gamma}$-PGA nanogels were fabricated by ultrasonication. The average size and surface charge of Dox-loaded disulfide cross-linked ${\gamma}$-PGA nanogels in aqueous solution were $136.3{\pm}37.6$ nm and $-32.5{\pm}5.3$ mV, respectively. The loading amount of Dox was approximately 38.7 ${\mu}g$ per mg of ${\gamma}$-PGA nanogel. The Dox-loaded disulfide cross-linked ${\gamma}$-PGA nanogels showed controlled drug release behavior in the presence of reducing agents, glutathione (GSH) (1-10 mM). Through fluorescence microscopy and FACS, the cellular uptake of ${\gamma}$-PGA nanogels into breast cancer cells (MCF-7) was analyzed. The cytotoxic effect was evaluated using the MTT assay and was determined to be dependent on both the concentration and treatment time of ${\gamma}$-PGA nanogels. The bio-derived ${\gamma}$-PGA nanogels are expected to be a well-designed delivery carrier for controlled drug delivery applications.

• Fisheries and Aquatic Sciences
• /
• 제23권3호
• /
• pp.6.1-6.9
• /
• 2020

Background: Halophyte plant (HPs), a salt-resistant flora, has been reported to provide several health benefits, but the knowledge of its cosmeceutical potential is still ambiguous. Here, 70% ethanol extracts of 22 HPs collected from along the coast of South Korea were investigated for their potentials of antioxidant, anti-aging, and whitening properties for use as materials in novel cosmeceuticals. Methods: Antioxidant activities were determined by DPPH (1,1-diphenyl-2-pricrylhydrazyl) free radical and hydrogen peroxide scavenging assays, and skin aging-related enzyme activities (anti-elastase, anti-collagenase, anti-hyaluronidase, and anti-tyrosinase) were evaluated by using the spectrophotometric method. Results: Among the 22 HPs, we found that Ischaemum antephoroides f. coreana and Atriplex gmelinii extracts presented the strongest scavenging effects against DPPH free radical and hydrogen peroxide, respectively. Our finding additionally suggested that Salicornia europaea extract might provide a major source of anti-elastase and anti-hyaluronidase; meanwhile, Rosa rugosa extract showed the highest anti-collagenase effect. Furthermore, the highest tyrosinase inhibitory activity was possessed by Spartina anglica extract. Conclusion: These findings may suggest that halophyte plants showing biological activities may be potent inhibitors of tyrosinase, elastase, collagenase, and hyaluronidase and could be useful for application in cosmeceuticals.

• 폴리머
• /
• 제33권4호
• /
• pp.307-312
• /
• 2009

전기방사법으로 식물성 폴리페놀을 함유하는 PHBV 나노섬유를 제조하였으며, 얻어진 나노섬유의 평균직경은 340-450 nm였다. 폴리페놀의 첨가에 의해 나노섬유의 직경이 증가하였으며 폴리페놀의 첨가량도 나노섬유의 직경 변화에 영향을 미쳤다. 이는 PHBV와 폴리페놀 사이의 수소결합에 기인하는 것으로 확인되었다. 제조된 나노섬유를 이용한 ATR-FTIR 분석 결과 PHBV와 폴리페놀 사이에 수소결합이 존재하는 것을 확인할 수 있었고, XRD 분석 결과 폴리페놀의 첨가에 의해 PHBV 나노섬유의 결정성이 높아졌다. 이들 폴리페놀을 함유하는 나노섬유는 우수한 항균특성을 보였다.

• Journal of Microbiology and Biotechnology
• /
• 제31권3호
• /
• pp.464-474
• /
• 2021

Bacterial cytochrome P450 (CYP) enzymes are responsible for the hydroxylation of diverse endogenous substances with a heme molecule used as a cofactor. This study characterized two CYP154C3 proteins from Streptomyces sp. W2061 (CYP154C3-1) and Streptomyces sp. KCCM40643 (CYP154C3-2). The enzymatic activity assays of both CYPs conducted using heterologous redox partners' putidaredoxin and putidaredoxin reductase showed substrate flexibility with different steroids and exhibited interesting product formation patterns. The enzymatic characterization revealed good activity over a pH range of 7.0 to 7.8 and the optimal temperature range for activity was 30 to 37℃. The major product was the C16-hydroxylated product and the kinetic profiles and patterns of the generated hydroxylated products differed between the two enzymes. Both enzymes showed a higher affinity toward progesterone, with CYP154C3-1 demonstrating slightly higher activity than CYP154C3-2 for most of the substrates. Oxidizing agents (diacetoxyiodo) benzene (PIDA) and hydrogen peroxide (H2O2) were also utilized to actively support the redox reactions, with optimum conversion achieved at concentrations of 3 mM and 65 mM, respectively. The oxidizing agents affected the product distribution, influencing the type and selectivity of the CYP-catalyzed reaction. Additionally, CYP154C3s also catalyzed the C-C bond cleavage of steroids. Therefore, CYP154C3s may be a good candidate for the production of modified steroids for various biological uses.

• 한국수소및신에너지학회논문집
• /
• 제34권1호
• /
• pp.59-68
• /
• 2023

In this study, the performance of high-pressure fuel pumps was compared to find a high-pressure pump suitable for dimethyl ether (DME) fuel, and to establish a database of basic data on flow rates. The use of DME in compression ignition engines can reduce pollutant emissions. The cetane value of DME is higher than that of diesel fuel. The physical properties of DME are similar to liquefied gasoline gas (LPG), and when pressurized at a pressure of 6 bar or more, it changes from gas to liquid. Two types of high pressure pumps used in this study were independent injection type pump and a wobble plate type pump. Two high-pressure pumps with different injection types were compared. By measuring and comparing the performance changes of the two high-pressure pumps, a pump suitable for DME was selected and performance improvement measures were proposed. The changed experimental conditions to measure the performance change of the high pressure pump were increased in the units of 100 to 1,000 rpm and 100 rpm, and the experiment was performed at common rail pressures 300 and 400 bar. it was confirmed that the DME inside the fuel supply system remained in a liquid state through temperature sensors, pressure sensors, and pressure gauges. As a result of the experiment, it was confirmed that the flow rate discharged from the high-pressure fuel pump increased as the motor rotational speed increased, and the flow rate of the high-pressure fuel pump

• 생명과학회지
• /
• 제20권8호
• /
• pp.1235-1240
• /
• 2010

천연물들은 현재까지 합성 항산화제들을 대체하기 위하여 많은 연구가 이뤄지고 있다. 본 연구에서는 천연 항산화제로서 화장품과 바이오산업에 적용하기 위해 정금나무 열매 70% 아세톤 추출물의 항산화능을 측정하였다. 정금나무 열매의 항산화능을 확인하기 위하여 폴리페놀의 함량을 측정, 전자공여능, $ABTS{\cdot}^+$, nitric oxide, hydrogen peroxide들의 소거 측정을 분석하여 다음과 같은 결과를 얻었다. 폴리페놀의 총 함량은 55.972 mg TAE/g로 정량 되었다. 전자공여능 실험에서는 농도 의존적으로 DPPH radical 소거능이 증가 하였으며 500 ${\mu}g/ml$에서 98% 이상의 활성을 나타내어 양성 대조군인 BHA의 활성을 초과하는 것을 알 수 있었다. $ABTS{\cdot}^+$에 대한 소거활성은 500 ${\mu}g/ml$에서 66.7%의 결과로 나타났고, nitric oxide radical 소거능은 100 ${\mu}g/ml$에서 57%의 활성을 나타내었다. 또한 정금나무 열매 70% 아세톤 추출물의 hydrogen peroxide의 소거활성은 50 ${\mu}g/ml$에서 정금나무 열매 추출물은 70% 이상의 활성을 나타났으며, BHA 보다 높은 활성을 나타내었다. 천연물의 산업화 가능성에 있어 가장 중요한 것은 재료의 영속적인 수급과 적은 농도를 첨가하여도 높은 효과를 나타내는지의 여부이다. 매년 수확이 가능한 정금나무 열매를 이용한 본 연구의 결과에서 열매의 항산화능 확인 및 화장품 등 바이오산업에 천연항산화제 원료로서의 적용 가능성을 확인할 수 있었다.

• 한국결정학회지
• /
• 제17권1호
• /
• pp.10-13
• /
• 2006

Ethylenediammonium chromate, $C_2H_{10}N_2{\cdot}CrO_4$ 결정구조는 a=6.667(2), b=8.845(2), c=11.827(2) ${\AA}$, 사방정계(Orthorhombic), 공간군 $P2_12_12_1$, 공간군 번호 19이며, Z=4, V=697.4(3) ${\AA}{^3},\;Dc=1.696gcm^{-3},\;{\mu}=1.594mm^{-1}$이었다. 구조분석은 중금속법으로 풀었으며, 최소 자승법으로 정밀화하였고, 최종 신뢰도 값들은 1204개의 회절반점에 대하여 $R_1=0.0254,\;R_w=0.070,\;R_{all}=0.0255$, S=1.133이었다. 두가지 이온들의 자료들은 기존 유사물질들의 자료에 상응하였으며, Ethylenediammonium 이온은 trans 구조로써 주위의 음이온과 사이에 많은 수소결합으로 연결되어 있다.

• 한국재료학회:학술대회논문집
• /
• 한국재료학회 2011년도 춘계학술발표대회
• /
• pp.53.1-53.1
• /
• 2011

Bioactive glass powders were synthesized by hydrothermal chemical route by the use of ultrasonic energy irradiation. We used sodalime, calcium nitrate tetra hydrate and di ammonium hydrogen phosphate as the precursor material to synthesize $SiO_2$ rich bio-active glass materials. The $SiO_2$ content was varied in the precursor mixture to 60, 52 and 45 mole%. Dense compacts were obtained by microwave sintering at $1,100^{\circ}C$. Mechanical properties were characterized for the fabricated dense bioactive glasses and were found to be comparable with conventional CaO-$SiO_2$-$Na_2O$-$P_2O_5$ bioactive glass. Detailed biocompatibility evaluation of the glass composition was investigated by in-vitro culture of MG-63 cell and mesenchyme stem cell. Cell adhesion behavior was investigated for both of the cell by one cell morphology for 30, 60 and 90 minutes. Cell proliferation behavior was investigated by culturing both of the cells for 1, 3 and 7 days and was found to be excellent. Both SEM and confocal laser scanning microscopy were used for the investigation. Western blot analysis was performed to evaluate the bimolecular level interaction and extent and rate of specific protein expression. The ability to form biological apatite in physiological condition was observed with simulated body fluid (SBF). In-vivo bone formation behavior was investigated after implanting the materials inside rabbit femur for 1 and 3 month. The bone formation behavior was excellent in all the bioglass compositions, specially the composition with 60% $SiO_2$ content showed most promising trend.

• 한국임상수의학회지
• /
• 제35권2호
• /
• pp.39-45
• /
• 2018

We evaluated the effects of green tea extract (GTE) supplementation at different dilution steps on boar sperm freezing and in vitro fertilization. Sperm intracellular hydrogen peroxide ($H_2O_2$), motility, viability, acrosome integrity and morphology were determined. In addition, sperm IVF parameters (penetration and monospermy) and glutathione (GSH) levels of presumptive zygotes (PZs) were evaluated. Semen was diluted in lactose egg yolk (LEY) and cooled at $5^{\circ}C$ for 3 h (first dilution step) and then diluted in LEY with 9% glycerol and maintained at $5^{\circ}C$ for 30 min (second dilution step). Four experimental groups were compared: first and second dilution steps without GTE (control), first dilution step with GTE (Step 1), second dilution step with GTE (Step 2) and first and second dilution step with GTE (Step 1+2). The spermatozoa were frozen in nitrogen vapor. Higher sperm motility, viability and acrosome integrity after thawing were observed in Step 1, Step 2 and Step 1+2 groups compared with the control (P < 0.05). Lower $H_2O_2$ level was observed in Step 1+2 compared with control and Step 1 (P < 0.05). For IVF, matured oocytes were co-cultured with spermatozoa frozen according to the experimental groups. GSH levels of PZs were significantly higher in Step 2 and Step 1+2 than in control and Step 1 (P < 0.05) without a significant difference in IVF parameters. In conclusion, supplementation with GTE in both first and second dilution steps during the freezing process resulted in better boar sperm cryopreservation and might be beneficial for further embryo development.

• 접착 및 계면
• /
• 제20권3호
• /
• pp.110-115
• /
• 2019

그래핀으로 박리시키기 위한 한 가지 방법으로 산화그래핀이 많은 관심이 집중되고 있다. 산화그래핀의 산화그룹은 다양한 기능기와 수소결합을 시킬 수 있어 여러 응용분야에 이를 적용시키기 위한 연구가 활발히 진행되고 있다. 하지만 산화그래핀 자체만으로는 실질적으로 응용에 요구되어지는 기계적 물성을 만족시킬 수 없다. 따라서 본 연구에서는 홍합 단백질을 생체모사한 폴리도파민을 이용하여 산화그래핀과 결합시키고 액체-기체 계면에서 대면적의 복합체막을 형성 시켰다. 또한 폴리도파민-산화그래핀 복합체 박막의 모폴로지 구조도 제어하여 나노 링클 구조를 가지는 복합체 막을 얻었다. 기계적으로 우수하며 정교한 나노 구조를 형성할 수 있어 차세대 해수담수화 멤브레인 또는 탄소 복합재료에 이용될 수 있을 것으로 기대될 수 있다.