勤勞者의 職業訓練 및 그 運營實態에 關한 硏究 : 事業體內 職業訓練을 中心으로

김석배 高麗大學校 敎育大學院 1979 국내석사

Arenga pinnata 뿌리의 화학성분

박예정 서울대학교 대학원 2015 국내석사

Arenga pinnata Merr.는 야자과(Arecaceae) Arenga 속의 목본나무이며 열대지방인 남아시아와 동남아시아에 분포되어 있다. Arenga pinnata는 주로 전통 설탕을 만들거나 열매의 과즙을 음료로 사용하고, 줄기의 전분으로 biopolymer를 만드는 데 사용되어 왔다. A. pinnata는 multipurpose의 식물로 각광받고 있지만 아직까지 그 화합물에 대한 연구는 아직까지 보고된 바 없다. 본 연구에서는 A. pinnata의 뿌리를 이용해 아직까지 알려진 바 없는 A. pinnata의 구성 화합물과 그 활성을 밝히고자 하였다. 아울러 염증성 질환을 치료할 수 있는 화합물을 찾고자 lipopolysaccharide (LPS)로 염증반응을 유도한 male mouse 유래 macrophage RAW264.7 세포주를 이용하여 활성을 측정하였다. A. pinnata 뿌리의 100% 메탄올 추출물을 용매의 극성에 따라 EtOAc, n-BuOH, H2O 층으로 나누었고, 이 중 농도 의존적으로 nitric oxide (NO) 생성 억제 활성이 나타난 EtOAC층을 대상으로 silica gel column chromatography와 MPLC, HPLC 등을 사용하여 총 13종의 화합물을 분리하였다. 각각의 화합물들은 UV, IR, FAB/ESI-MS, 1H-NMR, 13C-NMR, 1H-1H COSY, HMQC, HMBC, NOESY spectra와 선광도, Circular Dichroism 등의 분광학적 데이터와 이화학적 성상을 종합하여 trans-scripusin A (1), cis-scripusin A (2), trans-scripusin B (3), trans-longusol A (4), cassigarol D (5), 4-[8-(3,5-dihydroxyphenyl)-7,8-dihydro-4-hydroxy-7-(3,4-dihydroxyphenyl)benzo[1,2;4,3']difuran-2-yl]phenol (6), 11,11”-di hydroxy-vitisin E (7), cyperusphenol A (8), (3R,8R)-5,7-dihydroxy-3-[hydroxyl(4-hydroxyphenyl)methyl]- isobenzofuran–1(3H)-one (9), trans-resveratrol (10), trans- piceatannol (11), β-hydroxypropiovanillone (12), (+)-dehydrovomifoliol (13)로 동정하였다. 화합물 1~8, 10, 11은 stilbenoid 계열, 9는 phthalide 계열, 12는 phenolic 계열, 13은 norisoprenoid 계열 물질이다. 이들 화합물 중 6, 7, 9는 천연에서 처음 분리, 보고되는 물질이고, 화합물 1~9는 야자과 식물에서, 화합물 12, 13은 Arenga 속 식물에서 처음 분리, 보고되는 물질이다. RAW264.7 세포주를 이용한 Griess assay를 시행하여 분리된 화합물들의 산화질소 생성억제 활성을 측정한 결과 화합물 2, 3, 10, 11이 용량 의존적으로 산화질소의 생성을 억제하는 것으로 나타났다.

육종용의 화학 성분

홍국현 서울대학교 대학원 2016 국내석사

육종용(Cistanche salsa)은 열당과 (Orobanchaceae)의 기생식물로 중국, 인도, 몽골 러시아 등의 건조한 사막지대에 분포되어 있다. 육종용은 보양약으로 자양강장과 보정(補精)제로써 사용되며, 요슬냉통(腰膝冷痛), 빈뇨(頻尿), 혈붕(血崩), 대하(帶下)등의 치료에 사용된다. phenylethanoid계 배당체와 iridoid계 배당체가 그 주 성분이다. 본 연구에서는 육종용의 줄기의 성분을 연구하여 그 구성 화합물과 lipopolysaccharide (LPS)로 염증반응을 유도한 male mouse 유래 macrophage RAW264.7 세포주를 이용하여 염증성 질환을 치료할 수 있는 화합물을 분리하고자 하였다. 육종용 줄기의 100% 메탄올 추출물을 사용하여 용매의 극성에 따라 CHCl3, EtOAc, n-BuOH, H2O 층으로 나누고 농도 의존적으로 nitric oxide (NO) 생성 억제 활성이 나타난 층을 대상으로 silica gel column chromatography와 MPLC, HPLC 등을 사용하여 총 10종의 화합물을 분리하였다. 각각의 화합물들은 UV, 1H-NMR, 13C-NMR, 1H-1H COSY, HMQC, HMBC 와 선광도 등의 분광학적 데이터와 이화학적 성상을 종합하여 tubuloside B (1), 2'-acetylacteoside (2), acteoside (3), isoacteoside (4), syringalide A 3'-α-L-rhamnopyranoside (5), isosyringalide 3'-α-L-rhamnopyranoside (6), cistanoside C (7) salsaside B (8), echinacoside (9) tubuloside E (10)로 동정하였다. 화합물 1-10은 phenylethanoid 계열 물질이며 이들 화합물 중 5, 6는 이 식물에서 처음 분리, 보고 되는 물질이다. 산화질소의 생성 억제 활성을 RAW264.7 세포주를 이용한 Griess assay를 시행하여 측정한 결과 총 추출물과 분획물, 분리된 화합물들이 농도 의존적으로 산화질소의 생성을 억제하였다.

니카라과의 산디니스타 혁명과 미국과의 관계

최지훈 경북대학교 교육대학원 2014 국내석사

This study intends to analyze the relationship between the Sandinist revolution in Nicaragua and the United States. More specifically, it aims to examine Sandinista's perception of and policy toward the United States and the counter revolutionary offensive of the United States against the Sandinist regime in Nicaragua. In 1979, the Sandinistas in Nicaragua succeeded in their revolution. After undergoing many difficulties during their reins of power in the 1980s, however, they but lost the presidential election in 1990. The economic growth was not achieved in Nicaragua due to the long civil war and U.S. interference in Nicaragua that continued since the National Sandinista revolution. U.S. intervention in the National Sandinista revolution was a hindering factor for the Sandinista regime to properly pursue its revolutionary policies. Thus, the establishment of Nicaraguan relations with the United States was the most significant task for the Sandinista regime to solve the success of the revolution. After their success in revolution in Nicaragua, the Sandinistas could not focus on rebuilding the nation in accordance with their wishes because of U.S. counter revolutionary policy against them. The U.S. counter revolutionary offensive influenced the Nicareguan presidential election in 1990, and the Sandinista regime that lost the election collapsed. The Nicaraguan people suffered psychological fatigue and distress because of U.S. continued threats of war and economic sanctions. As a Result, the Nicaraguans elected anti­ Sandinist candidate supported by the United States. After trial and error Daniel Ortega of the Sandinista regime became the president again in 2007, Sandinista regime reappeared. Not so as to repeat its failure in the 1980s, the Sandinista regime this time have pursued pragmatic foreign policy, in particular in its relationship with the United States. The Sandinista regime have developed a coalition with leftist governments in Latin America to stand up to the United States. At the same time, the Sandinista government in Nicaragua have tried to develop and maintain close, amicable ties with the United States.

Noninvasive visualization of enhanced transdermal delivery using skin-adhesive polymeric nanovehicles

홍성준 한양대학교 대학원 2019 국내석사

A transdermal delivery system based on skin-adhesive deformable polymeric nanovehicles (PNVs) that provides remarkably enhanced drug delivery efficiency is reported. Core-phase deformable skin-adhesive PNVs were fabricated through co-assembly of two amphiphilic triblock copolymers, poly(ethylene oxide)-b-poly(ε-caprolactone)-b-poly(ethylene oxide) (PEO-b-PCL-b-PEO) and poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO-b-PPO-b-PEO). The deformability of the PNV cores was tuned successfully, while maintaining the particle size at ~110 nm, by incorporation of PEO-b-PPO-b-PEO into the PNVs to a volume fraction of 0.3. Through an ex vivo skin penetration test, we showed that transactivator of transcription (TAT)-decorated deformable PNVs could not only exert strong adhesion to skin but also increase cellular uptake, leading to a transdermal delivery efficiency that is twice that of a hard PNV control. Moreover, noninvasive visualization of a fluorescent drug probe in the skin via confocal laser scanning microscopy analysis showed that the skin adhesiveness and deformability of the PNVs contributed directly to the enhancement of transdermal delivery.

Angular dihydropyranocoumarins from Peucedanum japonicum roots

홍민지 서울대학교 2017 국내박사

Peucedanum japonicum Thunberg, belongs to Umbelliferae family, was distributed in southern and eastern Asian countries. Its roots were traditionally used as a medicine for cold and neuralgic diseases in Korea and Taiwan. It was reported that the roots of this plant contained coumarins, chromones, polyacetylenes, sugar alcohols, and steroid glycosides. Pharmacological researches revealed that P. japonicum roots showed antioxidative, anti-inflammatory, antifungal activity and cytotoxic effect against lymphocytic leukaemia. In this study, sixteen new angular dihydropyranocoumarins (1-16) and three new angular monohydromonohydroxyfuranocoumarins (41-43) were isolated along with forty-five known compounds from the n-hexane and CHCl3 fractions of the P. japonicum roots. The known compounds were characterized as angular dihydropyranocoumarins (17-40), linear furanocoumarins (44-47), an angular dihydrofuranocoumarin (48), a linear dihydropyranocoumarin (49), simple coumarins (50-58), a chromone (59), ferulic acid derivatives (60-61), a lignan (62), a phenylpropanoid (63), and an indole alkaloid (64). Isolated angular dihydropyranocoumarins (khellactones) included monoacyl- and diacyl-type khellactone esters. In the case of monoacylkhellactones, the absolute configuration was easily determined by the Mosher method. However, the absolute configuration of diacyl khellactone esters was difficult to assign due to the absence of free hydroxyl group. Therefore, partial alkaline hydrolysis prior to MTPA derivatization and X-ray diffraction analysis were applied to determine the absolute configurations at 3’- and 4’-positions. Because the success of partial hydrolysis and single crystallization was very difficult, ECD spectroscopy was suggested to confirm the absolute configuration of most of the compounds. Interestingly, a few enantiomers were discovered and isolated by enantio-selective column. Enantiomers were usually detected and isolated using chiral column. However, RP-HPLC analysis with MTPA reaction products could be alternative method to confirm enantiomer existence without testing a number of chiral-selective columns. In the case of cis-monoacylkhellactones, the interconversion of substituents at 3’- and 4’-position was observed. The major MS fragment peak of khellactone esters was detected without a C-4’ substituent. Thus, the position of substituents at 3’ and 4’ could be determined by MS fragmentation analysis without HMBC measurement. The NO production inhibitory activity of isolated compounds were tested using Griess assay in LPS-induced RAW264.7 cells. As a result, 1, 3-6, 22, 31, and 36-38 showed significant activity without cytotoxicity. The isobutyryl, senecioyl, 2-methylbutyryl, and isovaleryl moieties at 3’ position played more important role than the acetyl and angeloyl groups. In conclusion, the absolute configuration of isolated compounds were assigned by various methods. Those methods will become useful guide to solve similar structures. The isolated compounds which significantly inhibited NO production were suggested as anti-inflammatory candidates from natural resources.

음양곽의 화학 성분과 PCSK9 발현 억제 활성

김이레 서울대학교 대학원 2021 국내박사

Epimedium (Berberidaceae) is a genus of about 52 species of herbaceous planats and mainly distributed in East, South, Central Asia and Europe. The dried aerial parts of Epimedium koreanum Nakai, Herba Epimedii, have been used as a tonic or for the treatment of dementia, hypertension, impotence, rheumatic and paralytic diseases. Previous phytochemical studies reported that lignans, phenol glycosides, and prenylated flavonoids are present as chemical constituents of this plant. Individual constituents including icariin and extracts of E. koreanum demonstrated a variety of biological activities such as anti-hepatotoxic, anti-inflammatory, anti-osteoporosis, anti-tumor and immunoadjuvant activities as well as improvement of sexual function. Proprotein convertase subtisilin/kexin type 9 (PCSK9) is involved in degrading LDLR via clathrin-dependent endocytosis and preventing LDLR recycling, and resultantly decreasing the capacity of LDL uptake into cells. Thus, high expression of PCSK9 is often associated with the incidence of hypercholesterolemia and inhibition of PCSK9 expression or activity has been suggested as a tool to treat patients with familial hypercholesterolemia. Currently, two antibody drugs are prescribed clinically since 2015. As part of our ongoing project to discover PCSK9 expression inhibitory compounds from medicinal plants, n-BuOH-soluble fraction of the aerial parts of E. koreanum was selected for further investigation due to its initial PCSK9 mRNA expression inhibitory activity. Four new acylated flavonoids (1-4) and 18 known compounds (5-22) were isolated from n-BuOH soluble fraction of E. koreanum. The structures of new compounds were elucidated by NMR, MS, and chemical method. All isolated compounds were tested for their inhibitory activities against PCSK9 mRNA expression in the HepG2 cells. Of the isolates, compounds 6, 7 and 16 were found to inhibit PCSK9 mRNA expression. In addition, compound 7 showed to increase LDLR mRNA expression. Thus, this compound 7 may merit potential to increase LDL uptake and lower cholesterol level in blood. Epimedium은 Berberidaceae과에 속하는 식물로 주로 동, 남, 중앙아시아와 유럽 등지에 분포한다. 음양곽의 지상부는 오랫동안 강장제로 사용되었으며 치매, 고혈압, 발기부전, 류마티스성과 마비성 질환에 사용되었다. 이전의 연구 결과로부터 리그난, 페놀 배당체, 프레닐 플라보노이드 등의 활성 성분이 존재함이 알려져 있다. 이러한 활성 성분들은 간세포 보호, 항염증, 항골다공증, 항종양 활성과 면역 보강 활성을 가진 것으로 알려졌다. Proprotein convertase subtisilin/kexin type 9 (PCSK9)은 clathrin-dependent endocytosis를 통해 LDLR을 분해하고 LDLR의 재활용을 방해하여 결과적으로 LDL의 세포 내 흡수를 저해시키는데 관여한다. 따라서 PCSK9의 발현의 증가는 고지혈증의 발생과 연관이 있으며 PCSK9의 발현 혹은 활성 차단은 고지혈증 환자의 치료에 사용될 수 있다. 2015년 이후로 두가지의 항체치료제가 임상적으로 처방되고 있다. 약용 식물에서 PCSK9 발현 억제 화합물을 발견하기 위한 연구의 일환으로, E. koreanum 지상부의 n-BuOH 분획이 PCSK9 mRNA 발현을 억제함을 확인하였다. 그러나 이 식물로부터 PCSK9 억제 물질에 대한 보고가 없었으므로 식물화학적 연구를 진행하였고, 이들의 PCSK9 억제 활성을 확인하였다. 음양곽 지상부를 메탄올로 초음파 추출하여 극성에 따라 n-헥산, 클로로포름, n-부탄올 분획으로 나누었다. 이 중 PCSK9 mRNA 억제 활성을 보인 n-부탄올 분획을 대상으로 여러 크로마토그래피법을 사용하여 분리를 실시, 22종의 화합물을 분리하였다. 분리된 22종의 화합물을 각종 분광학적 방법을 통해 구조를 4’-methoxy-5-hydroxy-8-3,3-dimethylallylflavone 3-O-[4-O-acetyl-α-L-rhamnopyranoside]-7-O-β-D-gluco-pyranoside (1), 4’-methoxy-5-hydroxy-8-3,3-dimethylallylflavone 3-O-[2-O-2-((4-methoxy-4-oxobutan-2-yl)oxy) acetic acid-α-L-rhamnopyranoside]-7-O-β-D-gluco-pyranoside (2), 4’-methoxy-5-hydroxy-8-3,3-dimethylallylflavone 3-O-[2-O-2-((4-oxopropan-2-yl)oxy)acetic acid methyl ester-α-L-rhamnopyranoside]-7-O-β-D-glucopyranoside (3), 4’-methoxy-5-hydroxy-8-3,3-dimethylallylflavone 3-O-[2-O-2-((4-methoxy-4-oxobutan-2-yl)oxy)acetic acid butyl ester-α-L-rhamno-pyranoside]-7-O-β-D-glucopyranoside (4), koreanoside E (5), icariside I (6), ikarisoside A (7), icariside II (8), epimedoside A (9), icariin (10), epimedin A (11), korepimedoside C (12), epimedin B (13), epimedin C (14), anhydroicaritin 3-O-β-D-fuco-pyranosyl(1→2)-α-L-rhamnopyranoside-7-O-β-D-gluco-pyranoside (15), icarisid I (16), korepimedoside A (17), epimedokoreanoside I (18), korepimeoside C (19), epimedin L (20), caohuoside B (21), epimedoicarisoside A (22) 로 동정하였으며, 이 중 화합물 1~4는 천연에서 처음 분리, 보고되는 물질이다. 분리한 22종의 화합물에 대하여 HepG2 세포에서 PCSK9 mRNA 발현 억제 활성과 LDLR mRNA 발현 증식 효과를 평가한 결과 화합물 7 (ikarisoside A)이 PCSK9 mRNA 발현을 억제함과 동시에 LDLR mRNA의 발현을 유의미하게 증식시킴이 확인되었다.

쌍극자 상호작용에 기인하여 액적 퍼콜레이션 성능을 갖는 회합형 나노에멀젼 제조에 관한 연구

신경희 한양대학교 대학원 2018 국내박사

Nanoemulsions are emulsions having the droplet size of usually 20 ~ 500 nm in which oil or water droplets are finely dispersed in the opposite phase with the help of suitable emulsifiers to stabilize the system. They can be stable (metastable) for long times due to the extremely small sizes. Moreover, their small size leads to unique properties such as high surface area per unit volume, transparent appearance and tunable rheology. Nanoemulsions also are non-toxic and non-irritant systems and they can be used for skin or mucous membranes, parenteral and oral administration. These properties make nanoemulsions an attractive candidate for applications in the food, cosmetic, pharmaceutical industries and in drug delivery applications. In particular, transdermal delivery induced by nanoemulsions undergoes with quite different manners when compared to the delivery from conventional microscale complex formulations. The main advantages of using nanoemulsoins arise from their peculiar features, such as high diffusivity, high surface energy, and tailored architectures. Despite their great potential as a delivery carrier, transdermal delivery using nanoemulsions has been limitations due to the stability problem inherent to system (i.e. thermodynamically unstable system). Therefore, my major concern for transdermal delivery using nanoemulsions was to create an initial nanoemulsion with sufficiently small droplets, and then to ensure that it has a sufficiently long kinetic stability for commercial applications. For this goal, I have been developed structurally stable nanoemulsions by engineering a robust interface and controlled interdroplet interactions. In chapter 2, we introduce a robust approach for the fabrication of extremely stable oil-in-water nanoemulsions in which the interface is stabilized by assembly of amphiphilic poly(ethylene oxide)-block-poly(ε-caprolactone) (PEO-b-PCL) copolymers. Phase inversion emulsification, induced by variation of the water volume fraction, facilitated effective assembly of the block copolymers at the oil-water interface. Subsequent application of simple probe-type sonication reduced the droplet size of the precursor emulsions to approximately 200 nm. The prepared nanoemulsions were surprisingly stable against drop coalescence and aggregation, as confirmed by analysis of changes in the droplet size after repeated freeze-thaw cycling and by monitoring the creaming kinetics under conditions of high ionic strength and density mismatch. The results highlight that good structural assembly of the PEO-b-PCL block copolymers at the oil-water interface generated a mechanically flexible but tough polymer film, thereby remarkably improving the emulsion stability. In chapter 3, we introduce an extremely stable attractive nanoscale emulsion fluid, in which the amphiphilic block copolymer, PEO-b-PCL, is tightly packed with lecithin, thereby forming a mechanically robust thin-film at the oil-water interface. The molecular association of PEO-b-PCL with lecithin is critical for formation of a tighter and denser molecular assembly at the interface, which is systematically confirmed by T2 relaxation and DSC analyses. Moreover, our suspension rheology studies also reflect the interdroplet attractions over a wide volume fraction range of the dispersed oil phase; this results in a percolated network of stable drops that exhibit no signs of coalescence or phase separation. We have figured out that this unique rheological behavior is attributed to the dipolar interaction between the phosphorylcholine groups of lecithin and the methoxy end groups of PEO-b-PCL. Finally, we demonstrate that our nanoemulsion system significantly enhances transdermal delivery efficiency due to its favorable attraction to the skin as well as high diffusivity of the nanoscale emulsion drops. In chapter 4, we introduce a useful and promising approach to fabricate extremely stable silicone nanoemulsions of which interface is structured with a thin film of amphiphilic triblock copolymers. For this, two kinds of amphiphilic triblock polymers, poly [2-(methacryloyloxy) ethyl phosphorylcholine]-block-poly (ε-caprolactone)-block-poly [2-(methacryloyloxy) ethyl phosphorylcholine] (PMPC-PCL-PMPC) and poly (2-aminoethyl methacrylate)-block-poly (ε-caprolactone)-block-poly (2-aminoethyl methacrylate) (PAMA-PCL-PAMA), were synthesized by using atom transfer radical polymerization. The use of phase inversion from a water-in-oil emulsion to an oil-in-water emulsion was critical for formation of thin polymer interfaces, of which thickness is less than 10 nm, thus eventually producing structurally stable silicone nanoemulsions. Co-assembly of PAMA-PCL-PAMA with PMPC-PCL-PMPC enabled patching of positive charges on the surface of silicone emulsion drops. We showed that these charged silicon nanoemulsions could form a multilayer emulsion thin film by the layer-by-layer deposition. Finally, we experimentally demonstrated that the silicone nanoemulsions fabricated in this way were highly stable and had the ability to electrostatically interact with hairs, which enables complete coating of the hair surface with silicone oil layer. In chapter 5, we demonstrated that our nanoemulsion system is a powerful vehicle for enhanced cutaneous delivery of luteolin. Luteolin (3',4',5,7-tetrahydroxyflavone), a type of flavonoid found in medicinal herbs and vegetables, has been of great interest due to its anti-oxidative, anti-inflammatory, and anti-carcinogenic effects. Despite these beneficial biological properties, the ease with which luteolin forms molecular crystals in conventional aqueous formulations has hampered much wider applications. In this study, the luteolin-loaded nanoemulsion, which had an average hydrodynamic size of approximately 290 nm, was produced by the assembly of PEO-b-PCL and lecithin at the O/W interface. The luteolin-loaded nanoemulsion showed outstanding stability against drop coalescence and aggregation. This was confirmed from the slight drop size increase after repeated freeze-thaw cycling and long-term storage. Moreover, in vivo hair growth evaluation demonstrated that the luteolin-loaded nanoemulsions fabricated in this study possessed remarkable hair growth-promotion activity, which is comparable with the case of using a luteolin solution in an organic solvent.

Biomimetic shell engineering of microvehicles for encapsulation of bioactive compounds

서민태 한양대학교 대학원 2019 국내박사

Biomimicry is the study of nature and natural phenomena to understand the principles of underlying mechanisms, to obtain ideas from nature, and to apply concepts that may benefit science, engineering, and medicine. Biomimicry is centered on the idea that there is no model better than nature for developing something new and has produced excellent results in productivity and function. Examples of biomimetic studies include fluid-drag reduction swimsuits inspired by the structure of shark’s skin, velcro fastener modeled on burrs, shape of airplanes developed from the look of birds, and stable building structures copied from the backbone of honeycomb. A main biomimetic biological structures is to protect the inner fruit - in particular the seeds against various environmental influences including UV radiation, water loss or mechanical damage caused by impact on the ground when the ripe fruits or seeds are shed or by animals trying to eat the seeds. Their excellent protective properties make fruit walls highly interesting as role models for the development of puncture- and impact resistant materials and components. Therefore, when a new microcapsule is developed that meets all of the above requirements, my major concern is expected that the development of a new drug carrier and drug delivery technology In chapter 2, we introduces a new type of uniform liposome-analogous vesicle with a highly stable shell structure in which water-in-oil-in-water double emulsion drops fabricated in a capillary-based microfluidic device are used as templates. The vesicles developed in this work consist of a poly(ethylene glycol) hydrogel core surrounded by a polyurethane (PU) film between 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) layers. Subjecting the double emulsion templates to UV irradiation leads to the formation of a PU elastomer film between the DPPC layers. The presence of a thin PU film sandwiched between the DPPC layers was confirmed by confocal laser microscopy. The thicknesses of the PU films were measured to be approximately ~4 m. Further study revealed the incorporation of the PU film between the DPPC layers remarkably improves the shell impermeability. Our vesicle system is expected to be useful for regulating the permeation of small molecules through lipid-based vesicular films. In chapter 3, we introduce a robust and straightforward approach to fabricate structurally stable GUVs (giant unilamellar vesicles) of which DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) bilayer membrane was made rigid by the introduction of amphiphilic block polymers. In particular, we figured out that the lateral co-assembly of an amphiphilic triblock copolymer with an aliphatic middle block and a sufficiently long molecular weight (20K g/mol) remarkably enhanced the compressive membrane modulus (Kexp) of GUVs. When the membrane composition was optimized, the Kexp of polymer-hybridized GUVs increased to 60 MPa, which approximately 20 times higher than that of DPPC GUVs, thus leading to a much longer half-life. In chapter 4. the surface of the most fruits is covered with a peel that provides protection against dehydration and nutrient oxidation. For biomimicry of the structure and function of fruit peels, we coated gelatin hydrogel microcapsules with alternate biocelluose layers consisting of a cuticle and several biocellulose layers containing wax and phenolic compounds. Dodecane nanodrops of which interface was stabilized by poly(ethylene oxide)-block-poly(-caprolactone) copolymer (PEO-b-PCL) and lecithin were incorporated into the outermost cuticle layer. We observed the presence of dodecane nanodrops in the cuticle layer softened the layer, thus preventing generation of microcracks, which is essential for minimizing dehydration in the process of drying. We also incorporate a phenolic compound, gallic acid, which is encapsulated in the micelles of PEO-b-PCL and lecithin, into the epidermis layer. Gallic acid in the mesocarp exhibit antioxidation performance against influx of oxygen that generates free radical intermediates. Finally, we demonstrated that biomimetic fabrication of the mechanically reinforced shell enhanced encapsulation of antioxidants as well as oxygen attack from the surroundings.

가역적 피커링 에멀젼 회수를 위한 자성 야누스 콜로이드 계면활성제 합성에 관한 연구

김혜리 한양대학교 대학원 2018 국내석사

피커링 에멀젼은 기존의 계면활성제가 아닌 고체 입자를 통해 안정화된 에멀젼을 말한다. 피커링 에멀젼은 기존의 에멀젼보다 더 우수한 안정성을 가지며 고체입자의 종류에 따라 다양한 특성을 가질 수 있다. 또한 무해한 고체입자를 사용하는 경우, 체내에서의 응용도 가능하다는 장점을 가지고 있다. 피커링 에멀젼을 안정화시키는 입자의 종류에는 대표적으로 Silica, clay, 그리고 야누스입자가 있다. 다양한 고체입자 덕분에 피커링 에멀젼은 화장품, 제약 분야 등에서 폭넓은 응용성을 나타내고 있다. 본 장에서는 먼저 피커링 에멀젼에 대해 소개하고, 이 후 피커링 에멀젼의 핵심인 고체입자의 wettability, 크기, 및 농도와 관련된 이론적 해석을 진행하며 마지막으로 여러 고체입자의 종류에 대해 소개한다. 본 연구에서는 양친성과 자기응답성을 가지는 야누스 콜로이드 계면활성제의 합성법을 소개하고 있다. 히드록시기를 가진 양친성 야누스 마이크로 입자는 Seeded swelling 기법과 UV 중합법을 이용하여 제조되었다. 또한 PS-co-PVA seed 내 PVA의 함량 조절을 통해 seed와 PTA 간의 계면장력(g13)을 조절하였다. 이론적 및 실험적 관찰을 통해, 우리는 물에 대한 에탄올의 volume fraction 이 0.6이면서 g13이 8.5 mN/m 일 때 두 개의 상으로 완벽히 분리된 타원형의 야누스 마이크로 입자를 얻을 수 있음을 확인하였다. 뿐만 아니라, 우리는 기능성 야누스 입자의 제조를 위해 야누스 입자의 친수성 부분을 PEI로 코팅하여 PEI와 PVP로 안정화된 자성 나노입자가 전기적으로 결합할 수 있는 반응 site를 부여하였다. 이를 통해 자성 나노입자가 위치선택적으로 patching 된 자성 야누스 입자를 제조할 수 있었다. 이렇게 제조한 자성 야누스 콜로이드 입자는 피커링 에멀젼 내에서 우수한 계면 배향력을 가지며 에멀젼에 안정성 및 자기 응답성을 부여하였다. 끝으로, 같은 방식으로 제조된Pd 나노입자가 patching 된 야누스 촉매를 자성 야누스 입자와 함께 catalytic 유기 반응에 적용시킴으로써, 고수율 및 고회수성을 가진 친환경적 green chemistry를 구현할 수 있었다. We present a straightforward and robust method for the synthesis of Janus colloid surfactants with distinct amphiphilicity and magnetic responsiveness. To this end, hydroxyl-functionalized amphiphilic Janus microparticles are synthesized by seeded monomer swelling and subsequent photo-polymerization. By incorporating controlled amounts of hydroxyl groups on poly (styrene-co-vinyl alcohol) seed particles, we adjust the interfacial tension between the seed polymer and the poly (tetradecyl acrylate) secondary polymer (g13). From theoretical and experimental observations, we verify that when g13 is tuned to ~8.5 mN/m in a medium with controlled solvency, which corresponds to the 0.6 volume fraction of ethanol in water, the particles bicompartmentalize to form oval or ellipsoidal Janus microparticles with controllable bulb dimensions. We also show that bulb site-specific patching of magnetic nanoparticles can be achieved using the electrostatic interaction between the polyethylenimine-coated bulb surface and the polyvinylpyrrolidone-stabilized Fe2O3 nanoparticles. Finally, we demonstrate that our magnetic-patchy Janus microparticles can assemble at the oil-water interface, enabling magnetic-responsive reversible recovery of Pickering emulsions.