• 한국전기전자재료학회논문지
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• 제21권11호
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• pp.1010-1018
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• 2008

In this report, we describe the use of gold nanoparticles (AuNPs) immobilized on pH. responsive, cross-linked poly(4-vinylpyridine) (P4VP) thin films, as a potential application for pH nanosensors. The methodology is based on the variation in surface plasmon resonance of immobilized AuNPs with changing the interparticle distances, caused by the swelling/deswelling of the pH responsive P4VP polymer films. The change in optical properties of the immobilized AuNPs in response to the pH of surrounding media was investigated by a simple yet powerful tool; UV-vis absorption spectroscopy. The swelling of the P4VP chains at pH 2 causes an increase in the interparticle distances of immobilized AUNPS ($\sim20nm$) and hence leads to a blue shift of 48 nm in their surface plasmon resonance band peak. On the other hand, when the surrounding media was altered from pH 2 to 10, a red shift of absorption maxima was observed. The changes were rapid, and the effect was reversible. This system could prove to be useful in fabricating nanosensors for detecting the pH or pH changes of surrounding aqueous medium.

• 한국응용과학기술학회지
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• 제38권5호
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• pp.1325-1334
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• 2021

이 연구는 화장품에 사용가능한 촉매제를 사용하여 콜로이달 골드를 합성하는 제조법과 이를 이용한 피부 개선 효과를 가진 항노화 엠플에 응용하였다. 하이드로젠테트라클로로아우레이트테트라하이드레이트에 아스코르빅애씨드, 소듐보로하이드라이드를 환원촉매제로 사용하여 나노 콜로이드를 합성하였다. 촉매제인 아스코르빅애씨드의 함량의 질량이 증가될수록 입자가 작아지는 것을 확인하였다. 반면 소듐보로하이드라이드의 질량이 증가될수록 입자크기는 증가하는 경향을 보였다. 콜로이달 골드 반응 속도를 조절하기 위하여, 잔탄검과 하이드록시에칠셀룰로오스를 사용하여 100~500 nm의 입경분포를 가진 입자를 얻을 수 있었다. 최적의 합성조건은 18℃, 20~75 mmHg의 감압상태, 교반속도 10~50rpm, 1~4시간동안 반응하여 획득할 수 있었다. 합성된 콜로이달 골드의 외관은 진한 핑크색, pH=5.5, 비중은 1.0032, 점도는 80~310 cps로 특이한 고유 냄새를 가지고 있었다. 스킨케어 화장료의 응용으로, 안티에이징 엠플을 개발하였고, 이를 이용한 다양한 처방과 제형개발에 활용될 것으로 기대한다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.375-375
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• 2009

For many large-scale applications of high-temperature superconducting materials, large critical current density($J_c$) in high applied magnetic fields are required. A number of methods have been reported to introduce artificial pinning centers(APCs) in $YBa_2Cu_3O_{7-\delta}$(YBCO) films for enhancement of their $J_c$. We report measurements of critical current in $YBa_2Cu_3O_{7-\delta}$ films deposited by PLD on $SrTiO_3$ substrates decorated with Au nanoparticles. Au nanoparticles were synthesized on STO substrates with self assembled monolayer. Microstructural analysis of the obtained YBCO films was performed by using cross-section transmission electron microscopy(TEM). Phase and textural analysis was done using X-ray diffraction. The surface morphology and surface roughness(Ra) of the layers was measured by atomic force microscopy(AFM).

• 한국전기전자재료학회논문지
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• 제22권4호
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• pp.307-313
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• 2009

Quantitative analysis of optical scattering intensities from a Au nanoparticle with a diameter of 100 nm, which is effected by the localized surface plasmon resonance (LSPR), were numerically carried out by using a dark-field detection scheme on prism basal plane for two different beam incident modes of reflectance (R-mode) and transmittance (T-mode). Two-dimensional finite difference time domain (FDTD) algorithm was adopted, and its applicabilibility was verified by comparing the simulation results with the theoretical ones. Simulation results of the scattered light intensities from a Au nanoparticle revealed that the scattered intensity of the T-mode was much stronger than that of R-mode. Comparison of the calculated results with the theoretical intensity distribution on the prism showed that the scattered intensity is marimized when the evanescent field, which is generated from the interface of prism and air at TIR angle, is coupled with Au nanoparticle.

• 산업기술연구
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• 제38권1호
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• pp.15-19
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• 2018

In this study, hyaluronic acid (HA) was electro-spun to fabricate nanofibrous membranes for support materials. Because HA is very hygroscopic, it is difficult to obtain enough viscosity to apply electrospinning method. Therefore, we mixed HA with polyethylene oxide (PEO) to obtain proper viscosity and added adipic acid (ADH) to promote cross-linking of PEO/HA during electrospinning. The morphology of PEO/HA membrane was optimized according to PEO/HA concentration ratio and spinning rate. Finally, we fabricated gold-nanoparticle-embedded PEO/HA membranes and their catalyst activities were evaluated in tetramethylbenzidine (TMB) oxidation.

• 환경생물
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• 제28권1호
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• pp.14-19
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• 2010

신생혈관 형성은 세포의 성장 및 상처 치유 과정에서 중요한 현상이다. 그러나 성장인자의 불균형은 시각 및 면역질환과 같은 다양한 질환을 야기한다. 이러한 질환을 치료하는 방법 중 신생혈관 형성을 억제하는 것이 중요한 방법 중 하나이다. AuNPs의 기능과 기전이 신생혈관 형성에 있어서 아직 밝혀진 바가 없다. 현재 PEDF가 항신생혈관 형성 물질로 제안되고 있다. 본 연구에서 우리는 AuNPs가 BRECs에서 VEGF로 유도된 세포의 증식 및 이동, 신생혈관의 형성을 억제하였고 이는 세포의 성장과 침윤 및 전이와 관련된 신생혈관 형성을 억제한다고 사료된다.

• 환경생물
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• 제28권1호
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• pp.8-13
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• 2010

본 연구는 BRECs에서 AGEs로 유도된 세포의 이동 및 침윤에 있어서 AuNP의 역할에 관한 연구이다. 소 망막으로부터 내피세포를 분리하고, 세포 생존율은 MTT assay로 확인하였다. Wound migration assay는 BRECs의 이동력을 확인하기 위해 수행하였다. Tube formation은 on-gel system을 통해 확인하였다. AuNP의 apoptosis 유도는 caspase-3 assay를 통해 확인하였다. AGE-BSA은 세포증식 및 이동에 있어서 증가함을 보여주었다. 또한 AuNP는 AGE-BSA 존재 유무에 상관없이 세포의 증식, 이동, 신생혈관 형성을 억제하였고, caspase-3을 통해 apoptosis를 유도하였다. 이러한 결과, AuNP는 AGE로 유도된 신생혈관 형성 및 세포의 이동성을 억제하는 약재제로서, 당뇨성 합병증에 있어서 잠재적으로 중요한 분자가 될 것이다.

• 한국분말재료학회지
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• 제14권3호
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• pp.165-172
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• 2007

The purpose of this study was to analyze the sintering characteristics of gold and silver nanoparticles. In this study, gold and silver nanoparticles were prepared by using Inert Gas Cndensation (IGC). The sintering temperatures for gold and silver nanoparticles were $100{\sim}1000^{\circ}C\;and\'100{\sim}500^{\circ}C$, respectively. The sintering characteristics of gold and silver nanoparticles prepared by IGC were evaluated by X-ray diffraction(XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Gold and silver nanoparticles with the size of $1{\sim}100\;nm\;and\;10{\sim}100\;nm$, respectively, were obtained. The size of sintered gold and silver nanoparticles increased with an increase in the sintering temperature. XRD data showed that silver nanoparticles were similar with polycrystal single-phase.

• 한국재료학회지
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• 제13권8호
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• pp.550-554
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• 2003

Current nanogold cluster synthesized by chemical routine with 11 or 55 atoms of gold has been widely used for immuno chemistry probe as a form of nanocluster conjugated with biomolecules. It would be an undeveloped region that the 1 nm size of nanogold could be made by materials engineering processing. Therefore, objective of this study is to minimize the size of gold nanocluster as a function of operating temperature and chamber pressure in inert gas condensation (IGC) processing. Evaporation temperature was controlled by input current from 50 A to 65 A. Chamber pressure was controlled by argon gas with a range of 0.05 to 2 torr. The gold nanocluster by IGC was evaluated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The gold nanocluster for TEM analysis was directly sampled with special in-situ method during the processing. Atomic force microscopy (AFM) was used to observe 3-D nanogold layer surfaces on a slide glass for the following biomolecule conjugation step. The size of gold nanoclusters had a close relationship with the processing condition such as evaporation temperature and chamber pressure. The approximately 1 nm size of nanogold was obtained at the processing condition for 1 torr at $1124 ^{\circ}C$.

• 센서학회지
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• 제25권6호
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• pp.435-439
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• 2016

We report a novel detection technology for glycated hemoglobin (HbA1c) that is measured primarily to identify the three-month average plasma glucose concentration. In enzymatic measuring of glycated hemoglobin, the generated hydrogen peroxide was then used as a reducing agent of gold (III) for the synthesis of gold (0). Gold nanoparticles obtained from this novel approach were measured by optical and piezoelectric methods. In optical method, we have developed polymer based film-type sensor cartridge filled with all the reagents for glycated hemoglobin analysis and the cartridge worked very well having the detection limit of 0.53% of glycated hemoglobin. On the other hand, quartz crystal microbalance (QCM) sensors also have been developed to determine the abilities of surface modified QCM sensors at various levels of the concentration of glycated hemoglobin to bind gold nanoparticles and limit of detection was 0.90%. Finally, despite of relatively lower sensitivities of QCM sensor and film-type optical sensor than well-plate based optical detection, these two sensors were available to measure the glycated hemoglobin level for diabetes patients and normal person.