• Title/Summary/Keyword: 금 나노입자

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Influence of gas flow on structural and optical properties of ZnO submicron particles grown on Au nano thin films by vapor phase transport (가스 유입량이 기상이동법으로 금 나노박막위에 성장된 산화아연 입자에 미치는 영향)

  • Kim, So-A-Ram;Nam, Gi-Ung;Kim, Min-Su;Park, Hyeong-Gil;Yun, Hyeon-Sik;Im, Jae-Yeong
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2012.05a
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    • pp.211-212
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    • 2012
  • ZnO submicron particles were grown on Au-catalyzed Si substrate by a vapor phase transport (VPT) growth process under different mixture gas ratio at growth temperature of $900^{\circ}C$. The structural and optical properties of the ZnO submicron particles were investigated by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and photoluminescence (PL). The ZnO submicron particles could be clustered with the $O_2/Ar$ mixture gas ratio(%) higher than 10%, and it was mainly determined by the gas ambient. Particularly, when the $O_2/Ar$ mixture gas ratio was 30%, it was observed the ZnO submicron particles with diameters in the range of 125 to 500 nm and the narrowest full width at half maximum (FWHM) of XRD and PL spectra with $0.121^{\circ}$ and 92 meV, respectively. It was found that the structural and optical properties of the ZnO submicron particles were improved with increasing the $O_2/Ar$ mixture gas ratio through the XRD and PL spectra.

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Capacitance Enhancement and Evaluation of Gold-Deposited Carbon Nanotube Film Ion-Selective Electrode (금 입자 증착된 탄소나노튜브의 커패시턴스 증가 및 박막형 이온 선택성 전극으로서의 특성 평가)

  • Do Youn Kim;Hanbyeol Son;Hyo-Ryoung Lim
    • Journal of Powder Materials
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    • v.30 no.4
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    • pp.310-317
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    • 2023
  • Small-film-type ion sensors are garnering considerable interest in the fields of wearable healthcare and home-based monitoring systems. The performance of these sensors primarily relies on electrode capacitance, often employing nanocomposite materials composed of nano- and sub-micrometer particles. Traditional techniques for enhancing capacitance involve the creation of nanoparticles on film electrodes, which require cost-intensive and complex chemical synthesis processes, followed by additional coating optimization. In this study, we introduce a simple one-step electrochemical method for fabricating gold nanoparticles on a carbon nanotube (Au NP-CNT) electrode surface through cyclic voltammetry deposition. Furthermore, we assess the improvement in capacitance by distinguishing between the electrical double-layer capacitance and diffusion-controlled capacitance, thereby clarifying the principles underpinning the material design. The Au NP-CNT electrode maintains its stability and sensitivity for up to 50 d, signifying its potential for advanced ion sensing. Additionally, integration with a mobile wireless data system highlights the versatility of the sensor for health applications.

Synthesis of Osmium Redox Complex and Its Application for Biosensor Using an Electrochemical Method (오스뮴 착물 합성과 전기화학적인 방법을 이용한 바이오센서에 관한 연구)

  • Choi, Young-Bong;Kim, Hyug-Han
    • Journal of the Korean Electrochemical Society
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    • v.10 no.2
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    • pp.150-154
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    • 2007
  • Redox complexes to transport electrodes from biomaterial to electrodes are very important part in commercial biosensor industry. A novel osmium redox complex was synthesized by the coordinating pyridine group with osmium metal. A novel osmium complex is described as $[Os(dme-bpy)_2(ap-im)Cl]^{+/2+}$. We have been studied the electrochemical characteristics of this osmium complex with electrochemical techniques such as cyclic voltammetry and chronoamperommetry. In order to immobilize osmium redox complexes on the electrode, we deposited gold nano-particles on screen printed carbon electrode(SPE). The electrical signal converts the osmium redox films into an electrocatalyst for glucose oxidation. The catalytic currents were monitored that the catalytic currents were linearly increased from 1 mM to 5 mM concentrations of glucose.

Synthesis and Surface Properties of Hierarchical SiO2 Coating Layers by Forming Au Nanoparticles (금 나노입자 형성을 이용한 계층구조 SiO2 코팅층의 제조 및 표면 특성)

  • Kim, Ji Yeong;Kim, Eun-Kyeong;Kim, Sang Sub
    • Korean Journal of Materials Research
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    • v.23 no.1
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    • pp.53-58
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    • 2013
  • Superhydrophobic $SiO_2$ layers with a micro-nano hierarchical surface structure were prepared. $SiO_2$ layers deposited via an electrospray method combined with a sol-gel chemical route were rough on the microscale. Au particles were decorated on the surface of the microscale-rough $SiO_2$ layers by use of the photo-reduction process with different intensities ($0.11-1.9mW/cm^2$) and illumination times (60-240 sec) of ultraviolet light. With the aid of nanoscale Au nanoparticles, this consequently resulted in a micro-nano hierarchical surface structure. Subsequent fluorination treatment with a solution containing trichloro(1H,2H,2H,2H-perfluorooctyl)silane fluorinated the hierarchical $SiO_2$ layers. The change in surface roughness factor was in good agreement with that observed for the water contact angle, where the surface roughness factor developed as a measure needed to evaluate the degree of surface roughness. The resulting $SiO_2$ layers revealed excellent repellency toward various liquid droplets with different surface tensions ranging from 46 to 72.3 mN/m. Especially, the micro-nano hierarchical surface created at an illumination intensity of $0.11mW/cm^2$ and illumination time of 60 sec showed the largest water contact angle of $170^{\circ}$. Based on the Cassie-Baxter and Young-Dupre equations, the surface fraction and work of adhesion for the micronano hierarchical $SiO_2$ layers were evaluated. The work of adhesion was estimated to be less than $3{\times}10^{-3}N/m$ for all the liquid droplets. This exceptionally small work of adhesion is likely to be responsible for the strong repellency of the liquids to the micro-nano hierarchical $SiO_2$ layers.

Synthesis of 125I-Labeled Gold Nanoparticles for a Molecular Imaging (분자영상용 방사성 금 나노입자 합성)

  • Son, Min Ju;Rho, Jong Kook;Lee, Joo-Sang;Jang, Beom-Su;Park, Sang Hyun
    • Journal of Radiation Industry
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    • v.6 no.2
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    • pp.139-145
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    • 2012
  • Gold nanoparticles (GNPs) have led to the development of a new field in the diagnosis and treatment of diseases such as cancer. An efficient synthesis of gold nanoparticles within the range of 8~57 nm was established by ${\gamma}-ray$ irradiation. The good point of a radiation-based method is the production of gold nanoparticles with a higher concentration and narrower size distribution compared with conventional methods. The size of gold nanoparticles was controlled using two methods. : (i) varying the ${\gamma}-ray$ irradiation dose of 10 to 25 kGy and (ii) varying the concentration of $HAuCl_4$ solution from 4 to 40 mM. In addition, the GNPs were radiolabeled using $[^{125}I]NaI$ in a simple and fast manner with high yields. The produced gold nanoparticles were characterized using a transmission electron microscopy (TEM), a UV-visible spectrophotometer, and a radio-TLC imaging scanner. From these results, these radiolabeled GNPs can be applicable for a radioisotope tag of biomolecules.

Fabrication and Characterization of Enzyme Electrode for Lactate Fuel Cell (젖산 연료전지용 효소전극 제작 및 특성 분석)

  • Zhang, YanQing;Kim, Chang-Joon
    • Korean Chemical Engineering Research
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    • v.59 no.3
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    • pp.373-378
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    • 2021
  • The study aimed to develop a high-power enzymatic electrode for a wearable fuel cell that generates electricity utilizing lactate present in a sweat as fuel. Anode was fabricated by immobilizing lactate oxidase (LOx) on flexible carbon paper. As the lactate concentration in the electrolyte solution increased, the amount of current generated by catalysis of lactate oxidase increased. The immobilized LOx generated 1.5-times greater oxidation current density in the presence of gold nanoparticles than carbon paper only. Bilirubin oxidase (BOD)-immobilized cathode generated a larger amount of reduction current in the electrolyte saturated with oxygen than purged with nitrogen. A fuel cell composed of two electrodes was fabricated and cell voltage was measured under different discharge current. At the discharge current density of 66.7 ㎂/cm2, the cell voltage was 0.5±0.0 V leading to maximum cell power density of 33.8±2.5 ㎼/cm2.

Development of Voltammetric Nanobio-incorporated Analytical Method for Protein Biomarker Specific to Early Diagnosis of Lung Cancer (폐암 조기 진단을 위한 단백질 바이오마커 측정용 전압-전류법 기반의 나노바이오 분석법 개발)

  • Li, Jingjing;Si, Yunpei;Nde, Dieudonne Tanue;Lee, Hye Jin
    • Applied Chemistry for Engineering
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    • v.32 no.4
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    • pp.461-466
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    • 2021
  • In this article, a portable and cost-effective voltammetric biosensor with nanoparticles was developed for the measurements of heterogeneous nuclear ribonucleoprotein A1 protein (hnRNP A1) biomarker which can potentially be used for lung cancer diagnosis. Gold nanoparticles were first electrodeposited onto screen printed carbon electrode (SPCE) followed by immobilizing a single stranded DNA aptamer specific to hnRNP A1 onto the electrode surface. Ethanolamine was also used when immobilizing DNA aptamer on the surface to prevent signals from non-specific adsorption events. Sequential injection of hnRNP A1 biomarker and anti-hnRNP A1 conjugated with alkaline phosphatase (ALP) onto the aptamer chip surface allows to form the sandwich complex of DNA aptamer/hnRNP A1/ALP-anti-hnRNP A1 on the electrode surface which further reacted with 4-aminophenyl phosphate (APP). The electrocatalytic reaction of the enzyme, ALP, and the substrate, APP, resulting in the oxidative current response changes at -0.05 and -0.17 V (vs. Ag/AgCl) against the hnRNP A1 concentration was measured using cyclic and differential pulse voltammetry, respectively. The Au nanoparticles-integrated voltammetric biosensor was applied to analyze human normal serum solutions possibly suggesting potential applicability for lung cancer diagnosis.

Selective Enhancement of the Sheet Resistance of Graphene Using Dielectrophoresis (유전영동 현상을 이용한 그래핀 면저항의 선택적 향상 연구)

  • Oh, Sooyeoun;Kim, Jihyun
    • Korean Chemical Engineering Research
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    • v.55 no.2
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    • pp.253-257
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    • 2017
  • Graphene is a monolayer carbon material which consists of $sp^2$ bonding between carbon atoms. Its excellent intrinsic properties allow graphene to be used in various research fields. Many researchers believe that graphene is suitable for electronic device materials due to its high electrical conductivity and carrier mobility. Through chemical doping, n- or p-type graphene can be obtained, and consequently graphene-based devices which have more comparable structure to common semiconductor-based devices can be fabricated. In our research, we introduced the dielectrophoresis process to the chemical doping step in order to improve the effect of chemical doping of graphene selectively. Under 10 kHz and $5V_{pp}$ (peak-to-peak voltage), doping was conducted and the Au nanoparticles were effectively formed, as well as aligned along the edges of graphene. Effects of the selective chemical doping on graphene were investigated through Raman spectroscopy and the change of its electrical properties were explored. We proposed the method to enhance the doping effect in local region of a graphene layer.

Development of an Inverted Y-Shaped Strip for the Detection of Organophosphorus and Carbamate Residual Pesticides (유기인계 및 카바메이트계 농약 신속 검출을 위한 역 Y자 스트립의 개발)

  • Lee, Jeong-Eun;Kim, Sol-A;Park, Hyun-Jin;Mun, Hyoyoung;Shim, Won-Bo
    • Journal of Food Hygiene and Safety
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    • v.36 no.1
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    • pp.1-8
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    • 2021
  • The inverted Y-shaped strip detection method based on acetylcholinesterase (AChE) was developed for the rapid detection of organophosphorus and carbamate pesticides. The inactivation of AChE by organophosphorus and carbamate pesticides has been well known. The AChE catalyzes acetylthiocholine into thiocholine having (-) and (+) charges, and the (+) charge results in aggregation of gold nanoparticle (GNP). Malaoxon and carbofuran were used as standard organophosphorus and carbamate for the development of the inverted Y-shaped strip, respectively. In order to optimize the method, various angles of the Y-shaped strip, different types of nitrocellulose membrane, and concentration of AChE were tested as key parameters. The detection limit of the method was 10 ng/mL for both malaoxon and carbofuran pesticides. No cross-reaction was observed to other pesticides such as atrazine, cyanazine, simazine, bifenthrin, boscalid, metalaxyl, and chlorobenzilate. Recoveries from lettuce spiked when known concentrations of malaoxon and carbofuran were found ranging from 96.4 to 100.7% and 81 to 112.7%, respectively. This study suggests that the inverted Y-shaped strip method based on AChE may be a useful tool for the sensitive, specific, rapid detection of organophosphorus and carbamate pesticides in agricultural products.

A Study on Glucose Sensing Measured by Catalyst Containing Multiple Layers of Glucose Oxidase and Gold Nano Rod (글루코스산화효소와 금나노로드 입자의 다층막으로 구성된 촉매를 이용하여 측정한 글루코스 센싱에 대한 연구)

  • Chung, Yong-Jin;Hyun, Kyuhwan;Han, Sang Won;Min, Ji Hong;Chun, Seung-Kyu;Koh, Won-Gun;Kwon, Yongchai
    • Transactions of the Korean hydrogen and new energy society
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    • v.26 no.2
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    • pp.179-183
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    • 2015
  • In this study, we propose a catalyst structure including enzyme and metal nano rod for glucose sensing. In the catalyst structure, glucose oxidase (GOx) and gold nano rod (GNR) are alternatingly immobilized on the surface of carbon nanotube (CNT), while poly(ethyleneimine) (PEI) is inserted in between the GOx and GNR to fortify their bonding and give them opposite polarization ($[GOx/GNR]_nPEI/CNT$). To investigate the impact of $[GOx/GNR]_nPEI/CNT$ on glucose sensing, some electrochemical measurements are carried out. Initially, their optimal layer is determined by using cyclic voltammogram and as a result of that, it is proved that $[GOx/GNR/PEI]_2/CNT$ is the best layer. Its glucose sensitivity is $13.315{\mu}AmM^{-1}cm^{-2}$. When it comes to the redox reaction mechanism of flavin adenine dinucleotide (FAD) within $[GOx/GNR/PEI]_2/CNT$, (i) oxygen plays a mediator role in moving electrons and protons generated by glucose oxidation reaction to those for the reduction reaction of FAD and (ii) glucose does not affect the redox reaction of FAD. It is also recognized that the $[GOx/GNR/PEI]_3/CNT$ is limited to the surface reaction and the reaction is quasi-reversible.