• 한국재료학회:학술대회논문집
• /
• 한국재료학회 2009년도 춘계학술발표대회
• /
• pp.14.1-14.1
• /
• 2009

We found a high yield synthetic route to organic-soluble metal nanoparticles in the concentrated organic phase. The organic phase contains metal salt, amines, fatty acids, nonpolar solvent, and reducing agent. Even using only generic chemicals, organic-soluble silver and copper nanoparticles could be easily obtained by this simple and rapid reaction scheme at large scale. The hydrocarbon-protected metal nanoparticles showed excellent dispersion properties and were successfully printed onto polymer substrates. The printed pattern was heated at $200^{\circ}C$, which showed very low specific electrical resistance (< 10 uOhm$\cdot$cm), sufficient for conducting line of various printable devices.

• BMB Reports
• /
• 제55권3호
• /
• pp.111-112
• /
• 2022

We visualized the distribution of heterochromatin in a single nucleus using plasmonic nanoparticle-conjugated H3K9me3 and H3K27me3 antibodies. Due to distance-dependent plasmonic coupling effects between nanoprobes, their scattering spectra shift to longer wavelengths as the distance between heterochromatin histone markers reduced during oncogene-induced senescence (OIS). These observations were supported by simulating scattering profiles based on considerations of particle numbers, interparticle distances, and the spatial arrangements of plasmonic nanoprobes. Using this plasmon-based colourimetric imaging, we estimated changes in distances between H3K9me3 and H3K27me3 during the formation of senescence-associated heterochromatin foci in OIS cells. We anticipate that the devised analytical technique combined with high-spatial imaging and spectral simulation will eventually lead to a new means of diagnosing and monitoring disease progression and cellular senescence.

• 한국식품과학회지
• /
• 제46권3호
• /
• pp.347-351
• /
• 2014

키토산 바이오폴리머를 활용한 은나노 입자의 효과적인 녹색합성을 수행하였으며 얻어진 키토산-은나노 복합물질의 물리화학적 특성을 분석하고 키토산-은나노 복합필름을 제조, 이들의 항균성을 평가하였다. UV-Visible 흡수 spectrum과 TEM 분석을 통해 키토산 내 은나노 입자가 안정적으로 생성, 분포하고 있음을 확인하였고 키토산 및 질산은의 농도 그리고 반응시간의 변화에 따른 키토산 내 은나노 생성 특성을 조사하였다. 녹색합성된 키토산-은나노 복합물질로부터 EDS 분석 결과 0.9-8.9% 범위의 은나노를 함유한 키토산-은나노 복합필름이 얻어졌으며 FTIR 분석에 의해 은나노 합성과정에서 키토산의 활성아민기와 소량의 히드록시기가 은나노 환원반응에 참여함으로써 키토산이 은나노 입자의 합성을 위한 환원제 및 안정제로 작용하였음을 확인할 수 있었다. 이들 복합필름의 항균정성 평가 결과 순수 키토산 대조군 필름에서는 E. coli에 대한 항균성이 나타나지 않은 반면 키토산-은나노 필름에서는 뚜렷한 항균성을 보였으며 함유된 은의 농도 증가에 따라 항균력 또한 증가하였다. 본 연구결과를 통해 친환경 항균소재로서 녹색합성법에 의해 제조된 키토산-은나노 복합물질을 기능성 포장소재로 응용 가능함을 확인하였으며 향후 포장소재로서 요구되는 수분 및 가스차단성, 식품 내용물과의 반응성, 접촉안전성 및 안정성 등과 같은 다양한 요소의 체계적 연구가 뒤따라야 할 것으로 판단되며 복합필름의 연성, 강성, 내냉 내열성 등 식품포장필름 적용을 위한 지속적인 연구가 수행될 것이다.

• 한국재료학회지
• /
• 제17권9호
• /
• pp.453-457
• /
• 2007

Interest in use of ink-jet printing for pattern-on-demand fabrication of metal interconnects without complicated and wasteful etching process has been on rapid increase. However, ink-jet printing is a wet process and needs an additional thermal treatment such as an annealing process. Since a metal ink is a suspension containing metal nanoparticles and organic capping molecules to prevent aggregation of them, the microstructure of an ink-jet printed metal interconnect 'as dried' can be characterized as a stack of loosely packed nanoparticles. Therefore, during being treated thermally, an inkjet-printed interconnect is likely to evolve a characteristic microstructure, different from that of the conventionally vacuum-deposited metal films. Microstructure characteristics can significantly affect the corresponding electrical and mechanical properties. The characteristics of change in microstructure and electrical resistivity of inkjet-printed silver (Ag) films when annealed isothermally at a temperature between 170 and $240^{\circ}C$ were analyzed. The change in electrical resistivity was described using the first-order exponential decay kinetics. The corresponding activation energy of 0.44 eV was explained in terms of a thermally-activated mechanism, i.e., migration of point defects such as vacancy-oxygen pairs, rather than microstructure evolution such as grain growth or change in porosity.

• Mycobiology
• /
• 제48권5호
• /
• pp.383-391
• /
• 2020

Use of nanoparticles (NPs) in several commercial products has led to emergence of novel contaminants of air, soil and water bodies. The NPs may exhibit greater ecotoxicity due to nano-scale dependent properties over their bulk counterparts. The present investigation explores the effect of in vitro supplementation of TiO₂, silica and silver NPs on radial growth and ultrastructural changes in the hyphae and spores of two mushroom genera, Ganoderma lucidum and Volvariella volvaceae. A concentration dependent decrease in radial growth on NP amended potato dextrose agar medium was recorded. However, in comparison to control, there was decrease in radial diameter on supplementation with TiO₂ NPs while an increase was recorded for silica and silver NPs amendments as compared to their bulk salts at same concentrations after 48 h of incubation. Optical microscopy studies showed decrease in the number of spores while increase in spore diameter and thinning of hyphal diameter on NPs supplementation. Scanning electron microscopy analysis of fungal growth showed presence of deflated and oblong spores in two fruiting strains of Ganoderma while Volvariella exhibited decreased sporulation. Further, hyphal thinning and branching was recorded in response to NP amendments in both the test mushrooms. Enhancement of protein content was observed on NP compared to bulk supplementation for all cultures, concentrations and hours of incubation except for TiO₂ NPs. Likewise, bulk and NP supplementations (at 100 mg L^-1) resulted in enhanced laccase activity with occurrence of laccase specific protein bands on SDS-PAGE analysis.

• Bulletin of the Korean Chemical Society
• /
• 제32권spc8호
• /
• pp.2941-2948
• /
• 2011

A nanogap formed by a metal nanoparticle and a flat metal substrate is one kind of "hot site" for surface-enhanced Raman scattering (SERS). The characteristics of a typical nanogap formed by a planar Au and either an Au and Ag nanoparticle have been well studied using 4-aminobenzenethiol (4-ABT) as a probe. 4-ABT is, however, an unusual molecule in the sense that its SERS spectral feature is dependent not only on the kinds of SERS substrates but also on the measurement conditions; thus further characterization is required using other adsorbate molecules such as 1,4-phenylenediisocyanide (1,4-PDI). In fact, no Raman signal was observable when 1,4-PDI was selfassembled on a flat Au substrate, but a distinct spectrum was obtained when 60 nm-sized Au or Ag nanoparticles were adsorbed on the pendent -NC groups of 1,4-PDI. This is definitely due to the electromagnetic coupling between the localized surface plasmon of Au or Ag nanoparticle with the surface plasmon polariton of the planar Au substrate, allowing an intense electric field to be induced in the gap between them. A higher Raman signal was observed when Ag nanoparticles were attached to 1,4-PDI, irrespective of the excitation wavelength, and especially the highest Raman signal was measured at the 632.8 nm excitation (with the enhancement factor on the order of ${\sim}10^3$), followed by the excitation at 568 and 514.5 nm, in agreement with the finite-difference timedomain calculation. From a separate potential-dependent SERS study, the voltage applied to the planar Au appeared to be transmitted without loss to the Au or Ag nanoparticles, and from the study of the effect of volatile organics, the voltage transmission from Au or Ag nanoparticles to the planar Au also appeared as equally probable to that from the planar Au to the Au or Ag nanoparticles in a nanogap electrode. The response of the Au-Ag nanogap to the external stimuli was, however, not the same as that of the Au-Au nanogap.

• 한국재료학회:학술대회논문집
• /
• 한국재료학회 2009년도 추계학술발표대회
• /
• pp.46.1-46.1
• /
• 2009

산업이 점차 발달함에 따라 발생하는 환경오염으로 인해 인간의 삶에 있어 불가분의 관계에 있는 물에 대한 관심이 지속적으로 높아지고 있는 추세이다. 각종 질병의 요인이 되는 박테리아는 주로 물을 운송 매개체로 하기 때문에 이로 인한 물의 오염으로 인도의 경우 모든 질병 발생의 80%를 차지하는 것으로 세계보건기구(WHO)에 의해 보고되었다. 현재까지물 또는 공기의 항균 및 살균 정화를 위해 화학적, 생물학적 방식 등 다양한 기술이 개발되었으나 박테리아와같은 세균제거에는 무리가 있는 실정이다. 따라서 본 연구에서는 여러 물질 중에서도 특히 항균작용(Antibacterial activity)이 탁월한 은(Ag)을 나노입자화하여 in-situ 코팅을 통한 다공성 알루미늄 하이드록사이드 나노복합재의 제조함으로써 생물학, 생체의용공학, 약학 등에 응용될 수 있는 새로운 형태의 항균재료제조방법을 제안하였다. 우선, 다공성 알루미늄 하이드록사이드기판은 알루미늄 기판에 알칼리 표면개질을 실시함으로서 표면에 마이크로포어가 형성된 알루미늄 하이드록사이드 기판을 제조하였다. 이렇게 제조된 다공성 기판에 Polyol 공정으로 은나노입자를 합성 및 분산시킴으로서 in-situ로 은나노입자가 분산된 알루미늄 하이드록사이드 나노복합재 기판을 만들수 있었다. 본 연구를 통하여 제조된 은나노입자가 분산된 알루미늄 하이드록사이드 나노복합재 기판은 주사전자현미경(SEM) 및 투과전자현미경(TEM)을 통하여 미세구조와 상분석을 실시하였으며 X선 광전자분석(XPS)를 이용하여 기판 표면의 화학적 상태를 분석하였다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2010년도 하계학술대회 논문집
• /
• pp.53-53
• /
• 2010

The development of synthetic pathway to produce a highly yield nanoparticles is an important aspect of industrial technology. Herein, we report a simple, rapid approach to synthesize organic-soluble Cu and Ag nanoparticles in colloidal method for the application in a conductive pattern using inkjet printing. The silver nanoparticles have been synthesized in highly concentrated organic phase. The Cu nanoparticles have been synthesized by the reducing of the copper oxide materials using acid molecules in high concentrated organic phase. Their sintering and electric conductivity properties were investigated by melting process between $200^{\circ}C$ and $250^{\circ}C$ for application to printed electronics.

• 전기학회논문지
• /
• 제65권4호
• /
• pp.611-616
• /
• 2016

In this study, we synthesized $Ag_2Se$ nanoparticles (NPs) in an aqueous solution and investigated the thermoelectric characteristics of $Ag_2Se$ NPs thin films on plastic substrates. Regardless of thermal annealing treatment, all the $Ag_2Se$ NPs thin films show the negative Seebeck coefficients, indicating the n-type characteristics. As the annealing temperature increases, the electric conductivity increases while the Seebeck coefficient decreases. The electric conductivity of the thin film annealed at $180^{\circ}C$ is larger by $10^6$ times, compared with the as-prepared thin film, And the maximum power density for the thin film annealed at $180^{\circ}C$ is calculated to be $44{\mu}W/cm^2$.

• 청정기술
• /
• 제20권2호
• /
• pp.160-165
• /
• 2014

지난 수년간 나노기술의 혁신성과 다양한 나노소비제의 적용으로 수많은 나노물질들이 제조되었다. 아울러 나노물질과 나노소비재의 연간 생산량이 증가하고 있어서, 의도하지 않은 환경 노출이 야기되고 있다. 그러나 나노물질을 함유한 폐수는 기존 하폐수처리 시설을 이용하고 있는 실정이다. 국내는 지금까지 실제 하폐수처리장내 나노물질 제거효율을 평가한 사례가 없다. 이에 현장 노출평가에 앞서 파일럿 규모의 하수처리장치를 설계하고자, 설계인자 도출을 위한 슬러지내 나노물질 제거 모델식과 상용 공정 시뮬레이션을 이용하였다.