• Toxicological Research
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• 제35권3호
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• pp.257-270
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• 2019

Silver nanoparticles (AgNPs) have been widely used in a variety of applications in innovative development; consequently, people are more exposed to this particle. Growing concern about toxicity from AgNP exposure has attracted greater attention, while questions about nanosilver-responsive genes and consequences for human health remain unanswered. By considering early detection and prevention of nanotoxicology at the genetic level, this study aimed to identify 1) changes in gene expression levels that could be potential indicators for AgNP toxicity and 2) morphological phenotypes correlating to toxicity of HepG2 cells. To detect possible nanosilver-responsive genes in xenogenic targeted organs, a comprehensive systematic literature review of changes in gene expression in HepG2 cells after AgNP exposure and in silico method, connection up- and down-regulation expression analysis of microarrays (CU-DREAM), were performed. In addition, cells were extracted and processed for transmission electron microscopy to examine ultrastructural alterations. From the Gene Expression Omnibus (GEO) Series database, we selected genes that were up- and down-regulated in AgNPs, but not up- and down-regulated in silver ion exposed cells, as nanosilver-responsive genes. HepG2 cells in the AgNP-treated group showed distinct ultrastructural alterations. Our results suggested potential representative gene data after AgNPs exposure provide insight into assessment and prediction of toxicity from nanosilver exposure.

• Advances in nano research
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• 제15권4호
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• pp.355-366
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• 2023

Biological corrosion, a crucial aspect of metal degradation, has received limited attention despite its significance. It involves the deterioration of metals due to corrosion processes influenced by living organisms, including bacteria. Soil represents a substantial threat to pipeline corrosion as it contains chemical and microbial factors that cause severe damage to water, oil, and gas transmission projects. To combat fouling and corrosion, corrosion inhibitors are commonly used; however, their production often involves expensive and hazardous chemicals. Consequently, researchers are exploring natural and eco-friendly alternatives, specifically nano-sized products, as potent corrosion inhibitors. This study aims to environmentally synthesize silver nanoparticles using an extract from Lagoecia cuminoides L and evaluate their effectiveness in preventing biological corrosion of buried pipes in soil. The optimal experimental conditions were determined as follows: a volume of 4 ml for the extract, a volume of 4 ml for silver nitrate (AgNO3), pH 9, a duration of 60 minutes, and a temperature of 60 degrees Celsius. Analysis using transmission electron microscopy confirmed the formation of nanoparticles with an average size of approximately 28 nm, while X-ray diffraction patterns exhibited suitable peak intensities. By employing the Scherer equation, the average particle size was estimated to be around 30 nm. Furthermore, antibacterial studies revealed the potent antibacterial activity of the synthesized silver nanoparticles against both aerobic and anaerobic bacteria. This property effectively mitigates the biological corrosion caused by bacteria in steel pipes buried in soil.

• 한국분말재료학회지
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• 제12권1호
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• pp.56-63
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• 2005

Ag powder was prepared from $AgNO_3$ by wet chemical reduction method using various reduction agent system involving $AgNO_3$, $AgNO_2$(AgCl) and Ag complex ion aqueous solution. The pure Ag powder could be prepared regardless of reaction system but the particle shape and distribution were affected very much according to the kind of reduction agents and reaction systems. The optimum reaction system for the preparation of the silver powder having the uniform particle shape and size distribution was Ag complex ion aqueous solution-reduction agent system and in particular, $H_2O_2$ and $C_6H_8O_6$as a reduction agent leaded the more uniform particle shape and size distribution.

• 한국산학기술학회논문지
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• 제17권4호
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• pp.772-779
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• 2016

수용액에서 질산 은과 Trisodium Citrate(TSC)을 반응시켜 은 나노입자를 제조하였다. 은 나노입자의 크기와 모양은 주사 전자 현미경(SEM)을 사용하여 조사하였다. 은 나노입자의 합성실험은 질산 은 수용액의 농도, TSC의 첨가량, 용제, 계면활성제, 초음파 파쇄, 분산제를 변수로 하여 수행하였다. 질산 은의 농도를 높이거나 TSC의 농도를 증가시킬수록 입자의 크기가 커지거나 응집되는 결과를 확인할 수 있었다. 주사 전자 현미경(SEM) 분석 자료로부터 합성된 은 나노입자는 좁은 영역의 입자 크기 분포를 가진 구형 또는 구형에 가까운 것을 확인하였다. 용제를 첨가하여 분산을 시도하였는데, 소수성 용제는 분산성에 영향을 미치지 않았고 친수성 용제는 분산성을 향상시켜 주었다. 계면활성제(HPMC)를 첨가하면 은 나노입자의 크기가 50-100 nm로 커지며, 모양은 불균일하고 부분적인 응집이 발생하였다. 은 나노입자의 분산성은 분산제 첨가 후에 3 시간 이상의 초음파 파쇄에 의해 크게 향상되었다. 분산제의 첨가에 의해 완전한 분산이 일어났으며, 은 나노입자의 크기는 BYK-182(30-40 nm) < BYK-192(42-78 nm) < BYK-142 (51-113 nm)순으로 나타났다. 0.002 M 질산 은 용액에 2-4wt%의 TSC를 첨가하였을 때 38.45-46.28 nm의 은 나노입자가 합성되었다.

• 한국잠사곤충학회지
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• 제49권1호
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• pp.24-27
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• 2007

본 연구는 은나노 입자가 함유된 용액을 이용하여 기능성 천연실크를 생산하고자 수행하였다. 1. 은나노 적정농도는 500 ppm 처리구가 은함량, 화용비율 및 견층비율을 종합적인 비교 분석에서 적정농도로 조사되었다. 2. 일반 품종별 은함량 측정에서 흰고치(금옥잠) 품종 대비 연녹고치(C212)품종이 69%많았다. 3. 은나노 첨식 처리기간별 조사에서는 5령3일부터 상족전(18회 급상)까지 첨식한 처리구가 가장 우수 하였다. 4. 실크에 함유된 은나노 입자의 크기는 26.98nm에서 99.81nm임을 주사전자현미경으로 관찰되었다. 5. 그리고, 은나노 입자가 함유된 사료로 사육된 누에의 번데기, 누에고치 추출액과 같은 부산물 내에 기능성 은나노 입자가 균일하게 분포하게 됨을 확인하였다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2017년도 춘계학술대회 논문집
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• pp.97-97
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• 2017

This study investigated the corrosion protection by electrodeposited copper layer on AZ31 Mg alloy with and without additional silver layer by immersion test, salt spray test, OCP transient and potentiodynamic polarization experiment. The single electrodeposited Cu layer on AZ31 Mg alloy showed a nodular structure with many imperfections of crevices between the nodules, which resulted in the fast initiation of pitting corrosion within first few hours of immersion. Double-layer coating of Cu and outer Ag layer slightly increased the initiation time for pitting corrosion. Triple-layer coatings of Cu/Ag/Cu exhibited the most efficient corrosion protection of AZ31 Mg alloy, compared to the single- and double-layer coatings. Surface morphology of the outer Cu layer in the triple-layer was changed from the nodular structure to fine particle structure with no crevices due to the presence of an additional Ag layer. Thus, the improved corrosion resistance of AZ31 Mg alloy by electrodeposited Cu/Ag or Cu/Ag/Cu layers is readily ascribed to the decreased number of imperfections in the electrodeposited layers due to the additional silver layer. It is concluded that the additional silver layer provides many nucleation sites for the second Cu plating, resulting in the formation of finer and denser structure than the first Cu electrodeposit.

• 공업화학
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• 제18권4호
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• pp.396-399
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• 2007

본 연구에서는 질산은 용액을 감마선 조사에 의하여 은나노 입자를 제조한 후, 이것을 활성탄과 혼합하여 은/활성탄 복합체를 제조하여 대장균에 대한 항균특성을 조사하였다. 제조된 은/활성탄 복합체의 특성은 주사전자현미경, X-선 회절법 그리고 원자흡수분광법에 의해 알아보았다. 은/활성탄 복합체의 대장균에 대한 억제농도는 0.387 ppm으로 나타났으며 대장균에 대한 사멸농도는 1.017 ppm이었다. 이 결과로 은/활성탄 복합체의 대장균에 대한 우수한 항균효과를 확인할 수 있었다.

• Advances in nano research
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• 제4권2호
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• pp.129-143
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• 2016

The present work reports a facile, rapid and an eco-friendly method for the synthesis of silver nanoparticles using Luffa acutangula (L. acutangula) leaves extract and their antibacterial and cytotoxic effects. The synthesized silver nanoparticles (AgNPs) were characterized by UV-Visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction analysis (XRD). Additionally the topography, morphology and the elemental composition of the particles were determined by Scanning Electron Microscopy (SEM) and Energy dispersive spectrophotometric (EDS) technique and the measured particle sizes from SEM micrographs are in the range of 12.5 to 24.5nm. The in-vitro antimicrobial activity of the synthesized nanoparticles was high against gram positive Staphylococcus aureus and moderate against gram negative Escherichia coli and Pseudomonas aeruginosa strains. Further, the cytotoxic effects of synthesized AgNPs were evaluated against Human Breast Cancer (MCF 7) cell line.

• 설비공학논문집
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• 제18권5호
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• pp.384-392
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• 2006

Reported are the heat transfer characteristics of a two-phase loop thermosyphon (TLT) with nanofluids consisted of nano-size silver particles and distilled water as the working fluid. The nanofluids used in the present study are dispersed solutions with various amount of silver nanoparticle in distilled water. It is seen from the present study that the heat transfer performance of the test TLT with nanofluids increased as much as about 2 times higher than that of a TLT with pure water as the working fluid based on same heat flux. The study also showed that there was no deterioration of the TLT performance with time, up to a period of 8 days of continuous operation which implies that there was no coagulation of nanoparticles within the working nanofluid during the operation of the test TLT.

• 광물과 암석
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• 제33권3호
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• pp.233-242
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• 2020

나노물질에 대한 연구와 산업화가 급격히 진행되면서 수환경으로 유출되는 나노물질의 양도 점차 많아지고 있다. 특히 은나노물질의 경우 은의 항균성으로 인하여 다양한 분야에서 사용되고 있으며 환경으로 유출되어 입자상태와 용해된 상태로 존재할 수 있다. 은나노물질과 은이온은 생태환경에 악영향을 줄 수 있으며 미국에서는 2차 먹는물 규제 항목(secondary drinking water standards)으로 정하고 있으며 규제농도는 0.1 mg/L로 정하여 관리하고 있다. 본 연구에서는 경북지역의 지하수와 소규모 먹는 물 공급시설을 대상으로 은의 농도를 측정하였으며 오염 정도를 미국 EPA 기준과 비교하고 시료를 채취한 지역의 특성, 물의 사용 목적 등을 고려하여 분석하였다. 총 293개의 시료 중 EPA의 secondary drinking water standards를 초과한 시료는 2개이며 비율로 0.6 7%이다. 검출률은 마을 상수도와 소규모 급수시설에서 상대적으로 높으며 농도 기준으로는 지하수에서 상대적으로 높은 농도를 보여 인위적 오염원과 지질적 기원이 동시에 작용한 것으로 판단되었다.