Radiolytic Synthesis of Ag-Loaded Polystyrene(Ag-PS) Nanoparticles and Their Antimicrobial Efficiency Against Staphylococcus aureus and Klebsiella pneumoniase

Oh, Seong-Dae,Byun, Bok-Soo,Lee, Seung-Ho,Choi, Seong-Ho,Kim, Moon-Il,Park, Hyun-Gyu The Polymer Society of Korea 2007 Macromolecular Research Vol.15 No.4

Ag nanoparticles were distributed onto polystyrene nanoparticle (PS-Ag) beads using two synthetic methodologies. In the first methodology, polystyrene (PS) beads were prepared via emulsion polymerization, with Ag nanoparticles subsequently loaded onto the surface of the PS beads. The polymerization of styrene was radiolytically induced in an ethanol (EtOH)/water medium, generating PS beads. Subsequently, Ag nanoparticles were loaded onto the PS beads via the reduction of Ag ions. The results from the morphological studies, using field emission transmission electron microscopy (FE-TEM), reveal the PS particles were spherical and nanosized, and the average size of the PS spherical particles decreased with increasing volume % of water in the polymerization medium. The size of the PS spherical particles increases with increasing radiation dose for the polymerization. Also, the amount of Ag nanoparticle loading could be increased by increasing the irradiation dose for the reduction of the Ag ions. In the second methodology, the polymerization of styrene and reduction of Ag ions were simultaneously performed by irradiating a solution containing styrene and Ag ions in an EtOH/water medium. Interestingly, the Ag nanoparticles were preferentially homogeneously distributed within the PS particles (not on the surface of the PS particles). Thus, Ag nanoparticles were distributed onto the surface of the PS particles using the first approach, but into the PS clusters of the particles via the second. The antimicrobial efficiency of a cloth coated with the Ag-PS composite nanoparticles was tested against bacteria, such as Staphylococcus aureus and Klebsiella pneumoniase, for 100 water washing cycles.

고분자/은 혼성 나노입자의 제조 및 표면 플라즈몬 공명 현상

어경복(Kyoungbok Eo),김묘음(Myoeum Kim),임현준(Hyunjoon Ihm),정소연(Soyeon Jeong),권용구(Yong Ku Kwon) 한국고분자학회 2018 폴리머 Vol.42 No.1

단분산성 스타이렌-염화비닐벤젠 공중합체(PSBC) 나노입자의 표면을 개질하고 AgNO3과의 반응을 통하여 Ag 나노입자가 고정화된 100-200 nm 평균 입자직경을 가지는 Ag-고분자 혼성 나노입자를 제조한다. 먼저 무유화 에멀젼 중합 방법을 이용하여 단분산성 PSBC 공중합체 나노입자를 합성한 뒤, 이들 나노입자 표면의 chlorine그룹을 thiourea 등을 이용하여 thiol기로 변화, 개질(PSBSH)한다. 이들 PSBSH 고분자 나노입자와 AgNO3와의 반응을 통하여 Ag입자가 표면에 고정화된 고분자-Ag 복합체(PSBAg) 나노입자를 제조하였다. Ag입자의 고정화 과정은 PSBSH 나노입자 표면에서 Ag+ 이온과 표면의 thiol기와의 반응을 통하여 강한 Ag-S- 결합을 형성하고 반데르발스 힘에 의해 Ag 이온들이 고분자 표면에서 환원되면서 Ag 입자가 고정화된 PSBAg 복합나노입자를 제조하였다. 고분자 표면에 은 나노 입자들이 고정된 형태의 나노 복합체의 합성과 표면구조는 SEM, TEM, XRD, FTIR, UV-Vis spectroscopy 등 다양한 분석 방법을 확인하였고, PSBAg 복합나노입자는 표면에 존재하는 Ag 입자로부터 비롯된 표면 플라즈몬 공명(SPR) 현상을 확인할 수 있었고 고분자 입자의 크기와 PSBSH 고분자에 고정된 Ag 나노입자의 함량의 변화에 따른 SPR 현상의 변화를 관찰하였다. Hybrid polymeric nanoparticles containing metal silver nanoparticles were successfully synthesized. Monodisperse poly(styrene-co-vinylbenzyl chloride) (PSBC) nanoparticles with an average diameter of 100-200 nm were synthesized by surfactant-free emulsion polymerization. The chlorine group on the surfaces of the PSBC nanoparticles was converted into thiol group by surface modification with thiourea. The thiol groups of the surface-modified nanoparticles with thiol group (PSBSH) were reacted with Ag+ ions to form Ag-S bonds and then produce the PSBAg hybrid nanoparticles containing Ag nanoparticles, intercalatedon to the surfaces through reduction. The successful immobilization of Ag onto the surface of the polymer nanoparticles was confirmed using various characterization tools. The surface plasmon resonance (SPR) was observed from the Ag nanoparticles of the PSBAg nanoparticles. By varying the size of the polymer nanoparticles and the amount of silver adhered onto them, the surface plasmon resonance of the nanocomposite materials was investigated.

Synthesis of Au–Ag bimetallic nanoparticles using Korean red ginseng (Panax ginseng Meyer) root extract for chemo-photothermal anticancer therapy

Gayeon Lee,You Jeong Lee,Yeon-Jeong Kim,Youmie Park 대한약학회 2023 Archives of Pharmacal Research Vol.46 No.8

Green synthesis strategies have been widely applied for the preparation of versatile nanomaterials. Gold nanospheres with an average size of 6.95 ± 2.25 nm were green synthesized by using a 70% ethanol extract of Korean red ginseng (Panax ginseng Meyer) root as a reducing agent. A seed-mediated synthesis was conducted to prepare Au–Ag bimetallic nanoparticles using gold nanospheres as seeds. Remarkably, Au–Ag bimetallic nanoparticles with an average size of 80.4 ± 11.9 nm were synthesized. Scanning transmission electron microscopy, energy dispersive X-ray spectroscopy and elemental mappings revealed bimetallic nanoparticles with Au–Ag alloy core and Au-rich shells. A face-centered cubic structure of Au–Ag bimetallic nanoparticles was confirmed by X-ray diffraction analysis. For Au–Ag bimetallic nanoparticles, the ratio of Ag/Au was 0.20 which was detected and analyzed by inductively coupled plasma-mass spectrometry. Gold nanospheres and Au–Ag bimetallic nanoparticles were functionalized by PEGylation, folic acid conjugation and grafting onto graphene oxide. Finally, docetaxel was loaded for evaluating the in vitro cell viability on cancer cells. Successful functionalization was confirmed by Fourier-transform infrared spectra. The anticancer activity of the docetaxel-loaded nanoparticles was higher than that of their non-docetaxel-loaded counterparts. The highest anticancer activity on human gastric adenocarcinoma cells (AGS) was observed in the docetaxel-loaded gold nanospheres that were functionalized by PEGylation, folic acid conjugation and grafting onto graphene oxide. Additionally, grafting onto graphene oxide and docetaxel loading induced high intracellular reactive oxygen species generation. For chemo-photothermal (PTT) anticancer therapy, cell viability was investigated using near-infrared laser irradiation at 808 nm. The highest chemo-PTT anticancer activity on AGS cells was observed in the docetaxel-loaded Au–Ag bimetallic nanoparticles. Therefore, the newly prepared docetaxel-loaded Au–Ag bimetallic nanoparticles in the current report have potential applications in chemo-PTT anticancer therapy.

SiO₂/Ag 코어-쉘 나노입자의 합성 및 전도성 페이스트 적용

심상보 ( Sang-bo Sim ),한종대 ( Jong-dae Han ) 한국공업화학회 2021 공업화학 Vol.32 No.1

SiO₂/Ag 코어-쉘 나노입자를 수정된 Stöber 공정법과 물/dodecylbenzenesulfonic acid (DDBA)/cyclohexane의 역 미셀에서 acetoxime을 환원제로 사용하는 역 미셀 방법을 상호 조합하여 합성하였다. SiO₂/Ag 코어-쉘은 UV-visible spectroscopy, XRD, SEM 및 TEM을 사용하여 구조, 형태 및 크기를 조사하였다. SiO₂/Ag 코어-쉘의 나노입자 크기는 [물]/[DDBA]의 몰비(WR)의 값을 조절하여 제어할 수 있었다. SiO₂/Ag 코어-쉘의 크기와 다분산성은 WR 값이 증가함에 따라 증가하였다. 비정질 SiO₂ 나노입자 위에 생성된 Ag 나노입자는 430 nm에서 강한 표면 플라즈몬 공명 (SPR) 피크를 나타내었다. SPR 피크는 나노입자 크기의 증가에 따라 장파장으로의 적색 이동을 나타내었다. 합성된 SiO₂/Ag 코어-쉘을 분산시켜 70 wt% 조성의 전도성 페이스트를 제조하고, 스크린 인쇄법으로 PET 필름에 코팅하여 전도성을 조사하였다. SiO₂/Ag 코어-쉘 페이스트로 코팅된 필름은 상용 Ag 페이스트에 비하여 높은 460~750 μΩ/sq 영역의 표면저항을 나타내었다. SiO₂/Ag core-shell nanoparticles were synthesized by combining modified Stöber process and reverse micelle method using acetoxime as a reducing agent in water/dodecylbenzenesulfonic acid (DDBA)/cyclohexane reverse micells. The SiO₂/Ag core-shells were studied for structure, morphology and size using UV-visible spectroscopy, XRD, SEM and TEM. The size of a SiO₂/Ag core-shell could be controlled by changing the [water]/[DDBA] molar ratio (WR) values. The size and the polydispersity of SiO₂/Ag core-shells increased with increase of the WR value. The resultant Ag nanoparticles exhibit a strong surface plasmon resonance (SPR) peak at 430 nm over the amorphous SiO₂ nanoparticles. The SPR peak shifted to the red side with increase in nanoparticle size. Conductive pastes with 70 wt% SiO₂/Ag core-shell were prepared, and the pastes were coated on the PET films using a screen-printing method. The printed paste film of the SiO₂/Ag core-shell showed higher surface resistance than the commercial Ag paste in the range of 460~750 μΩ/sq.

올레핀/파라핀 분리용 AgNO₃ 전구체를 활용한 poly(ethylene oxide)/Ag nanoparticles/p-benzoquinone 복합체 분리막 제조

김민수,강상욱,kim, Minsu,Kang, Sang Wook 한국막학회 2018 멤브레인 Vol.28 No.4

올레핀/파라핀 분리를 위해 poly(ethylene oxide)(PEO)/Ag nanoparticles (AgNPs)(전구체: $AgBF_4$)/p-benzoquinone (p-BQ) 복합막이 제조되었으며, 이 복합체 분리막의 성능은 100시간까지 선택도 10과 투과도 15 GPU로 유지되는 것이 관찰되었다. 분리막의 성능이 100시간까지 유지할 수 있었던 이유는 p-BQ의 첨가로 인해 Ag ion이 안정적으로 Ag nanoparticles로 형성될 수 있었을 뿐더러 전자수용체인 p-BQ으로 인해 표면이 부분 양극성화 되어 올레핀 운반체로서 역할을 성공적으로 수행한 결과라 생각되었다. 본 연구에서는 Ag nanoparticles의 전구체로 사용된 $AgBF_4$의 가격이 고가이기 때문에 가격 측면에서 유리한 $AgNO_3$ Ag nanoparticles의 전구체로 사용하여 실험을 진행하였다. 그 결과로서 $AgNO_3$의 경우에는 앞선 $AgBF_4$과는 다르게 안정적으로 은 나노입자가 형성되지 못하고 이로 인하여 좋은 성능을 내지 못하는 것으로 분석되었다. Poly (ethylene oxide) (PEO)/Ag nanoparticles (AgNPs)(precursor : $AgBF_4$)/p-benzoquinone (p-BQ) composite membrane was prepared for olefin/paraffin separation. As a result, the performance of composite membrane was observed to be maintained at selectivity of 10 and permeance of 15 GPU up to 100 hours. The performance of the membrane was maintained for 100 hours was attributable to that Ag ions could be converted into stable Ag NPs by addition of p-BQ. Furthermore, the surface was partially polarized by the electron acceptor p-BQ, resulting in the formation of olefin carrier. In this study, since the cost of $AgBF_4$ used as a precursor of Ag NPs was relatively higher, $AgNO_3$ was utilized. As a result, it was confirmed that $AgNO_3$ couldn't show the stable formation of nanoparticle, resulting in the poor separation performance.

Preparation and Characterization of Ag-TiO₂ Core-Shell-Type Nanoparticles

Kim, Young Hwan,Kang, Young Soo,Jo, Beong Gi 한국공업화학회 2004 Journal of Industrial and Engineering Chemistry Vol.10 No.5

Ag nanoparticles were synthesized by thermal decompositon of an Ag-oleate complex by using an electric furnace (autoclave) at 300℃ for 4 hrs. The particles were characterized by using a UV-vis spectrophotometer, a transmission electron microscope (TEM), and an X-ray powder diffractometer (XRD). The synthesized Ag nanoparticles were used as seeds for Ag-TiO₂ nanoparticles, which had core-shell structures. TEM images of the Ag-TiO₂ nanoparticles showed that the silver core was coated with titanium oxide. Ag-TiO₂ nanoparticles composed of a silver core (20-㎚ diameter) coated with titanium dioxide (less than 5 nm layer) were produced by a sol-gel process.

Morphological changes of bacterial cells upon exposure of silver-silver chloride nanoparticles synthesized using <i>Agrimonia pilosa</i>

Patil, Maheshkumar Prakash,Seo, Yong Bae,Kim, Gun-Do Elsevier 2018 Microbial pathogenesis Vol.116 No.-

<P><B>Abstract</B></P> <P>Facile, eco-friendly synthesis of metal nanoparticles has been proposed as a cost effective method. In the present study, we propose the facile synthesis of silver-silver chloride (Ag-AgCl) nanoparticles (NPs) using the medicinally important <I>Agrimonia pilosa</I> plant extract without addition of capping or stabilizing agents. The Ag-AgCl NPs synthesis was observed at 40 °C after 10 min incubation; the synthesis of Ag-AgCl NPs was indicated by color change and confirmed by UV-vis spectroscopic peak at 454 nm. TEM analysis confirmed Ag-AgCl NPs were 10–20 nm in size and spherical, and oval in shape. Elemental composition was determined by energy dispersive X-ray analysis, and crystalline structure was confirmed by X-ray diffraction spectroscopy. Different phytocomponents present in the plant extract were analyzed by Gas Chromatography-Mass spectrometry, and the interaction of biomolecules in reduction process was analyzed by Fourier transform infrared spectroscopy studies. The synthesized Ag-AgCl NPs showed significant antibacterial efficiency, analyzed by well diffusion assay against pathogenic bacteria including <I>Bacillus cereus</I>, <I>Listeria monocytogenes</I>, <I>Staphylococcus aureus</I>, <I>Staphylococcus saprophyticus</I>, <I>Escherichia coli</I>, <I>Pseudomonas putida</I>. Minimum inhibitory concentration and minimum bactericidal concentration were evaluated by microbroth dilution, and spread plate method, respectively. The possible mechanism of bacterial growth inhibition is due to changes in bacterial cell wall morphology that was studied by FE-SEM analysis.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel method for eco-friendly synthesis of Ag-AgCl nanoparticles. </LI> <LI> Synthesized Ag-AgCl nanoparticles characterized by using TEM, EDX, XRD, FT-IR and Zeta potential measurement. </LI> <LI> <I>Agrimonia pilosa</I> extract-mediated Ag-AgCl nanoparticles can be a potential antibacterial agent in therapeutics. </LI> <LI> Detail mechanism of Ag-AgCl nanoparticles mediated bactericidal activity. </LI> </UL> </P>

Reactive Radical Species in Photocatalytic Activities of PET-Ag-TiO2 Nanoparticles Composites Under Visible Light Irradiation

Hui Zhang,Dou Wang,Cuihong Sheng,Deping Ben,Hailiang Wu,Ningtao Mao 한국섬유공학회 2021 Fibers and polymers Vol.22 No.3

In this research, the reactive radical species in photocatalytic activities of a composite photocatalyst made fromPET filaments loaded with Ag-TiO2 nanoparticles under visible light irradiation, in comparison with those of as-modifiedAg-TiO2 nanoparticles, were reported and its photocatalytic mechanism was investigated. The PET filaments were modifiedby using tetrabutyl titanate as the TiO2 precursor and silver nitrate as the dopant in a hydrothermal process. The Ag decoratedTiO2 nanoparticles were synthesized and deposited on the surfaces of PET filaments in the hydrothermal process at 120 oCfor 180 min. The morphology, phase structure, chemical binding state, and optical properties of the PET-Ag-TiO2nanoparticles composites were systemically studied by means of field emission scanning electron microscopy (FESEM), X-raydiffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL)spectroscopy, diffuse reflectance spectroscopy (DRS), and ultraviolet photoelectron spectroscopy (UPS) techniques. Thephotocatalytic activities of the PET-Ag-TiO2 nanoparticles composites were evaluated in the photodegradation of bothmethylene blue (MB) and methyl orange (MO) dyes under visible light irradiation. It was found that, unlike in the asobtainedTiO2 nanoparticles and Ag decorated TiO2 nanoparticles, the photoinduced holes (h+) were the major reactiveradical species in both PET-Ag-TiO2 composite photocatalyst and the PET filaments loaded with TiO2 nanoparticles in theMB photodegradation process. The experimental results also indicated that the PET-Ag-TiO2 nanoparticles composites led tothe improvement of the separation efficiency of photogenerated electron-hole pairs. The enhanced photocatalytic activity ofthe PET filaments coated with Ag decorated TiO2 nanoparticles was ascribed to both the incorporation of Ag nanoparticlesinto TiO2 nanoparticles and the possible infiltration of Ag/Ti nanoparticles into PET polymers. In addition, the wavelengthand intensity of monochromatic light had great influences on the photodegradation rate of dye used, which was closelycorrelated with the maximum absorption wavelength of the dye to be degraded.

Phase stability of Ag-Sn alloy nanoparticles

Sim, K.,Lee, J. Elsevier Sequoia 2014 JOURNAL OF ALLOYS AND COMPOUNDS Vol.590 No.-

Nanoparticles often possess phase stabilities that differ from those of bulk materials, as a result of their large surface-to-volume ratio. Park and Lee suggested that the phase diagram of metallic nanoparticles can be calculated using the CALPHAD method through the introduction of the size effect. Based on Park and Lee's model, the thermodynamic parameters for the Ag-Sn nanoparticle system (pure Ag and Sn, the intermetallic compound Ag<SUB>3</SUB>Sn, and liquid and solid solutions (fcc, hcp, and bct)) were optimized as a function of temperature, composition, and the size of the nanoparticle. The phase stability of the Ag<SUB>3</SUB>Sn nanoparticles was affected by the selection of the surface tension value for Ag<SUB>3</SUB>Sn; however, the eutectic temperature and composition are not affected by the phase stability of the Ag<SUB>3</SUB>Sn nanoparticles. When the size of the nanoparticles is decreased, the eutectic temperature decreases, and the eutectic composition approaches the Sn-rich corner. The present results exhibited a reasonable agreement with the reported experimental data.

Effect of PVP molecular weight on the formation of Ag nanoparticles on echinoid-like TiO₂

Jang, I.,Song, K.,Park, J.H.,Kim, M.,Kim, D.W.,Oh, S.G. North-Holland 2013 Materials letters Vol.96 No.-

Ag nanoparticles were immobilized on echinoid-like TiO<SUB>2</SUB> particles via an alcohol reduction process with poly(vinyl pyrrolidone) (PVP) of different molecular weights (Mw.). The sizes of Ag nanoparticles prepared by using PVP K15 (Mw.: 10,000) and K30 (Mw.: 40,000) were 12-15nm and 19-31nm, respectively. On the other hand, Ag nanoparticles were not observed when PVP K12 (Mw.: 3500) was used. The crystal structure of Ag nanoparticles formed on TiO<SUB>2</SUB> was face-centered cubic silver phase and the chemical states of Ag nanoparticles were Ag<SUP>+</SUP> and Ag<SUP>0</SUP>. The photocatalytic performance was enhanced by Ag deposition. Among the samples, the prepared Ag/TiO<SUB>2</SUB> composite by using PVP K15 exhibited better photocatalytic activity than other composites due to its higher Ag coverage on the TiO<SUB>2</SUB> surface.