• Journal of Radiation Industry
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• v.5 no.2
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• pp.119-124
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• 2011

Silver nano-particles (AgNPs) have attracted much attention for centuries due to their unique optical properties, electrical conductivities, oxidative catalysis, and antibacterial effect. In this study, AgNPs have been prepared by using aqueous $AgNO_3$ solution in the poly(vinyl alcohol) (PVA)/poly(ethylene glycol) (PEG) hydrogels. PVA and PEG powders were dissolved in deionized water, and then irradiated by a gamma-ray with a radiation dose of 50 kGy to make hydrogels. PVA/PEG hydrogels were dipped into $1.0{\times}10^{-2}M$ $AgNO_3$ solution for 1 hour. After that, the swollen hydrogels were irradiated by gamma-ray for the formation of AgNPs. FE-SEM is used to observe the formation of AgNPs as a function of the content of PEG and the irradiation dose. Also, AgNPs in the PVA/PEG hydrogels were monitored by UV-Vis. It is observed that the content of PEG and gamma-ray irradiation in the hydrogel is crucial to the formation of AgNPs. Finally, antibacterial tests indiacted that the hydrogel containing silver nanoparticle has antibacterial activity.

• Journal of Adhesion and Interface
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• v.22 no.3
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• pp.98-105
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• 2021

In this study, we prepared a silver nanoparticle transferable adhesive composition with transparency and adhesive properties using UV-curable urethane acrylate containing silane groups. The urethane-based adhesive composition was applied between the Ag/PET film in which silver nanoparticles were patterned on PET and the PC film to be transferred. Immediately after UV-curing with UV, PET was removed to complete the manufacture of Ag/PC film. UV-curable urethane acrylate containing silane groups was synthesized using polycaprolactone diol (PCL), isophrone diisocyanate (IPDI), 2-hydroxyethyl methacrylate (HEMA), and (3-aminopropyl) triethoxysilane (APTES). The silane group of APTES can improve interfacial adhesion by reacting with the specially treated silver nanoparticle surface of the Ag/PET film. In addition, we improved the adhesion between silver nanoparticle and PC film by mixing UV-curable urethane acrylate containing a silane group and a functional acrylic diluent used as a diluent. We analyzed the synthesis process of urethane acrylate using FT-IR, and compared the adhesive properties, optical properties, and transfer properties according to the molar ratio of APTES and the acrylic diluent composition. As a result, the best transfer properties were confirmed in the adhesive composition prepared under the conditions of PUA2S1_0.5.

• Microbiology and Biotechnology Letters
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• v.40 no.4
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• pp.403-408
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• 2012

Gelatin/Ag nanoparticle (AgNP) biocomposite was synthesized using the solution plasma process (SPP) that has been recently introduced as an effective method for synthesis of nanoparticles. In this study, gelatin/AgNP biocomposite was synthesized using various concentrations of Ag precursor ($AgNO_3$) and gelatin in the range of 1-5 mM and 1-3% (w/w), respectively, without using any chemical reducing agent. Physical properties of the gelatin/AgNP biocomposites were analyzed using EDS, FE-SEM, and TEM. The results indicated that spherical AgNPs with approximately 12~20 nm in diameter were synthesized successfully in the gelatin matrix by SPP. As the concentration of gelatin was increased (3%, w/w), disperse stability of AgNP was improved and micro-pores of gelatin became smaller and denser in the 3D scaffold. Bactericidal activity of the AgNPs was examined against Staphylococcus aureus and Escherichia coli by measuring zone of growth inhibition and decrease in colony forming unit (CFU). CFUs of S. aureus and E. coli were decreased approximately to 56% and 0%, respectively, by the gelatin/AgNP biocomposite, Ag5G3.

• Bulletin of the Korean Chemical Society
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• v.34 no.2
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• pp.539-544
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• 2013

$Ag@SiO_2@SiO_2$(FITC) nanocomposites were prepared by the simple polyol process and St$\ddot{o}$ber method. Fluorescence enhancement of fluorescein moiety (fluorescein isothiocyanate, FITC) was investigated in the presence of silver nanoparticles in $Ag@SiO_2@SiO_2$(FITC) system with varying thickness (X nm) of first silica shell. Maximum enhancement factor of 4.3 fold was achieved in $Ag@SiO_2@SiO_2$(FITC) structure with the first silica shell thickness of 8 nm and the average separation distance of 11 nm between the surface of silver nanoparticle and fluorescein moiety. The enhancement is believed to be originated from increased excitation rate of fluorescein moiety due to concentrated local electromagnetic field which was improved by interaction of light with silver nanoparticles.

• Macromolecular Research
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• v.15 no.4
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• pp.285-290
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• 2007

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.

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.11a
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• pp.89.2-89.2
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• 2007

• Bulletin of the Korean Chemical Society
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• v.32 no.10
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• pp.3581-3586
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• 2011

Silver nanoparticle (Ag-NPs)-immobilized and amine-functionalized carbon nanotubes (MWCNTs), MWCNT-Ag-$NH_2$, were easily prepared in order to develop an efficient delivery system of biomolecules without complicated processes of manufacture. For this, Ag-NPs-immobilized MWCNTs, MWCNT-Ag, were initially prepared in order to create large surface area to enable more efficient linkage with guest-molecules using pristine MWCNTs. The Ag-NPs on MWCNTs were further positively functionalized with 2-aminoethanthiol to allow ionic linkage with biomolecules. Ultimately, the positively charged delivery system proved to be highly effective for the binding capacity of bovine serum albumin (BSA) as a negatively charged model protein, when compared to that of lysozyme used as a positively charged model protein. The releasing profile of BSA was observed in almost linear pattern for about two weeks in a saline solution. This study demonstrated the potential usefulness of the pristine MWCNTs in conjunction with Ag-NPs for the selective delivery of many (negatively or positively) charged biomolecules including proteins and genes.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.613-619
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• 2011

Colloidal silver nanoparticles (AgNPs) have been commercialized as the typically stabilized form via the addition of a variety of surfactants or polymers. Herein, to examine the effects of stabilizing AgNPs in suspension, we modified the surface of bare AgNPs with four type of surfactants (NaDDBS, SDS, TW80, CTAB) and polymers (PVP, PAA, PAH, CMC). The modified AgNPs was applied to compare suspension stability and nanotoxicity test using Escherichia coli (E. coli) as a model organism. Modification of AgNPs surface using chemical stabilizer may be not related with molecular weight, but chemical structure such as ionic state and functional group of stabilizer. In this study, it is noteworthy that AgNPs modified with a cationic stabilizer (CTAB, PAH) were importantly toxic to E. coli, rather than anionic stabilizers (NaDDBS, SDS). Comparing similar anionic stabilizer, i.e., NaDDBS and SDS, the result showed that lipophilicity of chemical structure can affect on E. coli, because NaDDBS, which contains a lipophilic benzene ring, accelerated the cytotoxicity of AgNPs. Interestingly, none of the stabilizers tested, including biocompatible nonionic stabilizers (i.e., TW80 and cellulose) caused a reduction in AgNP toxicity. This showed that toxicity of AgNPs cannot be reduced using stabilizers.

• Environmental Engineering Research
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• v.15 no.1
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• pp.23-27
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• 2010

Genotoxic- and ecotoxic assessments of silver nanoparticles (AgNPs) were conducted on the freshwater crustacean Daphnia magna. AgNPs may have genotoxic effects on D. magna, given that the DNA strand breaks increased when exposed to this nanoparticle. Increased mortality was concomitantly observed with DNA damage in the AgNPs-exposed D. magna, which suggests AgNPs-induced DNA damage might provoke higher-level consequences. The results of the comparative toxicities of AgNPs and Ag ions suggest that AgNPs are slightly more toxic than Ag ions. Overall, these results suggest that AgNPs may be genotoxic toward D. magna, which may contribute to the knowledge relating to the aquatic toxicity of AgNPs on aquatic ecosystems, for which little data are available.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.1
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• pp.135-139
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• 2015

We present a fine patterning method of conductive lines on polyimide (PI) and glass substrates using silver (Ag) nanoparticles based on laser scanning. Controlled laser irradiation can realize selective sintering of conductive ink without damaging the substrate. Thus, this technique easily creates fine patterns on heat-sensitive substrates such as flexible plastics. The selective laser sintering of Ag nanoparticles was managed by optimizing the conditions for the laser scan velocity (1.0-20 mm/s) and power (10-150 mW) in order to achieve a small gap size, high electrical conductivity, and fine roughness. The fabricated electrodes had a minimum channel length of $5{\mu}m$ and conductivity of $4.2{\times}10^5S/cm$ (bulk Ag has a conductivity of $6.3{\times}10^5S/cm$) on the PI substrate. This method was used to successfully fabricate an organic field effect transistor with a poly(3-hexylthiophene) channel.