Publications by authors named "Jongchul Seo"

21 Publications

  • Page 1 of 1

PET/Bio-Based Terpolyester Blends with High Dimensional Thermal Stability.

Polymers (Basel) 2021 Feb 27;13(5). Epub 2021 Feb 27.

Department of Packaging, Yonsei University, 1 Yonseidae-gil, Wonju-si, Gangwon-do 26493, Korea.

To improve the dimensional thermal stability of polyethylene terephthalate (PET), a poly(ethylene glycol 1,4-cyclohexane dimethylene (CHDM) isosorbide (ISB) terephthalate) (PEICT) known as ECOZENT110 (EZT) was introduced into PET using a melt blending technique. The miscibility, morphology, and thermal properties of the PET/EZT samples were investigated. The introduction of amorphous EZT into semi-crystalline PET increased the glass transition temperature (T) but decreased the crystallinity, which could be related to the transesterification reaction. By adding EZT contents up to 20%, the PET/EZT samples showed a single T, which indicated the miscibility between PET and EZT. However, two T values were observed in the PET/EZT samples with higher EZT contents (30-70%), indicating partial miscibility. This may have been due to the slightly different rheological and thermodynamic parameters that were affected by a higher ratio of bulky (rigid ISB and ductile CHDM) groups in EZT. However, the heat distortion temperature of the PET/EZT samples remarkably increased, which indicated that the dimensional stability was truly enhanced. Although the crystallinity of the PET/EZT samples decreased with increasing EZT content, the tensile strength and Young's modulus decreased slightly. Based on these results, the as-prepared PET/EZT samples with high dimensional stability can be used as a high-temperature polymeric material in various applications.
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http://dx.doi.org/10.3390/polym13050728DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7956836PMC
February 2021

Photografting of biochelator onto polypropylene film as an antioxidant clean label.

Food Chem 2021 Jul 20;351:129362. Epub 2021 Feb 20.

Department of Packaging, Yonsei University, 1 Yonseidae-gil, Wonju-si, Gangwon-do 26493, South Korea. Electronic address:

A ligand film with citric acid (CA) on the surface as a biochelator was prepared via photografting. Polypropylene film was photochemically brushed by immobilizing glycidyl methacrylate onto the film surface (PP-g-GMA) in the presence of benzophenone. The ligand film (PP-g-GMA-g-CA) was developed via a ring-opening reaction between PP-g-GMA and CA. The chemical structure was examined using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Microstructure and grafting morphology were observed using scanning electron microscopy and atomic force microscopy, and brushed-like configuration and porous surface morphology were described. A large amount of carboxylic acid (215 ± 11 nm) was detected on the surface of PP-g-GMA-g-CA and afforded chelation of Fe (215 ± 11 nm). This ligand film exhibited chelating activity in vitamin C and virgin olive oil (p < 0.05), which extended the shelf-life of these foods. Moreover, overall migration analysis demonstrated that it can be considered as a non-migratory antioxidant.
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http://dx.doi.org/10.1016/j.foodchem.2021.129362DOI Listing
July 2021

Preparation and characterization of positively surface charged zinc oxide nanoparticles against bacterial pathogens.

Microb Pathog 2020 Dec 31;149:104290. Epub 2020 May 31.

Department of Packaging, Yonsei University, 1 Yonseidae-gil, Wonju-si, Gangwon-do, 26493, South Korea. Electronic address:

Solvothermal synthesis was used to investigate the formation of zinc oxide (ZnO) nanoparticles (NPs). A series of ZnO NPs was synthesized with different relative ratios of didodecyldimethylammonium bromide (DDAB) and zinc nitrate (ZN). The variation in the molarity influenced the crystallinity, size, and morphology of the obtained ZnO NPs. X-ray diffraction, Fourier-transform infrared spectroscopy, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, and zeta potential analysis were used to study the characteristic features of the ZnO NPs. The ZnO surface charge, size, and morphological structure were highly reliant on the concentrations of DDAB and ZN. With increasing relative ratio of DDAB to ZN, the particle size of ZnO NPs decreased and the surface charge increased to higher positive value. The ZnO NPs synthesized with cationic liquid DDAB presented enhanced performance in preventing the growth of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) strains. The antibacterial activity of ZnO NPs have direct contact with the microbial cell wall resulting in destruction of bacterial cell integrity, release of antimicrobial Zn ions, and induce cell death. This is due to the positively charged smaller ZnO NPs, prepared with DDAB cationic surfactant, effectively acting as an antimicrobial agent against food-borne pathogenic bacteria.
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http://dx.doi.org/10.1016/j.micpath.2020.104290DOI Listing
December 2020

Effects of incorporating calcined corals as natural antimicrobial agent into active packaging system for milk storage.

Mater Sci Eng C Mater Biol Appl 2020 Jun 26;111:110781. Epub 2020 Feb 26.

Department of Packaging, Yonsei University, 1 Yonseidae-gil, Wonju-si, Gangwon-do 26493, South Korea. Electronic address:

A series of nylon (NY)/linear low-density polyethylene (LLDPE) containing calcined corals (NY/LL-CORALS) composite films were prepared using the cast extrusion method. We investigated the effect of different contents of incorporated calcined corals on the physical properties and antimicrobial activity of the composite films as well as their feasibility for milk storage applications. The results indicated that the main compound in calcined corals was calcium oxide (CaO). As the calcined corals content increased, the crystallinity of the composite films slightly decreased, but no significant changes in their thermal stability and permeability were observed. The NY/LL-CORALS composite films exhibited excellent antimicrobial performance against Escherichia coli and Staphylococcus aureus. Notably, the NY/LL-CORALS packaging significantly extended the lag time of bacteria and delayed the bacterial growth cycle in milk during storage. Thus, the NY/LL-CORALS composite films could be a potential food packaging material that could prolong the shelf life of fresh food.
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http://dx.doi.org/10.1016/j.msec.2020.110781DOI Listing
June 2020

Calcined marine coral powders as a novel ecofriendly antimicrobial agent.

Mater Sci Eng C Mater Biol Appl 2020 Feb 11;107:110193. Epub 2019 Sep 11.

Department of Packaging, Yonsei University, Yonseidae-gil, Wonju-si, Gangwon-do, 26493, South Korea. Electronic address:

In this study, natural waste of marine corals was calcined to prepare an antimicrobial agent. Energy-dispersive X-ray fluorescence spectroscopy showed that the major element and compound of calcined corals were Ca and CaO, respectively, while X-ray photoelectron spectroscopy revealed the occurrence of more than one oxygen species (O) on the surface of calcined corals, which was ascribed to the presence of MgO. Scanning electron microscopy imaging showed that calcined corals had a rough surface and an irregular shape, and the particle size distribution indicated that the average particle size of the calcined corals was 7.3 μm. The calcined corals exhibited large zones of inhibition against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria as well as a fungus (Penicillium sp.), in the antimicrobial tests using well diffusion method. Notably, as a membrane-active and species-specific agent, pronounced antimicrobial activity for calcined corals was observed against S. aureus. Our newly developed bioactive calcined corals could be the potential antimicrobial agents in medical, biological, and food packaging applications.
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http://dx.doi.org/10.1016/j.msec.2019.110193DOI Listing
February 2020

Pollution, Toxicity and Carcinogenicity of Organic Dyes and their Catalytic Bio-Remediation.

Curr Pharm Des 2019 ;25(34):3645-3663

Chemistry Department, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia.

Water pollution due to waste effluents of the textile industry is seriously causing various health problems in humans. Water pollution with pathogenic bacteria, especially Escherichia coli (E. coli) and other microbes is due to the mixing of fecal material with drinking water, industrial and domestic sewage, pasture and agricultural runoff. Among the chemical pollutants, organic dyes due to toxic nature, are one of the major contaminants of industrial wastewater. Adequate sanitation services and drinking quality water would eliminate 200 million cases of diarrhea, which results in 2.1 million less deaths caused by diarrheal disease due to E. coli each year. Nanotechnology is an excellent platform as compared to conventional treatment methods of water treatment and remediation from microorganisms and organic dyes. In the current study, toxicity and carcinogenicity of the organic dyes have been studied as well as the remediation/inactivation of dyes and microorganism has been discussed. Remediation by biological, physical and chemical methods has been reviewed critically. A physical process like adsorption is cost-effective, but can't degrade dyes. Biological methods were considered to be ecofriendly and cost-effective. Microbiological degradation of dyes is cost-effective, eco-friendly and alternative to the chemical reduction. Besides, certain enzymes especially horseradish peroxidase are used as versatile catalysts in a number of industrial processes. Moreover, this document has been prepared by gathering recent research works related to the dyes and microbial pollution elimination from water sources by using heterogeneous photocatalysts, metal nanoparticles catalysts, metal oxides and enzymes.
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http://dx.doi.org/10.2174/1381612825666191021142026DOI Listing
June 2020

Allyl isothiocyanate encapsulated halloysite covered with polyacrylate as a potential antibacterial agent against food spoilage bacteria.

Mater Sci Eng C Mater Biol Appl 2019 Dec 26;105:110016. Epub 2019 Jul 26.

Department of Packaging, Yonsei University, 1 Yonseidae-gil, Wonju-si, Gangwon-do 26493, South Korea. Electronic address:

Allyl isothiocyanate (AITC) is a highly volatile organic compound that is a potential antibacterial agent against food spoilage bacteria. Naturally formed halloysite nanotubes (HNTs) have a length of 1 μm and diameter ranging from 10 to 50 nm. The biocompatibility of HNT allows safe release of drugs to bacterial cells at a relatively low concentration compared to other systems. We encapsulated AITC inside HNTs that were then coated with sodium polyacrylate (PA). The HNT-AITC-PA nanocomposites (NCs) were characterized by Fourier-transform infrared spectroscopy, thermal gravimetric, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy analyses. In vitro antibacterial activity was evaluated against gram positive (Staphylococcus aureus) and gram negative (Escherichia coli) bacteria capable of food spoilage. HNT-AITC-PA NCs effectively inhibited the growth of both bacteria. The activity was pronounced against E. coli at 100 μg/mL, with concentrations of 25 μg/mL and 200 μg/mL reducing the viable cell population by 41% and 96%, respectively. Thus, HNT-AITC-PA NCs are a novel and promising material against food spoilage bacteria for use in active antibacterial food packaging.
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http://dx.doi.org/10.1016/j.msec.2019.110016DOI Listing
December 2019

Poly(Lactic Acid)/Zno Bionanocomposite Films with Positively Charged Zno as Potential Antimicrobial Food Packaging Materials.

Polymers (Basel) 2019 Aug 30;11(9). Epub 2019 Aug 30.

Department of Packaging, Yonsei University, 1 Yonseidae-gil, Wonju-si, Gangwon-do 26493, Korea.

A series of PLA/ZnO bionanocomposite films were prepared by introducing positively surface charged zinc oxide nanoparticles (ZnO NPs) into biodegradable poly(lactic acid) (PLA) by the solvent casting method, and their physical properties and antibacterial activities were evaluated. The physical properties and antibacterial efficiencies of the bionanocomposite films were strongly dependent on the ZnO NPs content. The bionanocomposite films with over 3% ZnO NPs exhibited a rough surface, poor dispersion, hard agglomerates, and voids, leading to a reduction in the crystallinity and morphological defects. With the increasing ZnO NPs content, the thermal stability and barrier properties of the PLA/ZnO bionanocomposite films were decreased while their hydrophobicity increased. The bionanocomposite films showed appreciable antimicrobial activity against and . Especially, the films with over 3% of ZnO NPs exhibited a complete growth inhibition of E. coli. The strong interactions between the positively charged surface ZnO NPs and negatively charged surface of the bacterial membrane led to the production of reactive oxygen species (ROS) and eventually bacterial cell death. Consequently, these PLA/ZnO bionanocomposite films can potentially be used as a food packaging material with excellent UV protective and antibacterial properties.
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http://dx.doi.org/10.3390/polym11091427DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6780077PMC
August 2019

Influence of Mg doping on the structural, morphological, optical, thermal, and visible-light responsive antibacterial properties of ZnO nanoparticles synthesized via co-precipitation.

Mater Sci Eng C Mater Biol Appl 2019 May 9;98:717-725. Epub 2019 Jan 9.

Department of Packaging, Yonsei University, 1 Yonseidaegil, Wonju, Gangwondo 26493, Republic of Korea. Electronic address:

Mg-doped zinc oxide (ZnMgO, where x = 0.000, 0.001, 0.003, 0.005, and 0.010 M) nanoparticles (MgZnO NPs) were synthesized via a co-precipitation method and subjected to various analyses for application as functional additives in food packaging. The MgZnO NPs were successfully formed at approximately 360 °C and showed an increase in the optical band gap with respect to the increase in the concentration of Mg doping. The X-ray diffraction and scanning electron microscopy analyses of MgZnO NPs confirmed the formation of hexagonal wurtzite structure and rod-like morphology. X-ray photoelectron spectra revealed that the Mg (1s) peaks centered at 1303.35 and 1303.38 eV were ascribed to the presence of Mg replacing Zn. Transmission electron microscopy images showed rod shapes with the length of 208-650nm and width of 84-142 nm. Various concentrations of synthesized MgZnO NPs were investigated against a gram-negative (Escherichia coli - DH5α) bacterial strain under light and dark conditions. Among the studied samples, 0.010 M MgZnO NPs of concentration 3 mg/mL showed the best antibacterial activity under the light condition. MgZnO NPs revealed uneven ridges on the outer surface, which promote the diffusion ability of Zn and increased production of reactive oxygen species, and consequently lead to bacterial lysis. Furthermore, this study demonstrates excellent feasibility for the application of MgZnO NPs as fillers with good antibacterial activity, especially in antimicrobial food packaging applications.
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http://dx.doi.org/10.1016/j.msec.2019.01.035DOI Listing
May 2019

Preparation and Characterization of Poly(ether-block-amide)/Polyethylene Glycol Composite Films with Temperature-Dependent Permeation.

Polymers (Basel) 2018 Feb 24;10(2). Epub 2018 Feb 24.

Department of Packaging, Yonsei University, 1 Yonseidae-gil, Wonju-si, Gangwon-do 26493, Korea.

A series of poly(ether-block-amide) (PEBAX)/polyethylene glycol (PEG) composite films (PBXPG) were prepared by solution casting technique. This study demonstrates how the incorporation of different molecular weight PEG into PEBAX can improve the as-prepared composite film performance in gas permeability as a function of temperature. Additionally, we investigated the effect of PEG with different molecular weights on gas transport properties, morphologies, thermal properties, and water sorption. The thermal stability of the composite films increased with increasing molecular weight of PEG, whereas the water sorption and total surface energy decreased. As the temperature increased from 10 to 80 °C, the low (L)-PBXPG and medium (M)-PBXPG films showed a trend similar to the pure PEBAX film. However, the high (H)-PBXPG film with relatively high molecular weight exhibited a distinct permeation jump in the phase change region of H-PEG, which is related to the temperature dependent changes in the morphology structure such as crystallinity and the chemical affinity between the polymer film and gas molecule. Based on these results, it can be expected that H-PBXPG composite films can be used as self-ventilating materials in microwave cooking.
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http://dx.doi.org/10.3390/polym10020225DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6414837PMC
February 2018

Development of functional antimicrobial papers using chitosan/starch-silver nanoparticles.

Int J Biol Macromol 2018 Jun 31;112:530-536. Epub 2018 Jan 31.

Department of Packaging, Yonsei University, Gangwondo 26493, Republic of Korea. Electronic address:

In the present work, we report the synthesis of chitosan:starch‑silver nanoparticle (Cht:St-AgNPs) coated papers for antimicrobial packaging applications. The starch-assisted synthesized St-AgNPs are spherical in shape with an average particle size of 7 nm. Chitosan was mixed into the synthesized St-AgNPs solution with different ratios of 9:1, 8:2, 7:3, and 5:5 by weight. Further, the influence of different ratios of Cht:St-AgNPs on the various paper properties such as mechanical properties, water and oil resistance, and antimicrobial activities was investigated. It was observed that the properties of the coated papers were strongly dependent on the composition of Cht:St-AgNPs. The Cht:St-AgNPs-coated paper prepared with the ratio of 9:1 showed excellent mechanical properties and good resistance properties against water and oil. The Cht:St-AgNPs coated papers showed a remarkable enhancement in mechanical strength, oil and water resistance, and antibacterial and antifungal activity, which can make them a potential candidate for functional antimicrobial packaging applications.
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http://dx.doi.org/10.1016/j.ijbiomac.2018.01.155DOI Listing
June 2018

One-step synthesis of starch-silver nanoparticle solution and its application to antibacterial paper coating.

Int J Biol Macromol 2018 Feb 17;107(Pt B):2285-2290. Epub 2017 Oct 17.

Department of Packaging, Yonsei University, Gangwondo 26493, Republic of Korea. Electronic address:

Antibacterial starch-silver nanoparticles (ST-AgNPs) for use as coating solutions were prepared in a single step by ultrasonicating a mixture of starch, silver nitrate, and distilled water. The starch was used as an eco-friendly and inexpensive reducing agent. UV-vis spectra and transmission electron microscopy indicated that our single-step process was effective for synthesizing starch-based coating solution with AgNPs. Further, the as-prepared coating solution with AgNPs was applied to expand the application of paper for antibacterial packaging. The starch-coated paper with AgNPs showed not only highly enhanced oil resistance, but also excellent antibacterial activity, making our biodegradable starch-coated paper with AgNPs highly feasible for packaging applications.
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http://dx.doi.org/10.1016/j.ijbiomac.2017.10.108DOI Listing
February 2018

Chitosan-mediated synthesis of flowery-CuO, and its antibacterial and catalytic properties.

Carbohydr Polym 2017 Sep 24;172:78-84. Epub 2017 Apr 24.

Department of Packaging, Yonsei University, Gangwondo 26493, Republic of Korea. Electronic address:

In the current investigation, CuO with a flower-like morphology has been successfully synthesized in situ in a chitosan medium (0.0015gmL) from copper nitrate (Cu(NO)·3HO) and ammonia solution via a facile microwave-induced method. The as-prepared CuO was characterized by SEM, TEM, EDX, XRD, FTIR and TGA. The antibacterial activity of the flower-CuO against Escherichia coli was examined by analyzing colony forming units, and it was proved that the flower-CuO was able to kill >99% bacteria. Further, the flower-CuO exhibited excellent catalytic activity towards the reduction of 4-nitrophenol to 4-aminophenol in the presence of NaBH. The reaction kinetics followed a pseudo-first-order rate law with a rate constant of 0.183min. To the best of our knowledge, this is the first time that copper oxide with the flower-like morphology has been synthesized by using a chitosan solution.
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http://dx.doi.org/10.1016/j.carbpol.2017.04.070DOI Listing
September 2017

Development of a pH indicator composed of high moisture-absorbing materials for real-time monitoring of chicken breast freshness.

Food Sci Biotechnol 2017 28;26(1):37-42. Epub 2017 Feb 28.

Department of Packaging, Yonsei University, Wonju, Gangwon, 26493 Korea.

A colorimetric bromocresol purple dye-based pH-responsive indicator was developed to monitor the quality of chicken breast meat by direct surface contact. To prevent direct contact of the dye with the chicken breast and to improve its color change sensitivity, it was immobilized with polyvinyl alcohol and a high-absorbance material. The color of the pH indicator changes from yellow to blue and finally purple to indicate spoilage, which can be easily detected by the naked eye. The asprepared pH indicator exhibited good response to pH changes on the surface of chicken breast meat, and no migration of the dye from the indicator onto the surface of the chicken was observed. This pH indicator exhibits excellent feasibility for real-time, direct-contact monitoring of the freshness and quality of various foods.
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http://dx.doi.org/10.1007/s10068-017-0005-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6049484PMC
February 2017

Improving properties of Hanji by coating chitosan-silver nanoparticle solution.

Int J Biol Macromol 2016 Dec 20;93(Pt A):933-939. Epub 2016 Sep 20.

Department of Packaging, Yonsei University, Gangwondo 220-710, Republic of Korea. Electronic address:

A chitosan-silver nanoparticle solution (CSNS) was applied as a coating material to Hanji (Korean traditional paper), and the properties of the coated paper were investigated as a function of the dilution ratio. The required CSNS was first prepared from AgNO (30mmol) by utilizing chitosan as a reducing and stabilizing agent via ultrasonication. The as-prepared CSNS was diluted to various ratios (undiluted, 1/10, 1/100, and 1/1000) and applied to Hanji by a dip-coating method. The tensile, burst, oil resistance, and antibacterial properties of the coated Hanji against Escherichia coli were evaluated. Among the various dilution ratios, the maximum level of dilution that can positively influence the tensile, burst, oil resistance, and antibacterial properties of Hanji was identified as 1/10, 1/100, 1/10 and 1/1000 of the pure CSNS, respectively. These findings are significant because a specific property of Hanji can be economically improved by changing the dilution ratio.
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http://dx.doi.org/10.1016/j.ijbiomac.2016.09.067DOI Listing
December 2016

Identification of silver cubic structures during ultrasonication of chitosan AgNO3 solution.

Carbohydr Polym 2016 Nov 14;152:558-565. Epub 2016 Jul 14.

Department of Packaging, Yonsei University, Kangwondo 220-710, Republic of Korea. Electronic address:

During ultrasonication of chitosan AgNO3 solution (10mM), silver cubic structures were identified along with other dispersed silver nanoparticles. Temperature influenced the formation of the cubic structures. Formation of the silver cubic structures occurred via initial formation of 'four petal flower-like' structures that underwent transformation to the "cubic morphology" in the latter stages. Aging of the reaction mixture led to formation of complete dendrites. These dendrites comprised a large quantity of silver nanoparticles. Upon repetition of the experiment with starch instead of chitosan, the identified silver cubic structures were completely absent, indicating that formation of the 'silver cubic structures' is dependent on the polysaccharide used. It is believed that the structural features of chitosan facilitate the formation of 'silver cubic structures' under ultrasonic conditions. The phenomena occurring during the experiments were evaluated via scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), ultraviolet-visible (UV-vis) spectra, transmission electron microscopy (TEM), and selected area electron diffraction (SAED) analysis.
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http://dx.doi.org/10.1016/j.carbpol.2016.07.045DOI Listing
November 2016

CuO embedded chitosan spheres as antibacterial adsorbent for dyes.

Int J Biol Macromol 2016 Jul 16;88:113-9. Epub 2016 Mar 16.

Department of Packaging, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwon-do 220-710, Republic of Korea.

Chitosan/copper oxide (CS/CuO) composite spheres were prepared by simple mixing of CuO nanomaterials in CS solution followed by dropwise addition to NH4OH solution. The characterizations of all the prepared spheres were carried out by FESEM, EDS, XRD, XPS, and FTIR analyses while the thermal properties were analyzed by TGA. Further the ability of composite spheres was tested as an easily removable pollutant adsorbent from water containing different dyes and compared with pure CS. Composite spheres were found to be the best adsorbent when applied to remove indigo carmine (IC), congo red (CR) and methyl orange (MO) from water. Amongst the three dyes, CS/CuO composite spheres were more selective toward MO adsorption. CS/CuO composite spheres also displayed significant antibacterial activity by inhibiting Pseudomonas aeruginosa growth. Thus the fabricated composite spheres can be used as a biosorbent in the future.
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http://dx.doi.org/10.1016/j.ijbiomac.2016.03.026DOI Listing
July 2016

Step-reduced synthesis of starch-silver nanoparticles.

Int J Biol Macromol 2016 May 20;86:126-8. Epub 2016 Jan 20.

Department of Packaging, Yonsei University, Kangwondo 220-710, Republic of Korea. Electronic address:

In the present process, silver nanoparticles were directly synthesized in a single step by microwave irradiation of a mixture of starch, silver nitrate, and deionized water. This is different from the commonly adopted procedure for starch-silver nanoparticle synthesis in which silver nanoparticles are synthesized by preparing a starch solution as a reaction medium first. Thus, the additional step associated with the preparation of the starch solution was eliminated. In addition, no additional reducing agent was utilized. The adopted method was facile and straight forward, affording spherical silver nanoparticles with diameter below 10nm that exhibited good antibacterial activity. Further, influence of starch on the size of the silver nanoparticles was noticed.
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http://dx.doi.org/10.1016/j.ijbiomac.2016.01.057DOI Listing
May 2016

Microwave assisted antibacterial chitosan-silver nanocomposite films.

Int J Biol Macromol 2016 Mar 17;84:281-8. Epub 2015 Dec 17.

Department of Packaging, Yonsei University, Kangwondo 220-710, Republic of Korea. Electronic address:

In the current approach, antibacterial chitosan-silver nanocomposite films were fabricated through microwave irradiation. During the process, by utilizing chitosan as reducing agent, silver nanoparticles were synthesized within 11 min by microwave irradiation. Further, films were fabricated within 90 min. It involved an energy consumption of just 0.146 kWh to synthesize silver nanoparticles. This is many times less than the energy consumed during conventional methods. The silver nanoparticles were examined through UV-vis spectrum and transmission electron microscopy (TEM). The fabricated films were characterized by using scanning electron microscopy coupled with an energy dispersive spectrometer (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and contact angle (CA) measurements. The films exhibited antibacterial properties against both Gram-negative micro-organisms (Escherichia coli; E. coli) and Gram-positive micro-organisms (Staphylococcus aureus; S. aureus). In overall, the procedure adopted for fabricating these antibacterial films is environmental friendly, time-saving and energy-saving.
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http://dx.doi.org/10.1016/j.ijbiomac.2015.12.026DOI Listing
March 2016

Nano zinc oxide-sodium alginate antibacterial cellulose fibres.

Carbohydr Polym 2016 Jan 28;135:349-55. Epub 2015 Aug 28.

Department of Packaging, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwon-do 220-710, South Korea.

In the present study, antibacterial cellulose fibres were successfully fabricated by a simple and cost-effective procedure by utilizing nano zinc oxide. The possible nano zinc oxide was successfully synthesized by precipitation technique and then impregnated effectively over cellulose fibres through sodium alginate matrix. XRD analysis revealed the 'rod-like' shape alignment of zinc oxide with an interplanar d-spacing of 0.246nm corresponding to the (101) planes of the hexagonal wurtzite structure. TEM analysis confirmed the nano dimension of the synthesized zinc oxide nanoparticles. The presence of nano zinc oxide over cellulose fibres was evident from the SEM-EDS experiments. FTIR and TGA studies exhibited their effective bonding interaction. The tensile stress-strain curves data indicated the feasibility of the fabricated fibres for longer duration utility without any significant damage or breakage. The antibacterial studies against Escherichia coli revealed the excellent bacterial devastation property. Further, it was observed that when all the parameters remained constant, the variation of sodium alginate concentration showed impact in devastating the E. coli. In overall, the fabricated nano zinc oxide-sodium alginate cellulose fibres can be effectively utilized as antibacterial fibres for biomedical applications.
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http://dx.doi.org/10.1016/j.carbpol.2015.08.078DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7112416PMC
January 2016

Tyrosinase inhibitory effect of benzoic acid derivatives and their structure-activity relationships.

J Enzyme Inhib Med Chem 2010 Dec 17;25(6):812-7. Epub 2010 May 17.

Department of Chemical and Biomolecular Engineering, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul, South Korea.

A series of benzoic acid derivatives 1-10 have been synthesised by two different methods. Compounds 1-6 were synthesised by a facile procedure for esterification using N,N'-dicyclohexylcarbodiimide (DCC) as a coupling agent, methylene chloride as a solvent system and dimethylaminopyridine (DMAP). While 7-10 were synthesised by converting benzoic acid into benzoyl chloride by treating with thionyl chloride in the presence of benzene and performing a further reaction with amine in dried benzene. The structures of all the synthesised derivatives of benzoic acid (1-10) were assigned on the basis of extensive NMR studies. All of them showed inhibitory potential against tyrosinase. Among them, compound 7 was found to be the most potent (1.09 μM) when compared with the standard tyrosinase inhibitors of kojic acid (16.67 μM) and L-mimosine (3.68 μM). Finally in this paper, we have discussed the structure-activity relationships of the synthesised molecules.
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http://dx.doi.org/10.3109/14756366.2010.482529DOI Listing
December 2010