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Kang H.,Ewha Womans University | Kang H.,University of California at San Diego | Kim H.-J.,Yonsei University | Yang J.-H.,Ewha Womans University | And 6 more authors.
Applied Clay Science

We intercalated ferulic acid (FA) molecules into a layered double hydroxides (LDHs) via three different synthesis routes-ion-exchange, exfoliation-reassembly, and reconstruction-to obtain FA-LDH nanohybrids. All the nanohybrids started from same MgAl-CO3-LDH pristine, with a homogeneous particle size of 80nm, in order to control particle size of final products. According to infrared spectroscopy, all the synthesis routes resulted in successful hybridization between anionic ferulate and positive LDH layers. X-ray diffraction, UV-Vis spectroscopy and thermal analyses showed that the FA molecules were arranged in a zig-zag manner to maximize π-π interactions among them. From scanning electron microscopy, it was revealed that reconstruction gave rise to structural re-organization of LDH layers resulting in a house-of-cards morphology in the nanohybrid, while other methods produced a hexagonal plate-like shape. It seems that FA moieties intercalated by a reconstruction method could be accommodated in the inter-particle cavity as well as the interlayer space in FA-LDH nanohybrids. We investigated time-dependent FA release profiles from each nanohybrid in deionized water and saline. The release patterns and kinetic model fitting results revealed that the release behavior was different each nanohybrid according to the synthesis method and followed Elovich and power function models. © 2015 Elsevier B.V. Source

Kim H.-J.,Yonsei University | Ryu K.,Seoul National University | Kang J.-H.,Ewha Womans University | Choi A.-J.,National Institute of Horticultural and Herbal Science NIHHS of RDA | And 2 more authors.
The Scientific World Journal

We have successfully prepared nanohybrids of biofunctional ferulic acid and layered double hydroxide nanomaterials through reconstruction and exfoliation-reassembly routes. From X-ray diffraction and infrared spectroscopy, both nanohybrids were determined to incorporate ferulic acid molecules in anionic form. Micrsocopic results showed that the nanohybrids had average particle size of 150 nm with plate-like morphology. As the two nanohybridization routes involved crystal disorder and random stacking of layers, the nanohybrids showed slight alteration in z -axis crystallinity and particle size. The zeta potential values of pristine and nanohybrids in deionized water were determined to be positive, while those in cell culture media shifted to negative values. According to the in vitro anticancer activity test on human cervical cancer HeLa cells, it was revealed that nanohybrids showed twice anticancer activity compared with ferulic acid itself. Therefore we could conclude that the nanohybrids of ferulic acid and layered double hydroxide had cellular delivery property of intercalated molecules on cancer cell lines. © 2013 Hyoung-Jun Kim et al. Source

Kim T.-H.,Yonsei University | Kim H.-J.,Yonsei University | Choi A.-J.,National Institute of Horticultural and Herbal Science NIHHS of RDA | Choi H.-J.,Yonsei University | Oh J.-M.,Yonsei University
Journal of Nanoscience and Nanotechnology

We have hybridized layered double hydroxide (LDH) with Angelica gigas Nakai root extract (AGNR) through reversible dehydration-rehydration reaction which is known as reconstruction. LDHs having well-ordered hydrotalcite-like crystal structure and average size 250±20 nm were prepared by hydrothermal method. The root of Angelica gigas Nakai, which has been utilized in the treatment of female disorders as herbal medicine, was treated with methanol to obtain extract. Pristine LDHs were calcined at 400°C for 8 hours to obtain layered double oxide (LDO), which was further dispersed into extract solution with various AGNR/LDO weight ratios, 0.11, 0.21 and 0.43. The extract content in each hybrid increased in proportion to initial AGNR/LDO ratio, showing the highest content of ∼12%. The zeta potential of LDH shifted from +44 mV to +20 mV upon hybridization with extract, which was attributed to the adsorption of negatively charged organic moieties in AGNR on LDH surface. The scanning electron microscopic (SEM) results exhibited that the random stacking of LDH nanolayers resulted in LDH-AGNR hybrid with house-of-cards structure, of which inter-particle cavity serves nano-reservoir for natural extract. According to quantitative analyses, it was revealed that the content of active components in AGNR increased when they were hybridized with LDHs compared with those in AGNR alone. Copyright © 2016 American Scientific Publishers All rights reserved. Source

Kim K.-M.,Yonsei University | Park C.-B.,National Institute of Horticultural and Herbal Science NIHHS of RDA | Choi A.-J.,National Institute of Horticultural and Herbal Science NIHHS of RDA | Choy J.-H.,Ewha Womans University | Oh J.-M.,Yonsei University
Bulletin of the Korean Chemical Society

We investigated the selective deoxyribonucleic acid (DNA) adsorption on layered double hydroxide (LDH) nanoparticles via studying the interaction between positively charged LDH nanoparticle as adsorbent and negatively charged adsorbates such as methyl orange (MO), fluorescein (FL), and DNA strands. The size controlled LDH (Mg0.78Al0.22(OH)2(CO 3)0.11 · mH2O) was prepared by conventional coprecipitation method, followed by the hydrothermal treatment. According to the adsorption isotherms, the adsorbed amounts of MO and FL were similar, however, that of DNA were much larger. The adsorption behaviors were well fitted to Freundlich adsorption model. The concentration dependent adsorption behavior on LDH surface was described in order to verify the selective DNA separation ability. The result showed that the LDH has advantages in selective adsorption of DNA competing with single molecular anions. Source

Kim T.-H.,Yonsei University | Heo I.,Yonsei University | Paek S.-M.,Kyungpook National University | Park C.-B.,National Institute of Horticultural and Herbal Science NIHHS of RDA | And 4 more authors.
Bulletin of the Korean Chemical Society

Layered metal hydroxides (LMHs) containing calcium were synthesized by coprecipitation in solution having two different trivalent metal ions, iron and aluminum. Two mixed metal solutions (Ca 2+/Al 3+ and Ca 2+/Fe 3+ = 2/1) were added to sodium hydroxide solution and the final pH was adjusted to ∼11.5 and ∼13 for CaAl-and CaFe-LMHs. Powder X-ray diffraction (XRD) for the two LMH samples showed well developed (00l) diffractions indicating 2-dimensional crystal structure of the synthesized LMHs. Rietveld refinement of the Xray diffraction pattern, the local structure analysis through X-ray absorption spectroscopy, and thermal analysis also confirmed that the synthesized precipitates show typical structure of LMHs. The chemical formulae, Ca 2.04Al 1(OH) 6(NO 3)· 5.25H 2O and Ca 2.01Fe 1(OH) 6(NO 3)· 4.75H 2O were determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Particle morphology and thermal behavior for the synthesized LMHs were examined by field emission scanning electron microscopy and thermogravimetricdifferential scanning calorimetry. Source

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