Browsing by Author "Mou, Chung-Yuan"

Now showing 1 - 3 of 3

Corneal repair by human corneal keratocyte-reprogrammed iPSCs and amphiphatic carboxymethyl-hexanoyl chitosan hydrogel
(2012-11-01)
Chien, Yueh
;
Liao, Yi-Wen
;
Liu, Dean-Mo
;
Lin, Heng-Liang
;
Chen, Shih-Jen
Induced pluripotent stem cells (iPSCs) have promising potential in regenerative medicine, but whether iPSCs can promote corneal reconstruction remains undetermined. In this study, we successfully reprogrammed human corneal keratocytes into iPSCs. To prevent feeder cell contamination, these iPSCs were cultured onto a serum- and feeder-free system in which they remained stable through 30 passages and showed ESC-like pluripotent property. To investigate the availability of iPSCs as bioengineered substitutes in corneal repair, we developed a thermo-gelling injectable amphiphatic carboxymethyl-hexanoyl chitosan (CHC) nanoscale hydrogel and found that such gel increased the viability and CD44 + proportion of iPSCs, and maintained their stem-cell like gene expression, in the presence of culture media. Combined treatment of iPSC with CHC hydrogel (iPSC/CHC hydrogel) facilitated wound healing in surgical abrasion-injured corneas. In severe corneal damage induced by alkaline, iPSC/CHC hydrogel enhanced corneal reconstruction by downregulating oxidative stress and recruiting endogenous epithelial cells to restore corneal epithelial thickness. Therefore, we demonstrated that these human keratocyte-reprogrammed iPSCs, when combined with CHC hydrogel, can be used as a rapid delivery system to efficiently enhance corneal wound healing. In addition, iPSCs reprogrammed from corneal surgical residues may serve as an alternative cell source for personalized therapies for human corneal damage. (C) 2012 Elsevier Ltd. All rights reserved.
Mechanistic study for the selective oxidation of benzene and toluene catalyzed by Fe(ClO4)(2) in an H2O2-H2O-CH3CN system
(2017-11-01)
Ramu, Ravirala
;
Wanna, Wondemagegn Hailemichael
;
Janmanchi, Damodar
;
Tsai, Yi-Fang
;
Liu, Chih-Cheng
Iron(II) perchlorate in an H2O-H2O2-CH3CN mixture was used to efficiently carry out C-H bond activations of benzene to form phenol and/or hydroquinone, and of toluene to form benzaldehyde, benzyl alcohol, o-cresol, p-cresol, and/or methyl-p-benzoquinone. The reactions were facilely tuned and controlled to selectively yield either a single or double oxygenation of benzene as well as a sp(3) or sp(2) C-H bond oxidation of toluene. On the basis of HAD kinetic isotope effect data, we determined the aromatic oxidation to mostly proceed by way of formation of an arene oxide or a sigma-complex intermediate from high-valence iron species and to then undergo a 1,2-hydride shift, i.e., NIH-shift rearrangement. (C) 2017 Elsevier B.V. All rights reserved.
Mesostructured Arrays of Nanometer-spaced Gold Nanoparticles for Ultrahigh Number Density of SERS Hot Spots
(2014-05-01)
Lai, Ying-Huang
;
Chen, Shiaw-Woei
;
Hayashi, Michitoshi
;
Shiu, Ying-Jen
;
Huang, Chiao-Cheng
A novel one-trough synthesis via an air-water interface is demonstrated to provide hexagonally packed arrays of densely spaced metallic nanoparticles (NPs). In the synthesis, a mesostructured polyoxometalate (POM)-silicatropic template (PSS) is first self-assembled at the air-water interface; upon UV irradiation, anion exchange cycles enable the free-floating PSS film to continuously uptake gold precursors from the solution subphase for diffusion-controlled and POM-site-directed photoreduction inside the silica channels. NPs approximate to 2 nm can hence be homogeneously formed inside the silica-surfactant channels until saturation. As revealed via X-ray diffraction, small-angle X-ray scattering (SAXS), grazing incidence SAXS, and transmission electron microscopy, the Au NPs directed by the PSS template are arrayed into a 2D hexagonal lattice with inter-channel spacing of 3.2 nm and a mean along-channel NP spacing of 2.8 nm. This corresponds to an ultra-high number density (approximate to 10(19) NPs cm(-3)) of narrowly spaced Au NPs in the Au-NP@PSS composite, leading to 3D densely deployed hot-spots along and across the mesostructured POM-silica channels for surface-enhanced Raman scattering (SERS). Consequently, the Au-NP@PSS composite exhibits prominent SERS with 4-mercaptobenzoic acid (4-MBA) adsorbed onto Au NPs. The best 4-MBA detection limit is 5 nm, with corresponding SERS enhancement factors above 10(8).