191 results on '"Kai, Dan"'
Search Results
152. Electrospun Poly(L-Lactic Acid)-co-Poly( ϵ -Caprolactone) Nanofibres Containing Silver Nanoparticles for Skin-Tissue Engineering
- Author
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Jin, Guorui, primary, Prabhakaran, Molamma P., additional, Nadappuram, Binoy P., additional, Singh, Gurdev, additional, Kai, Dan, additional, and Ramakrishna, Seeram, additional
- Published
- 2012
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153. Electrospun composite scaffolds containing poly(octanediol‐co‐citrate) for cardiac tissue engineering
- Author
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Prabhakaran, Molamma P., primary, Nair, A. Sreekumaran, additional, Kai, Dan, additional, and Ramakrishna, Seeram, additional
- Published
- 2012
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154. Mechanical properties andin vitrobehavior of nanofiber–hydrogel composites for tissue engineering applications
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Kai, Dan, primary, Prabhakaran, Molamma P, additional, Stahl, Benjamin, additional, Eblenkamp, Markus, additional, Wintermantel, Erich, additional, and Ramakrishna, Seeram, additional
- Published
- 2012
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155. Electrospun photosensitive nanofibers: potential for photocurrent therapy in skin regeneration
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Jin, Guorui, primary, Prabhakaran, Molamma P., additional, Kai, Dan, additional, Kotaki, Masaya, additional, and Ramakrishna, Seeram, additional
- Published
- 2012
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156. Emulsion electrospun vascular endothelial growth factor encapsulated poly(l-lactic acid-co-ε-caprolactone) nanofibers for sustained release in cardiac tissue engineering
- Author
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Tian, Lingling, primary, Prabhakaran, Molamma P., additional, Ding, Xin, additional, Kai, Dan, additional, and Ramakrishna, Seeram, additional
- Published
- 2011
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157. Polypyrrole-contained electrospun conductive nanofibrous membranes for cardiac tissue engineering
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Kai, Dan, primary, Prabhakaran, Molamma P., additional, Jin, Guorui, additional, and Ramakrishna, Seeram, additional
- Published
- 2011
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158. Electrospun biocomposite nanofibrous patch for cardiac tissue engineering
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P Prabhakaran, Molamma, primary, Kai, Dan, additional, Ghasemi-Mobarakeh, Laleh, additional, and Ramakrishna, Seeram, additional
- Published
- 2011
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159. Guided orientation of cardiomyocytes on electrospun aligned nanofibers for cardiac tissue engineering
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Kai, Dan, primary, Prabhakaran, Molamma P, additional, Jin, Guorui, additional, and Ramakrishna, Seeram, additional
- Published
- 2011
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160. Biomimetic material strategies for cardiac tissue engineering
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Prabhakaran, Molamma P., primary, Venugopal, J., additional, Kai, Dan, additional, and Ramakrishna, Seeram, additional
- Published
- 2011
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161. Preparation of Tetracalcium Phosphate and the Effect on the Properties of Calcium Phosphate Cement
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Kai, Dan, primary, Fan, Hong Song, additional, Li, Dong Xiao, additional, Zhu, Xiang Dong, additional, and Zhang, Xing Dong, additional
- Published
- 2009
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162. Galangin induces apoptosis of hepatocellular carcinoma cellsviathe mitochondrial pathway
- Author
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Kai-Dan Zhu, Min Wen, Liubo Lan, Hui Luo, Jun Wu, Haitao Zhang, Hui-Ming Liu, Da-Hua Fan, and Xiaoyi Chen
- Subjects
Carcinoma, Hepatocellular ,Apoptosis ,Mitochondrion ,Pharmacology ,complex mixtures ,chemistry.chemical_compound ,Cell Line, Tumor ,Humans ,Viability assay ,Propidium iodide ,Flavonoids ,Membrane Potential, Mitochondrial ,Dose-Response Relationship, Drug ,biology ,Cytochrome c ,Liver Neoplasms ,Gastroenterology ,food and beverages ,General Medicine ,Transfection ,Molecular biology ,digestive system diseases ,Mitochondria ,Galangin ,Proto-Oncogene Proteins c-bcl-2 ,chemistry ,biology.protein ,Original Article ,Signal transduction ,Mutagens ,Signal Transduction - Abstract
AIM: To investigate the mechanism by which galangin, a polyphenolic compound derived from medicinal herbs, induces apoptosis of hepatocellular carcinoma (HCC) cells. METHODS: The 3-(4,5-Dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay was used to measure cell viability. Apoptosis was evaluated by in situ uptake of propidium iodide and Hoechst 33258 and was then detected by fluorescence microscopy. Protein expressions were detected by Western blotting. To confirm the apoptotic pathway mediated by galangin, cells were transfected by bcl-2 gene to overexpress Bcl-2 or siRNA to down-regulate Bcl-2 expression. RESULTS: Galangin (46.25-370.0 μmol/L) exerted an anti-proliferative effect, induced apoptosis, and decreased mitochondrial membrane potential in a dose and time-dependent manner. Treatment with galangin induced apoptosis by translocating the pro-apoptotic protein Bax to the mitochondria, which released apoptosis-inducing factor and cytochrome c into the cytosol. Overexpression of Bcl-2 attenuated galangin-induced HepG2 cell apoptosis, while decreasing Bcl-2 expression enhanced galangin-induced cell apoptosis. CONCLUSION: Our data suggests that galangin mediates apoptosis through a mitochondrial pathway, and may be a potential chemotherapeutic drug for the treatment of HCC.
- Published
- 2010
163. A Triazolyl-Pyridine-Supported CuI Dimer: Tunable Luminescence and Fabrication of Composite Fibers.
- Author
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Bai, Shi‐Qiang, Kai, Dan, Ke, Karen Lin, Lin, Ming, Jiang, Lu, Jiang, Ying, Young, David James, Loh, Xian Jun, Li, Xu, and Hor, T. S. Andy
- Subjects
- *
BENZONITRILE , *DIMERS spectra , *PYRIDINE , *PHOTOLUMINESCENCE measurement , *LUMINESCENCE measurement , *X-ray diffraction , *THERMOGRAVIMETRY - Abstract
The dinuclear complex [Cu2I2(L1)2] ( 1) (L1=3-((4-(pyridin-2-yl)-1 H-1,2,3-triazol-1-yl)methyl)benzonitrile) is characterized by single-crystal X-ray diffraction (XRD), powder XRD, IR, photoluminescence spectroscopy, and thermogravimetric analysis. Unlike other related, known copper iodide complexes, it exhibits strong yellow emission in the solid state at both room temperature and 77 K. Showing good compatibility with PMMA, it is blended with the polymer in different weight ratios to prepare luminescent composite fibers. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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164. Methods for Nano/Micropatterning of Substrates: Toward Stem Cells Differentiation.
- Author
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Prabhakaran, MolammaP., Vatankhah, Elham, Kai, Dan, and Ramakrishna, Seeram
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NANOTECHNOLOGY ,MEDICAL technology ,TISSUE engineering ,ELECTRON beams ,LITHOGRAPHY ,SUBSTRATES (Materials science) - Abstract
Micro- and nanoengineering of materials offer novel technologies and serve as an interface between material sciences and biomedical nanotechnology. Various techniques are used for the engineering of polymers, and it allows the precise orientation of biomolecules with designed nanoregions in a substrate, with defined sizes and continuity offering well featured substrate topographies. Methods such as the electron beam lithography coupled with microcontact printing have been applied for the fabrication of high resolution surface features that are smaller than the size of a cell. This review elaborates more deeply on the different methods used for the fabrication of patterned surfaces such as the photolithography, electron beam lithography, microcontact printing, soft lithography, capillary force lithography, and patterning of electrospun fibers. The nanoengineered substrates may have the ability to influence the differentiation of stem cells to specific lineages and here we survey a few details on the influence of surface topology and its potential for tissue regeneration. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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165. Differentiation of embryonic stem cells to cardiomyocytes on electrospun nanofibrous substrates.
- Author
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Prabhakaran, Molamma P., Mobarakeh, Laleh Ghasemi, Kai, Dan, Karbalaie, Khadijeh, Nasr-Esfahani, Mohammad Hossein, and Ramakrishna, Seeram
- Abstract
The potential of pluripotent embryonic stem cells (ESCs) isolated from the inner mass of blastocysts are investigated for its ability to differentiate on biocompatible electrospun nanofibers, for regeneration of the myocardially infracted heart. Nanostructured poly( d, l-lactide- co-glycolide)/collagen (PLGA/Col) scaffolds with fiber diameters in the range of 300 ± 65 nm, was fabricated by electrospinning to mimic the extracellular matrix of the native tissue. During the culture of embryoid bodies outgrowth on the scaffolds, and further differentiation of ESCs to cardiomyocytes, the PLGA/Col nanofibers was found better than that of the electrospun PLGA nanofibers, where a better interaction and growth of ESC differentiated cardiomyocytes was observed on the composite scaffolds. The phenotypical characteristics of ESC-derived cardiomyocytes and molecular protein expression were carried out by scanning electron microscopy and immunocytochemistry, respectively. Our studies highlight the significance of a suitable material, its architecture, and cell-biomaterial interactions that is essential at a nanoscale level signifying the application of a bioengineered cardiac graft for stem cell differentiation and transplantation, which could be an intriguing strategy for cardiac regeneration. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 447-454, 2014. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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166. Electrospun synthetic and natural nanofibers for regenerative medicine and stem cells.
- Author
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Kai, Dan, Jin, Guorui, Prabhakaran, Molamma P., and Ramakrishna, Seeram
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- 2013
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167. Electrospun Poly(L-Lactic Acid)-co-Poly(ε-Caprolactone) Nanofibres Containing Silver Nanoparticles for Skin-Tissue Engineering.
- Author
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Jin, Guorui, Prabhakaran, Molamma P., Nadappuram, Binoy P., Singh, Gurdev, Kai, Dan, and Ramakrishna, Seeram
- Subjects
LACTIC acid ,CAPROLACTONES ,SILVER nanoparticles ,TISSUE engineering ,MICROORGANISMS ,ANTIBACTERIAL agents ,MICROFABRICATION ,CELL proliferation - Abstract
Silver nanoparticles (AgNPs) and silver ions (Ag
+ ) show growth-inhibitory activity against microorganisms and have been used for decades as antibacterial agents in various fields. To fabricate a nanofibrous scaffold which is antibacterial against bacteria and non-toxic to cells, we electrospun composite poly(L-lactic acid)-co-poly(ϵ-caprolactone) nanofibres containing silver nanoparticles (PLLCL-AgNPs) with different concentrations (0.25, 0.50 and 0.75 wt%) of silver nitrate (AgNO3 ) in PLLCL. The diameters of the electrospun PLLCL-AgNPs nanofibres decreased with the increase of AgNO3 concentration in PLLCL solutions. Human skin fibroblasts cultured on the scaffolds showed that the PLLCL nanofibres containing lesser amounts of AgNPs (0.25 wt%) had better cell proliferation and retained the cell morphology similar to the phenotype observed on tissue culture plates (control). The antibacterial activity of AgNPs in PLLCL nanofibres was investigated against Staphylococcus aureus and Salmonella enterica and the antimicrobial activity was found to increase with the increasing concentration of nanoparticles present in the scaffold. Based on our studies, we propose that PLLCL nanofibres containing 0.25 wt% AgNO3 or PLLCL-Ag(25), favors cell proliferation and inhibits bacteria and could be a suitable substrate for wound healing. [ABSTRACT FROM AUTHOR]- Published
- 2012
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168. Emulsion electrospun vascular endothelial growth factor encapsulated poly( l-lactic acid- co-ε-caprolactone) nanofibers for sustained release in cardiac tissue engineering.
- Author
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Tian, Lingling, Prabhakaran, Molamma, Ding, Xin, Kai, Dan, and Ramakrishna, Seeram
- Subjects
EMULSIONS ,ELECTROSPINNING ,VASCULAR endothelial growth factors ,DEXTRAN ,SCANNING electron microscopy ,ALBUMINS ,MESENCHYMAL stem cells - Abstract
Emulsion electrospinning is a novel approach to fabricate core-shell nanofibers, and it is associated with several advantages such as the alleviation of initial burst release of drugs and it protects the bioactivity of incorporated drugs or proteins. Aiming to develop a sustained release scaffold which could be a promising substrate for cardiovascular tissue regeneration, we encapsulated vascular endothelial growth factor (VEGF) with either of the protective agents, dextran or bovine serum albumin (BSA) into the core of poly( l-lactic acid- co-ε-caprolactone) (PLCL) nanofibers by emulsion electrospinning. The morphologies and fiber diameters of the emulsion electrospun scaffolds were determined by scanning electron microscope, and the core-shell structure was evaluated by laser scanning confocal microscope. Uniform nanofibers of PLCL, PLCL-VEGF-BSA, and PLCL-VEGF-DEX with fiber diameters in the range of 572 ± 92, 460 ± 63, and 412 ± 61 nm, respectively were obtained by emulsion spinning. The release profile of VEGF in phosphate-buffered saline for up to 672 h (28 days) was evaluated, and the scaffold functionality was established by performing cell proliferations using human bone marrow derived mesenchymal stem cells. Results of our study demonstrated that the emulsion electrospun VEGF containing core-shell structured PLCL nanofibers offered controlled release of VEGF through the emulsion electrospun core-shell structured nanofibers and could be potential substrates for cardiac tissue regeneration. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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169. Mechanical properties and in vitro behavior of nanofiber-hydrogel composites for tissue engineering applications.
- Author
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Kai, Dan, Prabhakaran, Molamma P., Stahl, Benjamin, Eblenkamp, Markus, Wintermantel, Erich, and Ramakrishna, Seeram
- Subjects
- *
NANOFIBERS , *HYDROGELS , *BIOMATERIALS , *MECHANICAL behavior of materials , *TISSUE engineering , *TISSUE scaffolds , *FIBROUS composites , *MATERIALS compression testing - Abstract
Hydrogel-based biomaterial systems have great potential for tissue reconstruction by serving as temporary scaffolds and cell delivery vehicles for tissue engineering (TE). Hydrogels have poor mechanical properties and their rapid degradation limits the development and application of hydrogels in TE. In this study, nanofiber reinforced composite hydrogels were fabricated by incorporating electrospun poly(&egr;-caprolactone) (PCL)/gelatin 'blend' or 'coaxial' nanofibers into gelatin hydrogels. The morphological, mechanical, swelling and biodegradation properties of the nanocomposite hydrogels were evaluated and the results indicated that the moduli and compressive strengths of the nanofiber reinforced hydrogels were remarkably higher than those of pure gelatin hydrogels. By increasing the amount of incorporated nanofibers into the hydrogel, the Young's modulus of the composite hydrogels increased from 3.29 ± 1.02 kPa to 20.30 ± 1.79 kPa, while the strain at break decreased from 66.0 ± 1.1% to 52.0 ± 3.0%. Compared to composite hydrogels with coaxial nanofibers, those with blend nanofibers showed higher compressive strength and strain at break, but with lower modulus and energy dissipation properties. Biocompatibility evaluations of the nanofiber reinforced hydrogels were carried out using bone marrow mesenchymal stem cells (BM-MSCs) by cell proliferation assay and immunostaining analysis. The nanocomposite hydrogel with 25 mg ml-1 PCL/gelatin 'blend' nanofibers (PGB25) was found to enhance cell proliferation, indicating that the 'nanocomposite hydrogels' might provide the necessary mechanical support and could be promising cell delivery systems for tissue regeneration. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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170. Electrospun biocomposite nanofibrous patch for cardiac tissue engineering.
- Author
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Prabhakaran, Molamma P, Kai, Dan, Ghasemi-Mobarakeh, Laleh, and Ramakrishna, Seeram
- Published
- 2011
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171. Synergistic UV Protection Effects of Lignin Nanodiamond Complex
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Yew, Pek Yin Michelle, Zhu, Dan Dan, Lin, Qian Yu, Jiang, Lu, Chee, Pei Lin, Leong, Hai Sheng, Dong, Zhaogang, Dong Guo, Xin, Kai, Dan, and Loh, Xian Jun
- Abstract
There are various concerns with current sunscreen actives in the sun care industry which pushes for a natural-based active that is sustainable as well as effective. Lignin is a natural polymer, capable of UV filtration and maintaining photostability. In this study, a variety of tuneable lignin-poly(ethylene glycol) (LP) nanodiamond complexes (LP-ND) were developed with varying ratios of LP to nanodiamonds (ND). There are two fractions of LP-ND, of which uses detonation ND (LP-rND) and furnace ND (LP-mND). Both complexes demonstrated favourable UV filtration, enhanced photostability and uniform dispersion in water and cream. The LP-mND had maintained its particle size at <200nm with increasing LP ratio from 0.5 to 20 times as oppose to the increased particle size of that in LP-rND. The LP-mND complex excelled in its photostability during solar radiation from 1hour to 6hours, demonstrating its effectiveness in absorbing 70% in the UV B region. Results had indicated enhanced synergistic effect of LP-rND and LP-mND with commercial sunscreen. The LP-rND complex had enhanced the sunscreen from 29 to 62, while the LP-mND had further boost the SPF to 89. In a nutshell, the lignin nanodiamond complexes offers a sustainable alternative to current actives in the industry.
- Published
- 2021
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172. How far is Lignin from being a biomedical material?
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Sugiarto, Sigit, Leow, Yihao, Tan, Chong Li, Wang, Guan, and Kai, Dan
- Abstract
Lignin is a versatile biomass that possesses many different desirable properties such as antioxidant, antibacterial, anti-UV, and good biocompatibility. Natural lignin can be processed through several chemical processes. The processed lignin can be modified into functionalized lignin through chemical modifications to develop and enhance biomaterials. Thus, lignin is one of the prime candidate for various biomaterial applications such as drug and gene delivery, biosensors, bioimaging, 3D printing, tissue engineering, and dietary supplement additive. This review presents the potential of developing and utilizing lignin in the outlook of new and sustainable biomaterials. Thereafter, we also discuss on the challenges and outlook of utilizing lignin as a biomaterial.
- Published
- 2021
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173. Green Nanocellulose/PEI-Grafted Magnetic Nanoparticles for Effective Removal of Heavy Metal Ions.
- Author
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Sathasivam T, Kang Brian L, Andersen IM, Ru Tan H, Zhang Z, Wu T, Hong Lau H, Zhu Q, and Kai D
- Abstract
In response to the pressing issue of water pollution caused by heavy metal ions, there is a growing demand for green adsorbents that can effectively remove these contaminants while being easy to separate and regenerate. A novel magnetic composite was synthesized by bonding amino-functionalized Fe
3 O4 -SiO2 magnetic particles (MNP-NH2 ) to polyethyleneimine (PEI)-grafted cellulose nanofibers (CNF). The modification of CNF with PEI through a peptidic coupling reaction resulted in the uniform dispersion and strong attachment of MNP-NH2 particles (286.7 nm) onto the PEI-CNF surface. This composite exhibited exceptional adsorption capabilities for heavy metals, achieving 16.73 mg/g for Pb, 16.12 mg/g for Cu, and 12.53 mg/g for Co. These remarkable adsorption capacities are attributed to the complex interactions between the metal ions and the amino, carboxyl, and hydroxyl groups on the surface of PEI-CNF-MNP. The introduction of PEI significantly enhanced the adsorption capacities, and the adsorption sequence (Pb(II)>Cu(II)>Co(II)) can be explained by differences in ionic radius and surface complexation strength. Langmuir isotherm and pseudo-second-order kinetic models described the adsorption process, while Na2 EDTA was proved effective for desorption with high recovery rates. This magnetic composite holds promise for treating heavy metal-contaminated wastewater due to its impressive performance., (© 2023 Wiley-VCH GmbH.)- Published
- 2023
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174. Facile Fabrication of Lignin-Cellulose Green Nanogels.
- Author
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Sathasivam T, Hu L, Sugiarto S, Dou Q, Zhang Z, Ru Tan H, Leow Y, Zhu Q, Ken Lee CL, Yu HD, and Kai D
- Subjects
- Nanogels, Drug Delivery Systems, Polymers, Lignin chemistry, Cellulose chemistry
- Abstract
There has been increasing exploration of the development and production of biodegradable polymers in response to issues with petrol-based polymers and their impact on the environment. Here we report a new approach to synthesize a natural nanogel from lignin and nanocellulose. First, lignin nanobeads were synthesized by a solvent-shifting method, which showed a spherical shape with a diameter of 159.7 nm. Then the lignin nanobeads were incorporated into a nanocellulose network to form the lignin/cellulose nanogels. The nanocellulose fibrils (CNF-C) nanogels reveal a higher storage modulus than the nanocellulose crystal (CNC-C) ones due to the denser network with self-entanglement of longer cellulose chains. The presence of lignin nanobeads in the nanogels helped to increase the viscoelasticity of the nanogels. This work highlights that the new kinds of green nanogels could be potentially utilized in a variety of biomedical applications such as drug delivery and wound dressing., (© 2022 Wiley-VCH GmbH.)
- Published
- 2022
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175. Dynamic Grafting of Carboxylates onto Poly(Vinyl Alcohol) Polymers for Supramolecularly-Crosslinked Hydrogel Formation.
- Author
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Wong JHM, Ting Tan RP, Chang JJ, Ow V, Yew PYM, Chee PL, Kai D, Loh XJ, and Xue K
- Subjects
- Polymers, Polyethyleneimine, Calcium, Anti-Bacterial Agents, Polyvinyl Alcohol, Hydrogels
- Abstract
Supramolecular hydrogels have attracted considerable interest due to their unique stimuli-responsive and self-healing properties. However, these hydrogel systems are usually achieved by covalent grafting of supramolecular units onto the polymer backbone, which in turn limits their reprocessability. Herein, we prepared a supramolecular hydrogel system by forming dynamic covalent crosslinks between 4-carboxyphenylboronic acid (CPBA) and polyvinyl alcohol (PVA). The system was then further crosslinked with either calcium ions or branched polyethylenimine (PEI) to generate hydrogels with distinctly different properties. Incorporation of calcium ions resulted in the formation of hydrogels with higher storage modulus of 7290 Pa but without self-healing properties. On the other hand, PEI-crosslinked hydrogel (PVA-CPBA-PEI) exhibited >2000% critical strain value, demonstrated high stability over 52 days and showed sustained antibacterial effect. A combination of supramolecular interactions and dynamic covalent crosslinks can be an alternate strategy to fabricate next-generation hydrogel materials., (© 2022 Wiley-VCH GmbH.)
- Published
- 2022
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176. Site-specific and seasonal variation in habitat use of Eurasian otters ( Lutra lutra ) in western China: implications for conservation.
- Author
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Wang QY, Zheng KD, Han XS, He F, Zhao X, Fan PF, and Zhang L
- Subjects
- Animals, China, Population Density, Conservation of Natural Resources, Ecosystem, Otters physiology, Rivers, Seasons
- Abstract
As a top predator, the Eurasian otter ( Lutra lutra ) is an indicator of healthy freshwater ecosystems and a flagship species for conservation. Once widespread in China, the species is now distributed mainly in the upper reaches of the great rivers of western China. However, a lack of knowledge on local otter populations continues to hinder their conservation in China. Here, we conducted a detailed study on habitat use of Eurasian otters in Yushu City and Tangjiahe National Nature Reserve in western China using transect surveys. At both study sites, otters preferred to defecate on large rocks close to or protruding from the river and about 50 cm above the waterline. In Yushu, no spraints were found along the 5 km river bank section in the downtown area, with otters preferring sprainting sites with natural banks, riparian zones, and lower human population density. However, this pattern was not obvious at Tangjiahe, where river transformation and human disturbance are minor. Otter river use intensity was negatively correlated with elevation and human population density in Yushu in both seasons. In Tangjiahe, otter river use intensity was positively correlated with prey mass and flow rate and negatively correlated with human population in spring, but positively correlated with human population and negatively correlated with flow rate in autumn. These results reflect the flexible habitat use strategies of otters at different sites, underlining the necessity to study otters living in different regions and habitat types. We provide suggestions for river modification and call for more site-specific studies to promote otter conservation in China.
- Published
- 2021
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177. Gold-decorated TiO 2 nanofibrous hybrid for improved solar-driven photocatalytic pollutant degradation.
- Author
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Tang KY, Chen JX, Legaspi EDR, Owh C, Lin M, Tee ISY, Kai D, Loh XJ, Li Z, Regulacio MD, and Ye E
- Subjects
- Catalysis, Gold, Titanium, Environmental Pollutants, Metal Nanoparticles, Nanofibers
- Abstract
TiO
2 -based nanomaterials are among the most promising photocatalysts for degrading organic dye pollutants. In this work, Au-TiO2 nanofibers were fabricated by the electrospinning technique, followed by calcination in air at 500 °C. Morphological and structural analyses revealed that the composite consists of TiO2 nanofibers with embedded Au nanoparticles that are extensively distributed throughout the porous fibrous structure of TiO2 . The photocatalytic performance of these Au-embedded TiO2 nanofibers was evaluated in the photodegradation of Rhodamine B and methylene blue under solar simulator irradiation. Compared with pristine TiO2 nanofibers, the Au-embedded TiO2 nanofibers displayed far better photocatalytic degradation efficiency. The plasmon resonance absorption of Au nanoparticles in the visible spectral region and the effective charge separation at the heterojunction of the Au-TiO2 hybrid are the key factors that have led to the considerable enhancement of the photocatalytic activity. The results of this study clearly demonstrate the potential of Au-TiO2 electrospun nanofibers as solar-light-responsive photocatalysts for the effective removal of dye contaminants from aquatic environments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)- Published
- 2021
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178. pH-responsive and hyaluronic acid-functionalized metal-organic frameworks for therapy of osteoarthritis.
- Author
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Xiong F, Qin Z, Chen H, Lan Q, Wang Z, Lan N, Yang Y, Zheng L, Zhao J, and Kai D
- Subjects
- Animals, Anti-Inflammatory Agents therapeutic use, Biomarkers, Cell Survival drug effects, Chondrocytes metabolism, Hydrogen-Ion Concentration, Hydroxybenzoates, Inflammation drug therapy, Injections, Intra-Articular, Interleukin-1beta, Male, Osteoarthritis pathology, Rats, Rats, Sprague-Dawley, Reactive Oxygen Species, Hyaluronic Acid chemistry, Hyaluronic Acid pharmacology, Metal-Organic Frameworks chemistry, Metal-Organic Frameworks pharmacology, Osteoarthritis drug therapy
- Abstract
Drug therapy of osteoarthritis (OA) is limited by the short retention and lacking of stimulus-responsiveness after intra-articular (IA) injection. The weak acid microenvironment in joint provides a potential trigger for controlled drug release systems in the treatment of OA. Herein, we developed an pH-responsive metal - organic frameworks (MOFs) system modified by hyaluronic acid (HA) and loaded with an anti-inflammatory protocatechuic acid (PCA), designated as MOF@HA@PCA, for the therapy of OA. Results demonstrated that MOF@HA@PCA could smartly respond to acidic conditions in OA microenvironment and gradually release PCA, which could remarkably reduce synovial inflammation in both IL-1β induced chondrocytes and the OA joints. MOF@HA@PCA also down-regulated the expression of inflammatory markers of OA and promoted the expression of cartilage-specific makers. This work may provide a new insight for the design of efficient nanoprobes for precision theranostics of OA .
- Published
- 2020
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179. Implantable and degradable antioxidant poly(ε-caprolactone)-lignin nanofiber membrane for effective osteoarthritis treatment.
- Author
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Liang R, Zhao J, Li B, Cai P, Loh XJ, Xu C, Chen P, Kai D, and Zheng L
- Subjects
- Animals, Hydrogen Peroxide, Rabbits, Tissue Engineering, Tissue Scaffolds, Antioxidants pharmacology, Lignin therapeutic use, Nanofibers therapeutic use, Osteoarthritis drug therapy, Polyesters therapeutic use
- Abstract
Osteoarthritis (OA) is one of the most common musculoskeletal disorders worldwide. Oxidative stress initiated by excessive free radicals such as reactive oxygen species (ROS) is a leading cause of cartilage degradation and OA. However, conventional injection or oral intake of antioxidants usually cannot provide effective treatment due to rapid clearance and degradation or low bioavailability. Here, a new strategy is proposed based on nanofibers made of poly (ε-caprolactone) (PCL) and PCL-grafted lignin (PCL-g-lignin) copolymer. Lignin offers intrinsic antioxidant activity while PCL tailors the mechanical properties. Electrospun PCL-lignin nanofibers show excellent antioxidant activity, low cytotoxicity and excellent anti-inflammatory effects as demonstrated using both H
2 O2 -stimulated human chondrocytes and an OA rabbit model. PCL-lignin nanofibers inhibit ROS generation and activate antioxidant enzymes through autophagic mechanism. Arthroscopic implantation of nanofibrous membrane of PCL-lignin is effective to OA therapy because it is biocompatible, biodegradable and able to provide sustained antioxidant activity., (Copyright © 2019 Elsevier Ltd. All rights reserved.)- Published
- 2020
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180. Mechanically cartilage-mimicking poly(PCL-PTHF urethane)/collagen nanofibers induce chondrogenesis by blocking NF-kappa B signaling pathway.
- Author
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Jiang T, Kai D, Liu S, Huang X, Heng S, Zhao J, Chan BQY, Loh XJ, Zhu Y, Mao C, and Zheng L
- Subjects
- Animals, Butylene Glycols chemistry, Cartilage drug effects, Cattle, Cell Differentiation drug effects, Mesenchymal Stem Cells cytology, Mesenchymal Stem Cells drug effects, Mesenchymal Stem Cells ultrastructure, Nanofibers ultrastructure, Polyesters chemistry, Polymers chemistry, Polyurethanes chemistry, Rats, Sprague-Dawley, Regeneration drug effects, Signal Transduction drug effects, Transcriptome genetics, Butylene Glycols pharmacology, Cartilage physiology, Chondrogenesis drug effects, Collagen pharmacology, NF-kappa B metabolism, Nanofibers chemistry, Polyesters pharmacology, Polymers pharmacology, Polyurethanes pharmacology
- Abstract
Cartilage cannot self-repair and thus regeneration is a promising approach to its repair. Here we developed new electrospun nanofibers, made of poly (ε-caprolactone)/polytetrahydrofuran (PCL-PTHF urethane) and collagen I from calf skin (termed PC), to trigger the chondrogenic differentiation of mesenchymal stem cells (MSCs) and the cartilage regeneration in vivo. We found that the PC nanofibers had a modulus (4.3 Mpa) lower than the PCL-PTHF urethane nanofibers without collagen I from calf skin (termed P) (6.8 Mpa) although both values are within the range of the modulus of natural cartilage (1-10 MPa). Both P and PC nanofibers did not show obvious difference in the morphology and size. Surprisingly, in the absence of the additional chondrogenesis inducers, the softer PC nanofibers could induce the chondrogenic differentiation in vitro and cartilage regeneration in vivo more efficiently than the stiffer P nanofibers. Using mRNA-sequence analysis, we found that the PC nanofibers outperformed P nanofibers in inducing chondrogenesis by specifically blocking the NF-kappa B signaling pathway to suppress inflammation. Our work shows that the PC nanofibers can serve as building blocks of new scaffolds for cartilage regeneration and provides new insights on the effect of the mechanical properties of the nanofibers on the cartilage regeneration., (Copyright © 2018 Elsevier Ltd. All rights reserved.)
- Published
- 2018
- Full Text
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181. Bioimaging and biodetection assisted with TTA-UC materials.
- Author
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Dou Q, Jiang L, Kai D, Owh C, and Loh XJ
- Subjects
- Animals, Fluorescence, Humans, Diagnostic Imaging methods
- Abstract
Upconversion of light has attracted intensive studies for biomedical research, because it enables deeper tissue analysis owing to the longer wavelength of incident light, compared with conventional downconversion fluorescent materials. Triplet-triplet annihilation (TTA), as a typical mechanism of upconversion, does not necessitate high power excitation and exhibits a higher quantum yield than rare earth upconversion owing to more sensitizer options with higher absorption coefficients. A desirable wavelength range of excitation and emission can be realized by careful selection of the combination of sensitizer and activator. Therefore, TTA-UC is worth exploring further for biorelated applications, such as bioimaging and biodetection. Recent developments are reviewed in this article., (Copyright © 2017 Elsevier Ltd. All rights reserved.)
- Published
- 2017
- Full Text
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182. Electrospinning of poly(glycerol sebacate)-based nanofibers for nerve tissue engineering.
- Author
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Hu J, Kai D, Ye H, Tian L, Ding X, Ramakrishna S, and Loh XJ
- Subjects
- Animals, Cell Proliferation, Cell Shape, Decanoates, Glycerol chemical synthesis, Glycerol chemistry, Nanofibers ultrastructure, PC12 Cells, Polymers, Polymethyl Methacrylate chemical synthesis, Polymethyl Methacrylate chemistry, Proton Magnetic Resonance Spectroscopy, Rats, Glycerol analogs & derivatives, Nanofibers chemistry, Nerve Tissue physiology, Tissue Engineering methods
- Abstract
Nerve tissue engineering (TE) requires biomimetic scaffolds providing essential chemical and topographical cues for nerve regeneration. Poly(glycerol sebacate) (PGS) is a biodegradable and elastic polymer that has gained great interest as a TE scaffolding biomaterial. However, uncured PGS is difficult to be electrospun into nanofibers. PGS would, therefore, require the addition of electrospinning agents. In this study, we modified PGS by using atom transfer radical polymerization (ATRP) to synthesize PGS-based copolymers with methyl methacrylate (MMA). The synthesized PGS-PMMA copolymer showed a molecular weight of 82kDa and a glass transition temperature of 115°C. More importantly, the PGS-PMMA could be easily electrospun into nanofiber with a fiber diameter of 167±33nm. Blending gelatin into PGS-PMMA nanofibers was found to increase its hydrophilicity and biocompatibility. Rat PC12 cells were seeded onto the PGS-PMMA/gelatin nanofibers to investigate their potential for nerve regeneration. It was found that gelatin-containing PGS-based nanofibers promoted cell proliferation. The elongated cell morphology observed on such nanofibers indicated that the scaffolds could induce the neurite outgrowth of the nerve stem cells. Overall, our study suggested that the synthesis of PGS-based copolymers might be a promising approach to enhance their processability, and therefore advancing bioscaffold engineering for various TE applications., (Copyright © 2016 Elsevier B.V. All rights reserved.)
- Published
- 2017
- Full Text
- View/download PDF
183. Biocompatible electrically conductive nanofibers from inorganic-organic shape memory polymers.
- Author
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Kai D, Tan MJ, Prabhakaran MP, Chan BQY, Liow SS, Ramakrishna S, and Loh XJ
- Subjects
- Animals, Cell Communication, Electrochemical Techniques methods, Microscopy, Electron, Scanning, Nanofibers ultrastructure, Nerve Regeneration, PC12 Cells, Polyurethanes chemistry, Porosity, Rats, Soot chemistry, Temperature, Tissue Engineering methods, Tissue Scaffolds chemistry, Biocompatible Materials chemistry, Dimethylpolysiloxanes chemistry, Electric Conductivity, Nanofibers chemistry, Polyesters chemistry
- Abstract
A porous shape memory scaffold with both biomimetic structures and electrical conductivity properties is highly promising for nerve tissue engineering applications. In this study, a new shape memory polyurethane polymer which consists of inorganic polydimethylsiloxane (PDMS) segments with organic poly(ε-caprolactone) (PCL) segments was synthesized. Based on this poly(PCL/PDMS urethane), a series of electrically conductive nanofibers were electrospun by incorporating different amounts of carbon-black. Our results showed that after adding carbon black into nanofibers, the fiber diameters increased from 399±76 to 619±138nm, the crystallinity decreased from 33 to 25% and the resistivity reduced from 3.6 GΩ/mm to 1.8 kΩ/mm. Carbon black did not significantly influence the shape memory properties of the resulting nanofibers, and all the composite nanofibers exhibited decent shape recovery ratios of >90% and shape fixity ratios of >82% even after 5 thermo-mechanical cycles. PC12 cells were cultured on the shape memory nanofibers and the composite scaffolds showed good biocompatibility by promoting cell-cell interactions. Our study demonstrated that the poly(PCL/PDMS urethane)/carbon-black nanofibers with shape memory properties could be potentially used as smart 4-dimensional (4D) scaffolds for nerve tissue regeneration., (Copyright © 2016 Elsevier B.V. All rights reserved.)
- Published
- 2016
- Full Text
- View/download PDF
184. Elastic poly(ε-caprolactone)-polydimethylsiloxane copolymer fibers with shape memory effect for bone tissue engineering.
- Author
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Kai D, Prabhakaran MP, Chan BQ, Liow SS, Ramakrishna S, Xu F, and Loh XJ
- Subjects
- Cell Proliferation physiology, Cell Survival physiology, Cells, Cultured, Elastic Modulus, Equipment Design, Equipment Failure Analysis, Hot Temperature, Humans, Nanofibers ultrastructure, Osteoblasts cytology, Stress, Mechanical, Tensile Strength, Tissue Engineering instrumentation, Tissue Engineering methods, Bone Substitutes chemical synthesis, Dimethylpolysiloxanes chemistry, Nanofibers chemistry, Osteoblasts physiology, Polyesters chemical synthesis, Tissue Scaffolds
- Abstract
A porous shape memory scaffold with biomimetic architecture is highly promising for bone tissue engineering applications. In this study, a series of new shape memory polyurethanes consisting of organic poly(ε-caprolactone) (PCL) segments and inorganic polydimethylsiloxane (PDMS) segments in different ratios (9 : 1, 8 : 2 and 7 : 3) was synthesised. These PCL-PDMS copolymers were further engineered into porous fibrous scaffolds by electrospinning. With different ratios of PCL: PDMS, the fibers showed various fiber diameters, thermal behaviour and mechanical properties. Even after being processed into fibrous structures, these PCL-PDMS copolymers maintained their shape memory properties, and all the fibers exhibited excellent shape recovery ratios of >90% and shape fixity ratios of >92% after 7 thermo-mechanical cycles. Biological assay results corroborated that the fibrous PCL-PDMS scaffolds were biocompatible by promoting osteoblast proliferation, functionally enhanced biomineralization-relevant alkaline phosphatase expression and mineral deposition. Our study demonstrated that the PCL-PDMS fibers with excellent shape memory properties are promising substrates as bioengineered grafts for bone regeneration.
- Published
- 2016
- Full Text
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185. A Triazolyl-Pyridine-Supported Cu I Dimer: Tunable Luminescence and Fabrication of Composite Fibers.
- Author
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Bai SQ, Kai D, Ke KL, Lin M, Jiang L, Jiang Y, Young DJ, Loh XJ, Li X, and Hor TSA
- Abstract
The dinuclear complex [Cu
2 I2 (L1)2 ] (1) (L1=3-((4-(pyridin-2-yl)-1H-1,2,3-triazol-1-yl)methyl)benzonitrile) is characterized by single-crystal X-ray diffraction (XRD), powder XRD, IR, photoluminescence spectroscopy, and thermogravimetric analysis. Unlike other related, known copper iodide complexes, it exhibits strong yellow emission in the solid state at both room temperature and 77 K. Showing good compatibility with PMMA, it is blended with the polymer in different weight ratios to prepare luminescent composite fibers., (Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)- Published
- 2015
- Full Text
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186. Stem cell-loaded nanofibrous patch promotes the regeneration of infarcted myocardium with functional improvement in rat model.
- Author
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Kai D, Wang QL, Wang HJ, Prabhakaran MP, Zhang Y, Tan YZ, and Ramakrishna S
- Subjects
- Animals, Male, Rats, Rats, Sprague-Dawley, Heart physiology, Myocardial Infarction physiopathology, Nanofibers, Regeneration, Stem Cells cytology
- Abstract
Myocardial infarction (MI) leads to the loss of cardiomyocytes, followed by left ventricular (LV) remodeling and cardiac dysfunction. The authors hypothesize that an elastic, biodegradable nanofibrous cardiac patch loaded with mesenchymal stem cells (MSC) could restrain LV remodeling and improve cardiac function after MI. Poly(ε-caprolactone)/gelatin (PG) nanofibers were fabricated by electrospinning, and the nanofibers displayed a porous and uniform nanofibrous structure with a diameter of 244±51nm. An MI model was established by ligation of the left anterior descending coronary artery of female Sprague-Dawley rats. The PG nanofibrous patch seeded with MSC, isolated from rat bone marrow, was implanted on the epicardium of the infarcted region of the LV wall of the heart. After transplantation, the PG-cell patch restricted the expansion of the LV wall effectively and reduced the scar size, and the density of the microvessels increased. Cells within the patch were able to migrate towards the scar tissue, and promoted new blood vessel formation at the infarct site. Angiogenesis and the cardiac functions improved significantly after 4weeks of implantation. The MSC-seeded PG nanofibrous patches are demonstrated to provide sufficient mechanical support, to induce angiogenesis and to accelerate cardiac repair in a rat model of MI. The study highlights the positive impact of implantation of an MSC-seeded PG nanofibrous patch as a novel constituent for MI repair., (Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2014
- Full Text
- View/download PDF
187. Controlled release of multiple epidermal induction factors through core-shell nanofibers for skin regeneration.
- Author
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Jin G, Prabhakaran MP, Kai D, and Ramakrishna S
- Subjects
- Adipose Tissue cytology, Cell Differentiation, Cell Proliferation, Delayed-Action Preparations, Epidermal Growth Factor administration & dosage, Gelatin chemistry, Humans, Hydrocortisone administration & dosage, Insulin administration & dosage, Nanofibers, Polyesters chemistry, Stem Cells cytology, Tissue Scaffolds, Tretinoin administration & dosage, Drug Delivery Systems, Regeneration, Skin metabolism, Tissue Engineering methods
- Abstract
With advances in the field of tissue engineering, it is increasingly recognized that biodegradable and biocompatible scaffolds incorporated with multiple wound healing mediators might serve as the most promising medical devices for skin tissue regeneration. Through controlled drug delivery, these medical devices can reduce the toxicity effects and optimize clinical efficiency. In this study, we first encapsulated multiple epidermal induction factors (EIF) such as the epidermal growth factor (EGF), insulin, hydrocortisone, and retinoic acid (RA) with gelatin and poly(L-lactic acid)-co-poly-(ε-caprolactone) (PLLCL) solutions and performed electrospinning by two different approaches: blend spinning and core-shell spinning. No burst release was detected from EIF encapsulated core-shell nanofibers; however, an initial 44.9% burst release from EIF blended nanofibers was observed over a period of 15 days. The epidermal differentiation potential of adipose-derived stem cells (ADSCs) was evaluated for EIF-containing scaffolds prepared either by core-shell spinning or by blend spinning. After 15 days of cell culture, the proliferation of ADSCs on EIF encapsulated core-shell nanofibers was the highest. Moreover, a higher percentage of ADSCs got differentiated to epidermal lineages on EIF encapsulated core-shell nanofibers compared to the cell differentiation on EIF blended nanofibers, which can be attributed to the sustained release of EIF from the core-shell nanofibers. Our study demonstrated that the EIF encapsulated core-shell nanofibers might serve as a promising tissue engineered graft for skin regeneration., (Copyright © 2013 Elsevier B.V. All rights reserved.)
- Published
- 2013
- Full Text
- View/download PDF
188. Emulsion electrospun nanofibers as substrates for cardiomyogenic differentiation of mesenchymal stem cells.
- Author
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Tian L, Prabhakaran MP, Ding X, Kai D, and Ramakrishna S
- Subjects
- Biocompatible Materials, Cell Proliferation, Cells, Cultured, Microscopy, Electron, Scanning, Microscopy, Electron, Transmission, Cell Differentiation, Emulsions, Gelatin, Mesenchymal Stem Cells cytology, Myocytes, Cardiac cytology, Nanofibers, Polyesters, Tissue Scaffolds
- Abstract
The potential of cardiomyogenic differentiation of human mesenchymal stem cells (hMSCs) on emulsion electrospun scaffold containing poly(L-lactic acid)-co-poly-(ε-caprolactone), gelatin and vascular endothelial growth factor (PLCL/GV) was investigated in this study. The characterizations of the scaffold were carried out using scanning electron microscope (SEM), transmission electron microscope, water contact angle and porometer. The proliferation of hMSCs showed that 73.4% higher cell proliferation on PLCL/GV scaffolds than that on PLCL scaffold after 20 days of cell culture. Results of 5-chloromethylfluorescein diacetate staining and SEM morphology analysis indicated that hMSCs differentiated on PLCL/GV scaffolds showed irregular morphology of cardiomyocyte phenotype compared to the typical long and thin hMSC phenotype. Immunostaining results showed the expression of alpha actinin and myosin heavy chain. Our studies identified emulsion electrospinning as a method for fabrication of core-shell fibers suitable for the differentiation of stem cells to cardiac cells, with potential application in cardiac regeneration.
- Published
- 2013
- Full Text
- View/download PDF
189. Tissue engineered plant extracts as nanofibrous wound dressing.
- Author
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Jin G, Prabhakaran MP, Kai D, Annamalai SK, Arunachalam KD, and Ramakrishna S
- Subjects
- Actins analysis, Adipose Tissue cytology, Azadirachta chemistry, Biocompatible Materials chemistry, Cell Differentiation, Cell Line, Cell Proliferation, Collagen analysis, Epidermal Cells, Fibroblasts cytology, Humans, Indigofera chemistry, Myristicaceae chemistry, Nanofibers ultrastructure, Porosity, Stem Cells cytology, Nanofibers chemistry, Plant Extracts chemistry, Polyesters chemistry, Skin, Artificial, Tissue Engineering methods, Tissue Scaffolds chemistry
- Abstract
Use of plant extracts for treatment of burns and wound is a common practice followed over the decades and it is an important aspect of health management. Many medicinal plants have a long history of curative properties in wound healing. Electrospun nanofibers provide high porosity with large surface area-to-volume ratio and are more appropriate for cell accommodation, nutrition infiltration, gas exchange and waste excretion. Electrospinning makes it possible to combine the advantages of utilizing these plant extracts in the form of nanofibrous mats to serve as skin graft substitutes. In this study, we investigated the potential of electrospinning four different plant extracts, namely Indigofera aspalathoides, Azadirachta indica, Memecylon edule (ME) and Myristica andamanica along with a biodegradable polymer, polycaprolactone (PCL) for skin tissue engineering. The ability of human dermal fibroblasts (HDF) to proliferate on the electrospun nanofibrous scaffolds was evaluated via cell proliferation assay. HDF proliferation on PCL/ME nanofibers was found the highest among all the other electrospun nanofibrous scaffolds and it was 31% higher than the proliferation on PCL nanofibers after 9 days of cell culture. The interaction of HDF with the electrospun scaffold was studied by F-actin and collagen staining studies. The results confirmed that PCL/ME had the least cytotoxicity among the different plant extract containing scaffolds studied here. Therefore we performed the epidermal differentiation of adipose derived stem cells on PCL/ME scaffolds and obtained early and intermediate stages of epidermal differentiation. Our studies demonstrate the potential of electrospun PCL/ME nanofibers as substrates for skin tissue engineering., (Copyright © 2012 Elsevier Ltd. All rights reserved.)
- Published
- 2013
- Full Text
- View/download PDF
190. Electrospun Poly(L-Lactic Acid)-co-Poly(ϵ-Caprolactone) Nanofibres Containing Silver Nanoparticles for Skin-Tissue Engineering.
- Author
-
Jin G, Prabhakaran MP, Nadappuram BP, Singh G, Kai D, and Ramakrishna S
- Subjects
- Actins metabolism, Anti-Bacterial Agents chemistry, Anti-Bacterial Agents pharmacology, Biocompatible Materials chemistry, Biocompatible Materials pharmacology, Cell Proliferation drug effects, Fibroblasts cytology, Fibroblasts drug effects, Humans, Metal Nanoparticles chemistry, Salmonella enterica drug effects, Silver Nitrate chemistry, Skin cytology, Staphylococcus aureus drug effects, Tissue Scaffolds chemistry, Wound Healing drug effects, Electricity, Nanofibers chemistry, Nanotechnology, Polyesters chemistry, Silver chemistry, Skin drug effects, Tissue Engineering methods
- Abstract
Silver nanoparticles (AgNPs) and silver ions (Ag(+)) show growth-inhibitory activity against microorganisms and have been used for decades as antibacterial agents in various fields. To fabricate a nanofibrous scaffold which is antibacterial against bacteria and non-toxic to cells, we electrospun composite poly(L-lactic acid)-co-poly(ϵ-caprolactone) nanofibres containing silver nanoparticles (PLLCL-AgNPs) with different concentrations (0.25, 0.50 and 0.75 wt%) of silver nitrate (AgNO3) in PLLCL. The diameters of the electrospun PLLCL-AgNPs nanofibres decreased with the increase of AgNO3 concentration in PLLCL solutions. Human skin fibroblasts cultured on the scaffolds showed that the PLLCL nanofibres containing lesser amounts of AgNPs (0.25 wt%) had better cell proliferation and retained the cell morphology similar to the phenotype observed on tissue culture plates (control). The antibacterial activity of AgNPs in PLLCL nanofibres was investigated against Staphylococcus aureus and Salmonella enterica and the antimicrobial activity was found to increase with the increasing concentration of nanoparticles present in the scaffold. Based on our studies, we propose that PLLCL nanofibres containing 0.25 wt% AgNO3 or PLLCL-Ag(25), favors cell proliferation and inhibits bacteria and could be a suitable substrate for wound healing.
- Published
- 2012
- Full Text
- View/download PDF
191. Galangin induces apoptosis of hepatocellular carcinoma cells via the mitochondrial pathway.
- Author
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Zhang HT, Luo H, Wu J, Lan LB, Fan DH, Zhu KD, Chen XY, Wen M, and Liu HM
- Subjects
- Carcinoma, Hepatocellular drug therapy, Carcinoma, Hepatocellular metabolism, Cell Line, Tumor metabolism, Cell Line, Tumor pathology, Dose-Response Relationship, Drug, Flavonoids therapeutic use, Humans, Liver Neoplasms drug therapy, Liver Neoplasms metabolism, Membrane Potential, Mitochondrial drug effects, Mitochondria metabolism, Mutagens therapeutic use, Proto-Oncogene Proteins c-bcl-2 genetics, Proto-Oncogene Proteins c-bcl-2 metabolism, Signal Transduction drug effects, Signal Transduction physiology, Apoptosis drug effects, Carcinoma, Hepatocellular pathology, Cell Line, Tumor drug effects, Flavonoids pharmacology, Liver Neoplasms pathology, Mitochondria drug effects, Mutagens pharmacology
- Abstract
Aim: To investigate the mechanism by which galangin, a polyphenolic compound derived from medicinal herbs, induces apoptosis of hepatocellular carcinoma (HCC) cells., Methods: The 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay was used to measure cell viability. Apoptosis was evaluated by in situ uptake of propidium iodide and Hoechst 33258 and was then detected by fluorescence microscopy. Protein expressions were detected by Western blotting. To confirm the apoptotic pathway mediated by galangin, cells were transfected by bcl-2 gene to overexpress Bcl-2 or siRNA to down-regulate Bcl-2 expression., Results: Galangin (46.25-370.0 micromol/L) exerted an anti-proliferative effect, induced apoptosis, and decreased mitochondrial membrane potential in a dose and time-dependent manner. Treatment with galangin induced apoptosis by translocating the pro-apoptotic protein Bax to the mitochondria, which released apoptosis-inducing factor and cytochrome c into the cytosol. Overexpression of Bcl-2 attenuated galangin-induced HepG2 cell apoptosis, while decreasing Bcl-2 expression enhanced galangin-induced cell apoptosis., Conclusion: Our data suggests that galangin mediates apoptosis through a mitochondrial pathway, and may be a potential chemotherapeutic drug for the treatment of HCC.
- Published
- 2010
- Full Text
- View/download PDF
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