Electrospun

Kwon and coworkers prepared a series of nano- to microstmctured biodegradable PCLA porous fabrics by electrospinning. The nanoscale-fiber porous fabrics were electrospun with PCLA (1 1 mole ratio, approximately 0.3-1.2 mm in diameter) using l,l,l,3,3,3-hexafluoro-2-propanol as a solvent. 

Kwon K, Kidoaki S, and Matsuda T. Electrospun nano- to microfiber fabrics made of biodegradable copolyesters Structural characteristics, mechanical properties and cell adhesion potential. Biomaterials, 2005, 26, 3929-3939. 

Normal transmission IRLD can also be used to characterize polymeric fibers, although scattering can induce sloping baselines. Raman spectroscopy then becomes a convenient alternative. Rutledge et al. have recently probed the orientation in electrospun nanofibers composed of a core of Bombyx mori fibroin and an outer shell of poly (ethylene oxide) [24], The orientation values were low, less than 0.1, as is often the case in electrospun fibers. 

Their antimicrobial activities were found to be improved compared with those of silver(i) nitrate. Encapsulation of 69 by electrospun tecophilic nanofibres for the formation of antimicrobial nanosilver particles was also achieved. 

Wang X, Kim Y-G, Drew C, Ku B-C, Kumar J, Samuelson LA (2004) Electrostatic assembly of conjugated polymer thin layers on electrospun nanofibrous membranes for biosensors. 

Long Y, Chen H, Yang Y, Wang H, Yang Y, Li N, Li K, Pei J, Liu F (2009) Electrospun nanofibrous film doped with a conjugated polymer for DNT fluorescence sensor. Macromolecules 42 6501-6509... 

Figure 12.7 Photographs of electrospun fiber mats embedded with 1 (a) before and (b) after 254-nm UV irradiation (1 mW/cm ) for 3 min. (c) Scanning electron microscopy image of the microfibers containing polymerized 1. (c) Photographs of the polydiacetylene-embedded electrospun fiber mats prepared with various diacetylene monomers after exposure to organic solvent. Reprinted fi om Yoon et al. (2007). Copyright 2007 American Chemical Society. (See color insert.)...

Yoon J, Chae SK, Kim J-M. Colorimetric sensors for volatile organic compounds (VOCs) based on conjugated polymer-embedded electrospun fibers. J Am Chem Soc 2007 129 3038-3039. 

Wu H, Hu LB, Rowell MW, Kong DS, Cha JJ, McDonough JR, Zhu J, Yang YA, McGehee MD, Cui Y (2010) Electrospun metal nanofiher webs as high-performance transparent electrode. Nano Lett 10 4242... 

Early reports on electrospun scaffolds described poor cellular infiltration [175], Frequently, cells adhered at the surface and thus coated the nano- or submicrometer-scaled electrospun meshes due to the small pore size. In order to overcome this limitation, pore sizes were increased by combining ES with other methods. These approaches included the coating of microfibers with nanofibers [183], Other strategies combine ES with leaching [184, 185], freeze-drying [186], blowing agents [187], or ice templates [188],... 

To improve and control cell-fiber interactions, the fiber meshes can be either composed of biomacromolecules or postfunctionalized with appropriate biomolecules. The question arises as to which materials can be electrospun. In principle, all polymers can be spun if they provide enough entanglements in solution and adequate interactions between the solvent and solute. Biopolymers, in particular, show dominant H-bonding and/or polyelectrolyte effects, which lead to a strong viscosity increase or poor solvent evaporation. In order to prevent such... 

Fig. 9 Cell-fiber sandwiches can be constructed by LbL cell/fiber assembly. The cells are sandwiched between layers of electrospun fiber mashes. The mesh thickness and cell loading can be controlled within this process. Reprinted, with permission, from [190] copyright (2009) Mary Ann...

Synthetic nanofiber matrices can provide physically and chemically stable 3D surfaces for ex vivo growth of cells. Meiners and coworkers showed that fibroblasts or rat kidney cells that have been grown on electrospun polyamide nanofiber meshes displayed all the characteristics of their counterparts in vivo [205], In addition, breast epithelial cells underwent morphogenesis to form multicellular spheroids containing lumens. 

Figure 9 The electrospun fiber of fibroin (a) and the correlation between the concentration of fibroin and the diameter of electrospun fiber (b).

In order to improve the properties and the spinnability, fibroin sometimes has been electrospun together with other natural or synthetic polymers (Jin et al., 2002 Park et al., 2004, 2006 Wang et al., 2004, 2006). For instance, Jin et al. (2002) developed an aqueous process for silk electrospinning in combination with PEO. More recently, Cao (2008) used PVA/Silk Fibroin (SF), Gelatin/SF, and Hydroxyapatite (HAP)/SF to produce double-layered (core-shell) nanofibers (mats) by coelectrospinning. 

Figure 10 A novel micron-sized hybrid of silk fibroin and CaCOj, with a hollow structure and unusual rice-like shape is synthesized in the presence of regenerated silk fibroin via aggregation-mediated crystallization (a) mineralization of HAP on the electrospun mat of silk fibroin (b).

Cao, H. "Preparation of Silk Fibroin-based Electrospun Mat and Deposition of Inorganic Mineral on Silk Fibroin Matrix" Ph.D dissertation, Fudan University, 2008... 

Jin, H.J., Chen, J.S., Karageorgiou, V., Altman, G.H., and Kaplan, D.L. "Human bone marrow stromal cell responses on electrospun silk fibroin mats". Biomaterials 25(6), 1039-1047 (2004). 

Meechaisue, C., Wutticharoenmongkol, P., Waraput, R., Huangjing, T., Ketbumrung, N., Pavasant, P., and Supaphol, P. "Preparation of electrospun silk fibroin fiber mats as bone scaffolds A preliminary study". Biomed. Mater. 2(3), 181-188 (2007). 

Wang, H., Zhang, Y.P., Shao, H.L., and Hu, X.C. "Electrospun ultra-fine silk fibroin fibers from aqueous solutions". ]. Mater. Sci. 40(20), 5359-5363 (2005). 

Zarkoob, S., Reneker, D.H., Eby, R.K., Hudson, S.D., Ertley, D., and Adams, W.W. Structure and morphology of nano electrospun silk fibers. Abstracts of Papers of the American Chemical Society (1998), 216, U122-U122. 

X. M. Mo, C. Y. Xu, M. Kotaki, and S. Ramakrishna, Electrospun P(LLA-CL) nanofiber a biomimetic extracellular matrix for smooth muscle cell and endothelial cell proliferation, Biomater. 25, 1883-1890 (2004). 

Figure 3.5.15 Tin nanoparticles in an electrospun carbon fiber for use as a negative electrode (Ihs reprinted with permission from [34], copyright 2009 John Wiley Sons rhs reprinted with permission from [33], copyright 2009 American Chemical Society).

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