Electrospun layers

Production of composite materials consisting of electrospun layers, etc. 

Researchers have reported some properties of electrospun mats. They compared the performances of electrospun fibre mats with the properties of textiles and membranes currently used in protective clothing systems and showed that electrospun layers are extremely efficient for trapping airborne particles. Meanwhile, the air flow resistance and aerosol filtration properties are affected by the coating weight. It was shown that an extremely thin layer of electrospun nanofibres completely prevented particle penetration through the layer. 

A bilayer scaffold including an outer layer of an electrospun PEUU scaffold and an inner layer of porous PEUU scaffold was developed to address the cellular-ization issue [15]. The electrospun layer provided the mechanical support, while the porous scaffold layer supplied space for cell loading and infiltration. Prior to implantation, the cells including primary cells or stem cells were uniformly seeded into the porous layer using a customized vacuum device [15,40 2]. Rat vascular smooth muscle cells were seeded into the bilayer conduit and cultured in vitro for 2 days, and then this cellularized scaffold was implanted into the rat aorta model [42]. After 8 weeks, the patency of the cellularized scaffolds increased by 75% compared to 38% of the acellular scaffold. The failed scaffolds were blocked due to the intimal hyperplasia. The patent scaffolds contained a neointimal layer consisting of multiple layers of the immature contractile smooth muscle... 

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. 

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...

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. 

Fig. 4 (a) Photograph of the overall 3D woodpile structure with dimensions of 9 x 9 x 3.5 mm. (b) Hybrid basic unit layer composed of microfibers and the electrospun nanofiber matrix, (c, d) Magnified images of (b) (Adapted from [64])... 

Others have combined electrospun scaffolds with scaffolds created by other techniques to create a 3D bone-1 ike scaffold for bone regeneration. For instance, Martins et al. [62] combined both electrospinning and rapid prototyping in order to create a 3D bone-like structure. This method is very similar to the layer-by-layer... 

B. Ding, J. Kim, E. Kimura S. Shiratori, Layer-by-layer structured films of Ti02 nanoparticles and poly(acrylic acid) on electrospun nanofibres . Nanotechnology, 15,913-917, (2004). 

Composites of PANI-NFs, synthesized using a rapid mixing method, with amines have recently been presented as novel materials for phosgene detection [472]. Chemiresistor sensors with nanofibrous PANI films as a sensitive layer, prepared by chemical oxidative polymerization of aniline on Si substrates, which were surface-modified by amino-silane self-assembled monolayers, showed sensitivity to very low concentration (0.5 ppm) of ammonia gas [297]. Ultrafast sensor responses to ammonia gas of the dispersed PANI-CSA nanorods [303] and patterned PANI nanobowl monolayers containing Au nanoparticles [473] have recently been demonstrated. The gas response of the PANI-NTs to a series of chemical vapors such as ammonia, hydrazine, and triethylamine was studied [319,323]. The results indicated that the PANI-NTs show superior performance as chemical sensors. Electrospun isolated PANI-CSA nanofiber sensors of various aliphatic alcohol vapors have been proven to be comparable to or faster than those prepared from PANI-NF mats [474]. An electrochemical method for the detection of ultratrace amount of 2,4,6-trinitrotoluene with synthetic copolypeptide-doped PANI-NFs has recently been reported [475]. PANI-NFs, prepared through the in situ oxidative polymerization method, were used for the detection of aromatic organic compounds [476]. 

Other studies in 2000 by Drew et al. reported that it is very difficult to spin fibers of PANI complexed to sulfonated polystyrene (PANFSPS), even when solutions containing sodium chloride and dodecyl benzene sulfonic acid sodium salt were used to lower the surface tension and thereby enhance electrospinning [16,17]. However, PANFSPS nanofibers can be produced by adding a carrier polymer such as PEO, polyacrylonitrile, or polyurethane. Also reported was the use of electrostatically layered sulfonated polystyrene as a template for the surface polymerization of conjugated polymers in their conducting form. Enzymatic synthesis of PANI and a copolymer of pyrrole and PEDOT was done on electrospun nanofiber... 

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