The release behavior of doxorubicin hydrochloride from medicated fibers prepared by emulsion-electrospinning

The release behavior of a water-soluble small molecule drug from the drug-loaded nanofibers prepared by emulsion-electrospinning was investigated. Doxorubicin hydrochloride (Dox), a water-soluble anticancer agent, was used as the model drug. The laser scanning confocal microscopic images indicated that the drug was well incorporated into amphiphilic poly(ethylene glycol)-poly(L-lactic acid) (PEG-PLA) diblock copolymer nanofibers, forming "core-sheath" structured drug-loaded nanofibers.

Sintering-resistant hollow fibers of LaMgAl11O19 prepared by electrospinning

Lanthanum magnesium hexaaluminate (LMA) is very important ceramic material for catalytic combustion of natural gas. The sintering-resistant hollow fibers of LMA with diameters ranging from 1 to 3 mu m were fabricated from alcoholic solutions containing polyvinyl pyrrolidone (PVP) and aqueous solution of lanthanum, magnesium and aluminum nitrates. The interaction between PVP and nitrates were studied by X-ray diffraction and Fourier transmission-infrared spectroscopy. The forming mechanism of hollow fibers and the sintering ability of hollow LaMgAl11O19 fibers were discussed.

Type I collagen-templated assembly of silver nanoparticles and their application in surface-enhanced Raman scattering

Silver nanoparticles (Ag NPs) are one of the active substrates that are employed extensively in surface-enhanced Raman scattering (SERS), and aggregations of Ag NPs play an important role in enhancing the Raman signals. In this paper, we fabricated two kinds of SERS-active substrates utilizing the electrostatic adsorption and superior assembly properties of type I collagen. These were collagen-Ag NP aggregation films and nanoporous Ag films.

Fabrication, characterization, and application in surface-enhanced Raman spectrum of assembled type-I collagen-silver nanoparticle multilayered films

In this paper, we report a facile method for the fabrication of type-I collagen-silver nanoparticles (Ag NPs) multilayered films by utilizing type-I collagen as a medium. These samples were characterized by UV-vis spectra photometer, atomic force microscopy, scanning electron microscopy, and Fourier transform IR spectrum. Experimental results show that collagen molecules serve as effective templates to assemble Ag NPs into multilayer films. These samples exhibit high surface-enhanced Raman scattering (SERS) enhancement abilities.

Type I collagen-mediated synthesis of noble metallic nanoparticles networks and the applications in Surface-Enhanced Raman Scattering and electrochemistry

In this paper, we demonstrated an effective enviromentally friendly synthesis route to prepare noble metallic (Au, Ag, Pt and Pd) nanoparticles (NPs) networks mediated by type I collagen in the absence of any seeds or surfactants. In the reactions, type I collagen served as stabilizing agent and assembly template for the synthesized metallic NPs. The hydrophobic interaction between collagen and mica interface as well as the hydrogen bonds between inter- and intra-collagen molecules play important roles in the formation of collagen-metallic NPs networks. The noble metallic NPs networks have many advantages in the applications of Surface-Enhanced Raman Scattering (SERS) and electrochemistry detection. Typically, the as-prepared Ag NPs networks reveal great Raman enhancement activity for 4-ATP, and can even be used to detect low concentration of DNA base, adenine.

Electrodeposition of platinum nanoclusters on type I collagen modified electrode and its electrocatalytic activity for methanol oxidation

We firstly reported a novel polymer matrix fabricated by type I collagen and polymers, and this matrix can be used as nanoreactors for electrodepositing platinum nanoclusters (PNCs). The type I collagen film has a significant effect on the growth of PNCs. The size of the platinum nanoparticles could be readily tuned by adjusting deposition time, potential and the concentration of electrolyte, which have been verified by field-emitted scanning electron microscopy (FE-SEM). Furthermore, cyclic voltammetry (CV) has demonstrated that the as-prepared PNCs can catalyze methanol directly with higher activity than that prepared on PSS/PDDA film, and with better tolerance to poisoning than the commercial E-TEK catalyst. The collagen-polymer matrix can be used as a general reactor to electrodeposit other metal nanostructures.

Preparation of Hollow Carbon and Silicon Carbide Fibers with Different Cross-Sections by using Electrospun Fibers as Templates

Hollow carbon nanofibers with circular and rectangular opening were prepared by using electrospun silica fibers as templates. Silica fibers were synthesized by electrospinning, and they were coated with a carbon layer formed by thermal decomposition and carbonization of polystyrene under a nitrogen atmosphere. Hollow carbon nanofibers with circular and rectangular openings were then obtained after the silica core was etched by hydrofluoric acid. The carbon nanofibers with different morphologies also could be used as templates to fabricate silicon carbide fibers. The silicon carbide fibers with circular and rectangular openings could be obtained by using hollow carbon nanofibers and carbon belts as templates, respectively.

In Situ Observation of Tensile Deformation Processes of Soft Colloidal Crystalline Latex Fibers

The deformation mechanism or styrene/n-butyl acrylate copolymer latex films with fiber symmetric crystalline structure subjected to uniaxial stretching was studied using synchrotron small-angle X-ray scattering technique. The fibers were drawn at angles or 0, 35, and 55 degrees with respect to the Fiber axis. In all cases, the microscopic deformation within the crystallites was Found to deviate from affine deformation behavior with respect to the macroscopic deformation ratio. Moreover, the extent of this deviation is different in the three cases. This peculiar behavior can be attributed to the relative orientation of the (111) plane of the crystals, the plane of densest packing, with respect to the stretching direction in each case. When the stretching direction coincides with the crystallographic (111) plane, which is the case for stretching directions of 0 and 55 degrees with respect to the fiber axis, the microscopic deformation deviates less from affine behavior than when the stretching direction is arbitrarily oriented with respect to the crystallographic (111) plan.

Ultrafine PEG-PLA fibers loaded with both paclitaxel and doxorubicin hydrochloride and their in vitro cytotoxicity

By means of "emulsion-electrospinning", both hydrophobic and hydrophilic drugs, paclitaxel (PTX) and doxorubicin hydrochloride (DOX), were successfully loaded into PEG-PLA nanofiber mats to realize multi-drug delivery. The release behaviors of both the drugs from the same fiber mats were ascribed to their solubility properties and distribution status in the fibers. Due to its high hydrophilicity, DOX was easy to diffuse out from the fibers, and its release rate was always faster than that of hydrophobic PTX. Moreover, the release rate of PTX was accelerated by DOX's release from the same drug-loaded fibers. In vitro cytotoxicity against rat Glioma C6 cells indicated that the dual drug combination showed a higher inhibition and apoptosis against C6 cells than a single drug-loaded system, which suggests the promise for multi-drug delivery on combination therapy.

Type I collagen-mediated synthesis and assembly of UV-photoreduced gold nanoparticles and their application in surface-enhanced Raman scattering

We reported a simple method to synthesize gold nanoparticles (NPs) by photoreducing HAuCl4 in acetic acid solution in the presence of type I collagen. It was found that the collagen takes an important role in the formation of gold NPs. The introduction of collagen made the shape of the synthesized gold nanocrystals change from triangular and hexangular gold nanoplates to size-uniform NPs. On the other hand, thanks to the special characters of collagen molecules, such as its linear nanostructure, are positively charged when the pH < 7, and the excellent self-assembly ability, photoreduced gold NPs were assembled onto the collagen chains and formed gold NPs films and networks. A typical probe molecule, 4-aminothiophenol, was used to test the surface-enhanced Raman scattering activity of these gold NPs films and networks and the results indicated good Raman activity on these substrates.

Preparation of SrAl2O4:Eu2+, Dy3+ fibers by electrospinning combined with sol-gel process

One-dimensional SrAl2O4:Eu2+, Dy3+ fibers were fabricated by a simple electrospinning combined with sol-gel process. X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and photoluminescence were used to characterize the fibers. The results show that the phase structure of SrAl2O4:Eu2+, Dy3+ belongs to a monoclinic one, the composite fibers and fibers calcined at high temperature remain the original one-dimensional texture, and the SrAl2O4:Eu2+, Dy3+ was a green emission. (C) 2010 Elsevier Inc. All rights reserved.

PLLA-PCys co-electrospun fibers for capture and elution of glutathione S-transferase

The copolymer poly(L-lactic acid)-b-poly(L-cysteine) (PLA-b-PCys) was co-electrospun with PLGA into ultrafine fibers. The reduced glutathione (GSH) was conjugated to the fiber surfaces via disulfide bonds. The glutathione S-transferase (GST) was captured onto the GSH fibers via specific substrate-enzyme interaction between the bound GSH and GST. The captured GST was eluted with free GSH aqueous solution and lyophilized to get pure GST powders. The results show that the GSH moieties on the fiber surface retain the bioactivity of the free GSH and thus they can bind specifically with GST and the GST in solution is captured onto the fiber surface. In addition, the bound GSH is not as active as free GSH so that the captured GST can be eluted off from the fiber by free GSH aqueous solution. Based on this principle, GST itself or its fused proteins can be separated and purified very easily. The preliminary purification efficiency is 6.5 mg center dot(g(PCys))(-1). Further improvements are undertaken.

Syndiotactic 1,2-polybutadiene fibers produced by electrospinning

Syndiotactic 1,2-polybutadiene (s-PB) is a typical thermoplastic elastomer with various applications because of its high reactivity. In the past, it is difficult to form s-PB fibers with a diameter below 10 mu m because of the limitation of the conventional method such as melt spinning. Here, we report for the first time on the production of s-PB nanofibers by using a simple electrospinning method. Ultrafine s-PB fibers without beads were electrospun from s-PB solutions in dichloromethane and characterized by environmental scanning electron microscope (ESEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). At 4 wt.% concentration of s-PB, the average diameter of s-PB was about 130 nm. We found that dichloromethane was a unique suitable solvent for the electrospinning of s-PB fibers, and the structure of syndiotactic was changed through the electrospinning process.