Sharif Digital Repository

In the present study, the feasibility of electrospun polyethersolfone (PES) nanofibrous membrane as the solid substrate for microfluidic based immunoassays to enhance the density of immobilized antibody on the surface of membrane was assessed. Conversely, the efficacy of antibody immobilization was compared by two different strategies as 1-Ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC)/N-Hydroxysuccinimide (NHS) coupling chemistry and hydrophobic interaction. Compared to conventional immunoassays carried out in plates or gels, microfluidic based immunoassays grant a lot of advantages such as a consumption of little samples and reagents, shorter analysis time, and higher efficiency.... 

In this study, poly (vinylidene fluoride) PVDF/Starch nanofibers with a great potential for tissue engineering applications have been investigated. The electrospun nanofibers were formed by the electrospinning of the PVDF/Starch solutions in various ratios of PVDF to Starch. Characterizations of PVDF/Starch nanofiber were performed using rheometric mechanical spectroscopy (RMS), field emission scanning electron microscope (FE-SEM) and tensile test. The results showed that the addition of more Starch into the PVDF solution increased the viscosity of the prepared PVDF/Starch solutions. In addition, the mechanical properties of PVDF enhanced in the presence of Starch due to the higher... 

Electrostatic fiber fabrication technique has evinced more interest and attention in recent years, owing to its versatility, reliability, and potential for applications in diverse fields, particularly separation, extraction, and filtration. The sub-micro fibers are generated by employing strong electric field on polymeric solutions or melt is led to the soft nanometric mats. So far, more than 100 polymers have been Electrospun and this number is gradually increasing. Over recent decades, a remarkable variety of electrospun nanofibers as promising and authentic extracting platforms have been synthesized. They offer various advantages including high surface area-to-volume ratio and tunable... 

Electrostatic fiber fabrication technique has evinced more interest and attention in recent years, owing to its versatility, reliability, and potential for applications in diverse fields, particularly separation, extraction, and filtration. The sub-micro fibers are generated by employing strong electric field on polymeric solutions or melt is led to the soft nanometric mats. So far, more than 100 polymers have been Electrospun and this number is gradually increasing. Over recent decades, a remarkable variety of electrospun nanofibers as promising and authentic extracting platforms have been synthesized. They offer various advantages including high surface area-to-volume ratio and tunable... 

In this work, the synthesized graphene oxide/TiO2/doxorubicin (GO/TiO2/DOX) composites were loaded into the chitosan/poly(lactic acid) (PLA) solutions to fabricate the electrospun chitosan/PLA/GO/TiO2/DOX nanofibrous scaffolds via electrospinning process. The synthesized composites and nanofibers were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis. Three-factor three-level central composite design was used to determine the influence of PLA to chitosan ratio, TiO2/DOX content and GO/TiO2/DOX content on the release of DOX from nanofibrous scaffolds. Drug loading efficiency and drug release behavior from... 

Low-cost ethanol vapor sensors are fabricated by electrospinning of TiS2/PVP fibers on pre-patterned metal electrodes. TiS2 ribbons have been synthesized through sulfuration of titanium (Ti) foil using chemical vapor transport (CVT). We found selective and stable responses at a low concentration of ethanol vapor (2 ppm) at room temperature with the transient response and recovery times experimentally around 60 s and 2 s respectively. The relatively high responses of sensors (6800% at 18 ppm) are attributable to the synergy effect of TiS2/PVP composite structure. The mechanism of sensing is discussed based on proton hopping while the sensors exposed to ethanol vapor. © 2019 Wiley-VCH Verlag... 

Titania nanofibers were prepared using a colloidal solution of Titania nanoparticles and a templating method. The preparation comprises impregnation of cellulose fibers in the solution containing Titania nanoparticles followed by thermal removal of the cellulose template. It is evidenced by scanning electron microscopy (SEM) that the residue substance consists of micron size fibers with a microstructure of nanofibers. The pore size distribution of the substance is multi-scale and fractal morphology was demonstrated with two fractal regimes with dimensions of 1.78 and 2.97 for sizes below and above 7.5nm, respectively. The surface area of the Titania fibers was measured about 250m2/g. The... 

Electrospinning is a process that produces nanofiber through the action of an external electric field imposed on a polymer solution or melt. This paper introduces a new system capable of producing continuous uniaxially aligned PAN nanofiber yarn by manipulating the electric field. The manipulation was carried out by employing a negative charged bar in the electric field of conventional electrospinning system, leading to the formation of an electrostatic multipolar field. As a result, the main stream was redirected towards a rotating take up unit, collecting the twisted yarn consisting of uniaxially aligned nanofibers. The yarns were then treated in boiling water under tension and their... 

The effects of applied magnetic and electric fields on electrospinning were investigated to produce more efficient nanofibers. Considering the previous extensive studies, polyamide nanofibers were prepared by a conventional approach and under auxiliary electric and magnetic fields. The first sorbent was synthesized by electrospinning of a solution of 18% polyamide in formic acid. The second and third types of polyamide were prepared similarly while the electrospinning processes were assisted by an electric and a magnetic field. The third type of polyamide contained a magnetic ionic liquid (MIL) to induce sufficient magnetic susceptibility in the polymeric solution. The SEM images revealed... 

Peripheral nervous system in contrary to central one has the potential for regeneration, but its regrowth requires proper environmental conditions and supporting growth factors. The aim of this study is to design and fabricate a conductive polyaniline/graphene nanoparticles incorporated gelatin nanofibrous scaffolds suitable for peripheral nervous system regeneration. The scaffolds were fabricated with electrospinning and the fabrication process was designed with Design-Expert software via response surface methodology. The effect of process parameters including applied voltage (kV), syringe pump flow rate (cm3/h), and PAG concentration (wt%), on the scaffold conductivity, nanofibers diameter,... 

Fibrous biomaterials have received much attention in tissue engineering and regenerative medicine due to their morphology, resembling extracellular matrix. In comparison to synthetic fibers, cellulose based fibers have interesting properties for cellular applications such as biodegradability, biocompatibility, simple preparation and their potential for chemical modification. Among cellulose derivatives, carboxymethyl cellulose and quaternized cellulose are the most important and valuable cellulose ethers which have anionic and cationic surface charge. In this research, we report the fabrication of multifunctional cellulose microfibrous and nanofibrous scaffolds and the comparison of adhesion... 

ZnO/gC 3 N 4 hybrid nanofibers containing different concentrations of gC 3 N 4 nanosheets were prepared using electrospinning technique; this was followed by annealing at 460 forC for one hour in a box furnace. Based on scanning electron microscopy (SEM) image analysis, the mean diameter of the nanofibers was measured to be ~ 55 nm. Fourier transform infrared (FTIR) spectroscopy confirmed the presence of ZnO and gC 3 N 4 in the prepared nanofibers. The photocatalytic activity of the nanofibers was examined under UV photoirradiation, showing that the ZCN0.5 nanofibers containing 0.5 wt% of gC 3 N 4exhibited the highest performance, as compared to other photocatalysts. The observed improvement... 

Protein capturing on polymeric substrate of microfluidic devices is a key factor for the fabrication of immunoassay with high sensitivity. In this work, simple and versatile technique of electrospinning was used to produce electrospun nanofibrous membranes (e.NFMs) with high surface area as a substrate for microfluidic-based immunoassay to increase sensitivity. It was found that the simultaneous use of e.NFM and 1-Ethylethyl-3-(3-dimethylaminopropyl)-carbodiimide/N-Hydroxysuccinimide hydroxysuccinimide as coupling agent has synergic effect on antigen immobilization onto the microchannels. It was found that the oxygen plasma technique for the creation of oxygen containing functional group... 

Gelatin methacrylate (GelMA) was proved to be a promising bioink for corneal stromal cell delivery. However, GelMA has low mechanical properties which makes it difficult to be suturable and handled for clinical applicattion. In this study, three different ratios of 12.5 % GelMA and 10 % PEGDA were investigated for corneal stromal cells delivery. The mixture containing 75 % GelMA and 25 % PEGDA (75G25P) was found to have reasonable cell viability and suturing strength. Moreover, collagen nanofibers were incorporated into 75G25P hydrogel to improve the mechanical and biomimetic properties of the construct (75G25P-E). A hybrid structure was obtained by injecting the optimized bioink on the... 

Due to the increase in the number of cancer patients, because of environmental parameters, high stress, low immunity, etc., there is an urgent need to develop cost-effective sensors for early targeted detection of cancerous cells with adequate selectivity and efficiency. Early disease diagnosis is important, as it is necessary to start treatments before disease progression. On the other hand, we need new, more efficient cancer treatment approaches with minimized side effects, more biocompatibility, and easy disposal. Nanobiotechnology is a field that can assist in developing new diagnostic and treatment approaches, specifically in fatal cancers. Herein, a study on the different applications...