Modifying physicochemical properties of polymers through functionalization is a practical approach in the preparation of tissue engineering scaffolds. The aim of present research is to sulfonate polyethersulfone and to improve its biocompatibility in order to regulating cell behaviors. Sulfonated polyethersulfone with different degrees of sulfonation were prepared using three different concentrations of chlorosulfonic acid as the sulfonating agent. The degree of sulfonation was investigated quantitatively and qualitatively. The electrospun nanofibers were fabricated by prepared polymers afterward. Morphological properties, contact angle, and porosity of nanofibrous scaffolds were studied. The adhesion, growth and proliferation of cultured mesenchymal stem cells on the scaffolds were investigated. Polyethersulfone was sulfonated with three molar percentages of 14.2, 22.1, and 30.1, based on the titration results. The scanning electron microscopic images of nanofibers showed that polyethersulfone nanofibers at a concentration of 25% W/V had a uniform and beadless structure. The diameter size distribution of sulfonated polyethersulfone nanofibers was uniform with a flow rate of 0.09 ml/h. Sulfonation significantly changed many properties of the final scaffold. The water contact angle decreased from 130◦ to 117◦, 108◦, and 100◦, after sulfonation. The diameter of nanofibers decreased from 391 nm to 192 nm, 140 nm, and 121 nm. Cell studies showed that sulfonation of polyethersulfone nanofibers improves adhesion, and increases the growth and proliferation of stem cells. However, the degree of sulfonation must remain at an optimal level. As a result sulfonation is a suitable method to improve the properties of synthetic polymers such as polyethersulfone for biological applications.

Introduction: Amylases are used in various industries, mainly, starch processing that hydrolyze polysaccharides. Insoluble and solid supports are noteworthy in immobilization of enzymes for industry because of increasing enzyme stability. In this study, immobilization of alpha amylase in electrospun polyethersulfone (PES) nanofibers was studied. Materials and Methods: Covalent immobilization of the enzyme was done through the carboxyl groups made by oxygen plasma treatment and 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) as a carboxyl group activator agent. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) and contact angle analysis proved enzyme immobilization. The optimum conditions determined and the catalytic parameters of immobilized enzyme were calculated. Results: The results of this investigation showed that the optimum pH of immobilized enzyme was displaced toward acidic region by 1 unit. Comparison of the optimum temperature for immobilized and free amylase revealed 10° C increasing for the immobilized enzyme. Furthermore, the kinetic parameters, Vmax and Km for the immobilized enzyme were the same and higher than those of free ones, respectively. Storage stability of the immobilized amylase was obviously improved. Conclusions: The results illustrated that nanofibrous supported alpha amylase is a new and suitable matrix for industrial applications.

In this research, removal of the lead ion in the diffusion dialysis was investigated. The membranes was prepared using sulfonated polyethersulfone at 12, 14 and 18 wt. % concentration by the phase inversion method. Their physical properties including the ion exchange capacity, water content, porosity and thickness of membranes were investigated. For investigation of cation exchange membranes performance, experimental design was developed. Three parameters in three levels were selected. By using signal to noise ratio (SNR), the parameter which had the most effect on the lead ion transport was the concentration of the lead ion in the feed. Furthermore, the effect of sodium ion presence in the feed on the lead ion transport was studied. The effect of addition of nanoclay to the optimum membrane was studied. In the optimum condition, the feed with 100 ppm and 5000 ppm concentrations had the flux of 4. 08×10-5 and 6. 56×10-2 mmol/s m2, respectively.

Laser irradiation parameters, especially the laser fluence and the number of pulses are very important factors affecting microstructures formation and improvement of the surface characteristics in different medical, electronic and the other industrial applications. Information about the fluence domain and the number of pulses for the formation of the structures is very important and determines the desirable or unwanted effects of the laser irradiation on the surfaces regarding the desired applications. In this paper Polyethersulfone films were irradiated with a XeCl laser at fluences above the ablation threshold. The effects of the laser fluence and the number of pulses on the formation of different microstructures on the surface were investigated.

Phase inversion is a common method for preparation of polymeric membranes. It is noticeable that most of the membranes prepared by this method have an asymmetrical structure. In this type of membranes, separation of particles occurs only by top dense layer in a high operating pressure. On the other hand, these paration process using symmetric membranes containing surface pores occurs on the top surface and in the depth of the membrane at lower operating pressure. In thisresearch, preparation of polyethersulfone-based membranes was performed throughthe phase inversion method by dimethylacetamide as a solvent and water as the nonsolvent. Changing the coagulation conditions by applying one pause stage in anenvironment with the precise control of temperature and humidity, along with usingpolyvinylpyrrolidone as a hydrophilic additive, were attempted in order to controlthe porosity and structural changes of the membrane. Scanning electron microscopy) SEM (images, bubble point test, porosity, and mean pore radius measurementswere used to study the structure of the prepared membranes. The performance of themembranes was evaluated by pure water permeation test and elimination of bacteriafrom cell culture medium. The results obtained illustrate that the implemented methodis capable of preparation of membranes with symmetrical structure and pore diameterless than 0.4 μm featuring acceptable pure water flux and bacteria removalability. Itwas also observed that increase in the concentration of polyvinylpyrrolidone additiveleads to an increase in porosity, permeation and pore size of the membrane samples.On the other hand, the tensile strength and elongation-at-break of the membranesamples were reduced upon increasing in polyvinylpyrrolidone concentration.

In this study, the Surface of polyethersulfone nanofiltration membranes was modified by a nanocomposite Layer containing POSS nanoparticles. The effect of the Surface modification, on the structure, separation, and other properties of the membranes was checked. Pristine membranes were prepared by the phase inversion method. The surface of the membrane was modified by the dip coating method. Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) analysis, and scanning electron microscopy (SEM), were applied in membrane characterization. Moreover, Pure water flux, salt rejection, membrane porosity, mean pore size of the membrane, water content, and water contact angle were applied to evaluate membranes. The FTIR results proved the creation of a nanocomposite layer with the POSS nanoparticles on the surface of the virginal membrane. SEM images confirmed that a new layer was uniformly present on the surface of the modified membranes. The amount of water content for double-layer membranes had an increasing trend compared to pristine membranes, also, the results of the contact angle showed a decrease in the surface roughness for the modified membranes then with increasing concentration of glycidyl-pass nanoparticles, that is a hydrophobic substance, went through a decreasing trend. By increasing Acrylic Acid, the porosity was enhanced but after utilizing glycidyl-pass nanoparticles, it showed a decreasing trend. Also, the pure water flux showed a decreasing trend. The rate of return had an increasing trend for the membranes. The addition of glycidyl-pass nanoparticles up to 0.1% by weight resulted in the yield of 59.74% Na2SO4 and 64% for CrSO4.