In this work, poly(acrylic acid) (PAA) and PAA/multi-walled carbon nanotube (MWNTs) nanofibrous membranes are fabricated by electrospinning to immobilize acetylcholinesterase (AChE).3-Aminopropyltriethoxysilane (APTES) and glutaraldehyde are used for surface modification and PAA membrane stabilization in aqueous media. The structure of the nanofibrous membrane was studied by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, thermogravimetric and mechanical analyses. The AChE enzyme was immobilized on the PAA nanofibers with different amounts of MWNTs concentrations from 0 to 5 wt%. The SEM images revealed that the average diameter of the PAA nanofibers was 226 AE 25 nm which was increased by increasing the MWNTs concentration. The tensile strength and modulus of the nanofibrous membranes increased by 1.87 and 4.39 fold respectively after a crosslinking process. The results show that membranes containing MWNTs are a more appropriate support for enzyme immobilization. In comparison to pure PAA, the activity of the sample containing 4 wt% of MWNTs was increased by 5.07 fold. Also, the immobilized enzyme showed excellent reusability even after 10 cycles of washing and samples maintained more than 90% of their original activities. Moreover, the pH and thermal stability of the immobilized enzyme was improved compared to the free enzyme. The results show that a PAA/MWNTs nanofibrous membrane could be counted as a suitable support for AChE immobilization in addition to different applications such as biosensor manufacturing.

Research in the field of tissue engineering, especially heart tissue engineering, is growing rapidly. Herein, the morphological, chemical, mechanical and biological properties of poly (caprolactone) (PCL)/poly (glycerol sebacate) (PGS) and PCL/PGS/graphene nanofibrous scaffolds are investigated. Initially, PGS pre-polymer is synthesized and characterized by nuclear magnetic resonance and Fourier transform infrared spectroscopies. Then, in order to use the benefits of PGS, this polymer is mixed with PCL. Blending PGS with PCL resulted in the enhancement of ultimate elongation and reduction in the elastic modulus due to the intrinsic properties of PGS. The hydrophobicity of PCL nanofibers is reduced by adding PGS as hydrophilic polymer (105 ± 3 vs. 44 ± 2 ). Also, the addition of graphene to the blend nanofibers is balanced the hydrophilicity. Degradation rate of pure PCL nanofibers is very slow but it is increased in the presence of PGS. All nanofibrous scaffolds are biocompatible and non-toxic. The highest cell adhesion (covered area = 0.916 ± 0.032) and biocompatibility (98.79 ± 1%) are related to PCL/PGS loaded with 1% wt of graphene (PCL/PGS/graphene 1 ). Thus, this sample can be a good candidate for further examinations of cardiac tissue engineering.

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According to the results, these nanofiber mats loaded with eugenol can be used for treating cutaneous mucocutaneous candidiasis in high risk patients as a coating on a fabric substrate or temporary wound dressing.

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Cartilage is a connective tissue with a slow healing rate due to lack in blood circulation and slow metabolism. Designing tissue engineering scaffolds modified based on its specific features can assist its natural regeneration process. In this study, the chitosan-gelatin/single-walled carbon nanotubes functionalized by COOH (SWNTs-COOH) nanocomposite scaffolds were fabricated through electrospinning. The effect of each component and different duration of cross-linking were assessed in terms of morphology, porosity, chemical structure, thermal behavior, mechanical properties, wettability, biodegradability, and in vitro cell culture study. Adding SWNTs-COOH decreased fiber diameter, water contact angle and degradation rate while increased tensile strength, hydrophilicity, stability and cell viability, due to their high intrinsic electrical conductivity, and mechanical properties and the presence of COOH functional groups in its structure. All the sample presented a porosity percentage of more than 80%, which is essential for tissue engineering scaffolds. The presence SWNTs-COOH did not have any adverse effect on cytocompatibility. The optimal crosslinking time increased the stability of the scaffolds in PBS. It can be concluded that the chitosan-gelatin/1wt% SWNTs-COOH scaffold can be appropriate for cartilage tissue engineering applications.

Poly(glycerol sebacate) (PGS) is an attractive polymer that has many applications in medical fields, especially in tissue engineering. In this study, the influence of solvent system on electrospinnability, forming of bead-free nanofibers and the morphology of PGS nanofibers was investigated and discussed. Among different solvents, the acidic solvent as a benign solvent was used for electrospinning. The steps were as follows: (a) Synthesis the PGS pre-polymer and analysis its chemical structure by Fourier-transform infrared spectroscopy (FTIR); (b) Electrospinning of the PGS by mixing PCL in eight different solvent systems; (c) evaluation the morphology of produced nanofibers using the scanning electron microscope (SEM); (d) the study of biocompatibility of produced nanofibers by MTT assay. The average diameter of nanofibers in different solvent systems turned out to vary from 260 ± 63 to 4588 ± 970 nm and nanofibers with different morphologies were produced by changing the solvent system. Among the produced straight nanofibers, the best samples were FA 30,15 (formic acid), FA/AC 30,15 (formic acid/Acetone), FA/AA 30,15 (formic acid/acetic acid), CF/DMF 20,15 (chloroform/N,N-dimethylformamide), FA/AA 35,15 , and CF/DMF 23,15 , respectively (based on size and morphology). Also, the produced nanofibers in CF/ET (chloroform/ethanol) had a rough surface. When AA was used as solvent and polymer concentration was kept 35% w/v, sponge-like scaffold was produced. Moreover, spring-like nanofibers were fabricated by using DMF, (at 30% w/v) and AC (in all polymer concentrations). MTT results also demonstrated that CF/DMF 20,15 as produced sample via hazardous solvents (class 3) is biocompatible. These scaffolds can be used in different tissue engineering applications according to their morphology.