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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The aim of this work is to explore a new method for producing spun yarn on a modified ring spinning system which is called “clusterspun yarn”. Here, we describe the effects of the clustering of polyester multifilaments on the internal structure and properties of a composite yarn. Cotton fibers and polyester multifilaments were spun into 19 Ne cluster and core-spun yarns at five different twist levels. These yarns were then tested to compare their properties, including tenacity, elongation, and evenness. Surface morphology and structural variations of cluster and core-spun yarns were studied by scanning electron microscopy. Microtome and image-processing methods have been used to study the structure and packing of fibers in the cross-section of yarns. The results show that the special structure of a cluster-spun yarn results in pronounced enhancement in the structural mechanics and yarn properties. The statistical analysis results indicate that the tenacity and breaking elongation of cluster-spun yarn is significantly more than that in core-spun yarn. The results show that the twist factor at about 3.9(α e) gives the optimum properties. In addition, lower twist is needed to produce quality yarn in cluster-spun yarns as compared with normal core-spun yarns.

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