Crystallization Behavior and Dynamic Mechanical Properties of Poly(ε-caprolactone)/Octaisobutyl-Polyhedral Oligomeric Silsesquioxanes Composites Prepared via Different Methods

Fabricating a robust POSS-PCL nanofiber scaffold for nesting of mesenchymal stem cells: potential application in bone tissue regeneration

BACKGROUND

According to recent studies, electrospun Poly (Ɛ-caprolactone) (PCL) is an absorbing candidate for the formulation of biocompatible scaffolds used in tissue engineering. Tissue engineering is a set of techniques for producing or reconstructing tissue, whose primary purpose is to restore or improve the function of tissues in the human body. Tissue engineering combines the principles of materials and cell transplantation to develop alternative tissues or promote endogenous regeneration. However, this electrospun scaffold, consisting of PCL, has disadvantages such as low cell adhesion, inactivity of the surface, osteoinduction, and acidic destruction of the scaffold that causes inflammation at the implant site, often making it unsuitable implant. This study aimed to improve PCL base cellular scaffolds with the formulation of polyhedral oligomeric silsesquioxane - Polycaprolactone (POSS-PCL) nanofiber scaffolds. The present research focuses on the synthesis of nanofibers for their cell interaction features, and application in bone tissue engineering and regeneration.

RESULTS

POSS/ PCL Nanocomposites with 2, 5, and 10 wt.% of POSS were synthesized in the Trichloromethane, then POSS - PCL Nanofibers were prepared by the electrospinning technique. In this study, the structures of nanohybrids and nanofibers have been evaluated by FTIR, HNMR, XRD, SEM, EDX, and DSC. The biocompatibility of formulated POSS-PCL scaffolds was detected using mesenchymal stem cells (MSCs). Then several parameters were examined, involving DCFH ROS detection system, gene expression (cell viability/apoptosis, osteogenesis potentiality, and redox molecular homeostasis.

CONCLUSIONS

Based on our results, POSS-PCL nano-scaffolds in comparison with PCL have shown a robust potentiality in homing, growth, and differentiation of stem cells. Synthesis of POSS-PCL Nanofibers and their potential application in Bone Regeneration.

Significantly Enhanced Crystallization of Poly(ethylene succinate-co-1,2-propylene succinate) by Cellulose Nanocrystals as an Efficient Nucleating Agent

Poly(ethylene succinate-co-1,2-propylene succinate) (PEPS) is a novel aliphatic biodegradable polyester with good mechanical properties. Due to the presence of methyl as a side group, the crystallization rate of PEPS is remarkably slower than that of the poly(ethylene succinate) homopolymer. To promote the potential application of PEPS, the effect of cellulose nanocrystals (CNC) on the crystallization behavior, crystalline morphology, and crystal structure of PEPS was investigated in this research with the aim of increasing the crystallization rate. CNC enhanced both the melt crystallization behavior of PEPS during the cooling process and the overall crystallization rate during the isothermal crystallization process. The crystallization rate of PEPS became faster with an increase in CNC content. The crystalline morphology study directly confirmed the heterogeneous nucleating agent role of CNC. The crystal structure of PEPS remained unchanged in the composites. On the basis of the interfacial energy, the nucleation mechanism of PEPS in the composites was further discussed by taking into consideration the induction of CNC.

Fully Biodegradable Poly(hexamethylene succinate)/Cellulose Nanocrystals Composites with Enhanced Crystallization Rate and Mechanical Property

Through a common solution and casting method, low contents of cellulose nanocrystals (CNC) reinforced biodegradable poly(hexamethylene succinate) based composites were successfully prepared for the first time. CNC homogeneously dispersed in PHS matrix at low loadings, showing no obvious aggregation. PHS/CNC composites showed high thermal stability as PHS. As a heterogeneous nucleating agent, CNC promoted the crystallization of PHS under both nonisothermal and isothermal crystallization conditions. In addition, the higher the CNC content, the faster the crystallization of PHS/CNC composites. The heterogeneous nucleating agent role of CNC was directly confirmed by the crystalline morphology study; moreover, the crystal structure of PHS remained unmodified despite the presence of CNC. As a reinforcing nanofiller, CNC also improved the mechanical property of PHS, especially the Young’s modulus and yield strength. In brief, low contents of CNC may improve both the crystallization and mechanical property of PHS, providing an easy method to tune the physical property and promote the wider application of biodegradable polymers.