In this study, polyhydroxybutyrate (PHB) was blended with chitosan (CTS), and electrospun in order to produce more hydrophilic fibrous scaffolds with higher mass loss rates for cartilage tissue engineering application. First, the effects of diverse factors on the average and distribution of fiber's diameter of PHB scaffolds were systematically evaluated by experimental design. Then, PHB 9 wt % solutions were blended with various ratios of CTS (5%, 10%, 15%, and 20%) using trifluoroacetic acid as a co‐solvent, and electrospun. The addition of CTS could decrease both water droplet contact angle from ∼74° to ∼67° and tensile strength from, ∼87 MPa to ∼31 MPa. According to the results, the scaffolds containing 15% and 20% CTS were selected as optimized scaffolds for further investigations. Mass loss percentage of these scaffolds was directly proportional to the amount of CTS. Chondrocytes attached well to the surfaces of these scaffolds. The findings suggested that PHB/CTS blend fibrous scaffolds have tremendous potentials for further investigations for the intended application. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44171.

In this study, a nanofibrous electrospun substrate based on the silk fibroin (SF) and gelatin (GT) polymers were prepared and evaluated. The SF/GT blended solutions were prepared with various ratios of GT in formic acid and electrospun to obtain bead-free fibers. Results showed that addition of GT to SF increased nanofiber's diameter, bulk hydrophilicity, surface wettability, mass loss percentage, but decreased Young's modulus, tensile strength, and porosity of the SF/GT mats. According to the obtained results, the mat containing 10% of GT was selected as the optimized mat for further studies and loaded with thyme essential oil (TEO) and doxycycline monohydrate (DCMH) as the antibacterial agents. Release studies showed a burst release of TEO from the mat within the first 3 h, while the DCMH had a sustained release during 48 h. In comparison to the TEO-loaded mat, the DCMH-loaded one showed larger inhibition zones against Staphylococcus aureus and Klebsiella pneumoniae bacteria. Meanwhile, cellular studies using mouse fibroblast L929 cells showed excellent cell-compatibility of TEO- and DCMH-loaded mats. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1092-1103, 2018.

Providing affinity sites on alginate (ALG) matrix enables specific binding of growth factors to the polymer backbone and allows their release in a controlled fashion. In this study, we used a blend of alginate sulfate (ALG‐S) and polyvinyl alcohol (PVA) to fabricate electrospun scaffolds capable of delivering a heparin‐like growth factor, transforming growth factor‐beta1 (TGF‐β1). The alginate was sulfated with different degrees of sulfation (DS, from 0.8, 3.4 to 12.4%) by a simple process. The success of sulfation was determined by Fourier‐transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), elemental analysis, ultraviolet (UV) spectroscopy and staining with dimethylmethylene blue. The physical‐mechanical properties of nanofibrous mats were characterized by scanning electron microscopy (SEM), FTIR, energy‐dispersive X‐ray spectroscopy (EDX), tensile strength and mass loss analysis. Additionally, the release kinetics of transforming growth factor‐β1 (TGF‐β1) from PVA/ALG‐S and PVA/ALG scaffolds were compared. The results showed that the binding and entrapment of TGF‐β1 to the nanofibrous scaffolds are improved by the addition of sulfate group to alginate. In conclusion, our results support that nanofibrous scaffold based on PVA/ALG‐S can deliver growth factors in tissue engineering application. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 403–413, 2019.

Background:Poly (hydroxy butyrate) (PHB) is a biodegradable and biocompatible polymer with good mechanical properties. This polymer could be a promising material for scaffolds if some features improve.Materials and Methods:In the present work, new PHB/chitosan blend scaffolds were prepared as a three-dimensional substrate in cartilage tissue engineering. Chitosan in different weight percent was added to PHB and solved in trifluoroacetic acid. Statistical Taguchi method was employed in the design of experiments.Results:The Fourier-transform infrared spectroscopy test revealed that the crystallization of PHB in these blends is suppressed with increasing the amount of chitosan. Scanning electron microscopy images showed a thin and rough top layer with a nodular structure, supported with a porous sub-layer in the surface of the scaffolds. In vitro degradation rate of the scaffolds was higher than pure PHB scaffolds. Maximum degradation rate has been seen for the scaffold with 90% wt. NaCl and 40% wt. chitosan.Conclusions:The obtained results suggest that these newly developed PHB/chitosan blend scaffolds may serve as a three-dimensional substrate in cartilage tissue engineering.

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In this paper, preparation and characterization of a nanofibrous scaffold comprising both chitosan (CS) and gum tragacanth (GT) are reported for the first time. CS and GT were separately blended with poly(vinyl alcohol) (PVA) and simultaneously electrospun by a double-nozzle electrospinning apparatus, and the resulting nanofibrous mats were compared with CS/PVA and GT/PVA electrospun ones. Scanning electron microscopy images showed uniform bead-free nanofibers with some merging areas and an average fiber diameter of ∼273 nm for CS-PVA/GT-PVA. The ultimate tensile strength and strain at break of the hybrid nanofibers were ∼20 MPa and ∼9%, respectively, which were significantly higher than those of the CS/PVA and GT/PVA nanofibers. The CS-PVA/GT-PVA nanofibrous mats also showed a water droplet contact angle value (∼31°) between those of the CS/PVA and GT/PVA nanofibrous mats. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay using L929 fibroblast cells indicated more biocompatibility of the CS-PVA/GT-PVA hybrid nanofibers compared with the CS/PVA and GT/PVA ones. The obtained results showed that the CS-PVA/GT-PVA hybrid nanofibrous scaffold might be useful for tissue engineering applications.