The mechanical properties of the tissue engineering scaffold are important as they are tightly related the regeneration of structural tissue. The application of poly(L-lactic acid) (PLLA) nanofiber scaffolds in tissue engineering has been hindered by their insufficient mechanical properties. In the study, halloysite nanotubes (HNTs) were used to reinforce the mechanical properties of PLLA-based nanofibers. 4 wt% HNT/PLLA nanofiber membranes possess the best mechanical performance, which represents 61 % increase in tensile strength, 100 % improvement of Young's modulus, 49 % augment of elongation to break, as well as 181 % elevation in energy to break compared with neat PLLA samples. The satisfactory enhancement effect of HNTs can be attributed to the effective dispersion and incorporation of HNTs in PLLA matrix, which have been confirmed by the analysis of SEM, TEM, and FTIR. The addition of HNTs also improves the degree of crystallization and thermal stability of PLLA-based nanofibers. HNT-incorporated PLLA nanofiber membranes possess higher protein adsorption from fetal bovine serum than the neat PLLA specimen. Therefore, the introduction of HNTs can effectively enhance the mechanical properties of PLLA nanofiber scaffolds. HNT/PLLA nanofiber scaffolds possess potential application in skin tissue engineering.

No abstract

Optimization of the mechanical properties is necessary in the applications of electrospun nanofibrous matrices. In this work, mechanical reinforcement of electrospun nanofiber membranes of water-soluble polymer by the incorporation of commercial nanodiamonds (NDs) was studied. Through an ND/poly(vinyl alcohol) (ND/PVA) model system, it is demonstrated that 155% improvement of Young's modulus, 89% increase in tensile strength, and 336% elevation in energy to break are achieved by the addition of only 2 wt% ND. Fourier transform infrared spectroscopy results suggest the existence of molecular interactions between NDs and PVA matrix, which contributes to the effective load transfer from the polymer matrix to the fillers. However, higher level of ND addition (>2 wt%) aggravates the agglomeration of nanofillers in PVA matrix and offsets the reinforcing effect, as ND agglomerates may act as flaws in composite nanofibers. Furthermore, NDs have optimizing effect on the morphology of ND/PVA nanofibers through increasing the conductivity of the electrospinning solution. Therefore, ND nanofillers possess the potential to improve the mechanical performance of water-soluble polymer-based nanofiber membranes. POLYM. COMPOS., 34:1735COMPOS., 34: -1744

No abstract

remarkable features, such as high porosity, large specific area, and interconnected pore structure. As a novel class of nanofibers, core-shell structured nanofibers are composed of two discrete parts, i.e., the inner "core" portion and the outer "shell" layer. Because of being spatially partitioned, the core and the shell can perform their individual functions independently. Core/shell nanofibers offer decisive advantages over monolithic fibers. The multifaceted nature of core/shell structured nanofibers allows for achieving the on-demand properties for drug delivery system and engineered tissue scaffolds. [5] For nanofiberbased scaffolds, the core can provide the favorable environment for the sensitive biocompounds such as growth factors, antibiotics and drugs, whereas the shell can serve as a barrier to prevent the premature release of the water-soluble content in the core, and provide the tailored topography and composition to promote cell adhesion, To endow nanofibers with the desirable antibacterial and mechanical properties, a facile strategy using Pickering emulsion (PE) electrospinning is proposed to prepare functional nanofibers with core/shell structure for the first time. The water-in-oil (W/O) Pickering emulsion stabilized by oleic acid (OA)-coated magnetite iron oxide nanoparticles (OA-MIONs) is comprised of aqueous vancomycin hydrochloride (Van) solution and poly(lactic acid) (PLA) solution. The core/shell structure of the electrospun Van/OA-MIONs-PLA nanofibers is confirmed by scanning electron microscopy and transmission electron microscopy observation. Sustained release of Van from the PE electrospun nanofiber membrane is achieved within the time of 600 h. Compared with the neat PLA electrospun nanofiber membrane, 57% increase of tensile strength and 36% elevation of elongation at break are achieved on PE electrospun nanofiber membrane. In addition, the PE electrospun nanofiber membrane demonstrates excellent antibacterial property stemming from the combinational antibacterial activities of OA-MIONs and Van. The Van-loaded PE electrospinning nanofibers with sustained antibacterial performance possess potential applications in tissue engineering and drug delivery.

Optimization of mechanical properties is required in applications of tissue-engineered scaffolds. In this study, a polyelectrolyte complexation approach is proposed to improve the mechanical properties of the nanofibrous scaffolds. Through an electrospun chitosan/gelatin (CG) model system, it is demonstrated that the storage modulus of CG nanofiber-based complex membranes is over 10(3)-fold higher than that of neat chitosan or gelatin membranes. Further, an annealing process was found to promote the conjugation of the oppositely charged polymers and thus the tensile modulus of CG membranes is 1.9-fold elevated. When the molar ratio of aminoglucoside units in chitosan to carboxyl units in gelatin is 1:1, the complex nanofiber-based membranes (CG2) display the highest mechanical strength. In addition, the complex membranes reveal an excellent swelling capacity. By comparing the CG membranes electrospun with cast, it is deduced that the complexation is one of the main contributing factors to the improvement in mechanical properties. FTIR and DSC analyses confirm that more molecular interactions took place in the complexation. SEM observation clearly displays the electrospinnability of the complex. Therefore, polyelectrolyte complexation is an effective strategy for enhancing mechanical properties of nanofibrous scaffolds. These mechanically enhanced chitosan/gelatin nanofibrous membranes have wider applications than wound dressing.