Electrospinning is a simple and effective method for fabricating micro- and nanofiber matrices. Electrospun fibre matrices have numerous advantages for use as tissue engineering scaffolds, such as high surface area-to-volume ratio, mass production capability and structural similarity to the natural extracellular matrix (ECM). Therefore, electrospun matrices, which are composed of biocompatible polymers and various biomaterials, have been developed as biomimetic scaffolds for the tissue engineering applications. In particular, graphene oxide (GO) has recently been considered as a novel biomaterial for skeletal muscle regeneration because it can promote the growth and differentiation of myoblasts. Therefore, the aim of the present study was to fabricate the hybrid fibre matrices that stimulate myoblasts differentiation for skeletal muscle regeneration. Hybrid fibre matrices composed of poly(lactic-co-glycolic acid, PLGA) and collagen (Col) impregnated with GO (GO-PLGA-Col) were successfully fabricated using an electrospinning process. Our results indicated that the GO-PLGA-Col hybrid matrices were comprised of randomly-oriented continuous fibres with a three-dimensional non-woven porous structure. Compositional analysis showed that GO was dispersed uniformly throughout the GO-PLGA-Col matrices. In addition, the hydrophilicity of the fabricated matrices was significantly increased by blending with a small amount of Col and GO. The attachment and proliferation of the C2C12 skeletal myoblasts were significantly enhanced on the GO-PLGA-Col hybrid matrices. Furthermore, the GO-PLGA-Col matrices stimulated the myogenic differentiation of C2C12 skeletal myoblasts, which was enhanced further under the culture conditions of the differentiation media. Taking our findings into consideration, it is suggested that the GO-PLGA-Col hybrid fibre matrices can be exploited as potential biomimetic scaffolds for skeletal tissue engineering and regeneration because these GO-impregnated hybrid matrices have potent effects on the induction of spontaneous myogenesis and exhibit superior bioactivity and biocompatibility.

In the field of biomedical engineering, many studies have focused on the possible applications of graphene and related nanomaterials due to their potential for use as scaffolds, coating materials and delivery carriers. On the other hand, electrospun nanofiber matrices composed of diverse biocompatible polymers have attracted tremendous attention for tissue engineering and regenerative medicine. However, their combination is intriguing and still challenging. In the present study, we fabricated nanofiber matrices composed of M13 bacteriophage with RGD peptide displayed on its surface (RGD-M13 phage) and poly(lactic-co-glycolic acid, PLGA) and characterized their physicochemical properties. In addition, the effect of graphene oxide (GO) on the cellular behaviors of C2C12 myoblasts, which were cultured on PLGA decorated with RGD-M13 phage (RGD/PLGA) nanofiber matrices, was investigated. Our results revealed that the RGD/PLGA nanofiber matrices have suitable physicochemical properties as a tissue engineering scaffold and the growth of C2C12 myoblasts were significantly enhanced on the matrices. Moreover, the myogenic differentiation of C2C12 myoblasts was substantially stimulated when they were cultured on the RGD/PLGA matrices in the presence of GO. In conclusion, these findings propose that the combination of RGD/PLGA nanofiber matrices and GO can be used as a promising strategy for skeletal tissue engineering and regeneration.

Nanoprobes with multimodal functionality have attracted significant interest recently because of their potential applications in nanomedicine. This paper reports the successful development of lanthanide-doped Y₂O₃ nanoprobes for potential applications in optical and magnetic resonance (MR) imaging. The morphology, structural, and optical properties of these nanoprobes were characterized by transmission electron microscope (TEM), field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), energy-dispersive X-ray (EDX), and photoluminescence (PL). The cytotoxicity test showed that the prepared lanthanide-doped Y₂O₃ nanoprobes have good biocompatibility. The obvious contrast enhancement in the T₁-weighted MR images suggested that these nanoprobes can be used as a positive contrast agent in MRI. In addition, the clear fluorescence images of the L-929 cells incubated with the nanoprobes highlight their potential for optical imaging. Overall, these results suggest that prepared lanthanide-doped Y₂O₃ nanoprobes can be used for simultaneous optical and MR imaging.

Background: M13 bacteriophages can be readily fabricated as nanofibers due to non-toxic bacterial virus with a nanofiber-like shape. In the present study, we prepared hybrid nanofiber matrices composed of poly(lactic- co -glycolic acid, PLGA) and M13 bacteriophages which were genetically modified to display the RGD peptide on their surface (RGD-M13 phage). Results: The surface morphology and chemical composition of hybrid nanofiber matrices were characterized by scanning electron microscopy (SEM) and Raman spectroscopy, respectively. Immunofluorescence staining was conducted to investigate the existence of M13 bacteriophages in RGD-M13 phage/PLGA hybrid nanofibers. In addition, the attachment and proliferation of three different types of fibroblasts on RGD-M13 phage/PLGA nanofiber matrices were evaluated to explore how fibroblasts interact with these matrices. SEM images showed that RGD-M13 phage/PLGA hybrid matrices had the non-woven porous structure, quite similar to that of natural extracellular matrices, having an average fiber diameter of about 190 nm. Immunofluorescence images and Raman spectra revealed that RGD-M13 phages were homogeneously distributed in entire matrices. Moreover, the attachment and proliferation of fibroblasts cultured on RGD-M13 phage/PLGA matrices were significantly enhanced due to enriched RGD moieties on hybrid matrices. Conclusions: These results suggest that RGD-M13 phage/PLGA matrices can be efficiently used as biomimetic scaffolds for tissue engineering applications.

In biomedical applications, there is a need for tissue engineering scaffolds to promote and control cellular behaviors, including adhesion, proliferation and differentiation. In particular, the initial adhesion of cells has a great influence on those cellular behaviors. In this study, we concentrate on developing cell-adhesive substrates applicable for tissue engineering scaffolds. The hybrid nanofiber sheets were prepared by electrospinning poly(lactic-co-glycolic acid) (PLGA) and M13 phage, which was genetically modified to enhance cell adhesion thru expressing RGD peptides on their surface. The RGD peptide is a specific motif of extracellular matrix (ECM) for integrin receptors of cells. RGD peptide-decorated PLGA (RGD-PLGA) nanofiber sheets were characterized by scanning electron microscopy, immunofluorescence staining, contact angle measurement and differential scanning calorimetry. In addition, the initial adhesion and proliferation of four different types of mammalian cells were determined in order to evaluate the potential of RGD-PLGA nanofiber sheets as cell-adhesive substrates. Our results showed that the hybrid nanofiber sheets have a three-dimensional porous structure comparable to the native ECM. Furthermore, the initial adhesion and proliferation of cells were significantly enhanced on RGD-PLGA sheets. These results suggest that biomimetic RGD-PLGA nanofiber sheets can be promising cell-adhesive substrates for application as tissue engineering scaffolds.

Background: Hydrogels can serve as three-dimensional (3D) scaffolds for cell culture and be readily injected into the body. Recent advances in the image technology for 3D scaffolds like hydrogels have attracted considerable attention to overcome the drawbacks of ordinary imaging technologies such as optical and fluorescence microscopy. Multiphoton microscopy (MPM) is an effective method based on the excitation of two-photons. In the present study, C2C12 myoblasts differentiated in 3D gelatin hydroxyphenylpropionic acid (GHPA) hydrogels were imaged by using a custom-built multiphoton excitation fluorescence microscopy to compare the difference in the imaging capacity between conventional microscopy and MPM. Results: The physicochemical properties of GHPA hydrogels were characterized by using scanning electron microscopy and Fourier-transform infrared spectroscopy. In addition, the cell viability and proliferation of C2C12 myoblasts cultured in the GHPA hydrogels were analyzed by using Live/Dead Cell and CCK-8 assays, respectively. It was found that C2C12 cells were well grown and normally proliferated in the hydrogels. Furthermore, the hydrogels were shown to be suitable to facilitate the myogenic differentiation of C2C12 cells incubated in differentiation media, which had been corroborated by MPM. It was very hard to get clear images from a fluorescence microscope. Conclusions: Our findings suggest that the gelatin-based hydrogels can be beneficially utilized as 3D scaffolds for skeletal muscle engineering and that MPM can be effectively applied to imaging technology for tissue regeneration.