Scaffolds made of aligned nanofibers are favorable for nerve regeneration due to their superior nerve cell attachment and proliferation. However, it is challenging not only to produce a neat mat or a conduit form with aligned nanofibers but also to use these for surgical applications as a nerve guide conduit due to their insufficient mechanical strength. Furthermore, no studies have been reported on the fabrication of aligned nanofibers and randomly-oriented nanofibers on the same mat. In this study, we have successfully produced a mat with both aligned and randomly-oriented nanofibers by using a novel electrospinning set up. A new conduit with a highly-aligned electrospun mat is produced with this modified electrospinning method, and this proposed conduit with favorable features, such as selective permeability, hydrophilicity and nerve growth directional steering, were fabricated as nerve guide conduits (NGCs). The inner surface of the nerve conduit is covered with highly aligned electrospun nanofibers and is able to enhance the proliferation of neural cells. The central part of the tube is double-coated with randomly-oriented nanofibers over the aligned nanofibers, strengthening the weak mechanical strength of the aligned nanofibers.

Localized drug-delivery systems (LDDSs) are a promising approach for cancer treatment because they decrease systematic toxicity and enhance the therapeutic effect of the drugs via site-specific delivery of active compounds and possible gradual release. However, the development of LDDS with rationally controlled drug release and intelligent functionality holds great challenge. To this end, we have developed a tailorable fibrous site-specific drug-delivery platform functionalized with pH- and near-infrared (NIR)-responsive polypyrrole (PPy), with the aim of cancer treatment via a combination of photothermal ablation and chemotherapy. First, a paclitaxel (PTX)-loaded polycaprolactone (PCL) (PCL-PTX) mat was prepared by electrospinning and subsequently in situ membrane surface-functionalized with different concentrations of PPy. The obtained PPy-functionalized mats exhibited excellent photostability and heating property in response to NIR exposure. PPy-coated mats exhibited enhanced PTX release in a pH 5.5 environment compared to pH 7.4. Release was further accelerated in response to NIR under both conditions; however, superior release was observed at pH 5.5 compared to pH 7.4, indicating a dual stimuli-responsive (pH and NIR) drug-delivery platform. More importantly, the 808 nm NIR irradiation enabled markedly accelerated PTX release from PPy-coated PCL-PTX mats and slowed and sustained release following termination of laser irradiation, confirming representative stepwise drug-release properties. PPy-coated PCL-PTX mats presented significantly enhanced in vitro and in vivo anticancer efficacy under NIR irradiation compared to PPy-coated PCL-PTX mats not exposed to NIR or uncoated mats (PCL-PTX). This study has thus developed a promising fibrous site-specific drug-delivery platform with NIR- and pH-triggering that notably utilizes PPy as a dopant for synergistic photothermal chemotherapy.

Neural cells respond to topographical cues with alterations in cell growth and neurite sprouting mediated by changes in cell behavior. The interaction of fiber topography with cell adhesion receptors affects how the cells adhere to the surface of fibers and defines cell fate through alterations in the biochemistry, physiology, and morphology of neural cells. Although previous studies suggest topographical features influence neural cell proliferation and neurite sprouting, only a few studies have attempted to assess the use of both electrical and topological cues in piezoelectric scaffolds for nerve regeneration. In this study, variations in the shape‐modified collectors enable tunable surface topographic constructs, from micropatterns to fiber bundle structure. The crystallinity, chemical composition, and quantitative analysis confirm that the interplay between the topological structures of the fibers and the blending of nanocomposite materials is critical for the formation of the β‐phase. It is found that the topographical features and induced electrical characteristics affect cell growth. Also, the intracellular signaling pathway is induced that can provide clues as to how neural cells respond to the topological gradient structure modulated piezoelectric scaffolds. An analysis of the neuron‐specific cytoskeletal related markers further reveals that the specific topographical features piezoelectric fibrous scaffold reinforces neuron‐specific cytoskeletal proteins and microtubule assembly.

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In this article, Broussonetia kazinoki (BK) powdery extract is utilized to modify the silk fibroin (SF) scaffold and applied to the bone defect area. The BK/SF scaffold is an efficient cell carrier which promotes cell proliferation and osteogenic differentiation of rBMSCs (bone marrow derived mesenchymal stem cells). We confirmed biocompatibility and osteogenic differentiation capacity of BK/SF scaffolds compared to pristine SF scaffold in both in vitro and in vivo evaluation. Gene expression related to osteogenic differentiation and bone regeneration significantly upregulated in the BK/SF scaffold group. The implanted scaffolds were attached well to the surface of the bone defect region and integrated with surrounding tissues without significant inflammatory reaction. Furthermore, almost 45% of bone volume has been recovered at 8 weeks postsurgery, while the SF and control group showed 20% recovery. These results suggest that BK powdery extract incorporated with an SF scaffold might be a suitable substitute for an alternative bone graft for bone regeneration.