Wen Zhao

Shandong University, Chi-nan-shih, Shandong Sheng, China

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Publications (3)8.99 Total impact

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    ABSTRACT: For artificial nerve conduits, great improvements have been achieved in mimicking the structures and components of autologous nerves. However, there are still some problems in conduit construction, especially in terms of mechanical properties, biomimetic surface tomography, electrical conductivity and sustained release of neurotrophic factors or cells. In this study, we designed and fabricated a novel electrospun nerve conduit enhanced by multi-walled carbon nanotubes (MWNTs) on the basis of a collagen/poly(ε-caprolactone) (collagen/PCL) fibrous scaffold. Our aim was to provide further knowledge about the mechanical effects and efficacy of MWNTs on nerve conduits as well as the biocompatibility and toxicology of MWNTs when applied in vivo.The results showed that as one component, carboxyl MWNTs could greatly alter the composite scaffold's hydrophilicity, mechanical properties and degradability. The electrospun fibers enhanced by MWNTs could support Schwann cell adhesion and elongation as a substrate in vitro. In vivo animal studies demonstrated that the MWNT-enhanced collagen/PCL conduit could effectively promote nerve regeneration of sciatic nerve defect in rats and prevent muscle atrophy without invoking body rejection or serious chronic inflammation. All of these results showed that this MWNT-enhanced scaffold possesses good biocompatibility and MWNTs might be excellent candidates as engineered nanocarriers for further neurotrophic factor delivery research.
    No preview · Article · Mar 2014 · Nanotechnology
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    ABSTRACT: This study investigated the in vitro cytocompatibility of carbon nanotubes (CNTs) in a chitosan/collagen-based composite. Mouse fibroblasts were cultured on the surface of a novel material consisting of CNTs in a chitosan/collagen-based composite (chitosan/collagen+CNTs group). Chitosan/collagen composites without CNTs served as the control material (chitosan/collagen group) and cells cultured normally in tissue culture plates served as blank controls (blank control group). Cell adhesion and proliferation were observed, and cell apoptosis was measured. The doubling time (DT1) of cells was significantly shorter in the chitosan/collagen+CNTs group than in the chitosan/collagen group, and that in the chitosan/collagen group was shorter than in the blank control group. The CNTs in the chitosan/collagen-based composites promoted mouse fibroblast adhesion, producing a distinct cytoskeletal structure. At 24 h after culture, the cytoskeleton of the cells in the chitosan/collagen+CNTs group displayed typical fibroblastic morphology, with clear microfilaments. Cells in the chitosan/collagen group were typically round, with an unclear cytoskeleton. The blank control group even had a few unattached cells. At 4 days after incubation, no early apoptosis of cells was detected in the blank control group, whereas early apoptosis of cells was observed in the chitosan/collagen+CNTs and chitosan/collagen groups. No significant difference in the proportion of living cells was detected among the three groups. After entering the plateau stage, the average cell number in the chitosan/collagen+CNTs group was similar to that in the chitosan/collagen group and significantly smaller than that in the blank control group. Early apoptosis of cells in the blank control group was not detectable. There were significant differences in early apoptosis among the three groups. These results suggest that CNTs in a chitosan/collagen-based composite did not cause significant cytotoxic effects on mouse fibroblasts. Compared with chitosan/collagen composites, early adhesion and proliferation of fibroblasts were increased on chitosan/collagen+CNTs. However, at relatively high cell densities, the CNTs in the chitosan/collagen-based composite might exert an inhibitory effect on mouse fibroblast proliferation by inducing apoptosis.
    No preview · Article · Sep 2013 · Cellular and Molecular Neurobiology
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    ABSTRACT: To cope with the limitations faced by autograft acquisitions particularly for multiple nerve injuries, artificial nerve conduit has been introduced by researchers as a substitute for autologous nerve graft for the easy specification and availability for mass production. In order to best mimic the structures and components of autologous nerve, great efforts have been made to improve the designation of nerve conduits either from materials or fabrication techniques. Electrospinning is an easy and versatile technique that has recently been used to fabricate fibrous tissue-engineered scaffolds which have great similarity to the extracellular matrix on fiber structure. In this study we fabricated a collagen/poly(ε-caprolactone) (collagen/PCL) fibrous scaffold by electrospinning and explored its application as nerve guide substrate or conduit in vitro and in vivo. Material characterizations showed this electrospun composite material which was made of submicron fibers possessed good hydrophilicity and flexibility. In vitro study indicated electrospun collagen/PCL fibrous meshes promoted Schwann cell adhesion, elongation and proliferation. In vivo test showed electrospun collagen/PCL porous nerve conduits successfully supported nerve regeneration through an 8 mm sciatic nerve gap in adult rats, achieving similar electrophysiological and muscle reinnervation results as autografts. Although regenerated nerve fibers were still in a pre-mature stage 4 months postoperatively, the implanted collagen/PCL nerve conduits facilitated more axons regenerating through the conduit lumen and gradually degraded which well matched the nerve regeneration rate. All the results demonstrated this collagen/PCL nerve conduit with tailored degradation rate fabricated by electrospinning could be an efficient alternative to autograft for peripheral nerve regeneration research. Due to its advantage of high surface area for cell attachment, it is believed that this electrospun nerve conduit could find more application in cell therapy for nerve regeneration in future, to further improve functional regeneration outcome especially for longer nerve defect restoration.
    Full-text · Article · Jul 2011 · BMC Neuroscience