Time filter

Source Type

Yao Y.,Beihang University | Liu H.,Beihang University | Ding X.,Beihang University | Jing X.,Beihang University | And 4 more authors.
Journal of Bioactive and Compatible Polymers | Year: 2015

In recent years, silk fibroin has become one of the most promising tissue engineering materials because of its excellent cytocompatibility. Poly(l-lactide-co-ε-caprolactone), the copolymer of poly(l-lactide) and poly(ε-caprolactone), possesses good mechanical properties, and its degradation rates can be manipulated by varying the ratio of the constituent polymers. In this study, in order to combine their respective characteristics, silk fibroin/poly(l-lactide-co-ε-caprolactone) nanofibrous membranes were fabricated through electrospinning with different mass ratios of 100:0, 75:25, 50:50, 25:75, and 0:100. The surface properties, thermodynamic properties, mechanical properties, and cytocompatibility of silk fibroin/poly(l-lactide-co-ε-caprolactone) blended membranes were evaluated, and an optimal blending ratio was identified. The results showed that the silk fibroin/poly(l-lactide-co-ε-caprolactone) blended membranes containing 75% of silk fibroin and 25% of poly(l-lactide-co-ε-caprolactone) achieved the most improved performances compared with the single-component membranes or the blended membranes with other mixing ratios. The results from this study indicated that 75/25 silk fibroin/poly(l-lactide-co-ε-caprolactone) blended membranes which combined the advantages of poly(l-lactide-co-ε-caprolactone) and silk fibroin might be a suitable candidate material for use in tissue engineering. © SAGE Publications. Source

Zhou F.,Tianjin University | Jia X.,Beihang University | Yang Y.,Tianjin University | Yang Q.,Beihang University | And 5 more authors.
Materials Science and Engineering C | Year: 2016

The efficiency of biomaterials used in small vascular repair depends greatly on their ability to interact with vascular endothelial cells (VECs). Rapid endothelialization of the vascular grafts is a promising way to prevent thrombosis and intimal hyperplasia. In this work, modification of electrospun membranes of poly(ethylene glycol)-b-poly(l-lactide-co-ϵ-caprolactone) (PELCL) by three different peptides for regulation of VECs were studied in order to obtain ideal bioactive biomaterials as small diameter vascular grafts. QK (a mimetic peptide to vascular endothelial growth factor), Arg-Glu-Asp-Val (REDV, a specific adhesive peptide to VECs) and Val-Ala-Pro-Gly (VAPG, a specific adhesive peptide to vascular smooth muscle cells) were investigated. Surface properties of the modified membranes and the response of VECs were verified. It was found that protein adsorption and platelet adhesion were effectively suppressed with the introduction of QK, REDV or VAPG peptides on the PELCL electrospun membranes. Both QK- and REDV-modified electrospun membranes could accelerate the proliferation of VECs in the first 9 days, and the QK-modified electrospun membrane promoted cell proliferation more significantly than the REDV-modified one. The REDV-modified PELCL membrane was the most favorable for VECs adhesion than QK- and VAPG-modified membranes. It was suggested that QK- or REDV-modified PELCL electrospun membranes may have great potential applications in cardiovascular biomaterials for rapid endothelialization in situ. © 2016 Elsevier B.V. All rights reserved. Source

Chen W.,Beihang University | Pu F.,Beihang University | Yang Y.,Beihang University | Yao J.,Beihang University | And 4 more authors.
Medicine (United States) | Year: 2015

Equinus, varus, cavus, and adduction are typical signs of congenital talipes equinovarus (CTEV). Forefoot adduction remains a difficulty from using previous corrective methods. This study aims to develop a corrective method to reduce the severity of forefoot adduction of CTEV children with moderate deformities during their walking age. The devised method was compared with 2 other common corrective methods to evaluate its effectiveness. A Dennis Brown (DB) splint, DB splint with orthopedic shoes (OS), and forefoot abduct shoes (FAS) with OS were, respectively, applied to 15, 20, and 18 CTEV children with moderate deformities who were scored at their first visit according to the Diméglio classification. The mean follow-up was 44 months and the orthoses were changed as the children grew. A 3D scanner and a high-resolution pedobarograph were used to record morphological characteristics and plantar pressure distribution. One-way MAVONA analysis was used to compare the bimalleolar angle, bean-shape ratio, and pressure ratios in each study group. There were significant differences in the FAS+OS group compared to the DB and DB+OS groups (P<0.05) for most measurements. The most salient differences were as follows: the FAS+OS group had a significantly greater bimalleolar angle (P<0.05) and lower bean-shape ratio (P<0.01) than the other groups; the DB+OS and FAS+OS groups had higher heel/forefoot and heel/LMF ratios (P<0.01 and P<0.001) than the DB group. FAS are critical for correcting improper forefoot adduction and OS are important for the correction of equinus and varus in moderately afflicted CTEV children. This study suggests that the use of FAS+OS may improve treatment outcomes for moderate CTEV children who do not show signs of serious torsional deformity. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved. Source

Zhou F.,Tianjin University | Jia X.,Beihang University | Yang Q.,Beihang University | Yang Y.,Tianjin University | And 4 more authors.
Biomaterials Science | Year: 2016

Manipulation of gene expression by means of microRNAs (miRNAs) is one of the emerging strategies to treat cardiovascular and cancer diseases. Nevertheless, efficient delivery of miRNAs to a specific vascular tissue is limited. In this work, a short peptide Arg-Glu-Asp-Val (REDV) was linked to trimethyl chitosan (TMC) via a bifunctional poly(ethylene glycol) (PEG) linker for the targeted delivery of microRNA-126 (miRNA-126) to vascular endothelial cells (VECs). The morphology, serum stability and cytotoxicity of the polyplex/miRNA complexes, namely, TMC/miRNA, TMC-g-PEG/miRNA and TMC-g-PEG-REDV/miRNA, were investigated along with the cellular uptake, proliferation and in vitro miRNA transfection efficiency. By REDV modification, the TMC-g-PEG-REDV/miRNA complex showed negligible cytotoxicity, increased expression of miRNA-126 and enhanced VEC proliferation compared with the TMC/miRNA and TMC-g-PEG/miRNA complexes. In particular, the approaches adopted for the miRNA delivery and targeted peptide REDV modification promote the selective uptake and the growth of VECs over vascular smooth muscle cells. It was suggested that the REDV peptide-modified TMC-g-PEG polyplex could be potentially used as a miRNA carrier in artificial blood vessels for rapid endothelialization. © 2016 The Royal Society of Chemistry. Source

Ma L.,Beijing Institute of Technology | Ma L.,National Research Center for Rehabilitation Technical | Hu X.,Beijing Grish Hitech Co. | Zhang S.,Beijing Institute of Technology | Chen Y.,Beijing Institute of Technology
Journal of Chemistry | Year: 2015

The curing process of prosthetic socket base materials requires attention owing to a series of associated problems that are yet to be addressed and solved. However, to date, few relevant studies have been reported. In this paper, nanodiamonds modified with a silane coupling agent were dispersed into a prosthetic socket base material, and the performance of the modified base materials was investigated. Adding a predetermined amount of nanodiamonds to the prosthetic socket base material increased the glass transition temperature, improved the mechanical properties of the cured base material, and reduced the influence of the volatile gas formed during the curing process on the environment. With increasing nanodiamond contents, the glass transition temperature increased and the mechanical properties improved slightly. Owing to the high thermal conductivity of the nanodiamonds, the localized heat, as a result of the curing process, could be dissipated and released. Thus, adding nanodiamonds led to a more uniform temperature field forming in the curing system. This improved the curing process and reduced the formation of volatile monomers, thereby decreasing the adverse impact of the generated volatile gases on the environment. All of these provide a potential strategy for modifying prosthetic socket base materials. © 2015 Lifang Ma et al. Source

Discover hidden collaborations