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graphene scaffold

Jian-De Xie, Siyong Gu, Houan Zhang
This work outlines a synthetic strategy inducing the microwave-assisted synthesis of palladium (Pd) nanocrystals on a graphite sphere (GS) and reduced graphene oxide (rGO) supports, forming the Pd catalysts for non-enzymatic glucose oxidation reaction (GOR). The pulse microwave approach takes a short period (i.e., 10 min) to fast synthesize Pd nanocrystals onto a carbon support at 150 °C. The selection of carbon support plays a crucial role in affecting Pd particle size and dispersion uniformity. The robust design of Pd-rGO catalyst electrode displays an enhanced electrocatalytic activity and sensitivity toward GOR...
September 21, 2017: Sensors
Fa-Qian Liu, Li-Li Wang, Guo-Hua Li, Wei Li, Chao-Qin Li
Hierarchically porous materials containing interconnected macro-/meso-/micropores are promising candidates for energy storage, catalysis, and gas separation. Here, we present an effective approach for synthesizing three-dimensional (3D) sulfonated graphene coupled microporous organic polymers (SG-MOPs). The resulting SG-MOPs possess uniform macropores with an average size of ca. 350 nm, abundant mesopores, and micropores with an average size of ca. 0.6 nm. The SG-supported adsorbents exhibit a high nitrogen content (more than 38...
September 22, 2017: ACS Applied Materials & Interfaces
Yavuz Oz, Alexandre Barras, Rana Sanyal, Rabah Boukherroub, Sabine Szunerits, Amitav Sanyal
Materials based on reduced graphene oxide (rGO) have shown to be amenable to noncovalent functionalization through hydrophobic interactions. The scaffold, however, does not provide sufficient covalent linkage given the low number of reactive carboxyl and alcohol groups typically available on the rGO. The integration of clickable groups, particularly the ones that can undergo efficient conjugation without any metal catalyst, would allow facile functionalization of these materials. This study reports on the noncovalent association of a maleimide-containing catechol (dopa-MAL) surface anchor onto the rGO...
September 21, 2017: ACS Applied Materials & Interfaces
Cristina Martín, Sonia Merino, Jose M González-Domínguez, Rossana Rauti, Laura Ballerini, Maurizio Prato, Ester Vázquez
In tissue engineering strategies, the design of scaffolds based on nanostructures is a subject undergoing intense research: nanomaterials may affect the scaffolds properties, including their ability to interact with cells favouring cell growth and improving tissue performance. Hydrogels are synthetic materials widely used to obtain realistic tissue constructs, as they resemble living tissues. Here, different hydrogels with varying content of graphene, are synthesised by in situ radical polymerization of acrylamide in aqueous graphene dispersions...
September 8, 2017: Scientific Reports
Yoo-Jung Lee, Tae Hoon Seo, Seul-A Lee, Wonhee Jang, Myung Jong Kim, Jung-Suk Sung
Graphene is a non-cytotoxic monolayer platform with unique physical, chemical, and biological properties. It has been demonstrated that graphene substrate may provide a promising biocompatible scaffold for stem cell therapy. Since chemical vapor deposited graphene has a two dimensional poly-crystalline structure, it is important to control the individual domain size to obtain desirable properties for nano-material. However, the biological effects mediated by differences in domain size of graphene have not yet been reported...
September 6, 2017: Journal of Biomedical Materials Research. Part A
Shanmugam Manivannan, Inhak Kang, Yeji Seo, Hyo-Eon Jin, Seung-Wuk Lee, Kyuwon Kim
We report a virus-incorporated biological template (biotemplate) on electrode surfaces and its use in electrochemical nucleation of metal nanocomposites as an electrocatalytic material for energy applications. The biotemplate was developed with M13 virus (M13) incorporated in a silicate sol-gel matrix as a scaffold to nucleate Au-Pt alloy nanostructures by electrodeposition, together with reduced graphene oxide (rGO). The phage when engineered with Y3E peptides could nucleate Au-Pt alloy nanostructures, which ensured adequate packing density, simultaneous stabilization of rGO, and a significantly increased electrochemically active surface area...
September 13, 2017: ACS Applied Materials & Interfaces
Qian Wang, Yanyan Chu, Jianxin He, Weili Shao, Yuman Zhou, Kun Qi, Lidan Wang, Shizhong Cui
To better mimic natural bone, a graphene oxide-hydroxyapatite/silk fibroin (cGO-HA/SF) scaffold was fabricated by biomineralizing carboxylated GO sheets, blending with SF, and freeze-drying. The material has increasing porosity and decreasing density from outside to inside. Analysis of GO mineralization in simulated body fluid indicated that carboxylation and Chitosan may synergistically regulate HA growth along the c-axis of weakly crystalline, rod-like GO-HA particles. Compared with HA/SF gradient composites, a cGO-HA gradient scaffold with cGO:HA mass ratio 1:4 has 5-fold and 2...
November 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
Rashtrapal Zine, Mukty Sinha
The purpose of wound management is to prevent wound from infection, increase the fibroblast cell growth, and preserve cellular function. The polymeric electrospun nanofiber scaffold made up of natural and/or synthetic polymer provides an extracellular matrix for support and initiates the growth, proliferation and differentiation of fibroblast cells. The present study deals with the development of poly3-hydroxybutyric acid-co-3-hydroxyvaleric acid (PHBV) nanofibrous scaffold imbedded with graphene oxide (GO), and collagen...
November 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
Yu Zhang, Dongfeng Du, Xuejin Li, Hongman Sun, Li Li, Peng Bai, Wei Xing, Qingzhong Xue, Zifeng Yan
A novel sandwich-like composite with ultrathin CoAl-layered double hydroxide (LDH) nanoplates electrostatically assembled on both sides of two-dimensional polypyrrole/graphene (PG) substrate has been successfully fabricated using facile hydrothermal techniques. The PG not only serves as an excellent conductive and structural scaffold to enhance the transmission of electrons and prevent aggregation of CoAl-LDH nanoplates but also contributes to the enhancement of the specific capacitance. Owing to the homogeneous dispersion of CoAl-LDH nanoplates and its intimate interaction with PG substrate, the resulting CoAl-LDH/PG nanocomposite material exhibits excellent capacitive performance, for example, enhanced gravimetric specific capacitance (864 F g(-1) at 1 A g(-1) ), high rate performance (75% retention at 20 A g(-1)), and excellent cycle life (almost no degradation in supercapacitor performance after 5000 cycles) in aqueous KOH solution...
September 20, 2017: ACS Applied Materials & Interfaces
Ke Min Chan, Wang Xu, Hyukin Kwon, Anna M Kietrys, Eric T Kool
Nanometer-sized fragments of carbon in the form of multilayer graphene ("carbon dots") have been under highly active study for applications in imaging. While offering advantages of low toxicity and photostability, such nanomaterials are inhomogeneous and have limited wavelengths of emission. Here we address these issues by assembling luminescent aromatic C16-C38 hydrocarbons together on a DNA scaffold in homogeneous, soluble molecular compounds. Monomer deoxyribosides of five different aromatic hydrocarbons were synthesized and assembled into a library of 1296 different tetramer compounds on PEG-polystyrene beads...
September 12, 2017: Journal of the American Chemical Society
Jianfeng Li, Xiao Liu, Jeremy M Crook, Gordon G Wallace
Osseointegration in orthopedic surgery plays an important role for bone implantation success. Traditional treatment of implant surface aimed at improved osseointegration has limited capability for its poor performance in supporting cell growth and proliferation. Polydimethylsiloxane (PDMS) is a widely used silicon-based organic polymer material with properties that are useful in cosmetics, domestic applications and mechanical engineering. In addition, the biocompatibility of PDMS, in part due to the high solubility of oxygen, makes it an ideal material for cell-based implants...
August 1, 2017: Colloids and Surfaces. B, Biointerfaces
Ye Cao, Dejun Li, Mengli Zhao, Huanhuan Gong, Rongxin Wan, Hanqing Gu
AIM: The aim of the present research was to synthesize N(+) implanted 3D self-assembly graphene (N(+)/3D-SGHs) to overcome the weaknesses of graphene (small sizes and poor hydrophilicity) in tissue engineering scaffolds. MATERIALS & METHODS: N(+)/3D-SGHs was achieved by ion implantation on one-step hydrothermal synthesized 3D self-assembly graphene (3D-SGHs), and N(+)/3D-SGHs with different doses of nitrogen ions (1 × 10(16) ions/cm(2), 1 × 10(18) ions/cm(2) and 1 × 10(20) ions/cm(2)), which adjusted by nitrogen ion beam intensity...
August 17, 2017: Nanomedicine
L R Jaidev, Sachin Kumar, Kaushik Chatterjee
Despite several recent advances, poor vascularization in implanted scaffolds impedes complete regeneration for clinical success of bone tissue engineering. The present study aims to develop a multi-biofunctional nanocomposite for bone tissue regeneration using copper nanoparticle decorated reduced graphene oxide (RGO_Cu) hybrid particles in polycaprolactone (PCL) matrix (PCL/RGO_Cu). X-ray photoelectron spectroscopy and X-ray diffraction confirmed the presence of copper oxides (CuO and Cu2O) on RGO. Thermogravimetric analysis showed that 11...
August 4, 2017: Colloids and Surfaces. B, Biointerfaces
Saman Samadi, Mahboubeh Moradkhani, Hoda Beheshti, Mohammad Irani, Majid Aliabadi
In this work, the synthesized graphene oxide/TiO2/doxorubicin (GO/TiO2/DOX) composites were loaded into the chitosan/poly(lactic acid) (PLA) solutions to fabricate the electrospun chitosan/PLA/GO/TiO2/DOX nanofibrous scaffolds via electrospinning process. The synthesized composites and nanofibers were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis. Three-factor three-level central composite design was used to determine the influence of PLA to chitosan ratio, TiO2/DOX content and GO/TiO2/DOX content on the release of DOX from nanofibrous scaffolds...
August 9, 2017: International Journal of Biological Macromolecules
Xiaoyun Liu, He Shen, Saijie Song, Wei Chen, Zhijun Zhang
For bone tissue engineering, it requires that the scaffolds have excellent biocompatibility, proper mechanical and osteoinductive properties. Electrospun nanofibers with extracellular matrices mimicking structure have proven to be good scaffolds for bone tissue repairing. Hybrid nanofibers in particular, endow the nanofibers with specific and multiple functionalities, and therefore have attracted increasing interests in the recent years. In this study, we fabricated graphene oxide (GO)-incorporated cellulose acetate (CA) nanofibrous scaffolds by electrospinning technique for enhancement of biomineralization and osteogenic differentiation of human mesenchymal stem cells (hMSCs)...
July 29, 2017: Colloids and Surfaces. B, Biointerfaces
Xiang Zhu, Chengcheng Tian, Chi-Linh Do-Thanh, Sheng Dai
Membrane-based CO2 separation technology plays a significant role in environmental remediation and clean energy. Two-dimensional (2D) materials with atomically precise structures have emerged as prospective scaffolds to develop mixed-matrix membranes (MMMs) for gas separation. Summarized in this perspective review are the latest breakthrough studies in the synthesis of 2D-material-based MMMs to separate CO2 from gas mixtures. 2D materials including graphene oxide (GO), metal-organic framework (MOF)-derived nanosheets, covalent organic frameworks (COFs), and transition metal dichalcogenides (TMDs), as fascinating building blocks, have been comprehensively summarized, together with a focus on synthetic processes and gas separation properties...
September 11, 2017: ChemSusChem
Cheng Tang, Bin Wang, Hao-Fan Wang, Qiang Zhang
Rechargeable flexible solid Zn-air battery, with a high theoretical energy density of 1086 Wh kg(-1) , is among the most attractive energy technologies for future flexible and wearable electronics; nevertheless, the practical application is greatly hindered by the sluggish oxygen reduction reaction/oxygen evolution reaction (ORR/OER) kinetics on the air electrode. Precious metal-free functionalized carbon materials are widely demonstrated as the most promising candidates, while it still lacks effective synthetic methodology to controllably synthesize carbocatalysts with targeted active sites...
August 7, 2017: Advanced Materials
Johannes Holzwarth, Konstantin Yu Amsharov, Dmitry I Sharapa, David Reger, Kateryna Roshchyna, Dominik Lungerich, Norbert Jux, Frank Hauke, Timothy Clark, Andreas Hirsch
Hexa-peri-hexabenzocoronides (HBC) was successfully used as a model system for investigating the complex mechanism of the reductive functionalization of graphene. The well-defined molecular HBC system enabled deeper insights into the mechanism of the alkylation of reductively activated nanographenes. The separation and complete characterization of alkylation products clearly demonstrate that nanographene functionalization proceeds with exceptionally high regio- and stereoselectivities on the HBC scaffold. Experimental and theoretical studies lead to the conclusion that the intact basal graphene plane is chemically inert and addend binding can only take place at either preexisting defects or close to the periphery...
August 6, 2017: Angewandte Chemie
Weiguang Wang, Guilherme Caetano, William Stephen Ambler, Jonny James Blaker, Marco Andrey Frade, Parthasarathi Mandal, Carl Diver, Paulo Bártolo
Scaffolds are physical substrates for cell attachment, proliferation, and differentiation, ultimately leading to the regeneration of tissues. They must be designed according to specific biomechanical requirements, i.e., certain standards in terms of mechanical properties, surface characteristics, porosity, degradability, and biocompatibility. The optimal design of a scaffold for a specific tissue strongly depends on both materials and manufacturing processes, as well as surface treatment. Polymeric scaffolds reinforced with electro-active particles could play a key role in tissue engineering by modulating cell proliferation and differentiation...
December 7, 2016: Materials
Ilker S Bayer
Due to its biodegradable and bioabsorbable characteristics polylactic acid (PLA) has attracted considerable attention for numerous biomedical applications. Moreover, a number of tissue engineering problems for function restoration of impaired tissues have been addressed by using PLA and its copolymers due to their biocompatibility and distinctive mechanical properties. Recent studies on various stereocomplex formation between enantiomeric PLA, poly(l-lactide) (PLLA) and poly(d-lactide) (PDLA) indicated that stereocomplexation enhances the mechanical properties as well as the thermal- and hydrolysis-resistance of PLA polymers...
July 4, 2017: Materials
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