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1.
ACS Appl Mater Interfaces ; 11(5): 5146-5151, 2019 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-30640419

RESUMO

Efficient electrocatalysts for Li2CO3 decomposition play an important role in Li-CO2 batteries. In this paper, carbon nanotubes (CNTs) decorated with RuO2 is firstly introduced as cathode materials for Li-CO2 batteries. The CNT@RuO2 composite can not only deliver a high specific capacity but also a lower charge voltage. With the CNT@RuO2 cathodes, the Coulombic efficiency still remains around 100% until the 15th cycle. The charge voltage of early 30 cycles at a current of 50 mA·g-1 with a capacity limit of 500 mAh·g-1 can be fully lowered under 4.0 V. Particularly, the CNT@RuO2 cathode can realize most decomposition of prefilled Li2CO3 and show a platform at around 3.9 V. This catalytic activity toward both in situ formed and preloaded Li2CO3 is more feasible for practical application in complex environment.

2.
Int J Pharm ; 494(1): 264-70, 2015 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-26283278

RESUMO

In the present study, a composite system for the controlled and sustained release of hydrophobic/hydrophilic drugs is described. Composite hydrogels were prepared by blending silk fibroin (SF) with PLA-PEG-PLA copolymer under mild aqueous condition. Aspirin and indomethacin were incorporated into SF/Copolymer hydrogels as two model drugs with different water-solubility. The degradation of composite hydrogels during the drug release was mainly caused by the hydrolysis of copolymers. SF with stable ß-sheet-rich structure was not easily degraded which maintained the mechanical integrity of composite hydrogel. The hydrophobic/hydrophilic interactions of copolymers with model drugs would significantly alter the morphological features of composite hydrogels. Various parameters such as drug load, concentration ratio, and composition of copolymer were considered in vitro drug release. Aspirin as a hydrophilic drug could be controlled release from composite hydrogel at a constant rate for 5 days. Its release was mainly driven by diffusion-based mechanism. Hydrophobic indomethacin could be encapsulated in copolymer nanoparticles distributing in the composite hydrogel. Its sustained release was mainly degradation controlled which could last up to two weeks. SF/Copolymer hydrogel has potential as a useful composite system widely applying for controlled and sustained release of various drugs.


Assuntos
Preparações de Ação Retardada/química , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Fibroínas/química , Hidrogéis/química , Polímeros/química , Aspirina/química , Interações Hidrofóbicas e Hidrofílicas , Indometacina/química
3.
Mater Sci Eng C Mater Biol Appl ; 51: 287-93, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25842137

RESUMO

Use of organic templates for controlling the growth of inorganic crystals is one of the research topics in biomimetic field. In particular, oriented growth of hydroxyapatite (HAp) in organic fibrous matrix is provided a new view angle to study biomineralization of bone and its potential biomedical applications. The crystallization of HAp in fibrous hydrogels could mimic such biomineralization. In this paper, we report HAp nanorod crystal synthesized successfully by a biomimetic method using calcium chloride and ammonium dihydrogen phosphate as reagents in the presence of silk fibroin/sodium alginate (SF/SA) fibrous hydrogels. The effects of influence factors such as mineral times, pH, and temperature on controlling HAp nanorod crystals are discussed. The elongated HAp nanorods with rectangular column are grown with the increase of mineral times in biomimetic process. By changing pH, HAp nanorod crystals are obtained at alkaline condition in fibrous hydrogels. Moreover, compared to other temperatures, rod-shaped HAp crystals were formed at 20°C. The results imply this to be an effective method for preparing HAp crystals with controllable morphology for bone repair application.


Assuntos
Alginatos/química , Durapatita/síntese química , Fibroínas/química , Hidrogéis/química , Impressão Molecular/métodos , Nanotubos/química , Substitutos Ósseos/síntese química , Cristalização/métodos , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Teste de Materiais , Nanofibras/química , Nanofibras/ultraestrutura , Nanotubos/ultraestrutura , Tamanho da Partícula , Propriedades de Superfície
4.
Mater Sci Eng C Mater Biol Appl ; 37: 48-53, 2014 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-24582221

RESUMO

Bombyx mori silk fibroin from the silkworm was firstly found to be soluble in formic acid/hydroxyapatite system. The rheological behavior of silk fibroin solution was significantly influenced by HAp contents in dissolved solution. At the same time, silk fibroin nanofibers were observed in dissolved solution with 103.6±20.4nm in diameter. Moreover, the structure behavior of SF films prepared by formic acid/hydroxyapatite dissolution method was examined. The secondary structure of silk fibroin films was attributed to silk II structure (ß-sheet), indicating that the hydroxyapatite contents in dissolved solution were not significantly affected by the structure of silk fibroin. The X-ray diffraction results exhibited obviously hydroxyapatite crystalline nature existing in silk fibroin films; however, when the hydroxyapatite content was 5.0wt.% in dissolved solution, some hydroxyapatite crystals were converted to calcium hydrogen phosphate dehydrate in silk fibroin dissolution process. This result was also confirmed by Fourier transform infrared analysis and DSC measurement. In addition, silk fibroin films prepared by this dissolution method had higher breaking strength and extension at break. Based on these analyses, an understanding of novel SF dissolution method may provide an additional tool for designing and synthesizing advanced materials with more complex structures, which should be helpful in different fields, including biomaterial applications.


Assuntos
Durapatita/química , Fibroínas/química , Formiatos/química , Animais , Bombyx/química , Bombyx/metabolismo , Nanofibras/química , Solubilidade
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