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1.
ACS Appl Mater Interfaces ; 13(33): 39831-39843, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34374511

RESUMO

Herein, a unique hierarchically structured composite nanofiber membrane, consisting of a zeolitic imidazolate framework-8-embedded polyethersulfone (PES@ZIF8) fiber layer and a polysulfonamide/polyethersulfone (PSA/PES) fiber layer, was successfully developed to cope with the complex environments during the actual filtration/separation process and overcome the conflict between high filtration efficiency and low air pressure resistance. Due to the advantages of the synergistic effect of multicomponents and the bi-layer hierarchical structure, the integrated PES@ZIF8-PSA/PES filter possesses an extremely high air filtration efficiency (up to 99.986%) under a very low pressure drop (only 15 Pa), superior PM0.3 purification capacity (close to 99.95%), long-term recycling ability for purifying real smoke PM2.5 from >800 to <10 µg/m3, extremely high temperature resistance (exceed 200 °C), flame retardancy, good chemical stability, satisfactory transmittance, and robust self-cleaning ability. Apart from these, it achieves effective separation of oil-water mixtures and oil-water emulsions as a result of selective wettability including hydrophobicity and superoleophilicity. In particular, the PES@ZIF8-PSA/PES nanofiber membranes maintain outstanding air filtration and oil/water separation properties under the high temperature or strong acid/alkali conditions. This special comprehensive performance gives the PES@ZIF8-PSA/PES-based filtration/separation membranes a wider application prospect ranging from environmental governance to individual protection and industrial security.

2.
ACS Appl Bio Mater ; 3(10): 7103-7112, 2020 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-35019370

RESUMO

Natural polymer-based hydrogels attract great attention because of their inherent biocompatibility and controllable biodegradability. However, the broad applications of these hydrogels require a combination of high mechanical strength, high toughness, fatigue resistance, as well as self-healing. The integration of this combination into one natural polymer-based hydrogel remains challenging. Here, a molecular design strategy was proposed to fabricate mechanically robust silk fibroin-based hydrogels using host-guest interactions. Silk fibroin molecules was chemically modified with cholesterol (Chol, guest) or ß-cyclodextrin (ß-CD, host), and host-guest interaction between Chol and ß-CD moieties drove the supramolecular assemblies of hydrogels. The dissociation/reassociation behavior of host-guest complexation, serving as sacrificial bonds, endowed hydrogels with effective energy dissipation and rapid self-healing ability. The prepared silk fibroin-based hydrogels exhibited high mechanical strength, high toughness, and remarkable fatigue resistance, superior to conventional silk fibroin hydrogels. Moreover, due to reversible host-guest interactions, hydrogels achieved facile functional recovery after damage without any external stimuli. This design strategy provides an avenue to develop natural polymer-based materials with robust mechanical properties, thus broadening current hydrogel applications.

3.
Polymers (Basel) ; 11(6)2019 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-31167377

RESUMO

Fluorescent silk fibroin nanofibers were fabricated via electrospinning method with three kinds of fluorescent dyes. Electrospun fluorescent nanofibers showed smooth surfaces and average diameters of 873 ± 135 nm, 835 ± 195 nm, and 925 ± 205 nm, respectively, for silk fibroin-fluorescein sodium, silk fibroin-rhodamine B, and silk fibroin-acridine orange nanofibers containing 2.0 wt% fluorescent dyes. At the same time, the secondary structure of silk fibroin in fluorescent nanofibers was predominantly amorphous conformation without influence by adding different concentrations of fluorescent dyes, as characterized by Fourier transform infrared spectroscopy and X-ray diffraction. Thermal degradation behavior of fluorescent silk fibroin nanofibers with a dramatic decrease in weight residue was observed at around 250 °C. The fluorescence effect of fluorescent silk fibroin nanofibers was changed by changing the concentration of different fluorescent dyes. These fluorescent nanofibers may make promising textile materials for large scale application.

4.
Mater Sci Eng C Mater Biol Appl ; 59: 185-192, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26652363

RESUMO

Hydrogels prepared by silk fibroin solution have been studied. However, mimicking the nanofibrous structures of extracellular matrix for fabricating biomaterials remains a challenge. Here, a novel two-step method was applied to prepare fibrous hydrogels using regenerated silk fibroin solution containing nanofibrils in a range of tens to hundreds of nanometers. When the gelation process of silk solution occurred, it showed a top-down type gel within 30min. After gelation, silk fibroin fibrous hydrogels exhibited nanofiber network morphology with ß-sheet structure. Moreover, the compressive stress and modulus of fibrous hydrogels were 31.9±2.6 and 2.8±0.8kPa, respectively, which was formed using 2.0wt.% concentration solutions. In addition, fibrous hydrogels supported BMSCs attachment and proliferation over 12days. This study provides important insight in the in vitro processing of silk fibroin into useful new materials.


Assuntos
Células da Medula Óssea/metabolismo , Fibroínas/classificação , Hidrogéis/química , Teste de Materiais , Nanofibras/química , Animais , Células da Medula Óssea/citologia , Masculino , Ratos , Ratos Sprague-Dawley
5.
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
6.
Int J Biol Macromol ; 75: 398-401, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25677178

RESUMO

Regenerated silk fibroin aqueous solution was used to study the crystalline structure of Bombyx mori silk fibroin in vitro. By controlling environmental conditions and concentration of silk fibroin solution, it provided a means for the direct preparing silk I structure and understanding the details of silk fibroin molecules interactions in formation process. In this study, silk fibroin molecules were assembled to form random coil at low concentration of solution and then, as the concentration increases, were converted to silk I at 55% relative humidity (RH). At the same time, the structure of silk fibroin forming below 45 °C was mostly in silk I. A partial ternary phase diagram of temperature-humidity-concentration was constructed based on the results. The results showed silk I structure could be controlled by adjusting the external environmental conditions. The enhanced control over silk I structure, as embodied in phase diagram, could potentially be utilized to understand the molecular chain conformation of silk I in further research work.


Assuntos
Seda/química , Animais , Bombyx/química , Dessecação , Fibroínas/química , Transição de Fase , Conformação Proteica , Temperatura , Fatores de Tempo , Difração de Raios X
7.
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
8.
J Mater Chem B ; 2(24): 3879-3885, 2014 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-32261734

RESUMO

Native silk features strong, extensible and tough properties which originate from its hierarchical nanofibril structure. In the present study, native silk nanofibrils were obtained by dissolving degummed silk in salt-formic acid (FA), such as CaCl2-FA. The CaCl2-FA dissolved silk by breaking hydrogen bonds in the crystalline region while preserving the nanofibril structures. The dissolution behavior of silk from fibre to nanofibril was determined by Na2CO3 concentration during the degumming process, and was regulated by CaCl2 concentration during the dissolution process. The resulting solution containing silk fibroin (SF) nanofibrils could be easily processed into films with nanofibrous structures and high strength. In addition, high-quality electrospun SF nanofibres could also be generated easily from this solution. The novel dissolution and regeneration behavior of silk at the nanofibril scale provides new insights into methods for the preparation of high-quality silk materials for application in high-tech areas.

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