The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Sangram Keshari Samal - One of the best experts on this subject based on the ideXlab platform.
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silk chitosan biohybrid hydrogels and scaffolds via green technology
RSC Advances, 2014Co-Authors: Sangram Keshari Samal, Heidi Declercq, Mamoni Dash, Federica Chiellini, Emo Chiellini, Xiaoqin Wang, David L KaplanAbstract:Silk fibroin protein-based hydrogels and 3D scaffolds in combinations with chitosan were designed with a focus on green technology. The physico-Chemical properties were modulated using ultrasonication processing to avoid the use of organic solvents or Chemical Crosslinking. The ultrasonication of mixtures of silk and chitosan induced a conformational change of the silk from random coil to β-sheet resulting in the self-assembly of the hydrophobic peptide segments in the protein, entrapping chitosan chains in these silk networks. These biohybrid materials were prepared with different physico-Chemical properties by varying the relative concentrations of silk and chitosan. In combination with lyophilization, interconnected porous 3D scaffolds with controlled morphologies were generated. MC3T3-E1 cells were successfully encapsulated in silk fibroin protein and silk fibroin protein–chitosan hydrogels and colonized the scaffolds. These engineered biohybrid hydrogel and scaffold network systems can be utilized to encapsulate bioactive molecules, thus providing a versatile set of biomaterials with retention of degradability, but without the use of organic solvents or Chemical Crosslinking during preparation.
Xiao Dong Chen - One of the best experts on this subject based on the ideXlab platform.
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Chemical Crosslinking assembly of zsm 5 nanozeolites into uniform and hierarchically porous microparticles for high performance acid catalysis
ACS Applied Materials & Interfaces, 2019Co-Authors: Chao Shang, Xiao Dong ChenAbstract:Hierarchically porous zeolites combining the advantages of desirable mass transport of nanozeolites and easy separation and handling of micro-zeolites are ideal candidates in catalytic applications. Facile routes for the assembly of zeolite microparticles with hierarchical porosity and high mechanical strength are much expected. Herein, based on a microfluidic jet spray drying technology, we report a facile and scalable Chemical Crosslinking assembly strategy for the synthesis of hierarchical zeolite microparticles by directly using the conventional as-synthesized nanozeolite suspension as a precursor. This route not only avoids the energy-intensive centrifugal separation process of nanozeolites but also significantly increases the uniformity and mechanical strength of the microparticles. The soluble aluminosilicate species act as a stabilizer to improve the droplet stability during the drying process and then as a "cross-linker" to Chemically bind and interconnect zeolite nanoparticles to form robust bodies after drying and calcination. Zeolite microparticles with variable morphologies (spherical, bowl-like, and dimpled) and uniform and controllable sizes (from 70 to 108 μm) can be obtained by adjusting the experimental parameters. The particle formation mechanism is discussed based on the zeolite microparticles obtained from the purified nanozeolite suspension as a control. The zeolite microparticles possess emerged uniform mesopores (∼6 nm) and a well-maintained high surface area, large pore volume, high microporosity, and strong acidity of the original nanozeolites. As a result, they exhibit excellent acid catalytic performances in acetolysis of epichlorohydrin and catalytic cracking of low-density polyethylene, far better than those of the commercial ZSM-5.
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Chemical Crosslinking Assembly of ZSM‑5 Nanozeolites into Uniform and Hierarchically Porous Microparticles for High-Performance Acid Catalysis
2019Co-Authors: Chao Shang, Xiao Dong ChenAbstract:Hierarchically porous zeolites combining the advantages of desirable mass transport of nanozeolites and easy separation and handling of micro-zeolites are ideal candidates in catalytic applications. Facile routes for the assembly of zeolite microparticles with hierarchical porosity and high mechanical strength are much expected. Herein, based on a microfluidic jet spray drying technology, we report a facile and scalable Chemical Crosslinking assembly strategy for the synthesis of hierarchical zeolite microparticles by directly using the conventional as-synthesized nanozeolite suspension as a precursor. This route not only avoids the energy-intensive centrifugal separation process of nanozeolites but also significantly increases the uniformity and mechanical strength of the microparticles. The soluble aluminosilicate species act as a stabilizer to improve the droplet stability during the drying process and then as a “cross-linker” to Chemically bind and interconnect zeolite nanoparticles to form robust bodies after drying and calcination. Zeolite microparticles with variable morphologies (spherical, bowl-like, and dimpled) and uniform and controllable sizes (from 70 to 108 μm) can be obtained by adjusting the experimental parameters. The particle formation mechanism is discussed based on the zeolite microparticles obtained from the purified nanozeolite suspension as a control. The zeolite microparticles possess emerged uniform mesopores (∼6 nm) and a well-maintained high surface area, large pore volume, high microporosity, and strong acidity of the original nanozeolites. As a result, they exhibit excellent acid catalytic performances in acetolysis of epichlorohydrin and catalytic cracking of low-density polyethylene, far better than those of the commercial ZSM-5
Siriporn Damrongsakkul - One of the best experts on this subject based on the ideXlab platform.
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balanced electrostatic blending approach an alternative to Chemical Crosslinking of thai silk fibroin gelatin scaffold
International Journal of Biological Macromolecules, 2012Co-Authors: Panida Jetbumpenkul, Phakdee Amornsudthiwat, Sorada Kanokpanont, Siriporn DamrongsakkulAbstract:In tissue engineering, Chemical Crosslinking is widely used for conjugating two or more biomaterials to mainly control biodegradability and strength. For example, Thai silk fibroin/gelatin scaffold will offer mechanical strength from Thai silk fibroin and cell attraction from gelatin. However, Chemical Crosslinking requires Crosslinking agent which could potentially pose negative impact from remaining trace amount of Chemicals especially in medical application. Here we present an alternative approach to Chemical Crosslinking—a balance electrostatic blending approach. In this approach, two opposite charge biomaterials were selected for blending, with different ratios. Both materials were bound together with electrostatic force. The maximum binding was achieved when mixture electric potential approaches zero. In this work, we compared this approach with traditionally Chemical Crosslinking in terms of physical appearance, binding effectiveness, mechanical strength (in dry/wet conditions), in vitro biodegradation, and cell proliferation. We found that 50/50 weight ratio of Thai silk fibroin/gelatin scaffold had almost comparable properties to Chemical crosslinked scaffold. It has similar appearance, binding effectiveness, and affinity for cell proliferation. For mechanical properties, even this approach yields lower dry compressive modulus compared with Chemical Crosslinking. But in wet condition, the compressive modulus from both methods is similar. However, the biodegradation time of non-crosslinked scaffolds is slightly faster than that of Chemical crosslinked ones. These results demonstrate that a balance electrostatic approach is an alternative approach to Chemical Crosslinking when there is a concern of remaining trace amount of Crosslinking agent in medical application.
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influences of physical and Chemical Crosslinking techniques on electrospun type a and b gelatin fiber mats
International Journal of Biological Macromolecules, 2010Co-Authors: Juthamas Ratanavaraporn, Sorada Kanokpanont, Ratthapol Rangkupan, Hathairat Jeeratawatchai, Siriporn DamrongsakkulAbstract:This work has investigated the factors influencing the production of electrospun gelatin fibers including electrical potential and concentration of gelatin solution. Electrospun gelatin fibers were prepared from both type A and B gelatin solutions at the concentration of 2.5–60% w/v and 10–25 kV. Concentration of gelatin solution at 20–40% w/v was found to be the optimized range to produce the gelatin fibers with smooth surface throughout the fiber length. The electrical potential did not exhibit a dominant effect on the gelatin fibers obtained. Further study of the different Crosslinking techniques for the gelatin fiber mats showed the various effects on the Crosslinking degrees and fiber structure. Physical Crosslinking such as dehydrothermal treatment, plasma treatment and their combination resulted in low Crosslinking extent of gelatin fiber mats due to the Crosslinking occurring only at the surface of the material. Combination of dehydrothermal and Chemical Crosslinking using 1-ethyl-3-(3-dimethylamino propyl) carbodiimide hydrochloride (EDC) or glutaraldehyde (GA) indicated higher Crosslinking degree since both the surface and the bulk of the material were crosslinked. Spraying/immersion in EDC solution, a modified technique, resulted in swollen fibers while interconnected pores remained. Merged fibers were obtained from the Crosslinking by GA vapor. We concluded that Crosslinking is one of the key methods to control structure and degradation of the gelatin fiber mats. Various structures of gelatin fiber mats are expected to be useful for numerous applications.
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biodegradability and property characterizations of methyl cellulose effect of nanocompositing and Chemical Crosslinking
Carbohydrate Polymers, 2008Co-Authors: Sarawut Rimdusit, Sorada Jingjid, Siriporn Damrongsakkul, Sunan Tiptipakorn, Tsutomu TakeichiAbstract:Abstract Broader range of biodegradability and other essential properties of Methyl Cellulose (MC) were achieved through nanocomposite formation and Chemical Crosslinking. Methyl Cellulose/Montmorillonite (MC/MMT) nanocomposites as well as MC-glutaraldehyde crosslinked films were characterized for thermal properties, tensile properties, moisture absorption, and biodegradability. MC/MMT nanocomposite films prepared by MMT suspension exhibited exfoliation which was confirmed by XRD and TEM results. In the Chemical crosslinked system, the FTIR spectra revealed the crosslinkage between MC and GA. The tensile properties of the crosslinked films indicated that optimum GA content was 4.5 wt%. In addition, MC prepared from each method was capable of enhancing different properties. The MC/MMT nanocomposites could significantly improve tensile modulus (nanocompositing: 65%; Crosslinking: 45%), while MC crosslinked film could outstandingly increase glass transition temperature (nanocompositing: 4 °C; Crosslinking: 17 °C) and decrease moisture absorption properties (nanocompositing: 19%; Crosslinking: 26%). The crosslinkage technique had more potential to hinder the biodegradation process. In 6 weeks, the CO2 emission of crosslinked films was reduced around 80% in comparison with that of pure MC.
Lucia Tellezjurado - One of the best experts on this subject based on the ideXlab platform.
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siloxane inorganic Chemical Crosslinking of hyaluronic acid based hybrid hydrogels structural characterization
Carbohydrate Polymers, 2020Co-Authors: D A Sancheztellez, Luis M Rodriguezlorenzo, Lucia TellezjuradoAbstract:HA-based hybrid hydrogels were successfully developed. The polysaccharide (HA) chains were Chemically modified and hybridized via amidation of their carboxylic groups with aminosilane molecules. HA-polysaccharide chains were crosslinked by a 3D siloxane organic-inorganic matrix via sol-gel. The novel inorganic Crosslinking network (PDMS-SiO2) provided to sodium hyaluronate (HA) strong Chemical bonds, giving restriction to their natural hydrophilicity and stiffness to its structure (improved rheological properties). It was observed that synthesis conditions such as starting HA concentration solution and temperature determined gelling times, efficiency in the polysaccharide Chemical modification and in Crosslinking hydrolysis-condensation reactions, resulting in the siloxane organic-inorganic matrix. Drying processes influenced Crosslinking in HA hybrid hydrogels, either by enhancing polycondensation reactions or inhibiting them. Room temperature-drying produced more densified hybrid structures. Freeze-drying increased porosity and surface hydroxyl groups (-OH) resulting in more Q3 structural units. 60 °C-drying boosted polycondensation of monodendate structural units, enhancing the formation of hybrid D-Q bonds.
David L Kaplan - One of the best experts on this subject based on the ideXlab platform.
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silk chitosan biohybrid hydrogels and scaffolds via green technology
RSC Advances, 2014Co-Authors: Sangram Keshari Samal, Heidi Declercq, Mamoni Dash, Federica Chiellini, Emo Chiellini, Xiaoqin Wang, David L KaplanAbstract:Silk fibroin protein-based hydrogels and 3D scaffolds in combinations with chitosan were designed with a focus on green technology. The physico-Chemical properties were modulated using ultrasonication processing to avoid the use of organic solvents or Chemical Crosslinking. The ultrasonication of mixtures of silk and chitosan induced a conformational change of the silk from random coil to β-sheet resulting in the self-assembly of the hydrophobic peptide segments in the protein, entrapping chitosan chains in these silk networks. These biohybrid materials were prepared with different physico-Chemical properties by varying the relative concentrations of silk and chitosan. In combination with lyophilization, interconnected porous 3D scaffolds with controlled morphologies were generated. MC3T3-E1 cells were successfully encapsulated in silk fibroin protein and silk fibroin protein–chitosan hydrogels and colonized the scaffolds. These engineered biohybrid hydrogel and scaffold network systems can be utilized to encapsulate bioactive molecules, thus providing a versatile set of biomaterials with retention of degradability, but without the use of organic solvents or Chemical Crosslinking during preparation.