Lipase Immobilized within Novel Silica-based Hybrid Foams: Synthesis, Characterizations and Catalytic Properties

2010 ◽  
Vol 1272 ◽  
Author(s):  
Nicolas Brun ◽  
Annick Babeau ◽  
Victor Oestreicher ◽  
Hervé Deleuze ◽  
Clément Sanchez ◽  
...  
Keyword(s):  
Cell Hybrid ◽  
High Stability ◽  
Catalytic Properties ◽  
Sol Gel ◽  
Batch Process ◽  
Covalent Immobilization ◽  
Open Cell ◽  
Sol Gel Process ◽  
Post Synthesis ◽  
Hybrid Foams

AbstractThe covalent immobilization of crude lipases within silica-based macroporous frameworks have been performed by combining sol-gel process, concentrated direct emulsion, lyotropic mesophase and post-synthesis functionalizations. The as-synthesized open cell hybrid monoliths exhibit high macroscopic porosity, around 90 %, providing interconnected scaffold while reducing the diffusion low kinetic issue. The entrapment of enzymes in such foams deals with a high stability over esterification and transesterification batch process catalysis.

Mechanical Behavior of Bioactive Glass-Polyvinyl Alcohol Hybrid Foams Obtained by the Sol-Gel Process

2005 ◽  
pp. 757-760 ◽  
Author(s):  
Marivalda Pereira ◽  
Showan N. Nazhat ◽  
Julian R. Jones ◽  
Larry L. Hench
Keyword(s):  
Polyvinyl Alcohol ◽  
Bioactive Glass ◽  
Mechanical Behavior ◽  
Sol Gel ◽  
Sol Gel Process ◽  
Hybrid Foams

Mechanical Behavior of Bioactive Glass-Polyvinyl Alcohol Hybrid Foams Obtained by the Sol-Gel Process

2005 ◽  
Vol 284-286 ◽  
pp. 757-760 ◽  
Author(s):  
Marivalda Pereira ◽  
Showan N. Nazhat ◽  
Julian R. Jones ◽  
Larry L. Hench
Keyword(s):  
Polyvinyl Alcohol ◽  
Bioactive Glass ◽  
Mechanical Behavior ◽  
Sol Gel ◽  
Precursor Solution ◽  
High Porosity ◽  
Soft Tissue Regeneration ◽  
Sol Gel Process ◽  
Potential Applications ◽  
Hybrid Foams

The possibility of enhancing mechanical properties by incorporation of polymeric components to sol-gel derived materials is extremely attractive to prepare macroporous scaffolds, leading to materials with potential applications in both hard and soft tissue regeneration. In this work bioactive glass-polyvinyl alcohol hybrids were developed and their mechanical behavior was evaluated. Hybrids were synthesized by adding polyvinyl alcohol to a sol-gel precursor solution, which was then foamed with the addition of a surfactant and vigorous agitation. The foams were cast, aged and dried at 40°C. A cleaning step to decrease the acidic character of the obtained hybrids was undertaken by immersion in a NH4OH solution. The mechanical behavior of the hybrids was evaluated in compression using both stress and strain control tests. Hybrid foams had a high porosity varying from 60-90% and the macropore diameter ranged from 10 to 600 µm. The modal macropore diameter varied with the inorganic phase composition and with the polymer content in the hybrid. The strain at fracture of the as prepared hybrid foams was substantially greater than pure gel-glass foams. The cleaned hybrids presented a slightly higher strength and lower deformation than the as prepared foams.

Effect of Cores on Photoluminescence of Hybrid SiO2-Coated CdTe Quantum Dots

2020 ◽  
Vol 20 (9) ◽  
pp. 5478-5485
Author(s):  
Cong Xie ◽  
Yubin Zhao ◽  
Yuxiang Song ◽  
Yingjie Liu ◽  
Yaya Wang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
High Stability ◽  
Sol Gel ◽  
Quantum Yields ◽  
Core Shell ◽  
Aqueous Synthesis ◽  
Pl Spectra ◽  
Cdte Qds ◽  
Sol Gel Process ◽  
20 Nm

Compared with conventional semiconductor quantum dots, hybrid SiO2 coated CdTe QDs exhibited high stability, long fluorescent lifetime, high photoluminescence quantum yields, and well biocompatibility. In this paper, CdTe QDs with tunable PL from green to red emitting were prepared by an aqueous synthesis. A sol–gel process resulted in CdTe QDs coated with a hybrid SiO2 shell contained CdS-like clusters to obtain red-shifted PL spectra, increased PL efficiency and high stability. The clusters were formed by the reaction of Cd2+ and S2− ions generated via the decomposition of thioglycolic acid. The clusters around CdTe cores created a core–shell structure which is very similar with traditional semiconductor core–shell QDs. After being coated with a hybrid SiO2 shell, the PL of green-emitting naked CdTe QDs was red-shifted largely (~30 nm) while the PL of yellowemitting CdTe QDs revealed a small red-shifted (~20 nm). Furthermore, The PL of red-emitting naked CdTe QDs was red-shifted much small (less than 10 nm). This phenomenon is ascribed to the change of band gap of CdTe cores with sizes. The red-shift of PL spectra is attributed to the CdS-like clusters around the core rather than the thickness of the hybrid SiO2 shell.

Polyurethane-silica hybrid foams from a one-step foaming reaction, coupled with a sol-gel process, for enhanced wound healing

2017 ◽  
Vol 79 ◽  
pp. 866-874 ◽  
Author(s):  
Eun-Ho Song ◽  
Seol-Ha Jeong ◽  
Ji-Ung Park ◽  
Sukwha Kim ◽  
Hyoun-Ee Kim ◽  
...  
Keyword(s):  
Wound Healing ◽  
Sol Gel ◽  
Sol Gel Process ◽  
One Step ◽  
Hybrid Foams ◽  
Silica Hybrid

Effect of Increasing Polyvinyl Alcohol Content on the Porous Structure and Mechanical Properties of Sol-Gel Derived Hybrids Foams

2007 ◽  
Vol 361-363 ◽  
pp. 555-558 ◽  
Author(s):  
Agda Aline Rocha de Oliveira ◽  
R.L. Oréfice ◽  
Herman S. Mansur ◽  
Marivalda Pereira
Keyword(s):  
Mechanical Properties ◽  
Polyvinyl Alcohol ◽  
Bioactive Glass ◽  
Structural Characteristics ◽  
Sol Gel ◽  
Acetate Solution ◽  
Compression Tests ◽  
Sol Gel Process ◽  
Hybrid Foams

Bioactive glass/polymer hybrids are promising materials for biomedical applications because they combine the bioactivity of these bioceramics with the flexibility of polymers. In previous work hybrid foams with 80% bioactive glass and 20% polyvinyl alcohol (PVA) were prepared by the sol-gel process for application as scaffold for bone tissue engineering. In this work it was evaluated the effect of increasing the PVA content of the hybrids on structural characteristics and mechanical properties of hybrid foams produced by this method. The hybrids were prepared with inorganic phase composition of 70%SiO2-30%CaO and PVA fractions of 20 to 60% by the sol-gel method. The structural and mechanical characterization of the obtained foams was done by FTIR, SEM, Helium Picnometry, and compression tests. To reduce the acidic character of the hybrids due to the catalysts added, different neutralization solutions were tested. The immersion of hybrids in a calcium acetate solution was the most adequate neutralization method, avoiding calcium loss while maintaining pH nearly 7,0 and low PVA loss. The foams presented porosity of 60-85% and pore diameters of 100-500μm with interconnected structure. The pore structure varied with the polymer content in the hybrid. The compression tests showed that an increase of PVA fraction in the hybrids improved their mechanical properties.

Structural, Magnetic, and Catalytic Properties of Mn-Doped Titania Nanoparticles Synthesized by a Sol–Gel Process

2018 ◽  
Vol 29 (6) ◽  
pp. 1255-1267 ◽  
Author(s):  
M. Chandra Sekhar ◽  
B. Purusottam Reddy ◽  
S. V. Prabhakar Vattikuti ◽  
Gnanendra Shanmugam ◽  
Chang-Hoi Ahn ◽  
...  
Keyword(s):  
Catalytic Properties ◽  
Sol Gel ◽  
Titania Nanoparticles ◽  
Sol Gel Process ◽  
Doped Titania ◽  
Mn Doped

Synthesis and catalytic properties of arene complexes of ruthenium(II) prepared from Si, Zr, Ti and Al alkoxides by the sol-gel process

1998 ◽  
Vol 8 (8) ◽  
pp. 1835-1838 ◽  
Author(s):  
Bekir Çetinkaya ◽  
Turgay Seçkin ◽  
Ismail Özdemir ◽  
Bülent Alıcı
Keyword(s):  
Catalytic Properties ◽  
Sol Gel ◽  
Arene Complexes ◽  
Sol Gel Process ◽  
Al Alkoxides
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