Formation and Structure of Porous Gel Networks from Si(OMe)4 in the Presence of A(CH2)nSi(OR)3 (A = Functional Group)

Hüsing, Nicola; Schubert, Ulrich; Misof, K.; Fratzl, Peter

doi:10.1021/cm980706g

Cited by 98 publications

(70 citation statements)

References 24 publications

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“…32 The surfactants and solvents function to stabilise the steric forces and allow dispersion of the two phases. 33 Organosilanes are molecules that have 90 organic and inorganic functional moieties in the same molecule which can bond to organic and inorganic chains, respectively. Ren et al used this concept to produce a class II biodegradable gelatin-siloxane hybrid by covalently crosslinking gelatin with the organosilane glycidoxypropyl 95 trimethoxysilane (GPTMS).…”

Section: 24 75mentioning

confidence: 99%

Synthesis of bioactive class II poly(γ-glutamic acid)/silica hybrids for bone regeneration

Poologasundarampillai

Ionescu

Tsigkou

et al. 2010

J. Mater. Chem.

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Bone grafts are commonly used to regenerate bone in defect sites resulting from disease or trauma but there is clinical need for artificial materials that will be readily available and reduce pain and recovery time for the patient. Current artificial bone graft materials are bioactive ceramics and glasses, which are too brittle for bone defects that experience cyclic load. The synthesis of a new nanocomposite material is described that has the potential of being a tough off-the-shelf artificial bone graft that can regenerate a bone defect and have enough flexibility to press-fit into place. The poly(γ-glutamic acid)/bioactive silica hybrid material with composition 40 wt% organic and 60 wt% bioactive inorganic (composition 70 mol% SiO 2 and 30 mol% CaO) was synthesised using a sol-gel route. The potential advantage of a hybrid material over conventional composites is the molecular scale interactions between the bioactive inorganic and the tough degradable organic. The organic and inorganic chains were covalently crosslinked using an organosilane that has an organic functionality to bond to poly(γ-glutamic acid) (γ-PGA) and an alkoxysilane group that condenses with the inorganic phase. The covalent cross-linking (class II hybrid)is required to control the dissolution and improve mechanical properties of the material. The two key variables, the concentration of cross-linking agent and the addition of calcium, were investigated by 29 Si solid-state NMR and electron microscopy. The hybrid materials were bioactive in simulated body fluid (SBF) with a hydroxy carbonate apatite (HCA) layer detected after immersion for 72 h. The hybrid material favours cell attachment and is not cytotoxic as demonstrated by culture of the osteosarcoma cell line SaOs-2 on the material for 4 days. This journal is

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Section: 24 75mentioning

confidence: 99%

Synthesis of bioactive class II poly(γ-glutamic acid)/silica hybrids for bone regeneration

Poologasundarampillai

Ionescu

Tsigkou

et al. 2010

J. Mater. Chem.

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“…The addition of TEOS, i.e., another source of Si/O units, raised the question in which part of the structure the extra Si/O units would be incorporated. Under basic conditions, TEOS reacts faster than RSi(OMe) 3 , 18 and therefore there was a chance that the Si/O units from TEOS would "dilute" the Ti/O core of the primary particles. On the other hand, if the reaction of the Ti(O i Pr) 3 moieties would be faster than that of both TEOS and the Si(OMe) 3 part of 1, the primary particle size would be unchanged, and Si/O units would be incorporated into the Si/O part of the overall structure.…”

Section: I(q) ) A‚p(q)‚s(q)mentioning

confidence: 99%

Mixed Silica Titania Materials Prepared from a Single-Source Sol−Gel Precursor: A Time-Resolved SAXS Study of the Gelation, Aging, Supercritical Drying, and Calcination Processes

et al. 2005

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The morphology of gels prepared from a silica/titania single-source precursor (1), obtained by reaction of 3-oxoethyl-6-trimethoxysilyl-hexan-2-one with Ti(O i Pr) 4 , was investigated by small-angle X-ray scattering (SAXS) through all stages of the preparation process, that is, gelation, aging, drying, and calcination. The same investigations were performed for mixtures of 1 and Si(OEt) 4 . Immediately after the start of the reaction small primary particles are formed, the size of which (r ) 0.5 ( 0.1 nm) remains constant through the gelation and aging process. Anomalous small-angle X-ray scattering (ASAXS) measurements strongly indicate that the primary particles are formed by hydrolysis and condensation of the titanium alkoxide moiety of 1. Condensation proceeds by a slower aggregation of the primary particles. Additional Si/O from Si(OEt) 4 is incorporated between the clusters. The size of the mass fractal secondary particles formed by aggregation of the primary particles increases approximately exponentially with the time. Drying by either solvent evaporation or supercritical extraction with CO 2 results in a decrease of the primary particle size to r ) 0.4 nm, and the secondary particles also become smaller. The primary particles disappear during calcination in air, that is, when the organic groups tethering the silicon and titanium atoms are destroyed. However, the general structure of the network is maintained.

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“…A hybrid material consists of interpenetrating networks of organic and inorganic components ( Fig. 1) [1][2][3][4][5][6][7][8]. The properties of hybrids are customisable and can be tailored precisely to the needs of their intended application.…”

Section: Introductionmentioning

confidence: 99%

Silica–gelatin hybrids for tissue regeneration: inter-relationships between the process variables

Mahony

Sheng

Turdean-Ionescu

et al. 2013

J Sol-Gel Sci Technol

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Owing to their diverse range of highly tailorable material properties, inorganic/organic hybrids have the potential to meet the needs of biodegradable porous scaffolds across a range of tissue engineering applications. One such hybrid platform, the silica-gelatin sol-gel system, was examined and developed in this study. These hybrid scaffolds exhibit covalently linked interpenetrating networks of organic and inorganic components, which allows for independent control over their mechanical and degradation properties. A combination of the sol-gel foaming process and freeze drying was used to create an interconnected pore network. The synthesis and processing of the scaffolds has many variables that affect their structure and properties. The focus of this study was to develop a matrix tool that shows the inter-relationship between process variables by correlating the key hybrid material properties with the synthesis parameters that govern them. This was achieved by investigating the effect of the organic (gelatin) molecular weight and collating previously reported data.Control of molecular weight of the polymer is as an avenue that allows the modification of hybrid material properties without changing the surface chemistry of the material, which is a factor that governs the cell and tissue interaction with the scaffold. This presents a significant step forward in understanding the complete potential of the silica-gelatin hybrid system as a medical device.

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Formation and Structure of Porous Gel Networks from Si(OMe)₄ in the Presence of A(CH₂)_nSi(OR)₃ (A = Functional Group)

Cited by 98 publications

References 24 publications

Synthesis of bioactive class II poly(γ-glutamic acid)/silica hybrids for bone regeneration

Synthesis of bioactive class II poly(γ-glutamic acid)/silica hybrids for bone regeneration

Mixed Silica Titania Materials Prepared from a Single-Source Sol−Gel Precursor: A Time-Resolved SAXS Study of the Gelation, Aging, Supercritical Drying, and Calcination Processes

Silica–gelatin hybrids for tissue regeneration: inter-relationships between the process variables

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