In situ X‐ray Measurements to Probe a New Solid‐State Polycondensation Mechanism for the Design of Supramolecular Organo‐Bridged Silsesquioxanes

Dieudonné, Philippe; Man, Michel Wong Chi; Pichon, Benoît P.; Vellutini, Luc; Bantigniès, Jean-Louis; Blanc, Christophe; Creff, Gaëlle; Finet, Stéphanie; Sauvajol, Jean‐Louis; Bied, Catherine; Moreau, Joël J. E.

doi:10.1002/smll.200800254

Cited by 27 publications

(25 citation statements)

References 83 publications

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“…Such systems include disulfide‐ and tetrasulfide‐doped PMO NPs (for glutathione‐mediated biodegradation in cells), and degradable oxamide‐ or lysine‐doped PMO NPs. Fourth, solid nonporous BS NPs can also be constructed from bridged multi‐organoalkoxysilanes (Figure D) . The absence of specific interactions between micelles and bridged organoalkoxysilanes produces dense NPs with high organic content in the composite matrix …”

Section: Two‐photon‐sensitive Organosilica Nanomaterialsmentioning

confidence: 99%

Two‐Photon‐Excited Silica and Organosilica Nanoparticles for Spatiotemporal Cancer Treatment

Croissant

Zink

Raehm

et al. 2018

Adv Healthcare Materials

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Coherent two-photon-excited (TPE) therapy in the near-infrared (NIR) provides safer cancer treatments than current therapies lacking spatial and temporal selectivities because it is characterized by a 3D spatial resolution of 1 µm and very low scattering. In this review, the principle of TPE and its significance in combination with organosilica nanoparticles (NPs) are introduced and then studies involving the design of pioneering TPE-NIR organosilica nanomaterials are discussed for bioimaging, drug delivery, and photodynamic therapy. Organosilica nanoparticles and their rich and well-established chemistry, tunable composition, porosity, size, and morphology provide ideal platforms for minimal side-effect therapies via TPE-NIR. Mesoporous silica and organosilica nanoparticles endowed with high surface areas can be functionalized to carry hydrophobic and biologically unstable two-photon absorbers for drug delivery and diagnosis. Currently, most light-actuated clinical therapeutic applications with NPs involve photodynamic therapy by singlet oxygen generation, but low photosensitizing efficiencies, tumor resistance, and lack of spatial resolution limit their applicability. On the contrary, higher photosensitizing yields, versatile therapies, and a unique spatial resolution are available with engineered two-photon-sensitive organosilica particles that selectively impact tumors while healthy tissues remain untouched. Patients suffering pathologies such as retinoblastoma, breast, and skin cancers will greatly benefit from TPE-NIR ultrasensitive diagnosis and therapy.

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Section: Two‐photon‐sensitive Organosilica Nanomaterialsmentioning

confidence: 99%

Two‐Photon‐Excited Silica and Organosilica Nanoparticles for Spatiotemporal Cancer Treatment

Croissant

Zink

Raehm

et al. 2018

Adv Healthcare Materials

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“…Along the same line of thought, Moreau et al showed in 2009 that a particular set of experimental conditions to decouple crystallization and con-densation was an effective way to form self-assembled mesostructures. [80]…”

Section: Solid-state Self-assemblymentioning

confidence: 99%

Ordered Hybrids from Template‐Free Organosilane Self‐Assembly

Chemtob

Croutxé‐Barghorn

et al. 2014

Chemistry A European J

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Despite considerable achievements over the last two decades, nonporous organic-inorganic hybrid materials are mostly amorphous, especially in the absence of solvothermal processes. The organosilane self-assembly approach is one of the few opportunities for creating a regular assembly of organic and inorganic moieties. Additionally, well-established organosilicon chemistry enables the introduction of numerous organic functionalities. The synthesis of periodically ordered hybrids relies on mono-, bis-, or multisilylated organosilane building blocks self-assembling into hybrid mesostructures or superstructures, subsequently cross-linked by siloxane Si-O-Si condensation. The general synthesis procedure is template-free and one-step. However, three concurrent processes underlie the generation of self-organized hybrid networks: thermodynamics of amphiphilic aggregation, dynamic self-assembly, and kinetically controlled sol-gel chemistry. Hence, the set of experimental conditions and the precursor structure are of paramount importance in achieving long-range order. Since the first developments in the mid-1990s, the subject has seen considerable progress leading to many innovative advanced nanomaterials providing promising applications in membranes, pollutant remediation, catalysis, conductive coatings, and optoelectronics. This work reviews, comprehensively, the primary evolution of this expanding field of research.

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“…Additionally, the resultant amphipathic silicic acid species (≡Si-OH) generated in situ remain ill-defined and transient. Consequently, they do not display a clearly defined phase behavior compared to conventional surfactants, and are difficult to isolate because subjected to irreversible condensation reactions to form stable siloxane bonds [15,16]. Last but not least, alkoxysilane self-directed self-assembly is not only a question of precursor design, because this process strongly relies also on environmental conditions (relative humidity, temperature…), processing parameters (catalyst, solvent, dilution…), as well as on sol-gel condensation rates [17].…”

Section: Introductionmentioning

confidence: 99%

Non-symmetrical bis-silylated precursor can (also) self-direct the assembly of Silsesquioxane films

Chemtob

Croutxé‐Barghorn

et al. 2017

J Sol-Gel Sci Technol

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Symmetric α,ω-bis-silylated precursors are the standard building blocks of self-assembled bridged silsesquioxanes, a unique class of robust ordered nanomaterials prepared by sol-gel process without external surfactant. We report an unprecedented approach based on the utilization of a dissymmetric bis-silylated precursor, 1,2-bis(trimethoxysilyl)decane (1), in which the two alkoxy groups are carried by adjacent methylene groups. Extensive characterizationbased on X-ray diffraction, real-time FTIR, electron and optical microscopy, 29 Si solid-state NMR, thermogravimetry, and molecular modelingshows surprisingly that such non-symmetrical precursor is highly conducive to achieve highly ordered lamellar mesostructure, able to sustain temperature up to 120 °C. To emphasize the effect of the alkoxy group functionality and position, comparison is made systematically with analogous silsesquioxanes derived from bis-(2) and mono-silylated (3) precursors. The sol-gel polymerization of 1 is unique by its ability to produce a homogeneous film possessing structural characteristic on multiple scales: uniform microcrystallites consisting of nanolamellar organosilica hybrid material. The most likely mesostructure consists of bilayers of slightly interpenetrated trans C 8 H 9 chains, with a single central siloxy-hydrocarbon chain (Si 2 O(OH) 4-C 2 H 3) n. To permit a good lateral chain packing, the hydrocarbon chain of two adjacent silicon atoms point in opposite directions.

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In situ X‐ray Measurements to Probe a New Solid‐State Polycondensation Mechanism for the Design of Supramolecular Organo‐Bridged Silsesquioxanes

Cited by 27 publications

References 83 publications

Two‐Photon‐Excited Silica and Organosilica Nanoparticles for Spatiotemporal Cancer Treatment

Two‐Photon‐Excited Silica and Organosilica Nanoparticles for Spatiotemporal Cancer Treatment

Ordered Hybrids from Template‐Free Organosilane Self‐Assembly

Non-symmetrical bis-silylated precursor can (also) self-direct the assembly of Silsesquioxane films

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