Organosilica Microspheres Research Articles

Dual-Modal Lateral Flow Test Strip Assisted by Near-Infrared-Powered Nanomotors for Direct Quantitative Detection of Circulating MicroRNA Biomarkers from Serum.

Quantification of microRNA (miRNA) has attracted intense interest owing to its importance as a biomarker for the early diagnosis of multiple diseases. However, the inefficient capture of microRNAs from complex biological samples due to the passive diffusion of detection probes essentially restricts their accurate quantification. Herein, we report near-infrared (NIR)-powered Janus nanomotors composed of Au nanorods and periodic mesoporous organo-silica microspheres (AuNR/PMO JNMs) as "swimming probes" to assist a lateral flow test strip (LFTS) for direct, amplification-free, and quantitative miRNA-21 detection in serum and cell medium. The AuNR/PMO JNMs were conjugated with designed hDNA as a recognition probe for miRNA-21. Under NIR irradiation, the exposed AuNRs can generate asymmetric thermal gradients around the JNMs to achieve vigorous self-propelled thermophoretic motion. The active movement significantly accelerated the recognition of miRNA-21 targets, which greatly improved the capture efficiency from 59.39 to 86.12% in the reaction buffer. The enhanced miRNA-21 capture enabled direct quantitative miRNA-21 detection on the LFTS assay with both visual and thermal signals. Under the assistance of AuNR/PMO JNMs, a limit-of-detection of 18 fmol/L for miRNA-21 was achieved, which was 12.22-fold compared to that of LFTS assay with static probes. The constructed LFTS assay was further successfully deployed to directly sense the miRNA-21 in spiked serum samples and MDA-MB-231 medium. Overall, the AuNR/PMO JNM-assisted LFTS system unveils a concrete point-of-care testing strategy for precise miRNA detection in real biological samples, which holds great potential for early diagnosis and treatment of miRNA-related diseases.

Interface Assembly to Magnetic Mesoporous Organosilica Microspheres with Tunable Surface Roughness as Advanced Catalyst Carriers and Adsorbents

Surface roughness endows microspheres with unique and useful features and properties like improved hydrophobicity, enhanced adhesion, improved stability at the oil-water interface, and superior cell uptake properties, thus expanding their applications. Core-shell magnetic mesoporous microspheres combine the advantages of magnetic particles and mesoporous materials and have exhibited wide applications in adsorption, catalysis, separation, and drug delivery. In this study, virus-like rough core-shell-shell-structured magnetic mesoporous organosilica (denoted as RMMOS) microspheres with controllable surface roughness were successfully obtained through electrostatic interaction-directed interface co-assembly. The obtained RMMOS microspheres possess uniform spherical morphology with tunable surface roughness, radially aligned pore channels with a diameter of 3.0 nm in the outer organosilica shell, high specific surface area (396 m2/g), large pore volume (0.66 cm3/g), high magnetization (35.1 emu/g), and superparamagnetic property. The RMMOS microspheres serve as desirable candidates to support Au nanoparticles (2.5 nm) and show superior catalytic activity and excellent stability in hydrogenation of 4-nitrophenol. In addition, the RMMOS microspheres modified with carboxylic groups further displayed promising performance in convenient adsorption removal of dyes in polluted water.

Light diffusing and flame-retardant polycarbonate modified by highly efficient and multifunctional organosilica microspheres

Polycarbonate (PC) is widely used as a matrix in light diffusing material due to its high transparency. To prepare a light diffusing material, PC is blended with microparticles to scatter the incoming light and create haze without suffering much detriment in light transmittance. It also becomes critical to endow light diffusing PC with concurrent flame retardancy to extend its advanced application. A highly efficient and multifunctional potassium sulfonate functionalized organosilica microspheres (OM-SO3K) were synthesized and employed to produce light diffusing and flame-retardant PC. When the addition of OM-SO3K was only 0.4 mass%, the transmittance and haze of the composite were 78.6% and 90.2%, respectively, while the limiting oxygen index was increased significantly to 37.5% and the V-0 rating of UL 94 test was attained. The flame-retardant mechanism was studied by the characterization of pyrolysis gas, TGA, cone calorimeter test and the analysis of charred residue.

Engineering trace AuNPs on monodispersed carbonized organosilica microspheres drives highly efficient and low-cost solar water purification

The as-prepared AuNPs@silica/FFP (GSP) membrane displays strong and reusable performance for highly efficient water desalination and decontamination.

Waste-free and efficient hydrosilylation of olefins

High purity silicone precursors can now be synthesized by hydrosilylation of solvent-free olefins catalyzed by a highly stable and active glass hybrid catalyst consisting of mesoporous organosilica microspheres doped with Pt nanoparticles.

One-Step Synthesis of Hydrophobic Multicompartment Organosilica Microspheres with Highly Interconnected Macro-mesopores for the Stabilization of Liquid Marbles with Excellent Catalysis.

The combination of an emulsion template with polymerization is a very convenient approach to the one-step realization of both simple control porous structures via a change in emulsion formulation and easy functionalization via the concomitant choice of an on-demand monomer. A major challenge of this approach is the inherent instability of the oil/water interface in emulsions, especially the occurrence of chemical reactions in oil or aqueous phases. This study reports the pioneering preparation of highly interconnected macro-mesopores and multicompartment (HIMC) vinyl organosilica microspheres with hydrophobicity by the one-step formation of W/O/W emulsions acting as a template. The emulsion system consists of acidified deionized water, a stabilizer, and vinyltriethoxysilane (VTEO) in which VTEO can be used to produce an organosilica skeleton of the resultant microsphere by a sol-gel process. The study demonstrated that the marvelous stability of W/O/W emulsions aids the formation of multicompartment organosilica microspheres with highly interconnected macro-mesopores by emulsion droplets rather than single-compartment (SC) microspheres. Meanwhile, the internal porous structure and surface morphology of as-prepared organosilica microspheres could be largely tuned by a simple variation of the pH value, the volume fraction of the water phase, and the stabilizer concentration in the initiating multiemulsions. Benefiting from such a well-orchestrated structure and the existence of numerous vinyl groups on the surface, HIMC organosilica microspheres exhibit very high hydrophobicity (with a water contact angle larger than 160°), which allows them to stabilize liquid marbles with excellent stability and high mechanical robustness. Because of its strong catalyst, Ag nanoparticles within HIMC organosilica microspheres enable Ag/HIMC-vinyl organosilica microsphere-based liquid marbles to be an efficient catalytic microreactor, realizing the complete degradation of MB to leuco methylene blue by NaBH4 in 10 min. The result of this work could provide some guidance for the easy, low-cost, benign preparation of HIMC microspheres having the potential to be excellent supporter of metal nanoparticles or other functionalized compounds for applications in sensing, optoelectronics, and catalysis.

Organically-modified silica based microspheres for self-curing polyurethane one component foams

Hybrid organosilica microspheres (MSs) doped with aqueous glycerol are tested as enablers for self-curing polyurethane one-component foams (OCF). The MSs have been characterized by Scanning Electron Microscopy, Fourier Transformed Infrared Spectroscopy, Thermal Gravimetric Analyses and leaching test. Shaking rate, of the pre-polymer inside the aerosol can, and curing speed tests of the sprayed foam, in a low moisture environment, were performed in order to evaluate the effect of the MSs on the OCF can's lifespan, as well as their contribution to the PU foam's curing process. The organic functionality of these silica-based MSs (methyl and glycidyloxy groups) was found to be responsible for a reduced leaching and low water absorption tendency, which is critical for a longer shelf life of the product required for commercial applications. In addition, the methyl functional MSs presented a significant increase in the curing rate of the PU foam.

Solid Curing Agents for Polyurethane Foams: Proof of Concept of the Release Mechanism

We show the first evidence that the microporous GreenCaps organosilica microspheres, functionalized with glycerol and sprayed from a pressurized one component polyurethane foam completely break and release their functional payload, thereby noticeably increasing the rate and the extent of the foam's curing. Further positive results concerning the main froth parameters used by urethane foam manufacturers in the presence of the GreenCaps confirm the potential of these materials to cure better and greener spray polyurethane foams.

Cover Picture: Sol-Gel Microspheres Doped with Glycerol: A Structural Insight in Light of Forthcoming Applications in the Polyurethane Foam Industry (ChemistryOpen 2/2015)

The cover picture shows a GreenCaps microcapsule breaking and releasing encapsulated glycerol after the organosilica microspheres are sprayed from a pressurized polyurethane foam can. This shows how glycerol acts as a solid curing agent, promoting crosslinking of partially polymerized diphenylmethane diisocyanate. For more details, see the Full Paper on p. 120 ff.

Sol-gel microspheres doped with glycerol: a structural insight in light of forthcoming applications in the polyurethane foam industry.

Invited for this months cover are the groups of Professor Mario Pagliaro at the Istituto per lo Studio dei Materiali Nanostrutturati in Palermo and Professor Laura Ilharco at the Instituto Superior Técnico in Lisboa. The cover picture shows a­ GreenCaps­ microcapsule breaking and releasing encapsulated glycerol after the organosilica microspheres are sprayed from a pressurized polyurethane foam can. This shows how glycerol acts as a solid curing agent, promoting crosslinking of partially polymerized diphenylmethane diisocyanate. For more details, see the Full Paper on p. 120 ff.

Sol-gel microspheres doped with glycerol: a structural insight in light of forthcoming applications in the polyurethane foam industry.

Porous silica-based microspheres encapsulating aqueous glycerol can be potential curing agents for one-component foams (OCFs). Such agents have the advantage of an enhanced sustainability profile on top of being environmentally friendly materials. A synthetically convenient and scalable sol-gel process was used to make silica and organosilica microspheres doped with aqueous glycerol. These methyl-modified silica microspheres, named “GreenCaps”, exhibit remarkable physical and chemical stability. The microspheres were characterized by scanning electron microscopy, transmission electron microscopy at reduced pressure, and cryogenic nitrogen adsorption—desorption analysis. The structure of the materials was also analyzed at the molecular level by diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. As expected, the degree of methylation affects the degree of encapsulation and pore structure. Microspheres similarly methylated, however, can differ considerably in surface area and pore size due to the templating effect of glycerol on the organosilica structure. The results of the structure analysis reveal that glycerol is efficiently encapsulated, acts as a template, barely leaches over time, but is released by depressurization. A proper application of these microspheres can later on enhance both the environmental and health profile, as well as the technical performance (curing speed, foam quality, and froth thixotropy) of spray polyurethane foams.

In situ assembly of dispersed Ag nanoparticles on hierarchically porous organosilica microspheres for controllable reduction of 4-nitrophenol

Hierarchically porous organosilica microspheres have been facilely synthesized by improved self-assembly of flexible-bridged organosilica precursor without templates and harsh conditions. Subsequently, monodispersed silver nanoparticles (Ag NPs) are in situ grown on the porous microspheres via silver mirror reaction. The as-prepared hybrid composites of Ag supported on porous microspheres are characterized by scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy, X-ray diffraction, thermal gravimetric analysis and nitrogen adsorption and desorption, respectively. These results indicate that not only Ag NPs (20–40 nm) are grown on the organosilica uniformly but also the content of Ag NPs immobilized in the hybrid materials can be well controlled by simply tuning the amount of the Ag(NH3)2OH. The resultant hybrid microspheres exhibit remarkable and durable performances for the reduction of 4-nitrophenol to 4-aminophenol by NaBH4 in aqueous solution. Moreover, the catalytic kinetic mode can be tuned by adjusting the parameter in catalytic reaction, and it can be recycled for seven successive cycles with excellent conversion of 100 % within 8 min. Therefore, the present structure design and scalable route for the synthesis of hierarchical catalyst can provide a highly efficient solution for the reduction of nitro-aromatic compounds in the view of environmentally friendly strategy.

Thermogravimetric investigation of sol–gel microspheres doped with aqueous glycerol

Abstract Background Silica-based microspheres encapsulating aqueous glycerol are promising curing agents affording the formation of better one-component polyurethane foams, namely thermoset polymers cured by atmospheric moisture that are widely and increasingly utilized in the construction industry. The use of renewable, non toxic glycerol from biodiesel and oleochemicals industry to cure PU foams in place of traditionally employed oil-derived mono and diethylene glycols is both technically and environmentally beneficial. The higher amount of hydroxyl groups in glycerol compared to both mono- and diethylene glycol results in considerably lower percentage of free monomeric methylene diphenyl diisocyanate (MDI) and higher crosslinking density of the cured foam. Results We investigate by thermogravimetric analysis the nature and amount of the microencapsulated species in sol–gel silica and organosilica microspheres encapsulating aqueous glycerol. Along with a percentage of glycerol in weight up to 35%, the microspheres contain about 5 wt% water and 4 wt% entrapped surfactant. Conclusions The investigation shows the efficacy of the surfactant-assisted sol–gel microencapsulation aqueous glycerol in silica as well as in methyl-silica particles at least until 10% degree of methylation. The results are relevant to the practical development of functional materials that can be used to cure better and greener polyurethane foams largely employed as coatings, adhesives and sealants in many industrial sectors.

GreenCaps: towards solid curing agents for sustainable polyurethane foams

Abstract Testing and further investigation of organosilica microspheres functionalized with aqueous glycerol as solid curing agents for polyurethane (PU) foams confirms the potential of these materials to cure better and greener PU foams. The developed microspheres were found to be stable in the foam precursor mixture, allowing handling and mixing of the foam cans, and were shown to provide a slight improvement of the curing speed. The foams obtained from the froth containing the microspheres were found to maintain the level of quality of reference foam samples. Termed “GreenCaps”, these microspheres will subsequently be tested in pre-commercial applications.

A strategy for fabrication of uniform double-shell hollow microspheres as effective acoustic echo imaging contrast agents through a new polymer-backbone-transition method.

We present a novel self-templating strategy for directly fabricating monodisperse hollow polymer microspheres (HPMs) from vinyl-containing organosilica microspheres (VOMs) through a polymer-backbone-transition method (PBTM). The VOMs play the roles of both templates and precursors in the new shells. The uniform HPMs with varying sizes from 320 nm to 1.6 μm could be obtained by controlling the diameter of the VOMs. Depending on the progress of outer-to-inner shell formation, the range of shell thickness is broadly tunable from 15 nm to 290 nm. Theoretically, through introduction of a suitable vinyl monomer in the shell-formation step, a variety of double-shell hollow polymer microspheres (ds-HPMs) could be fabricated based on this strategy. We then synthesize ds-HPMs by copolymerization of VOMs with N-isopropyl acrylamide (NIPAM) in order to improve the dispersion stability of HPMs in water and provide better oscillation and compressibility. In vitro and in vivo experimental results showed that the ds-HPMs possessed excellent echoing characteristics which could be applied as ultrasound contrast agents for the real-time guidance during the surgical process.

Facile preparation of hollow amino-functionalized organosilica microspheres by a template-free method

A facile method was developed to fabricate hollow amino-functionalized organosilica microspheres based on the hydrolysis and condensation of 3-aminopropyltriethoxysilane (APTES) and tetraethoxysilane (TEOS) in an aqueous system without an additional template and catalyst. The hollow hybrid organosilica microspheres obtained have been characterized by scanning electron microscopy, transmission electron microscopy, and N2 adsorption–desorption measurements. The results of Fourier transform infrared spectroscopy, solid-state NMR spectroscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis displayed the composition of the synthesized hollow microspheres and the presence of amino groups on the surface. A self-templated and self-catalyzed mechanism for the formation of the hollow microspheres is proposed: the protonated APTES acts as both a catalyst for the reaction and a stabilizer for the hydrophobic precursor droplets, while the droplets themselves act as soft templates, and the consumption of the precursors leads to the formation of a hollow structure. The morphology and the size distribution of the organosilica microspheres can be controlled by tuning the composition of the precursors, and the stirring speed, as well as the reaction temperature. The large cavity with an open hole on the shell and the reactive amino groups on the surface of the hybrid organosilica microspheres promise many potential applications. Examples of employing the microspheres as adsorbents and phase change microcapsules have been presented.

Magnetic core–shell-structured nanoporous organosilica microspheres for the Suzuki–Miyaura coupling of aryl chlorides: improved catalytic activity and facile catalyst recovery

Download options Please wait... Supplementary files Supplementary information PDF (891K) Article information DOI https://doi.org/10.1039/C2JM15693H Article type Paper Submitted 06 Nov 2011 Accepted 30 Jan 2012 First published 24 Feb 2012 Download Citation J. Mater. Chem., 2012,22, 6639-6648 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions Magnetic core–shell-structured nanoporous organosilica microspheres for the Suzuki–Miyaura coupling of aryl chlorides: improved catalytic activity and facile catalyst recovery H. Yang, G. Li and Z. Ma, J. Mater. Chem., 2012, 22, 6639 DOI: 10.1039/C2JM15693H To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Search articles by author Hengquan Yang Guang Li Zhancheng Ma

Enrichment and Detection of Peptides from Biological Systems Using Designed Periodic Mesoporous Organosilica Microspheres

Periodic mesoporous organosilica microspheres (PMOMs) are designed with integrated structural features, including a cubic mesostructure, hydrophobic wall composition, a uniform pore size of ≈3 nm, and a spherical morphology in micrometers, all advantageous for size-selective and highly efficient enrichment of peptides from mixtures. Consequently, PMOMs can be used to capture peptides in a range of complex biological systems.

Aerosol-assisted synthesis of mesoporous organosilica microspheres with controlled organic contents

Periodic mesoporous organosilica (PMO) spherical particles with different organic contents were synthesized in one pot by reacting 1,2-bis(triethoxysilyl)ethane (BTSE) with tetraethylorthosilicate (TEOS) using a spray-drying technique. The scanning electron microscopy observation of spray-dried products clearly showed the formation of spherical particles. The 29Si magic angle spinning nuclear magnetic resonance data revealed that the organic contents due to ethane fragments embedded in the frameworks were controllable and consistent with the BTSE/TEOS molar ratios of precursor solutions. Transmission electron microscopy, small-angle x-ray scattering, and N2 adsorption data of PMO with controlled organic contents indicated that the ethane fragments were embedded in the frameworks with the formation of ordered mesostructures. PMO with a high organic content (BTSE/TEOS=0.50) only showed a hydrophobic property. According to the same procedure, benzene groups were also integrated to a similar degree in the frameworks by using 1,4-bis(triethoxysilyl)benzene.

Improving the Signal-to-Noise Performance of Molecular Diagnostics with PEG-Lysine Copolymer Dendrons

The synthesis, characterization, and use of dendron-like poly(ethylene glycol)-lysine (PEG-Lys) copolymers as an intermediate layer for biomolecular diagnostic signal enhancement is presented. Solid phase Fmoc-peptide synthesis was used to synthesize polymers with one, two, and three PEG-Lys comonomer units in both a linear and first and second-generation dendronic structure directly onto organosilica microspheres. The microsphere surface loadings (number of free amine sites) were modified and quantified through an innovative use of the protecting groups of coupled amino acids. Surfaces with 0.1-100% of the original loading corresponding to 0.3-270 nmol/m2 of free amines were achieved. The influence of polymer structure and surface loading (grafting density) on the signal-to-noise of the microsphere-based molecular diagnostic was assessed measuring the difference in the signal of a model protease digestion assay and reduction in the nonspecific adsorption of bovine serum albumin. Increasing the polymer grafting density and the addition of dendronic branching were both found to increase the assay signal and reduce the nonspecific protein adsorption.