Mesoporous Organosilica Nanospheres Research Articles

Facile synthesis of copper sulfide loaded mesoporous organosilica nanospheres with a triple-shelled hollow structure

Facile synthesis of copper sulfide loaded mesoporous organosilica nanospheres with a triple-shelled hollow structure

One-step synthesis of hollow and yolk-shell mesoporous organosilica nanospheres for efficient separation of lead ions

In this work, we demonstrate that monodispersed hollow mesoporous organosilica nanospheres (MONs) and yolk-shell MONs possessing controlled core cavity and mesoporous shell is successfully synthesized through a one-pot approach, which involves co-condensation of 3-aminopropyltriethoxysilane and 1,2-bis(triethoxysilyl)ethane templated by lauryl sulfonate betaine and sodium dodecyl benzenesulfonate. The MONs present an open mesoporosity, hollow cavity with a morphology tailored by the various core templates, and high surface area (328 m2/g). In addition, the composition of the hollow MONs could be further tuned through the same approach. The as-prepared hollow MONs as adsorbent deliver an enormous adsorption capacity (414 mg/g) towards the removal of Pb2+ from water solution. Importantly, the prepared hollow MONs present acceptable recycling and stability, since the performance in Pb2+ removal from water remains above 80 % even after 5 consecutive cycles. The adsorption of Pb2+ on hollow MONs follows the pseudo-second-order mechanics and Langmuir isotherm models. The results confirm hollow MONs exhibit considerable promise for the remarkably efficient separation of Pb2+ ions in water solution.

Pyromellitic diamide-diacid bridged mesoporous organosilica nanospheres with controllable morphologies: a novel PMO for the facile and expeditious synthesis of imidazole derivatives.

In this work, novel pyromellitic diamide–diacid bridged mesoporous organosilica (PMAMOS) nanospheres with controllable morphologies and Brønsted acid catalytic centers were designed and prepared through a convenient method by altering the addition sequence of precursors, solvent, and aging time. The obtained PMAMOSs demonstrate high surface areas and uniform pore sizes. FESEM, HRTEM, BET, EDX, XRD, FTIR and TGA analyses were performed to characterize and examine the effective factors for the preparation of PMAMOS nanospheres. Due to the appropriate physicochemical properties including Brønsted acid centers, suitable surface area and thermal stability of the PMAMOS nanosphere material, it was explored in the three-component reaction of benzyl or benzoin, ammonium acetate, and different aldehyde derivatives as a case study of multicomponent reactions. Corresponding imidazole derivatives were obtained in EtOH under reflux conditions in high to quantitative yields and short reaction times. It was also shown that the heterogeneous solid acid can be reused at least five times with negligible loss of its catalytic activity, indicating the appropriate stability and high activity of the newly introduced mesoporous organosilica.

Design of Brønsted acidic ionic liquid functionalized mesoporous organosilica nanospheres for efficient synthesis of ethyl levulinate and levulinic acid from 5-hydroxymethylfurfural

Mesoporous organosilica nanosphere-immobilized Brønsted acidic ionic liquids with a controlled particle size and pore morphology exhibit high activity and selectivity.

Hollow mesoporous organosilica nanospheres with multiple tiny silver nanoparticles: A polymer mediated growth approach and catalytic application

The fabrication of nanostructured catalysts based on noble metal nanoparticles has attracted much attention. In this study, multiple tiny Ag nanoparticles loaded hollow mesoporous organosilica spheres (MT-Ag@HMOS) were synthesized by a novel polymer mediated growth approach. During the preparation, polyacrylic acid@hollow mesoporous organosilica spheres (PAA@HMOS) were first produced formed by condensation of organosilica precursor on polyacrylic acid (PAA) colloids; subsequently, tiny Ag nanoparticles were in situ immobilized both in the cavity and on the shell of PAA@HMOS due to their abundant thioether groups and unique structure. The produced materials were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), N2 adsorption-desorption instruments, X-ray diffraction (XRD), and X-ray photoelectron spectra (XPS). The MT-Ag@HMOS exhibited a spherical morphology with an average diameter of about 120 nm, a high surface area of 76.5 m2·g−1, as well as high content of tiny Ag nanoparticles (approximately 3 nm). In addition, the catalytic activities of the MT-Ag@HMOS on 4-nitrophenol (4-NP), Congo red (CR), and Rhodamine B (RhB) reduction in the presence of NaBH4 in aqueous medium were investigated. Experimental results show MT-Ag@HMOS particles are promising candidates for the treatment of waste water supplemented contaminated by 4-NP and various dyes.

Virus-mimicking mesoporous organosilica nanocapsules with soft framework and rough surface for enhanced cellular uptake and tumor penetration.

An enveloped virus with soft and rough shells has strong penetration ability for cells. Inspired by the unique structure of virus, we successfully constructed virus-mimicking mesoporous organosilica nanocapsules (denoted as VMONs) for the first time by decorating small-sized silica nanoparticles on soft mesoporous organosilica hollow spheres. TEM and SEM images reveal that the prepared VMONs display uniform diameters (240 nm), a soft framework, a rough surface, and excellent dispersity. Quantitative nanomechanical mapping further demonstrates that the VMONs possess an extremely low Young's modulus (36 MPa) and a scraggly surface. In view of the successful construction of the virus-mimicking nanocapsules, the VMONs are further modified with human serum albumin (HSA) and Cy5.5-maleimide (Mal-Cy5.5) to investigate their cell penetration ability. Flow cytometry analysis reveals that the internalization of VMONs@HSA-Cy5.5 increases 2.74-fold compared to that of the conventional mesoporous nanosphere. Confocal laser scanning microscopy images show that the VMONs@HSA-Cy5.5 diffuses deeper for multicellular spheroids compared to both hard and soft mesoporous organosilica nanospheres. The penetration ability of the VMONs and SMONs increases 18.49 and 6.13-fold compared to that of MONs at the depth of 60 μm. Thanks to the excellent cellular penetration ability, the virus-mimicking VMONs@HSA-Cy5.5 can effectively deliver the anticancer drug doxorubicin (Dox) into drug-resistant MCF-7/ADR human breast cancer cells and significantly enhance the chemotherapeutic efficacy. Taken together, the constructed virus-mimicking organosilica nanocapsules with a soft framework and a rough surface possess strong cellular internalization and tumor penetration abilities, providing a unique and effective nanoplatform for biomedical applications.

Simultaneous T Cell Activation and Macrophage Polarization to Promote Potent Tumor Suppression by Iron Oxide-Embedded Large-Pore Mesoporous Organosilica Core-Shell Nanospheres.

Nanomaterial-based immunotherapy stimulating T cell activation or tumor-associated macrophage (TAM) conversion holds great promise for promoting tumor suppression. Herein, a novel nanoplatform, iron oxide-embedded large-pore mesoporous organosilica nanospheres (IO-LPMONs), is prepared for the first time to simultaneously activate cytotoxic T cells and polarize macrophages for potent tumor immunotherapy. The IO-LPMONs have large mesopores (6.3 nm) and inorganic-organic hybrid shells, which contribute to a high payload (500 µg mg-1 ) of the antigen ovalbumin (OVA). The IO-LPMONs effectively deliver OVA to dendritic cells (DCs) and activate DCs. Subsequently, high activation of both CD4+ and CD8+ effector antigen-specific T cells is achieved for powerful antitumor effects. Moreover, the IO-LPMONs also act as an immune modulator to polarize TAMs from an immunosuppressive M2 to a tumor-killing M1 phenotype, which induces efficient apoptosis of tumor cells. The combined T cell activation and macrophage polarization strategy based on the IO-LPMONs elicits remarkable combined antitumor effects in vivo, showing great promise for tumor treatment.

Controlled PEGylation of periodic mesoporous organosilica nanospheres for improving their stability in physiological solutions

The stability of periodic mesoporous organosilica (PMO) nanoparticles in physiological solutions greatly affects their potential biomedical applications. Herein, thioether-bridged PMO nanospheres with a diameter of 61 nm are synthesized. Then, the thioether-bridged PMO nanospheres are modified with different molecular weighted polyethylene glycol (PEG) via click reaction for the first time. FI-IR and thermogravimetric analysis confirm the successful modification of PEG on the PMO. The influence of PEG molecular weight on the dispersity and stability of the PMO-PEG in phosphate buffer (PBS) and Dulbecco’s modified Eagle’s medium (DMEM) is studied. The results show that the PEG coating increases the stability and dispersity of PMO in the biological solutions. The PMO-PEG1K, PMO-PEG2K, and PMO-PEG5K have better stability in PBS solution. The PMO-PEG2K shows best stability and dispersity in DMEM. Over all, this work provides important method and knowledge to guide the modification of PMO for biomedical applications

One-pot co-condensation strategy for dendritic mesoporous organosilica nanospheres with fine size and morphology control

A one-pot co-condensation strategy was developed for dendritic mesoporous organosilica nanospheres with fine size and morphology control.

Amino‐Functionalized Multilayer Core–Shell Mesoporous Organosilica Nanospheres for Cr(VI) Removal

AbstractDeveloping low‐cost and highly efficient adsorbents for the removal of toxic heavy metal ions is the subject of intensive research with the increasingly stringent water pollution control standards. In this paper, three types of amino‐functionalized multilayer core–shell mesoporous organosilica nanospheres (MCMONs) are synthesized using an indirect cocondensation method for Cr(VI) removal applications. Results show that amino groups are successfully immobilized on the nanospheres and these amino‐functionalized MCMONs exhibit unique organic–inorganic multilayer core–shell structures. When used as adsorbent for Cr(VI) removal, the N‐(3‐trimethoxysilylpropyl)diethylenetriamine functionalized MCMONs exhibit a maximum adsorption capacity of 279.92 mg g−1 at initial Cr(VI) concentration of 150 mg L−1. This is about 20% greater than the highest Cr(VI) adsorption capacity previously reported for other core–shell silica‐based adsorbents, demonstrating the great potential of MCMONs in Cr(VI) removal applications.

Hollow mesoporous organosilica nanospheres templated with flower-like micelles of pentablock copolymers

We present a facile preparation of hollow mesoporous organosilica nanospheres with well-defined, uniform mesopores by controlling the morphology of pentablock copolymer templates under acidic conditions. The CBABC type poly(lactic acid-co-glycolic acid)-b-poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide)-b-poly(lactic acid-co-glycolic acid) (PLGA-b-PEO-b-PPO-b-PEO-b-PLGA) pentablock copolymers were synthesized via a step-growth and ring-opening polymerization method using Pluronic F68 and F108 as macro-initiators. Two kinds of pentablock copolymers, (LA45GA12)EO75PO30EO75(LA45GA12) and (LA28GA9)EO141PO54 EO141(LA28GA9), were used as single soft templates to prepare mesoporous ethane-silica and benzene-silica hollow nanospheres by sol-gel chemistry in acidic aqueous solutions. The inner cavity diameter was controlled up to ∼20 nm by varying acidity and the chain length of the hydrophobic PLGA block without using additional swelling agents. The evolution of hollow nanospheres could be explained by single flower-like micelle template mechanism and the variation of morphology of pentablock copolymers upon solution acidity. Moreover, the amine-functionalized hollow benzene-silica nanospheres showed high carbon dioxide adsorption at ambient conditions. The hollow organosilica nanospheres were characterized by small-angle X-ray scattering, nitrogen adsorption-desorption, solid-state 13C- and 29Si nuclear magnetic resonance, and scanning and transmission electron microscopy and so on.

Gold nanorod embedded large-pore mesoporous organosilica nanospheres for gene and photothermal cooperative therapy of triple negative breast cancer.

To date, clinicians still lack an effective strategy to treat triple negative breast cancer (TNBC). In this work, we design for the first time a gold nanorod embedded large-pore mesoporous organosilica (GNR@LPMO) nanoplatform for gene and photothermal cooperative therapy of TNBC. The synthesized GNR@LPMOs possess a uniform size (175 nm), high surface area (631 m2 g-1), large pore size, excellent photothermal efficiency, and good biocompatibility. Thanks to the large-pore mesoporous organosilica layer, the GNR@LPMO nanoplatforms display much higher loading capacity of siRNA compared with traditional liposome and bare gold nanorods. Thus, functional siRNA can be efficiently delivered into TNBC cells by GNR@LPMOs, causing much higher cell apoptosis through knocking down the PLK1 proteins. By combining the effective gene delivery and photothermal abilities, the GNR@LPMO nanoplatforms are further used for gene and photothermal cooperative therapy of TNBC, which induce a 15 fold higher mice tumor inhibition rate than sole therapy modality, indicating the potential clinical use of this novel nanoplatform in treating TNBC.

Synergistic Chemo-Photothermal Therapy of Breast Cancer by Mesenchymal Stem Cell-Encapsulated Yolk-Shell GNR@HPMO-PTX Nanospheres.

Mesenchymal stem cells (MSCs) have attracted increasing attention as vehicles for cancer treatment. Herein, MSC-based synergistic oncotherapy strategy is presented for the first time. To achieve this goal, yolk-shell structured gold nanorod embedded hollow periodic mesoporous organosilica nanospheres (GNR@HPMOs) with high paclitaxel (PTX) loading capability and excellent photothermal transfer ability upon near-infrared (NIR) light irradiation are first prepared. Cytotoxicity and migration assays show that the viability and tumor-homing capability of MSCs are well-retained after internalization of high content of PTX loaded GNR@HPMOs (denoted as GNR@HPMOs-PTX). In vitro experiments show the GNR@HPMOs-PTX loaded MSCs (GNR@HPMOs-PTX@MSCs) possess synergistic chemo-photothermal killing effects for breast cancer cells. Also, photoacoustic imaging shows that the MSCs can improve dispersion and distribution in tumor tissue for GNR@HPMOs-PTX after intratumoral injection. In vivo experiments in breast cancer model of nude mice further demonstrate that the GNR@HPMOs-PTX@MSCs significantly inhibit tumor growth, suggesting their great potential for synergistic therapy of cancer.

Hollow periodic mesoporous organosilica nanospheres by a facile emulsion approach

Periodic mesoporous organosilicas (PMOs) with homogeneously incorporated organic groups, highly ordered mesopores, and controllable morphology have attracted increasing attention. In this work, one-step emulsion approach for preparation of hollow periodic mesoporous organosilica (HPMO) nanospheres has been established. The method is intrinsically simple and does not require any sacrificial templates, corrosive and toxic etching agents. The obtained HPMO nanospheres have high surface area (∼950m2g−1), accessible ordered mesochannels (∼3.4nm), large pore volume (∼3.96cm3g−1), high condensation degree (77%), and diameter (∼560nm), hollow chamber size (∼400nm), and shell thickness (∼80nm). Furthermore, cytotoxicity show the cell viability is higher than 86% after incubating with the HPMO nanospheres at a concentration of up to 1200μgmL−1 for 24h. The hemolysis of HPMO nanospheres is lower than 1.1% at concentrations ranging from 10 to 2000μgmL−1. The lower hemolysis and cytotoxicity make the HPMO nanospheres great promise for future biomedical applications.

An organosilane-directed growth-induced etching strategy for preparing hollow/yolk–shell mesoporous organosilica nanospheres with perpendicular mesochannels and amphiphilic frameworks

An amphiphilic PMO hollow shell with order mesostructure is constructed for application in sorption and catalysis.

Amine-bridged periodic mesoporous organosilica nanospheres as an active and reusable solid base-catalyst for water-medium and solvent-free organic reactions

An amine-bridged periodic mesoporous organosilica catalyst in uniform nanospheres (∼85nm) (NH-PMO-NS) was synthesized by surfactant-directed co-condensation between amine-bridged silane and tetraethoxysilane (TEOS). As-prepared NH-PMO-NS contained short and straight mesoporous channels with amine-groups integrally incorporated into silica walls. In water-medium Knoevenagel condensation and solvent-free Henry reactions, this catalyst exhibited much higher activity and selectivity than both the common amine-bridged PMO (NH-PMO-com) with irregular shape synthesized by traditional method and the amine-functionalized MCM-41 in nanospheres (NH-MCM-NS) prepared by grafting amine-groups onto the pore surface. In addition, it displayed comparable catalytic efficiencies with the homogeneous base-catalyst (diethylamine), and could also be easily recovered and used repetitively. Based on the structural characterizations and kinetic studies, the high catalytic activity and selectivity were ascribed to the short and straight mesoporous channels in nanospheres with amine-groups incorporated into silica walls. The accessible basic catalytic sites may facilitate the diffusion and thus, promoted the adsorption of organic reactant molecules, leading to the enhanced activity and selectivity.

Chiral Mesoporous Organosilica Nanospheres: Effect of Pore Structure on the Performance in Asymmetric Catalysis

(R)-(+)-1,1'-Bi-2-naphthol ((R)-(+)-Binol)-functionalized (Binol=2,2'-dihydroxy-1,1'-binaphthyl) chiral mesoporous organosilica nanospheres with uniform particle size (100 to 300 nm) have been synthesized by co-condensation of tetraethoxysilane and (R)-2,2'-di(methoxymethyl)oxy-6,6'-di(1-propyl trimethoxysilyl)-1,1'-binaphthyl in a basic medium with cetyltrimethylammonium bromide as the template. Nanospheres with a radiative 2D hexagonal channel arrangement exhibit higher enantioselectivity and turnover frequency than those with a penetrating 2D hexagonal channel arrangement (94 versus 88 % and 43 versus 15 h(-1), respectively) in the asymmetric addition of diethylzinc to aldehydes. In addition, under similar conditions, the enantioselectivity of the nanospheres can be greatly improved as the structural order of the framework increases. These results clearly show that the structural order of nanospheres affects enantioselective reactions. The enantioselectivity of the nanospheres synthesized by the co-condensation method is higher than that of nanospheres prepared by a grafting method and even higher than that of their homogeneous counterpart. These results indicate that the bite angle of (R)-(+)-Binol bridging in a more rigid porous network is in a more favorable position for achieving higher enantioselectivity. The efficiency of a co-condensation method for the synthesis of high-performance heterogeneous asymmetric catalysts is also reported.