Mesoporous Organosilica Research Articles

Hollow multi-shelled structure engineering of organosilica for efficient and selective uranium extraction from seawater

Uranium extraction from seawater is critical for the development of nuclear energy, but the progress is still seriously limited by the performance and cost of current adsorbents. Herein, a convenient and general co-condensation process is designed to prepare amidoximated multi-shelled hollow mesoporous organosilica adsorbent (AO-HMO), which exhibits a high uranium extraction capacity of 862.07 mg·g−1 in uranium-spiked simulated seawater and 9.67 mg·g−1 in natural seawater. The run-through mesoporous structure and multi-shelled surface provide fast diffusion channels and more active sites for uranium adsorption. Moreover, AO-HMO exhibits a long service life due to its robust structure, maintaining an ideal adsorption capacity over 10 adsorption-desorption cycles. Coupled with the synthesis-cost advantage, AO-HMO will surely show great application potential in uranium extraction form seawater in future.

Multifunctional Hierarchical Nanoplatform with Anisotropic Bimodal Mesopores for Effective Neural Circuit Reconstruction after Spinal Cord Injury.

A persistent inflammatory response, intrinsic limitations in axonal regenerative capacity, and widespread presence of extrinsic axonal inhibitors impede the restoration of motor function after a spinal cord injury (SCI). A versatile treatment platform is urgently needed to address diverse clinical manifestations of SCI. Herein, we present a multifunctional nanoplatform with anisotropic bimodal mesopores for effective neural circuit reconstruction after SCI. The hierarchical nanoplatform features of a Janus structure consist of dual compartments of hydrophilic mesoporous silica (mSiO2) and hydrophobic periodic mesoporous organosilica (PMO), each possessing distinct pore sizes of 12 and 3 nm, respectively. Unlike traditional hierarchical mesoporous nanomaterials with dual-mesopores interlaced with each other, the two sets of mesopores in this Janus nanoplatform are spatially independent and possess completely distinct chemical properties. The Janus mesopores facilitate controllable codelivery of dual drugs with distinct properties: the hydrophilic macromolecular enoxaparin (ENO) and the hydrophobic small molecular paclitaxel (PTX). Anchoring with CeO2, the resulting mSiO2&PMO-CeO2-PTX&ENO nanoformulation not only effectively alleviates ROS-induced neuronal apoptosis but also enhances microtubule stability to promote intrinsic axonal regeneration and facilitates axonal extension by diminishing the inhibitory effect of extracellular chondroitin sulfate proteoglycans. We believe that this functional dual-mesoporous nanoplatform holds significant potential for combination therapy in treating severe multifaceted diseases.

Mesoporous Organosilica-Platinum Janus nanomotor coordinated by charge reversal for deep tumor penetration and promoted chemotherapy

Enhancing the diffusion capability of nanoparticles through rational engineering is an effective strategy for promoting the penetration of nanotherapeutic systems into tumors. However, the efficiency of diffusion remains inadequate due to the unchanged passive diffusion mode. Nanomotors hold promise for achieving deep tumor permeability due to their self-propelled motility. Developing smart-responsive nanomotor therapeutic systems for long circulation, deep tumor penetration, and well-timed drug release presents significant challenges. Herein, we design and synthesize a kind of nanomotor with charge reversal capability that shifts from negative to positive charge in response to weakly acidic tumor microenvironment on the base of the Janus nanostructure, which consists of the mesoporous organosilica degraded in response to glutathione and asymmetric Pt provided driving force by catalyzing endogenous H2O2 to decompose into O2. The cap-like Janus structure is prepared by a facile adsorption − reduction method. Such a nanomotor can achieve deep tumor penetration by the synergism of charge reversal and self-propelled motion. The drug-loaded nanomotor displays a superior tumor killing effect, which provides a promising strategy for the nano-chemotherapy system with deep penetration ability to break through the limitation of current tumor treatment.

A mesoporous superparamagnetic iron oxide nanoparticle as a generic drug delivery system for tumor ferroptosis therapy

As a famous drug delivery system (DDS), mesoporous organosilica nanoparticles (MON) are degraded slowly in vivo and the degraded components are not useful for cell nutrition or cancer theranostics, and superparamagnetic iron oxide nanoparticles (SPION) are not mesoporous with low drug loading content (DLC). To overcome the problems of MON and SPION, we developed mesoporous SPIONs (MSPIONs) with an average diameter of 70 nm and pore size of 3.9 nm. Sorafenib (SFN) and/or brequinar (BQR) were loaded into the mesopores of MSPION, generating SFN@MSPION, BQR@MSPION and SFN/BQR@MSPION with high DLC of 11.5% (SFN), 10.1% (BQR) and 10.0% (SNF + BQR), demonstrating that our MSPION is a generic DDS. SFN/BQR@MSPION can be used for high performance ferroptosis therapy of tumors because: (1) the released Fe2+/3+ in tumor microenvironment (TME) can produce •OH via Fenton reaction; (2) the released SFN in TME can inhibit the cystine/glutamate reverse transporter, decrease the intracellular glutathione (GSH) and GSH peroxidase 4 levels, and thus enhance reactive oxygen species and lipid peroxide levels; (3) the released BQR in TME can further enhance the intracellular oxidative stress via dihydroorotate dehydrogenase inhibition. The ferroptosis therapeutic mechanism, efficacy and biosafety of MSPION-based DDS were verified on tumor cells and tumor-bearing mice.

Synergistic chemo-photodynamic therapy based on hollow mesoporous organosilica nanoparticles for reducing psoriasis-like inflammation

Psoriasis is a prevalent chronic inflammatory and proliferative skin condition characterized by its tendency for recurrence, prolonged duration, and challenging treatment. The most commonly employed treatment approach in clinical practice involves methotrexate (MTX)-based systemic therapy. However, long-term oral intake of MTX is associated with numerous side effects, ranging from induced liver and kidney toxicity to severe cases of bone marrow suppression. To reduce the incidence of adverse reactions, the topical application of nano-drug delivery systems by modifying MTX might potentially prove beneficial. This study introduces a novel chemo-photodynamic therapy approach utilizing hollow mesoporous silica nanoparticles (MTX@HMN-Ce6-HA) loaded with methotrexate (MTX) (loading: 78 %) and chlorine e6 (Ce6) (loading: 80 %). These nanoparticles generate reactive oxygen species (ROS) under light conditions, which aid in breaking the disulfide bond in the silica nanoparticles to release MTX and encapsulated hyaluronic acid (HA), thereby enhancing the permeability of the nanomaterials. The efficacy of this approach was evaluated at both cellular and animal levels. MTX@HMN-Ce6@HA demonstrated significant reductions in HaCaT cell viability, induction of cell apoptosis, and inflammation reduction by modulating the mitochondrial apoptosis pathway and STAT3-NF-κB p65 pathway. Importantly, this strategy synergistically treats psoriasis showing enhanced therapeutic efficacy by combining MTX chemotherapy with Ce6 phototherapy. In summary, MTX@HMN-Ce6@HA demonstrated powerful therapeutic efficacy against psoriasis-like skin inflammation without displaying any noticeable toxic effects. This finding could serve as a theoretical foundation and experimental validation for the topical treatment of psoriasis.

Engineered Multi-Shelled hollow mesoporous organosilica for efficient Pb(II) and Cr(VI) removal

Adsorbents with fast kinetics and high capacity have always been attractive for wastewater treatment. Herein, multi-shelled hollow mesoporous organosilica functionalized by hydroxyphosphatoethyl groups on dual-pore surfaces (P-HMO) is prepared by general one-pot co-condensation. The resulting P-HMO exhibits high hydrophilicity, large surface area and well-developed pore structure, providing P-HMO fast adsorption kinetics (C0 = 320 mg·L-1, equilibrium within 5 min) and ultrahigh adsorption efficiency for Pb(II) and Cr(VI), the adsorption capacity reaches 1056.53 and 869.56 mg·g−1, respectively. Furthermore, P-HMO displays outstanding reusability over 10 adsorption–desorption cycles thanks to the stable framework structure that can resist wear and tear during water treatment. The advantages of long service life, high efficiency and broad pH range make P-HMO promising in industrial water purification.

A Pioglitazone Nanoformulation Designed for Cancer-Associated Fibroblast Reprogramming and Cancer Treatment.

The recent focus of cancer therapeutics research revolves around modulating the immunosuppressive tumor microenvironment (TME) to enhance efficacy. The tumor stroma, primarily composed of cancer-associated fibroblasts (CAFs), poses significant obstacles to therapeutic penetration, influencing resistance and tumor progression. Reprogramming CAFs into an inactivated state has emerged as a promising strategy, necessitating innovative approaches. This study pioneers the design of a nanoformulation using pioglitazone, a Food and Drug Administration-approved anti-diabetic drug, to reprogram CAFs in the breast cancer TME. Glutathione (GSH)-responsive dendritic mesoporous organosilica nanoparticles loaded with pioglitazone (DMON-P) are designed for the delivery of cargo to the GSH-rich cytosol of CAFs. DMON-P facilitates pioglitazone-mediated CAF reprogramming, enhancing the penetration of doxorubicin (Dox), a therapeutic drug. Treatment with DMON-P results in the downregulation of CAF biomarkers and inhibits tumor growth through the effective delivery of Dox. This innovative approach holds promise as an alternative strategy for enhancing therapeutic outcomes in CAF-abundant tumors, particularly in breast cancer.

Transition Metal Ru(II) Catalysts Immobilized Nanoreactors for Conditional Bioorthogonal Catalysis in Cells.

Employing transition metal catalysts (TMCs) to perform bioorthogonal activation of prodrugs and pro-fluorophores in biological systems, particularly in a conditional fashion, remains a challenge. Here, we used a mesoporous organosilica nanoscaffold (RuMSN), which localizes Ru(II) conjugates on the pore wall, enabling the biorthogonal photoreduction reactions of azide groups. Due to easily adjustable surface charges and pore diameter, this efficiently engineering RuMSN catalyst, with abundant active sites on the inner pore well, could spontaneously repel or attract substrates with different molecular sizes and charges and thus ensure selective bioorthogonal catalysis. Depending on it, engineering RuMSN nanoreactors showed fascinating application scales from conditional bioorthogonal activation of prodrugs and pro-fluorophores in either intra- or extracellular localization to performing intracellular concurrent and tandem catalysis together with natural enzymes.

Cobalt and nitrogen co-modified hollow periodic mesoporous organosilica spheres for selective oxidation of aryl alkanes

Hollow periodic mesoporous organosilica spheres (HPMOs) have stimulated great research interest owing to its unique organic–inorganic hybrid skeleton. In this work, HPMOs were synthesized by hydrothermal method, and then cobalt and nitrogen co-doped carbon catalyst was prepared by using HPMOs as supports. The optimal catalyst (Co-Nx/HPMOs-D) performed excellent activity in the selective oxidation reaction of aryl alkanes, with the conversion of ethylbenzene up to 97.0% and the selectivity of acetophenone was 98.9%, which was attributed to the Co-Nx active species and the unique HPMOs supports. The unique amphiphilic property of Co-Nx/HPMOs-D could better facilitate the adsorption and diffusion of organic substrates in the aqueous phase. The addition of dicyandiamide not only enhanced the nitrogen content in the catalyst, but also promoted the conversion of pyrrolic-N to pyridinic-N during the pyrolysis process, thus strengthened the interaction between the substrate and cobalt and improved the stability of the catalyst. This work presented a green and environmentally friendly method for the preparation of HPMOs and a facile strategy to obtain high performance catalysts for selective oxidation of aryl alkanes.

High-sensitive detection of H2O2 in biological systems by persistent luminescent nanoprobes

Autofluorescence interference in the conventional fluorescence detection of hydrogen peroxide (H2O2) in biological systems represents a long-lasting problem in the field of biosensing. Here, we report a Cr3+, Y3+ co-doped ZnGaSnO4 (ZGSCY) nanoprobes which show long persistent luminescence (PL) that can be specifically enhanced by H2O2 without background fluorescence interference. The mesoporous organosilica are coated on the surface of ZGSCY to enhance the biocompatibility of the nanoprobes. Importantly, PL intensity of the nanoprobes can be further improved, because of the specific response of tetrasulfide bond in organosilica to H2O2. ZGSCY@MON show high-sensitive detection of H2O2 in living cells and human serum with the advantages of high specificity, low detection limit (91 nM), and wide linear range (0.5–60 μM, 60–400 μM). Furthermore, the extraordinary detection capability of H2O2 enables that the successful differentiate normal breast cells from breast cancer cells and the highly sensitive determination of serum glucose and cholesterol. We also clarified that the endogenous response originates from the UV-induced the interfacial electron transfer on ZGSCY regulated by H2O2 and exogenous response stems from the elimination of the adsorption of PL from the organosilica by H2O2. These findings open up a new effective way for autofluorescence-free detection of H2O2 in biological systems.

Lactic acid responsive sequential production of hydrogen peroxide and consumption of glutathione for enhanced ferroptosis tumor therapy

Ferroptosis is characterized by the lethal accumulation of lipid reactive oxygen species (ROS), which has great potential for tumor therapy. However, developing new ferroptosis-inducing strategies by combining nanomaterials with small molecule inducers is important. In this study, an enzyme-gated biodegradable natural-product delivery system based on lactate oxidase (LOD)-gated biodegradable iridium (Ir)-doped hollow mesoporous organosilica nanoparticles (HMONs) loaded with honokiol (HNK) (HNK@Ir-HMONs-LOD, HIHL) is designed to enhance ferroptosis in colon tumor therapy. After reaching the tumor microenvironment, the outer LOD dissociates and releases the HNK to induce ferroptosis. Moreover, the released dopant Ir4+ and disulfide-bridged organosilica frameworks deplete intracellular glutathione (GSH), which is followed by GSH-mediated Ir(IV)/Ir(III) conversion. This leads to the repression of glutathione peroxidase 4 (GPX4) activity and decomposition of intratumoral hydrogen peroxide (H2O2) into hydroxyl radicals (•OH) by Ir3+-mediated Fenton-like reactions. Moreover, LOD efficiently depletes lactic acid to facilitate the generation of H2O2 and boost the Fenton reaction, which in turn enhances ROS generation. With the synergistic effects of these cascade reactions and the release of HNK, notable ferroptosis efficacy was observed both in vitro and in vivo. This combination of natural product-induced and lactic acid-responsive sequential production of H2O2 as well as the consumption of glutathione may provide a new paradigm for achieving effective ferroptosis-based cancer therapy.

A Biodegradable Nanosuspension Locally Used for Inhibiting Postoperative Recurrence and Brain Metastasis of Breast Cancer.

Addressing the urgent need to prevent breast cancer postoperative recurrence and brain metastasis, Fe-metal organic framework (MOF)-coated hollow mesoporous organosilica nanoparticles (HMON) with tumor microenvironment dual-responsive degradability were prepared to encapsulate doxorubicin (DOX), formulating a tissue-adhesive nanosuspension for perioperative topical medication. This nanosuspension can not only retain the sustainably released drug in the postoperative residual tumor sites but also enhance the intracellular oxidative stress of tumors for remarkable tumor ferroptosis. Interestingly, the nanosuspension can act as an immune amplifier, which could not only stimulate DC cells to secrete chemokines for T cell recruitment but also elevate antigen exposure to facilitate the antigen presentation in lymph nodes. Thus, this nanosuspension could significantly activate antitumor immune responses in both in situ tumors and metastatic encephaloma for enhanced immunotherapy. In conjunction with the clinical PD-1 antibody, the locally administered nanosuspension could achieve an advanced therapeutic outcome for inhibiting postoperative recurrence and metastasis.

Confinement and Polarity Effects on the Peptide Packing Density on Mesoporous Silica Nanoparticles.

The adsorption of cationic peptide JM21 onto different mesoporous silica nanoparticles (MSNs) from an aqueous solution was studied as a function of pH. In agreement with the literature, the highest loading degrees could be achieved at pH close to the isoelectric point of the peptide where the peptide-peptide repulsion is minimum. However, mesopore size, mesopore geometry, and surface polarity all had an influence on the peptide adsorption in terms of both affinity and maximum loading at a given pH. This adsorption behavior could largely be explained by a combination of pH-dependent electrostatic interactions and confinement effects. It is demonstrated that hydrophobic interactions enhance the degree of peptide adsorption under pH conditions where the electrostatic attraction was absent in the case of mesoporous organosilica nanoparticles (MONs). The lower surface concentration of silanol groups for MON led to a lower level of peptide adsorption under optimum pH conditions compared to all-silica particles. Finally, the study confirmed the protective role of MSNs in preserving the biological activity of JM#21 against enzymatic degradation, even for large-pore MSNs, emphasizing their potential as nanocarriers for therapeutic peptides. By integrating experimental findings with theoretical modeling, this research elucidates the complex interplay of factors that influence peptide-silica interactions, providing vital insights for optimizing peptide loading and stabilization in biomedical applications.

Tailoring pore size of mesoporous silica and organosilica using biodegradable pentablock copolymer templates via EISA process

In this work, we have designed unique 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) pentablock copolymers using Pluronic F68 and F108 triblock copolymers as macroinitiators. The poly(lactic acid-co-glycolic acid) (PLGA) blocks were attached as glycolide and lactide monomers at the both ends of each F68 and F108 triblock copolymer. The molecular weights and the block fractions were confirmed by gel permeation chromatography (GPC) and proton nuclear magnetic resonance (1H NMR) for the four kinds of pentablock copolymers. Using these pentablock copolymers as templates, we synthesized mesoporous ethane-silicas as well as silicas by the evaporation-induced self-assembly (EISA) method. 1,2-bis(triethoxysily)ethane (BTEE) were used as an organosilica precursor. The mesoporous ethane-silica samples were characterized using synchrotron small angle X-ray scattering (SAXS), nitrogen sorption experiments, transmission electron microscopy (TEM), and solid-state 29Si CP-MAS NMR. Based on the experimental results, it was confirmed that the porosity and pore diameter can be varied with the PLGA weight fraction of the pentablock copolymer. It is due to the PLGA block in polymer forming the hydrophobic domain in micelles, which leads to the formation of increased pore size over 20 nm without any additive pore expander. In addition, it seems that as the organosilica precursor increases, the association number of block copolymers forming one micelle decreases, resulting in a decrease in pore size. In summary, the polymer template plays a vital part in tuning the structure of the mesoporous ethane-silica samples. Thus, the development of synthetic method of mesoporous organosilica materials using polymer templates with different topology is still challenging and can endow the unique structure and property for mesoporous organosilica for future applications.

Amine-containing yolk-shell structured magnetic organosilica nanocomposite as a highly efficient catalyst for the Knoevenagel reaction.

The yolk-shell structured silica nanocomposites have been considered by many researchers due to their specific physical and chemical properties. These materials have been widely used in adsorption and catalysis processes. Especially, the void space of yolk-shell nanostructures can provide a unique environment for storage, compartmentation, and confinement in host-guest interactions. In this paper, for the first time, the preparation, characterization, and catalytic application of a novel amine-containing magnetic methylene-based periodic mesoporous organosilica with yolk-shell structure (YS-MPMO/pr-NH2) are developed. The magnetic periodic mesoporous organosilica nanocomposite was synthesized through surfactant-directed co-condensation of bis(triethoxysilyl)methane (BTEM) and tetraethoxysilane around Fe3O4 nanoparticles. After Soxhlet extraction, the surface of YS-MPMO nanocomposite was modified with 3-aminopropyl trimethoxysilane to deliver YS-MPMO-pr-NH2 nanocatalyst. This catalyst was characterized by using EDX, FT-IR, VSM, TGA, XRD, nitrogen-sorption, and SEM analyses. The catalytic activity of YS-MPMO/pr-NH2 was studied in the Knoevenagel reaction giving the corresponding products in a high yield and selectivity. The YS-MPMO/pr-NH2 nanocatalyst was recovered and reused at least four times without a significant decrease in efficiency and activity. A leaching test was performed to study the nature of the catalyst during reaction conditions Also, the catalytic performance of our designed nanocomposite was compared with some of the previous catalysts used in the Knoevenagel reaction.

Kinetic Insights into Bridge Cleavage Pathways in Periodic Mesoporous Organosilicas.

Bridging functionalities in periodic mesoporous organosilicas (PMOs) enable new functionalities for a wide range of applications. Bridge cleavage is frequently observed during anneals required to form porous structures, yet the mechanism of these bridge cleavages has not been completely resolved. Here, these chemical transformations and their kinetic pathways on sub-millisecond timescales induced by laser heating are revealed. By varying anneal times and temperatures, the transformation dynamics of bridge cleavage and structural transformations and their activation energies are determined. The structural relaxation time for individual reactions and their effective local heating time are determined and compared, and the results directly demonstrate the manipulation of different molecules through kinetic control of the sequence of reactions. By isolating and understanding the earliest stage of structural transformations, this study identifies the kinetic principles for new synthesis and post-processing routes to control individual molecules and reactions in PMOs and other material systems withmulti-functionalities.

PH-responsive degradable mesoporous organosilica nanoparticle for tumor targeting and phototherapy combined with chemotherapy

In the context of the tumor microenvironment, the design of a high concentration glutathione (GSH) driven degradation drug delivery system (ID@MON-HA) is according to a different quantity of GSH to normal tissues. This system involves loading doxorubicin (DOX) and new indocyanine green (IR820) onto mesoporous organosilica nanoparticles (MON). The disulfide linkages in MON are broken in response to high amounts of GSH in tumor cells, resulting in the degradation of the overall structure and preventing carrier accumulation. To connect the hyaluronic acid (HA) and the carrier with encapsulated drugs, a pH-sensitive Schiff based bond is utilized. Furthermore, MON specifically target to tumor sites due to the selective binding of HA to tumor cells that overexpress the CD44 receptor. Experiments have shown that increased GSH concentrations and pH levels below physiological can accelerate drug release. Additionally, in vitro cellular experiments have demonstrated that combining chemotherapy and phototherapy enhances the suppression of tumor cells (median inhibition concentration IC50 = 1.53 μg mL_1). These findings indicate that the study offers an acceptable approach for developing degradable nanoplatforms for tumor combination therapy.

Preparation of mesoporous silica and organosilica nanostructures functionalized with C2‐symmetric diol and their catalytic performance in diethylzinc addition to aromatic aldehydes

In this study, heterogenization of C2‐symmetric (1R,2R)‐1,2‐bis(4‐(3‐(triethoxysilyl)propyl)phenyl)ethane‐1,2‐diol compound and investigation of the effect of structural arrangements of nanocatalysts on catalytic activity were carried out. For this, bissilyl derivative of (1R,2R)‐1,2‐bis(4′‐bromophenyl)‐ethane‐1,2‐diol, named as C2‐BSi, was obtained by 2‐step synthesis. Then, mesoporous silica nanocatalysts C2‐BSi@SBA‐15 and C2‐BSi@MCM‐41 were synthesized by grafting of C2‐BSi onto SBA‐15 and MCM‐41, whereas mesoporous organosilica nanocatalysts C2‐BSi‐MON‐(a) and C2‐BSi‐MON‐(b) were synthesized by co‐condenzation of C2‐BSi and tetraethyl orthosilicate (TEOS). Structure determinations of synthesized organic substances were performed by 1H, 13C NMR, Fourier transform infrared (FT‐IR), polarimeter, and mass analysis, whereas the structural properties of heterogeneous catalysts C2‐BSi@SBA‐15, C2‐BSi@MCM‐41, C2‐BSi‐MON‐(a), and C2‐BSi‐MON‐(b) were determined by FT‐IR, X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA), and N2 sorption analyses. The catalytic activities of novel heterogenous materials were tested in the reaction of Ti‐promoted enantioselective diethylzinc addition to aromatic aldehydes. The effects of the structural arrangements of the prepared heterogeneous catalyst on the catalytic activity were examined and compared with the catalytic activity values of their homogeneous analog. According to the results, all catalysts catalyzed the reactions and afforded the corresponding products with high conversion (82–99%) but low enantioselectivity (rac‐7% ee). The conversion values in heterogeneous catalysis were higher than those in homogeneous catalysis. C2‐BSi‐MON‐(a) with the largest pore width stood out as the most effective catalyst (99% conversion, 7% ee). The findings from the catalytic activity experiments confirmed that the structural arrangement of the nanocatalysts has an effect on the performance of the catalysts in the reaction.

Light/glutathione-ignited nanobombs integrating azo and tetrasulfide bonds for multimodal therapy of colorectal cancer

Reactive chemical bonds are associated with the generation of therapeutic radicals and gases under internal-external stimuli, which are highly attractive for cancer treatments. However, designing multifunctional nanostructures that incorporate multiple chemical bonds remains a significant challenge. Herein, novel core–shell nanobombs integrating azo (NN) and tetrasulfide bonds (SSSS) have been constructed with sensitive ignition by both near-infrared (NIR) laser and tumor microenvironments (TME) for treating colorectal tumors. The nanobombs (GNR/AIPH@MON@PVP, GAMP) were prepared by the in-situ growth of tetrasulfide-contained mesoporous organosilica nanoshell (MON) on gold nanorods (GNR) as the photothermal initiator, the load of azo compound (AIPH) as the radical producer and polymer modification. Upon NIR irradiation, the GNR core exhibits stable and high photothermal effects because of the passivation of the MON shell, leading to the thermal ablation of cancer cells. Simultaneously, the local hyperthermia ignites AIPH to release alkyl radicals to cause extensive oxidative stress without oxygen dependence. Moreover, the MON shell can be gradually decomposed in a reduced environment and release therapeutic H2S gas because of the cleavage of SSSS bonds by the glutathione (GSH) overexpressed in TME, causing mitochondrial injury. Owing to multifunctional functions, the GAMP significantly inhibits the growth rate of tumors upon NIR irradiation and achieves the highest efficacy among treatments. Therefore, this study presents activatable nanoagents containing multiple chemical bonds and provides insights into developing comprehensive antitumor strategies.

Mesoporous organosilicas with highly-content tyrosine framework as extractive phases for non-steroidal anti-inflammatory drugs in aquatic media

BackgroundAttentions regarding ordered mesoporous silica materials (OMSs), with large specific surface areas and narrow pore size distribution, which are prepared via self-assembly techniques, have been raised in sorption, separation, and sample preparation. However, in order to extend and improve their applications, a functionalization step is required. Organic units can be anchored on the inner or outer surface as well as in the silica wall framework by co-condensation-, grafting-, and periodic mesoporous organosilica (PMO) preparation approaches. Apparently, by synthesizing PMO with extensive and flexible organic bridging groups within the mesoporous wall, an efficient extractive phase can be achieved. ResultsWe employed tyrosine amino acid to synthesize a PMO-based extractive phase. The FT-IR, 1H NMR, HR-ESI-MS, Low angle-XRD, TEM, FESEM, BET, and EDX-MAP analyses confirmed the successful synthesis of PMO within the salt-assisted templating method. A comprehensive study on sorption behavior of PMO was performed and its efficiency was evaluated against the grafting and co-condensation methods. Then, it was implemented to the pipette tip-micro solid phase extraction (PT-μ-SPE) of widely used non-steroidal anti-inflammatory drugs (NSAIDs) in water/wastewaters. Limits of detection and quantification were obtained in the range of 0.1–1.5 and 0.3–5 μg L−1, respectively. The calibration plots are linear in the 1–1000, 3–1000, 10–750, and 3–750 μg L−1, respectively. The intra-and inter-day precision at 50 and 200 μg L−1 levels are 2.9–7.1 % and 3.5–8%, while recoveries are between 84 and 111 %. SignificanceHigh-capacity tyrosine functionalized PMO with 2D hexagonal symmetry silica mesoporous structures found to be highly efficient extractive media. Despite the bulkiness and flexibility of the bridging group within the mesoporous wall, the synthesis condition was optimized in order to load more organic content in the PMO structure. The PMO performance was superior over organically modified ordered mesoporous silica materials prepared by the grafting and co-condensation methods.