Dendritic Mesoporous Silica Research Articles

Silica nanoparticle conjugation with gallic acid towards enhanced free radical scavenging capacity and activity on osteosarcoma cells in vitro.

Gallic acid (GA), derived from land plants, possesses diverse physiological benefits, including anti-inflammatory and anticancer effects, making it valuable for biomedical applications. In this study, GA was used to modify the surface of dendritic mesoporous silica nanoparticles (DMSNs) via carbamate (DMSN-NCO-GA) or amide (DMSN-NH-GA) bonds, using a post-grafting technique. To explore GA-conjugated materials' potential in modulating cancer cell redox status, three variants of osteosarcoma cells (U2-OS) were used. These variants comprised the wild-type cells (NEO), the cells overexpressing the wild-type human Golgi anti-apoptotic protein (hGAAP), and the null mutant of hGAAP (Ct-mut), as this protein was previously demonstrated to play a role in intracellular reactive oxygen species (ROS) accumulation and cell migration. In the absence of external ROS triggers, non-modified DMSNs increased intracellular ROS in Ct-mut and NEO cells, while GA-conjugated materials, particularly DMSN-NH-GA, significantly reduced ROS levels, especially pronounced with higher GA concentrations and notably in hGAAP cells with inherently higher ROS levels. Additionaly, NH-GA conjugates were less cytotoxic, more effective in reducing cell migration, and had higher ROS buffering capacity compared to DMSN-NCO-GA materials. However, in the presence of the external stressor tert-butyl-hydroperoxide (TBHP), NCO-GA conjugates showed more efficient reduction of intracellular ROS. These findings suggest that varying chemical decoration strategies of nanomaterials, along with the accessibility of functional groups to the cellular environment, significantly influence the biological response in osteosarcoma cells. Highlighting this, GA-conjugation is a promising method for implementing antioxidant properties and inhibiting cancer cell migration, warranting further research in anticancer treatment and drug development.

Amine-Impregnated Dendritic Mesoporous Silica for the Adsorption of Formaldehyde.

To adsorb and remove formaldehyde, which is a harmful volatile organic chemical (VOC) detected indoors, an alkylamine was introduced into the substrate as a formaldehyde adsorbent. In this study, Tetraethylenepentaamine (TEPA) was introduced into the mesoporous silica using the amine impregnation method. Since the impregnated alkylamine can block the pores of the silica substrate, the pore size and pore volume are very important factors for its use as a substrate for an adsorbent. Focusing on the substrate's pore properties, Santa Barbara Amorphous-15 (SBA-15) was chosen as a conventional one-dimensional pore-structured mesoporous silica, and dendritic mesoporous silica (DMS) as a three-dimensional pore-structured mesoporous silica. To 1 g each of silica substrate DMS and SBA-15, 0, 0.5, 1.5, and 2.5 g of TEPA were introduced. A fixed concentration and amount of formaldehyde gas was flowed through the adsorbent and then the adsorbent was changed to the 2,4-Dinitrophenylhydrazine (2,4-DNPH) cartridge to adsorb the remaining formaldehyde. According to the methods recommended by the World Health Organization (WHO) and National Institute for Occupational Safety & Health (NIOSH), the formaldehyde captured by 2,4-DNPH was analyzed using high-performance liquid chromatography (HPLC). A comparison of DMS and SBA-15 in the amine impregnation method shows that not only surface area, but also large pore size and high pore volume, contribute to the formaldehyde adsorption ability.

Homogeneous fluorescence immunoassay based on AuNPs quenching dendritic silica assembled with multicolor QDs for the simultaneous determination of four mycotoxins in cereals

In this work, a novel homogeneous fluorescence immunoassay for the simultaneous detection of ochratoxin A (OTA), aflatoxin B1 (AFB1), fumonisins B1 (FB1), and zearalenone (ZEN) in cereal samples is established. Here, amino groups and thiol groups are grafted onto the surface of dendritic mesoporous silica nanoparticles (DMSNs) to improve loading rate and fluorescence preservation rate of quantum dots (QDs), enabling enrichment and amplification of fluorescence signals. In this test system, the fluorescence of the signal probe (DMSNs@QDs@Ab) is quenched by AuNPs, and then the presence of the targets makes the fluorescence of the signal probes recover. The correlation between the recovered fluorescence value and mycotoxin concentration is applied to achieve quantitative detecting mycotoxins. This assay displays good linear correlation in range of 0.01–100 μg L-1, with the limit of detection (LOD) of 0.0001 μg L-1 for OTA, 0.0008 μg L-1 for AFB1, 0.001 μg L-1 for FB1, and 0.0006 μg L-1 for ZEN, respectively. The proposed assay is applied to detect multiple mycotoxins in contaminated cereal samples and the test results is confirmed by liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Avail of silica with high loading capacity for assembling multicolor QDs to achieve simultaneous multi-signal output, a simple and efficient homogeneous fluorescence immunoassay is proposed for the first time. This multiplex test strategy provides a good idea for simultaneous, rapid, and sensitive detection of multiple hazardous substances in food and environment samples.

A bubble-enhanced lanthanide-doped up/down-conversion platform with tumor microenvironment response for dual-modal photoacoustic and near-infrared-II fluorescence imaging

As an important tumor diagnosis strategy in precision medicine, multimodal imaging has been widely studied. However, the weak imaging signal with low spatial resolution and the constant signal of lack of specific activation severely limit its disease diagnosis. Herein, a bubble-enhanced lanthanide-based up/down-conversion platform with tumor microenvironment response for dual-mode imaging, LDNP@DMSN-Au@CaCO3 nanoparticles (named as LDAC NPs) were successfully developed. Combining the advantages of photoacoustic imaging (PAI) and the second near-infrared window (NIR-II) fluorescence imaging (FI), significantly improved the accuracy of diseases diagnosis. LDAC NPs with flower-like structure were synthesized through the encapsulation of uniform lanthanide-doped nanoparticles (NaYbF4:Ce,Er@NaYF4 named LDNPs) with dendritic mesoporous silica (DMSN). The gold nanoparticles (Au NPs) were then in situ grown on the surface of DMSN and the surface were finally coated with a layer of calcium carbonate (CaCO3). Under the excitation of the 980 nm laser, LDNPs showed strong emission of NIR-II at 1550 nm due to the doping of Ce and Er ions, showcasing excellent spatial resolution and deep tissue penetration characteristics, while the resulting visible light emission (540 nm) enables Au NPs to generate PAI signals with the aid of LDNPs via the fluorescence resonance energy transfer effect. In acidic tumoral environment, CaCO3 layer could produce CO2 microbubbles, and the PAI signals of LDAC NPs could be further enhanced with the generation of CO2 bubbles due to the bubble cavitation effect. Simultaneously, the NIR-II FI of LDAC NPs was self-enhanced with the degradation of the CaCO3. This intelligent nanoparticle with stimulus-activated dual-mode imaging capability holds great promise in future precision diagnostics.

In Situ Synthesis of Highly Fluorescent, Phosphorus-Doping Carbon-Dot-Functionalized, Dendritic Silica Nanoparticles Applied for Multi-Component Lateral Flow Immunoassay.

The sensitivity of fluorescent lateral flow immunoassay (LFIA) test strips is compromised by the low fluorescence intensity of the signaling molecules. In this study, we synthesized novel phosphorus-doped carbon-dot-based dendritic mesoporous silica nanoparticles (DMSNs-BCDs) with a quantum yield as high as 93.7% to break this bottleneck. Meanwhile, the in situ growth method increased the loading capacity of carbon dots on dendritic mesoporous silica, effectively enhancing the fluorescence intensity of the composite nanospheres. Applied DMSNs-BCDs in LFIA can not only semi-quantitatively detect a single component in a short time frame (procalcitonin (PCT), within 15 min) but also detect the dual components with a low limit of detection (LOD) (carbohydrate antigen 199 (CA199) LOD: 1 U/mL; alpha-fetoprotein (AFP) LOD: 0.01 ng/mL). And the LOD of PCT detection (0.01 ng/mL) is lower by 1.7 orders of magnitude compared to conventional colloidal gold strips. For CA199, the LOD is reduced by a factor of four compared to LFIA using gold nanoparticles as substrates, and for AFP, the LOD is lowered by two orders of magnitude compared to colloidal gold LFIA. Furthermore, the coefficients of variation (CV) for intra-assay and inter-assay measurements are both less than 11%.

Monodisperse dendritic micro-mesoporous composite self-assembled with tiny TS-1 seeds as efficient catalysts for hydrodesulfurization of dibenzothiophenes

Novel TS-1/dendritic mesoporous silica nanoparticles (TS-1/DMSNs, TD) micro-mesoporous composites with different morphology were prepared for NiMo catalysts (NiMo/TD-TEA). Series catalysts were tested in dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) hydrodesulfurization (HDS) reactions in a fix-bed reactor. TS-1 were uniformly compounded with mesoporous materials in the form of Si-O-Ti bonds, which did not affect the typical dendritic morphology. The introduction of TEA could inhibit the growth of support particles, and modulate the acidity and the metal-support interaction (MSI) of catalysts. Optimized NiMo/TD-TEA catalyst showed the optimal DBT (98.0 %) and 4,6-DMDBT (92.3 %) desulfurization rate as well as the excellent hydrogenation (HYD) selectivity for DBT and 4,6-DMDBT HDS with the optimal reaction rate constant (12.2 mol·g−1·h−1, 6.7 mol·g−1·h−1) and turnover frequency (2.3 h−1, 1.4 h−1). By correlating to the catalyst acidity–activity and active phase–activity, the activity and selectivity were not only depended on the presence of Brønsted (B) acid and the total acid content but also associated with the dispersion and morphology of MoS2 slabs.

Magnetic dendritic mesoporous silica nanoparticles based integrated platform for rapid and efficient analysis of saccharides

BackgroundAs an essential compound in living organism, saccharides have attracted enormous attentions from scientists in various fields. Understanding the distribution of saccharides in various samples is of great scientific importance. However, the low signal response and lack of specific recognition technology of saccharides and the complex matrix of samples make the analysis of saccharides a very challenge task. Thus, the development of a simple and straightforward strategy for the analysis of saccharides would represent a great contribution to the field. ResultsIn this study, by employing the sulfonyl functionalized magnetic dendritic mesoporous silica nanoparticles as the substrate, we develop an integrated platform for analysis of saccharides. The construction of the platform mainly relied on multi-functional boronic acid, which serves as separation and derivation ligands at the same time. In the general procedure, the boronic acid is first immobilized onto the surface of substrate, then the selective enrichment of saccharides can be realized via boronate affinity separation. Finally, by the rational choice of the solution, we are able to elute the labelled complex (boronic acid-saccharide) from the substrate, which can be direct subjected to HPLC-UV analysis. The reliable precision (<15 %), accuracy (80–100 %), reproducibility (<10 %), improved sensitivity (20x) and limited time-consuming (down to minutes) of the proposed platform are experimentally demonstrated. Significance and noveltyThe successful quantification of different saccharides (alditols, glucose) in real samples is achieved. The proposed strategy is not only straightforward and fast, but also avoid the requirement of special equipment. With these attractive features, we believe that this strategy will greatly prompt the analysis of saccharides in various samples (eg. food, pharmaceutics and biosamples).

Synergistic reinforcement of immunogenic cell death and transformation of tumor-associated macrophages via an M1-type macrophage membrane-camouflaged ferrous-supply-regeneration nanoplatform

The immune system's role in tumor growth and spread has led to the importance of activating immune function in tumor therapy. We present a strategy using an M1-type macrophage membrane-camouflaged ferrous-supply-regeneration nanoplatform (M1mDDTF) to synergistically reinforce immunogenic cell death (ICD) and transform tumor-associated macrophages (TAMs) against tumors. The M1mDDTF nanoparticles consist of doxorubicin-loaded dendritic mesoporous silica nanoparticles chelated with FeIII-tannic acid (FeIIITA) and coated with M1-type macrophage membranes. In the acidic tumor microenvironment, FeIIITA releases Fe2+ and generates ·OH, aided by near infrared irradiation for enhanced doxorubicin release. Furthermore, the M1mDDTF nanoplatform not only directly kills tumor cells but stimulates ICD, which can increase the proportion of CD86+ CD80+ cells and promote dendritic cell maturation. Particularly, the M1mDDTF nanoplatform can also promote the gradual polarization of TAMs into the M1-type and promote tumor cell killing. This study demonstrates the safety and multifunctionality of M1mDDTF nanoparticles, highlighting their potential for clinical tumor treatment. Statement of significanceMalignant tumors are a global concern and a major cause of death. Nanoparticles' passive targeting is ineffective and hindered by reticuloendothelial system clearance. Therefore, enhancing nanoparticle accumulation in tumors while minimizing toxicity is a challenge. Coating nanoparticles with cell membranes enhances biocompatibility, immune evasion, and specific targeting. This approach has led to the development of numerous cell membrane-mimicking nanomaterials with remarkable properties and functions. This study developed an M1-type macrophage membrane-camouflaged ferrous-supply-regeneration nanoplatform, boosting immunogenic cell death and transforming tumor-associated macrophages. Tannic acid in the tumor microenvironment reduced Fe3+ to Fe2+, generating ·OH. M1mDDTF nanosystem induced M1-type macrophage polarization, inhibiting tumor growth and triggering immune cell death. Safe and versatile, these M1mDDTF nanoparticles hold promise for clinical tumor treatment.

Co‐delivery of Curcumin and Doxorubicin Using a pH‐photothermal Dual‐responsive and CD44‐targeted Nanocarrier for Enhanced Chemo‐photothermal Synergistic Tumor Treatment

AbstractIn this study, we have developed a novel approach for synergistic tumor treatment by utilizing degradable dendritic mesoporous silica nanoparticles loaded with doxorubicin and curcumin (Cur). These nanoparticles are equipped with polydopamine (PDA) for photothermal therapy and hyaluronic acid (HA) as a targeting ligand. The incorporation of PDA not only ensures the controlled release of therapeutic agents but also confers pH and photothermal responsiveness to the nanocarriers. Cur, a natural compound, serves as an antitumor sensitizer, elevating intracellular ROS levels to promote apoptosis. In addition, the excellent biocompatibility and targeting property of nanocarriers were enhanced by the HA‐modification, improving the effective accumulation in tumor cells. Comprehensive research including MTT assay, live/dead staining and ROS generation proved that the excellent antitumor capability of dual‐drug loaded nanocarriers was a result of chemo‐photothermal synergistic therapy and Cur‐induced cellular amplified ROS generation. The cellular uptake assays further demonstrated the efficiency of HA‐mediated intracellular accumulation, accelerated uptake driven by photothermal‐induced and a precise internalization pathway of nanocarriers. Furthermore, the results of in vivo biocompatibility revealed no significant blood and organ toxicity associated to the prepared nanocarriers. Our findings underscore the substantial potential of the proposed dual‐drug loaded nanocarriers for chemo‐photothermal synergistic therapy, offering a safe and promising strategy for effective tumor treatment.

Developing magnetic functionalized dendritic fibrous mesoporous silica as advanced adsorbent for quaternary ammonium alkaloids.

Anovel π-conjugated polymer-modified magnetic dendritic fibrous mesoporous silica adsorbent (MB@KCC-1@π-CP) is reportedfor the accurate determination of quaternary ammonium alkaloids (QAAs) in complex body fluid matrices. It is demonstrated that the magnetic dendritic fibrous mesoporous silica (MB@KCC-1) is an excellent carrier combining magnetism, high specific surface area, unique hierarchical pore structure, and fast mass transfer rate. The π-conjugated polymer (π-CP) can efficiently retain QAAs (berberine, coptisine, palmatine, jatrorrhizine) by multiple interactions. In addition, the adsorption kinetics and adsorption mechanism were also studied and discussed. Under optimized extraction conditions, MB@KCC-1@π-CP-based magnetic solid-phase extraction (MSPE) and high-performance liquid chromatography (HPLC) method affords a wide linear range (0.5-20000ngmL-1), low limits of detection (0.2-2ngmL-1), and satisfactory relative standard deviations (RSD) of inter-day (< 2.4%) and intra-day (< 3.1%) for QAAs. Trace QAAs in complex human blood plasma samples were successfully detected by the established method.

Synergistic effect of silanols in mesopores leading to unexpected catalysis of dendritic mesoporous silica particles in the aqueous-phase synthesis of 5-hydroxymethylfurfural from fructose

Synthesis of 5-hydroxymethylfurfural (5-HMF) from fructose in water over acids catalysts usually produces unsatisfactorily low yield and selectivity due to inevitable side reactions, i.e., rehydration and condensation. Unprecedentedly, these complications in the aqueous phase synthesis of 5-HMF could be overcome by dendritic mesoporous silica particles (DMSNs). In the hydrothermal reactions of fructose, it was discovered that the synergy of silanols and mesopores transformed seemingly inert DMSNs into active catalysts, leading to a fructose conversion and 5-HMF yield of over 90%. The silanols on DMSNs offered weak Brønsted acid sites for catalyzing the dehydration of fructose to 5-HMF, while undesired reactions were substantially prohibited. The presence of glucose in the reaction suggests that fructose converts to 5-HMF via the acyclic route, and the competing reaction is indeed the isomerization. As revealed experimentally, mesopores full of silanols promoted the conversion of fructose to 5-HMF, but mesopores with a few silanols were relatively hydrophobic, offering a preferential partitioning of 5-HMF in mesopores of DMSNs. DFT analysis theoretically supported that in the presence of silanols, transforming fructose to 5-HMF is thermodynamically more favorable than the isomerization of fructose to glucose.

CO2 hydrogenation to methanol over PdZn catalysts on bimetallic modified dendritic mesoporous silica nanospheres

Catalysts with the CeTi bimetallic modified dendritic mesoporous silica nanospheres (CTD) as supports, and the PdZn as active metal phase, PdZn/CTD catalysts with higher Pd metal dispersion and more oxygen vacancies were synthesized for efficient CO2 hydrogenation to methanol (MeOH). The modification of PdZn/CTD using CeTi metals can increase the dispersion of PdZn and improve the Ce3+/Ce4+ ratios. Higher active metal dispersion of PdZn/CTD catalyst is conducive to more H2 adsorption and to the expose of activation sites. Higher Ce3+/Ce4+ ratio of PdZn/CTD is beneficial to generate more oxygen vacancies, which can adsorb and activate CO2 molecules efficiently. The optimized PdZn/CTD catalysts exhibit superior CO2 conversion (33.6 %), MeOH selectivity (32.9 %), MeOH yield (11.1 %), TOF value (22.5 h−1), space–time yield (STY) (4.44 molMeOH kg-1 h−1) and 100 h long-term stability. Besides, through in-situ DRIFTS, HCOO* and CH3O* species are found to be the primary intermediates of the CO2 hydrogenation to MeOH reaction over the PdZn/CTD catalysts.

A coronavirus-mimic mesoporous silica nanosystem enables efficient targeted delivery of siRNA for anti-SARS-CoV‐2

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been a threat to human beings' health. However, there is still a lack of effective specific antiviral drugs for SARS-CoV-2 at present, which calls for the exploitation of new potent and safe therapeutic agents. Short-interfering RNA (siRNA), as a powerful RNA interference (RNAi) tool, can be designed to target virus-related genes and degrade them with high efficiency, presenting great potential for confronting SARS-CoV-2 infection. Despite the promises, effective delivery of synthetic siRNA into the virus-infected host cells for therapy remains a challenge. Herein, a SARS-CoV-2 spike (S) protein-decorated dendritic mesoporous silica nanoparticle (DMSN) was developed for targeted delivery of the RNA-dependent RNA polymerase (RdRp)-specific siRNA for anti-SARS-CoV‐2. The biocompatible DMSN with a large pore structure and surface area enabled the high siRNA loading and protected siRNA from nuclease-mediated degradation. On the basis of the specific binding between S protein and angiotensin-converting enzyme 2 (ACE2) receptor, the designed nanosystem could imitate coronavirus to target the host cells and promote the cellular internalization of siRNA. The results demonstrated that the designed siRNA delivery nanosystem showed an improved silencing effect on the transfected SARS-CoV-2 RdRp gene in the ACE2-overexpressed host cells. Moreover, such nanosystem could be inhaled and accumulated in the lung of living body through a nebulized administration, offering a promising treatment option for SARS-CoV‐2 infection.

Platinum-loaded dendritic mesoporous silica as novel ethylene scavenger to extend shelf life of banana (Musa nana).

Ethylene, released from fruits and vegetables (F&V) after harvest and during storage, often accelerates the ripening or over-ripening and may be caused decay, leading to substantial economic loss. Dendritic mesoporous silica supported (DMS) platinum (Pt/DMS) catalyst as ethylene scavenger was prepared and various characterization results indicated that the as-prepared Pt/DMS with ultra-low Pt loading exhibited excellent ethylene scavenging performance, which could maintain the complete ethylene conversion (100%) over 50h at 25°C and even 0°C for 100min with superior consecutive cycles by repeating the use of Pt/DMS. The presence of Pt/DMS delayed banana softening, and browning, reduced weight loss and kept the freshness for 14days. In conclusion, the active packaging incorporated with Pt/DMS catalysts with high ethylene scavenging efficiency is expected to be extremely beneficial to the post-harvest storage life of other fruits and vegetables that needs further related investigation.

Thin-Film Composite Membrane with Porous Interlayer Composed of Dendritic Mesoporous Silica Nanoparticles for Enhanced Nanofiltration.

Positively charged nanofiltration (NF) membranes show great potential in the fields of water treatment and resource recovery. However, this kind of NF membrane usually suffers from relatively low water permeance. Herein, a positively charged NF membrane with a porous interlayer is developed, where the interlayer is formed by assembling dendritic mesoporous silica nanoparticles (DMSNs) after the formation of a polyamide layer. This post-assembly strategy avoids the adverse effect of the interlayer on the formation of positively charged NF membranes. The porous DMSN interlayer provides abundant connected channels for water transport, thus endowing the NF membrane with enhanced water permeance. A series of DMSNs with different sizes was synthesized, and their influence on membrane formation and membrane performance was systematically investigated. The optimized membrane exhibits a CaCl2 rejection rate of 95.2% and a water flux of 133.6 L·h-1·m-2, which is 1.6 times that of the control group without an interlayer. This work represents an approach to the fabrication of a positively charged NF membrane with porous interlayers for high-efficiency cation rejection.

Enhanced Photocatalytic Degradation of Tetracycline-Class Pollutants in Water Using a Dendritic Mesoporous Silica Nanocomposite Modified with UiO-66

Enhanced Photocatalytic Degradation of Tetracycline-Class Pollutants in Water Using a Dendritic Mesoporous Silica Nanocomposite Modified with UiO-66

Clearing intratumoral bacteria to augment tumor-therapeutic response by engineering antimicrobial dendritic mesoporous silica nanomedicine

As an important component of the tumor microenvironment, the intratumoral bacteria can significantly reduce the chemotherapeutic response, in which Fusobacterium nucleatum has been established as the representative intratumoral bacteria in colorectal cancer, promoting chemotherapy resistance by activating autophagy pathways. Herein, the concept of antibacterial-augmented antitumor nanomedicine for pathogen-related cancer therapy was elaborated by designing antibacterial-antineoplastic nanoagents that modulate intratumoral bacteria to augment anticancer efficiency. A generic coordination-redox strategy was used for homogeneous in situ growth of antibacterial ultrasmall silver nanoparticles into the dendritic mesoporous silica nanoparticles, which were further loaded with chemotherapeutic drugs. The antibacterial-antineoplastic agents exhibited excellent antitumor efficacy by scavenging Fusobacterium nucleatum to modulate autophagy, thereby overcoming chemoresistance to heighten the therapeutic effect. This work proposes a conceptual framework of antibacterial-augmented antitumor nanomedicine for refined cancer-therapeutic efficacy by modulating intratumoral bacteria to enhance therapeutic responses of chemotherapy, opening new horizons on nanomedicine design for more effective tumor therapy.

Cerium doped dendritic mesoporous bioactive glass nanoparticles with bioactivity and drug delivery capability

Dendritic mesoporous bioactive glass nanoparticles (DMBGNs) with unique three-dimensional structures are attracting increasing attention for biomedical applications. However, it is still challenging to tune the chemical composition of DMBGNs. In this work, we provide for the first time a feasible post-impregnation approach to incorporate metallic ions (Ca and Ce) into dendritic mesoporous silica nanoparticles, resulting in SiO2-CaO and SiO2-CaO-CeO2 (Ce-DMBGNs) without destroying the dendritic mesoporous topography. Both DMBGNs and Ce-DMBGNs were amorphous, negatively charged, with a hydrodynamic size of ∼200 nm. The synthesized DMBGNs and Ce-DMBGNs exhibited high bioactivity as evidenced by the rapid formation of hydroxyapatite (HA) after immersion in simulated body fluid (SBF) for 7 days. In addition, DMBGNs and Ce-DMBGNs showed high propolis loading efficiency and sustained release behavior. The results suggest that the developed Ce-DMBGNs have the potential to be used as a delivery vehicle of therapeutic ions and drugs in bone regeneration applications.

Dendritic micro-mesoporous composites via nano-assembly strategy towards high-efficiency catalysts for hydrodesulfurization of dibenzothiophenes

Based on the three-dimensional center-radial framework structure of dendritic mesoporous silica nanospheres (DMSNs), a unique type of hierarchical micro-mesoporous composite material, namely, Beta-DMSNs (BD) was prepared through a nano-assembly method, which was utilized as superior supports for high-efficiency catalysts (NiMo/BD) for hydrodesulfurization (HDS) of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT). The controllable introduction of Beta nanocrystals endows the NiMo/BD catalysts with more acidic and catalytic active sites, and shows no influence on the dendritic morphology of the mesoporous supports, resulting in the remarkable HDS performance of NiMo/BD catalysts. Owing to the dendritic open channels, high surface area, abundant acidic sites and highly dispersed MoS2 active phases, the optimized NiMo/BD exhibited superior HDS activities of 99.1% and 98.3% for DBT and 4,6-DMDBT, respectively, with the optimal reaction rate constant of 3.0 × 10−7 mol g−1 s−1 and 2.4 × 10−7 mol g−1 s−1, and with the turnover frequency of 5.9 × 10−4 s−1 and 4.8 × 10−4 s−1. Besides, the enhanced Brønsted acid and the synergistic effect of Brønsted & Lewis acid contributed to the superior isomerization selectivity for 4,6-DMDBT, which was conducive to its HDS.

Consuming intracellular glucose and regulating the levels of O2/H2O2 via the closed cascade catalysis system of Cu-CeO2 nanozyme and glucose oxidase

Imbalances in the intracellular environment caused by high levels of glucose, H2O2, and hypoxia can greatly impact cancer development and treatment. However, there is limited research on regulating the levels of these species simultaneously in tumor cells. Here, a pH-responsive nanozyme-enzyme hybrid system was developed to regulate intracellular glucose, H2O2 and O2. The system, named DMSN@Cu-CeO2@GOx, consists of Cu-CeO2 nanoparticles and glucose oxidase (GOx) immobilized in dendritic mesoporous silica (DMSN) spheres. GOx efficiently consumes glucose in tumor cells, causing a drop in pH and producing a significant amount of H2O2. Cu-CeO2 then catalyzes the conversion of H2O2 to O2 due to its high catalase-like (CAT) activity in weakly acidic conditions. The process was monitored by fluorescence probes, and the mechanism was investigated through fluorescence spectroscopy and confocal laser scanning microscopy. The cascade catalytic system with excellent biocompatibility continuously consumes glucose and elevates the level of O2 in cells. This hybrid nanomaterial offers a means to regulate the glucose/H2O2/O2 levels in cells and may provide insights into starvation therapy by modulating reactive species within cells.