Mesoporous Silica Nanospheres Research Articles

Loading of g-C3 N4 on Core-Shell Magnetic Mesoporous Silica Nanospheres as a Solid Base Catalyst for the Green Synthesis of some Chromene Derivatives under Different Conditions.

Using heterogeneous basic catalysts has a great importance in chemical reactions because of their advantages (such as easy separation and thermal stability at harsh conditions) over homogeneous catalysts. In this study, magnetic mesoporous silica nanoparticles (mSiO2) containing graphitic carbon nitride layers (mSiO2/g‐C3N4(x)) were fabricated through a facile process (x signifies the amount of melamine applied during synthesis). Graphitic carbon nitride layers were decorated on mSiO2 by calcination of immobilized melamine (as graphitic carbon nitride precursor) on mSiO2 in the last step of catalyst synthesis. The structure of the prepared catalysts was confirmed using XRD, BET, FESEM, EDX, elemental mapping and TEM methods. The catalytic efficiency of the so‐obtained solid base composite was investigated for the synthesis of some dihydropyranochromenes and spiro‐dihydropyranochromenes under thermal and microwave conditions. Using mSiO2/g‐C3N4(x) led to high yields under green conditions and in short reaction times and without a decrease in catalytic activity after four consecutive cycles.

Confined Jet Impingement Continuous Microchannel Reactor Synthesis of Ultrahigh-Quality Mesoporous Silica Nanospheres for CO2 Capture

Li4SiO4 has been evaluated as one of the most promising CO2 absorbers to mitigate climate changes caused by excessive CO2 emissions. Li4SiO4 absorbents with a high specific surface area would hold higher CO2 capture capacity. However, with the lack of suitable SiO2 precursors, the synthesis of Li4SiO4 absorbents with a high specific surface area and a well-defined hollow sphere structure was still challenging. Here, a two-stream confined jet impingement continuous microchannel reactor was proposed to produce ultrahigh-quality mesoporous silica nanospheres (UHMSNs) with an ultrahigh specific surface area and a small particle size. The obtained UHMSNs possessed excellent water dispersibility, a uniform diameter (142–207 nm), tunable perpendicular mesopores (2.6–3.3 nm), a high surface area (1347∼1854 m2/g), and a large pore volume 0.86∼1.23 cm3/g). Moreover, MesoDyn simulation provided valuable information to optimize the nucleation stage and the crystallization stage of UHMSNs. Additionally, UHMSNs were used as the silicon source to synthesize the petal-like hollow structure of Li4SiO4 microspheres, which enhanced CO2 adsorption.

Engineering hollow mesoporous silica supported cobalt molybdate catalyst by dissolution-regrowth strategy for efficiently aerobic oxidative desulfurization

Heterogeneous catalysts show superior separable and recyclable property in comparison with homogeneous catalysts. However, the conventional synthetic method faces the problem of uneven distribution of active sites. Here, a facile dissolution-regrowth strategy was developed to prepare hollow mesoporous silica nanospheres supported cobalt molybdate (CoMoO4/HMS) under mild conditions, simultaneously, CoMoO4 was obtained in situ. The homogenous dispersion of the active species made the catalyst manifest an outstanding desulfurization efficiency in aerobic oxidative desulfurization compared with the supported single-metal oxides catalysts or supported CoMoO4 catalyst prepared by wet impregnation. The removal efficiency of three sulfur-containing substances, such as dibenzothiophene, 4-methyldibenzothiophene and 4,6-dimethyldibenzothiophene, could reach 100% by 5 h with molecular oxygen as an oxidant. Besides, the sulfur removal of DBT almost did not reduce after at least 8 cycles under the optimal reaction conditions. Through electron spin resonance spectroscopy and radical quenching experiments, O2− was determined as the main active oxygen species for sulfur oxidation. This dissolution-regrowth strategy can be used to prepare a series of supported multi-metal oxides for various applications.

Pt-NixOy heteroaggregate nanoparticles confined in hollow mesoporous silica nanospheres for enhanced hydrolysis of ammonia borane

In this work, Pt-NixOy heteroaggragate nanoparticles confined in hollow mesoporous silica nanospheres (Pt-NixOy@HMSNs) are synthesized in one-pot, which features Pt-NixOy hybrid nanoparticles inside hollow cavities of mesoporous silica nanospheres. Through adjusting the ratios of Pt2+/Ni2+ in micelles, Pt-NixOy@HMSNs with different Pt/Ni ratios are synthesized. The obtained materials were tested for hydrolysis of ammonia borane with detailed kinetic studies. Compared to Pt@HMSNs and Ni@HMSNs, Pt4-(NixOy)1/x@HMSNs show the enhanced performance in AB hydrolysis. The catalytic activity improvement is ascribed to the synergistic effect of Pt-NixOy and the void confinement, where the interfaces of Pt-NixOy greatly enhance the hydrolysis activity and the confinement of functional nanoparticles inside the central voids increases their structural and catalytic stability.

Magnetic solid-phase extraction based on modified magnetic meso-porous silica nanospheres for pre-concentration of trace amounts of gold/silver samples in the water and plant environment before analyzing by flame atomic absorption spectrometry

Magnetic solid-phase extraction based on modified magnetic meso-porous silica nanospheres for pre-concentration of trace amounts of gold/silver samples in the water and plant environment before analyzing by flame atomic absorption spectrometry

Pore architecture influences the enzyme immobilization performance of mesoporous silica nanospheres

Immobilized enzymes on silica nano-carriers are stable biocatalysts with the potential for use in a plethora of applications. Studying how the structural characteristics of silica nano-carriers influence the performance of immobilized enzymes allows for the optimization of performance. This work investigates the influence of the pore architecture of silica nanospheres on enzyme loading, release, and reusability. Compared to dendritic mesoporous silica nanospheres (DMSN) with funnel-shaped wide-open pores, fractal silica nanoparticles (FSN) have a far more complex pore structure. FSN showed significantly higher immobilization capacity, sustained release, and enhanced reusability towards two model enzymes. The knowledge gained from this work paves the way for the rational design of enzyme nano-carriers for various applications.

A Space-Time Conversion Vehicle for Programmed Multi-Drugs Delivery into Pancreatic Tumor to Overcome Matrix and Reflux Barriers.

The numerous biological barriers, which limit pharmacotherapy of pancreatic carcinoma, including inadequate drug accumulation in the tumor environment, a dense extracellular matrix (ECM) and efficient drug‐efflux mechanisms, illustrate the requirement of multifunctional delivery systems to overcome the individual barriers at the right place at the right time. Herein, a space–time conversion vehicle based on covalent organic framework (COF)‐coated mesoporous silica nanospheres (MSN) with a sandwiched polyethyleneimine (PEI) layer (MPCP), is designed. The space‐specific drugs‐loaded vehicle (MGPPCLP) is obtained by separately incorporating a chemotherapeutic agent (gemcitabine, G) into the MSN core, a P glycoprotein inhibitor (LY 335979, P) into the PEI layer, and an extracellular matrix disruptor (losartan, L) into the COF shell. Thereafter, a programmed drug delivery is achieved via the ordered degradation from COF shell to MSN core. Sequential release of the individual drugs, synergized with a change of nanoparticle surface charge, contribute to an obvious extracellular matrix distraction, distinct drug efflux inhibition, and consequently enhance chemotherapeutic outcomes in pancreatic carcinoma. This MPCP‐based vehicle design suggests a robust space–time conversion strategy to achieve programmed multi‐drugs delivery and represents a new avenue to the treatment of pancreatic carcinoma by overcoming extracellular matrix and drug reflux barriers.

Monitoring of Cobalt and Cadmium in Daily Cosmetics Using Powder and Paper Optical Chemosensors.

Daily used cosmetics may contain high levels of heavy metals which are added to improve the quality and shine of cosmetics but represent a threat to human health. In this report, powder- and paper-based optical nanosensors using mesoporous silica nanospheres as carriers were designed for determination of Co2+ and Cd2+ in commonly used cosmetics. Powder optical chemosensors (POCs) were prepared via direct decoration of optical probes into a porous carrier. Paper-based chemosensors (PBCs) were designed via adsorbing the organic chromophore onto filter papers treated with mesoporous silica. POCs and PBCs were constructed with thick decoration of optical probes, leading to the formation of active surface centers for monitoring of Co2+ and Cd2+ in cosmetic products. The uniform structures of POCs and PBCs have resulted in selective sensing and low detection limits up to parts per billion, wide detection range determination, and fast response (on the order of seconds). Digital image colorimetric analysis (DICA) was used to quantify the color of PBCs and deduce the corresponding concentrations of Co2+ and Cd2+ using calibration curves. DICA data correlated well with that obtained from UV–vis spectrophotometry. The developed POCs and PBCs showed wide detection ranges of metal ions and a considerably low detection limit under optimal analysis conditions. The low limit of detection of Co2+ and Cd2+ ions using POCs was 6.7 × 10–9 and 3.5 × 10–9 M, respectively. To the best of our knowledge, this is the first time simple PBCs have been designed for monitoring Co2+ and Cd2+ with detection limits of 2.2 × 10–7 and 1.3 × 10–7 M. A limited amount of manufactured POCs (about 20 mg) were used for all measurements, and commercial filter paper treated with mesoporous nanosphere silica was used for sensing Co2+ and Cd2+ ions. The developed optical chemosensors had short regeneration times and exhibited high stability and surface functionality and are capable of monitoring Co2+ and Cd2+ in various cosmetic products.

Copper Clusters Encapsulated in Carbonaceous Mesoporous Silica Nanospheres for the Valorization of Biomass-Derived Molecules

Copper Clusters Encapsulated in Carbonaceous Mesoporous Silica Nanospheres for the Valorization of Biomass-Derived Molecules

Desirable bonding interactions between organo-functional triazinedithiol groups and heavy metal ions for significantly improved adsorption or dispersion property

Effective bonding interactions between various organo-functional groups and metals can contribute to novel materials or fancy performances. In order to reveal the superiority of triazinedithiolsilanes with di-sulfydryl groups over the conventional mercapto silanes with mono-sulfydryl, and amino silanes with mono-amine, for the first time, the above three silanes have been chemically anchored onto cutting-edge dendritic mesoporous silica nanospheres (DMSNs) for performance comparison. The three composite materials have been designed to serve as not only the adsorbents to remove heavy metal cadmium Cd(II), but also the catalyst-supports to load and disperse metal (noble metal Ag, Pd, and base metal Ni) nanoparticles (NPs). The abilities of triazinedithiol-functionalized DMSNs are far superior to the other two specimens both in Cd(II) capture and metal dispersion, owing to the specific nature of triazinedithiol group. The qe values of triazinedithiol-, mercapto-, and amino-functionalized DMSNs can reach to 1280, 816, 900 mg/g, respectively. Moreover, triazinedithiol-functionalized DMSNs could disperse metal NPs more uniformly that the conventional silane-modified ones. It is expected that triazinedithiolsilane compounds could faultlessly replace conventional mercapto silanes in some practical application fields and would shine brilliantly in the future.

Highly efficient luminescence and enhanced stability of nanocomposites by encapsulating perovskite quantum dots in defect-related luminescent silica nanospheres

The metal-halide perovskite quantum dots (PQDs) have been emerged as new stars of optoelectronic materials with fascinating luminescence properties. However, the poor stability of these materials severely restricts their practical applications. In this work, the novel defect-related luminescent mesoporous silica nanospheres are employed as protective matrix to improve the stability of PQDs for the first time. Firstly, the monodisperse CsPbBr3 and CsPbBr1.5I1.5 PQDs with perfect nanocube morphology and eminent luminescence properties have been prepared respectively by a facile synthesis strategy. Then, the CsPbBr3 and CsPbBr1.5I1.5 PQDs are encapsulated into the non-luminescent (SN) and luminescent silica matrix (DL-SN) respectively, resulting in the PQDs@SN and PQDs@DL-SN nanocomposites. The incorporation of the PQDs and silica matrix can be confirmed by XRD, FT-IR, TEM, XPS, elemental mapping images, N2 adsorption/desorption isotherms, and density functional theory. The as-synthesized silica matrix especially for the DL-SN presents a remarkable enhancement of stability against temperature, storage time, and water for both CsPbBr3 and CsPbBr1.5I1.5 in comparison to the pristine PQDs. Furthermore, the formation mechanism and stability improvement mechanism have been discussed in detail. This work provides a facile and general approach to solve the intrinsic instability of all-inorganic PQDs, which may have a significant impact on their practical applications.

Simple Preparation of Large Pore Mesoporous Silica Nanospheres and Their Protein Sequestration Ability

AbstractA simple and efficient method for the preparation of large pore MSNs is Ca ion‐etching of the as‐prepared mesoporous silica nanospheres (MSNs) containing ammonium‐based organic template. In this facile process, the generation of new large mesopores through the partial collapse of several mesopores and template removal through cation‐exchange occurred simultaneously. We found that CaCl2 could also act as a good etching source. Template‐free cubic phase MSN (cMSN) with large pores could be obtained by treating CaCl2 under mild conditions in high yield. Both surface area and pore volume increased in the order Ca(NO3)2‐treated cMSN<CaCl2‐treated cMSN (Ca‐cMSN)<calcined cMSN, while the pore size increased in the order calcined cMSN<Ca‐cMSN<Ca(NO3)2‐treated cMSN. Compared to the calcined sample, the large pore cMSN (Ca‐cMSN) showed good adsorption capacities for proteins.

Preparation of Mesoporous Silica Nanosphere-Doped Color-Sensitive Materials and Application in Monitoring the TVB-N of Oysters.

In this work, a new colorimetric sensor based on mesoporous silica nanosphere-modified color-sensitive materials was established for application in monitoring the total volatile basic nitrogen (TVB-N) of oysters. Firstly, mesoporous silica nanospheres (MSNs) were synthesized based on the improved Stober method, then the color-sensitive materials were doped with MSNs. The “before image” and the “after image” of the colorimetric senor array, which was composed of nanocolorimetric-sensitive materials by a charge-coupled device (CCD) camera were then collected. The different values of the before and after image were analyzed by principal component analysis (PCA). Moreover, the error back-propagation artificial neural network (BP-ANN) was used to quantitatively predict the TVB-N values of the oysters. The correlation coefficient of the colorimetric sensor array after being doped with MSNs was greatly improved; the Rc and Rp of BP-ANN were 0.9971 and 0.9628, respectively when the principal components (PCs) were 10. Finally, a paired sample t-test was used to verify the accuracy and applicability of the BP-ANN model. The result shows that the colorimetric-sensitive materials doped with MSNs could improve the sensitivity of the colorimetric sensor array, and this research provides a fast and accurate method to detect the TVB-N values in oysters.

Azeotropic Distillation-Induced Self-Assembly of Mesostructured Spherical Nanoparticles as Drug Cargos for Controlled Release of Curcumin.

Methods of large-scale controllable production of uniform monodispersed spherical nanoparticles have been one of the research directions of scientists in recent years. In this paper, we report an azeotropic distillation-induced evaporation self-assembly method as a universal method, and monodispersed hydrophobic ordered mesoporous silica nanospheres (MHSs) were successfully synthesized by this method, using triethoxymethylsilane (MTES) as the silica precursor and hexadecyl trimethyl ammonium bromide (CTAB) as the template. SEM and TEM images showed good monodispersity, sphericity, and uniform diameter. Meanwhile, SAXS and N2 adsorption–desorption measurements demonstrated a highly ordered lamellar mesostructure with a large pore volume. The model drug, curcumin was successfully encapsulated in MHSs for drug delivery testing, and their adsorption capacity was 3.45 mg g−1, which greatly improved the stability of curcumin. The release time when net release rate of curcumin reached 50% was extended to 6 days.

Abstract P3-02-08: Diagnosis, navigation, treatment: A versatile biocompatible and biodegradable mesoporous silica platform of NIR II fluorescence imaging for early diagnosis, breast cancer precisely surgery, and radiosensitization

Abstract Background: Triple-negative breast cancer (TNBC) has the highest recurrence and distant metastasis rates among breast cancer molecular types. In breast-conserving surgery, the insensitivity discrimination of negative margins correlating with locoregional recurrence and poor patient outcomes. As for immunotherapy, only 20 %-40 % of the patients respond to the atezolizumab treatment due to the change of PDL1 receptor. Meanwhile, TNBC has radiotherapy resistance. Novel radiosensitization targets need to be found to enhance both the local and systematic benefits of radiotherapy. Objectives and rationale: We aim to construct an “all in one” multi-functional nanoprobe (MSN-Gd@Aptamer-ICG, NPs) using mesoporous silica as the framework. The mesoporous silica nanospheres are co-doped with gadolinium (Gd3+), loads indocyanine green (ICG) in its mesoporous channel, and conjugates with a specific PDL1 targeting aptamer on the surface. The biocompatible and biodegradable NPs are capable of release ICG by the reaction of intracellular high GSH and tetrasulfide bonds in silica frame. In the diagnosis, NIR II fluorescent imaging of ICG with the high resolution and deep tissue penetration depth screens out PDL1 highly expressed tumors. In surgical resection, it can show a real-time cancerous tissues margin in intraoperative scenarios and the tumors are successfully remove under the navigation of NIR II fluorescent imaging. During metastasis therapy of post-operation, the released Gd3+ effectively deposits X-rays and produces abundant hydroxyl radicals (•OH) and oxidative stress to induce radiosensitizing effects. More importantly, the therapy efficiency is monitored by NIR II fluorescent imaging. Therefore, our multifunctional NPs have roles in the accurate diagnosis of PDL1 expression of tumor in early stage, intraoperative navigation for radical excision, and metastasis eradication with radiosensitization efficiency enhanced, which lays a solid foundation for clinical TNBC therapy. Methods: The probe was 50 nm and it was successfully synthesized and certified. MTT assay suggested that it was nontoxic to normal breast cells and TNBC cells. Transmission Electron Microscope images showed that the probe was stable at the extracellular fluid and was degradable at tumor intracellular conditions. The leaching of ICG and Gd3+ was negligible at the extracellular fluid. The tumor targeting capability of the probe in vitro was evaluated on 4T1 (TNBC, PDL1 low expressed) and MDA-MB-231 (TNBC, PDL1 high expressed) cells by flow cytometry and laser confocal microscope. In vivo, the NIR II fluorescence imaging with a high resolution and tissue penetration depth successfully distinguished 4T1 and MDA-MB-231 bearing mice indicated the superior diagnostic capability of PDL1 via aptamer. In the surgical resection, the NIR II fluorescence imaging of NPs guided to remove the tumor with precisely discriminate the boundary of the tumor. When combined with RT, IHC staining of Ki67 showed that the NPs exhibited superior radiosensitizing effects under NIR II fluorescent imaging guidance in comparison with undoped Gd mesoporous silica nanoprobes. TUNEL fluorescent staining and H&E staining further confirmed that NPs radiation therapy induced more •OH and extensive DNA double-strand breaks. Results and Conclusion: Our biocompatible and biodegradable platform is nontoxic, can screen out PDL1 high expression tumors, and navigate the precise resection in the operation. Besides, it enhances the radioimmunotherapy efficacy of breast metastasis. Our platform is potential to provide new hope for breast cancer diagnostic, guiding resection, and radiosensitization under NIR II fluorescent imaging. Citation Format: Min Wei, Peiyuan Wang, Guojun Zhang. Diagnosis, navigation, treatment: A versatile biocompatible and biodegradable mesoporous silica platform of NIR II fluorescence imaging for early diagnosis, breast cancer precisely surgery, and radiosensitization [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-02-08.

Biodegradable polydopamine and tetrasulfide bond co-doped hollowed mesoporous silica nanospheres as GSH-triggered nanosystem for synergistic chemo-photothermal therapy of breast cancer

Breast cancer, as the common malignant carcinoma in women, seriously reduces the life quality and increases mortality of female worldwide. Fortunately, insufficient chemotherapy with external photothermal therapy could remarkably improve the therapeutic efficiency of breast cancer. In this work, we proposed a polydopamine (PDA) and tetrasulfide bond co-doped hollowed mesoporous silica nanospheres with Dox loading and surface hyaluronic acid coating for drug leakage avoidance (PhMSON@Dox-HA). After intravenously injected into tumor bearing-mice, this therapeutic agent could effectively target to the tumor site owing to the HA modification. The biocompatible property and GSH-induced decomposition capability endows the precise release of drugs in the cytoplasm of tumor cells. Meanwhile, PDA facilitated the efficient photothermal therapy under 808 nm laser irradiation. Therefore, the synergistic effect of chemo-photothermal therapy possessed most effective tumor eradication ability. Our work exploits the design approach of biocompatible and degradable drug delivery nanocarriers and sheds bright light on the chemotherapy and photothermal therapy combination for the malignant tumor elimination.

Heterogeneously supported active Pd(0) complex on silica mediated by PEG as efficient dimerization catalyst for the production of high energy density fuel

High energy-density hydrocarbon fuels are the key materials for aircraft to increase payload and expand flight distance. Under the catalysis of atomically dispersed Pd(0) complex, saturated hexacyclic exo-exo product with good fuel property can be synthesized via co-dimerization of norbornadiene (NBD) with quadricyclane (QC). But the fragile coordination state of homogeneous Pd(0) complex limited its application in fuel production. In this work, Pd(0) complex has been heterogeneously supported on silica support with the regulation of polyethylene glycol (PEG) to increase its stability and recyclability with limited sacrifice of the activity and dimer selectivity. The structure of silica support was tuned to achieve the proper interaction with PEG and Pd(0) complex. The chain length and concentration of PEG were adjusted to further optimize the state of Pd(0) complex on silica. The as-developed heterogeneous Pd(0) complex supported on dendritic mesoporous silica nanospheres regulated by PEG2000 exhibited superior performance for the production of high energy density fuel through selective NBD-QC co-dimerization.

Development of a Sensitive and Selective Optical Sensor for Measuring Ultra‐Trace Amounts of Fe(II) and Fe(III) Ions in Water

AbstractA smart spectrophotometric method for the analytical determination of iron concentration in whichever oxidation state was developed using a novel optical sensor. The optical sensor was prepared by direct immobilization of novel synthesized chromophore, 5‐(((1,10‐phenanthrolin‐5‐yl)imino)methyl)‐2‐hydroxybenzoic acid (Phimhb) onto mesoporous silica nanospheres (MSNSs). The novel Phimhb chromophore has two sites, one is selective to Fe(II) ions and the other is selective to Fe(III) ions. The ions′ color can be seen with the human eye and monitored using spectrophotometric techniques or a smartphone. The influence of several parameters on the evaluation of iron ions content was studied and optimized. The proposed method was validated in terms of LOD, LOQ, linearity, and precision according to ICH guidelines. The optical Phimhb sensor has wide linear dynamic ranges with low detection limits of 4.94 ppb (1.83×10−7 mol L−1) and 10.4 ppb (3.85×10−7 mol L−1) for Fe(II) and Fe(III), respectively. The response time of this sensor for both ions was 60 s. The Phimhb sensor could be reproduced multiple times and used with a higher capacity each time. The effect of potential interfering ions on the estimation of Fe(II) and Fe(III) was investigated. The outcomes clarified that the prepared Phimhb sensor was very selective to Fe(II) and Fe(III) ions. Therefore, the Phimhb sensor had been successfully used in the determination of Fe(II) and Fe(III) in real water even without any pre‐concentration, it has high specificity.

Magnetic Mesoporous Silica Nanorods Loaded with Ceria and Functionalized with Fluorophores for Multimodal Imaging.

Multifunctional magnetic nanocomposites based on mesoporous silica have a wide range of potential applications in catalysis, biomedicine, or sensing. Such particles combine responsiveness to external magnetic fields with other functionalities endowed by the agents loaded inside the pores or conjugated to the particle surface. Different applications might benefit from specific particle morphologies. In the case of biomedical applications, mesoporous silica nanospheres have been extensively studied while nanorods, with a more challenging preparation, have attracted much less attention despite the positive impact on the therapeutic performance shown by seminal studies. Here, we report on a sol–gel synthesis of mesoporous rodlike silica particles of two distinct lengths (1.4 and 0.9 μm) and aspect ratios (4.7 and 2.2) using Pluronic P123 as a structure-directing template and rendering ∼1 g of rods per batch. Iron oxide nanoparticles have been synthesized within the pores yielding maghemite (γ-Fe2O3) nanocrystals of elongated shape (∼7 nm × 5 nm) with a [110] preferential orientation along the rod axis and a superparamagnetic character. The performance of the rods as T2-weighted MRI contrast agents has also been confirmed. In a subsequent step, the mesoporous silica rods were loaded with a cerium compound and their surface was functionalized with fluorophores (fluorescamine and Cyanine5) emitting at λ = 525 and 730 nm, respectively, thus highlighting the possibility of multiple imaging modalities. The biocompatibility of the rods was evaluated in vitro in a zebrafish (Danio rerio) liver cell line (ZFL), with results showing that neither long nor short rods with magnetic particles caused cytotoxicity in ZFL cells for concentrations up to 50 μg/ml. We advocate that such nanocomposites can find applications in medical imaging and therapy, where the influence of shape on performance can be also assessed.

Highly effective microwave catalytic oxidative dehydrogenation of propane by CO2 over V-La-doped dendritic mesoporous silica-based microwave catalysts

The great potential of the oxidative dehydrogenation of propane by CO2 (CO2-ODHP) reaction in facilitating propylene production from propane and elimination of CO2 has attracted much attention. However, the challenge of the oxidative dehydrogenation of propane by CO2 (CO2-ODHP) reaction is the high thermodynamic stability of CO2, which requires high temperature for activation but the predominance of propane cracking reactions at high temperatures leads to difficulties in maintaining high selectivity for propylene at high conversion rates. Herein, a new and effective method for CO2-ODHP by microwave catalysis has been developed. Meanwhile, a novel vanadium-lanthanum-doped three-dimensional dendritic mesoporous silica nanospheres (V-La-MSNS) based microwave catalyst is synthesized by the in situ growth approach. Importantly, the propane conversion increases from 2% in conventional reaction mode (CRM) to 13% in microwave catalytic reaction mode (MCRM) at 500 °C, with the propylene selectivity still remained at a high level. The catalyst exhibits good stability and reproducibility in microwave catalytic reaction mode. Besides, the doping of La in V-MSNS can dramatically increase the catalytic activity. More importantly, the apparent activation energy of the V-La-MSNS + SiC microwave catalyst drops from 132.7 kJ/mol in the CRM to 71.4 kJ/mol in the MCRM, indicating a significant microwave direct catalytic effect. This work presents a new method for high-efficient catalytic CO2-ODHP reaction under microwave irradiation.