MCM-41 Mesoporous Nanoparticles Research Articles

Fast fabrication of mesostructured MCM-41-type nanoparticles by microwave-induced synthesis

This work reports the synthesis of mesoporous MCM-41 nanoparticles by applying microwave radiation (MWR) in the range of 400–1000 W. Silica nanoparticles were produced at short time (10 min) and low power radiation (400 W) which showed large surface area (SBET ∼1000 m2g-1) and a suitable chemical surface composition. Both, scanning and transmission electron microscopies (SEM and TEM) revealed that the mesoporous silica had a nanometric size close to 100 nm with a predominant spherical morphology. Also, it was found that the particles were smaller and agglomerated at higher microwave radiation power (>600 W) and longer heating time (>10 min). On the other hand, low microwave radiation power (400 W) was sufficient to obtain MCM-41 with high surface area (1182 m2g-1) keeping the same particle size. Under MWR synthesis, pore diameters slightly expanded up to ∼4.00 nm which are larger for those obtained by the hydrothermal method (∼2.0 nm). According to the FTIR results, the surface of the sample labeled as MCM400W10 exhibited a number of free silanol groups (αΟΗ) of ∼4.08 per nm2 which could improve their surface modification for being used in diverse biomedical applications including drug delivery.

Doxorubicin and Quercetin Double Loading in Modified MCM-41 Lowered Cardiotoxicity in H9c2 Cardioblast Cells In Vitro.

One of the therapeutic limitations of the use of doxorubicin (DOX) as an anticancer drug is its cardiotoxicity. Its hydrophilicity also causes difficulties in achieving sustained release. The simultaneous delivery with the well-known natural antioxidant quercetin could ameliorate its cardiotoxicity. Thus, the main aim of this work is to study the potential of carboxylated and non-carboxylated mesoporous silica MCM-41 nanoparticles for double loading of the hydrophilic doxorubicin hydrochloride and hydrophobic quercetin (Q) in one nanocarrier with a modified release pattern to reduce the cardiotoxic side effects of doxorubicin in vitro. The methods included the modification of MCM-41, single and double loading of modified and non-modified MCM-41, physicochemical characterization, in vitro release tests and kinetic study, and in vitro cell viability studies. Doxorubicin and quercetin were successfully double-loaded with encapsulation efficiency (EE) of 43 ± 4.1% and 37 ± 4.5%, respectively, in native MCM-41. The post-synthetic carboxylation led to 49 ± 4.3% EE (DOX) and 36 ± 4.0% (Q) and double lowering of the cardiotoxicity on H9c2 (IC50 = 5.96 µm). Sustained release profiles over 72 h were achieved. A successful procedure was proposed for the efficient double loading of a hydrophilic drug and a hydrophobic drug. The carboxy-modified double-loaded nanosystems demonstrate a decreased in vitro cardiotoxicity of doxorubicin and can be considered as a potential chemotherapeutic formulation.

Hierarchically Porous Three-Dimensional (3D) Carbon Nanorod Networks with a High Content of FeNx Sites for Efficient Oxygen Reduction Reaction.

Efficient, durable, and inexpensive electrocatalysts are recommendable for accelerating the kinetics of oxygen reduction reaction and achieving high performance. Herein, with predesigned hierarchically porous silica nanorods as a hard template, hierarchically macro-bimodal meso/microporous 3D carbon interwoven nanorod networks containing a high content of single-atom FeNx species (Fe/RNC) were prepared by melting of precursors and confined pyrolysis within the pores of the hard template. What distinguishes the use of silica nanorods as a hard template is that it not only provides a porous texture for confined pyrolysis of the precursors but also the interwoven texture of the nanorods gives rise to a macroporous mesh-like morphology. Benefiting from the ultrahigh iron content (5.69 wt %) of the FeNx sites, a 3D porous network configuration with high accessibility of active centers, as well as a high specific surface area of 793 m2g-1, the as-prepared Fe/RNC exhibited superior activity and durability for ORR and zinc-air batteries. For comparison, the catalyst Fe/NC-MCM, which was prepared with a similar procedure but with unimodal mesoporous silica MCM-41 nanoparticles as the hard template, possesses a less porous structure and active accessibility and thus exhibits inferior ORR activity. This work provides an effective design/nanoengineering for electrocatalysts in ORR and zinc-air batteries and will inspire more research on accessibility of active sites in non-noble carbon-based electrocatalysts.

A Novel Formulation of Mesoporous Silica Nanoparticles Functionalized with Polyaniline Brush Polymer: Synthesis and Characterization

Mesoporous silica nanoparticles and polyaniline (PANI) are widely used in many potential applications. This work establishes a new formulation that functionalizes the surface of mesoporous silica MCM-41 nanoparticles with a brush polymer of polyaniline to synergistically combine their properties. The new formulation is designed to fit in many applications due to its high surface area and good electrical conductivity. Results showed the successful preparation of MCM-41 with a spherical porous structure. The polyaniline functionalization on MCM-41 was confirmed by FTIR.

Tert-Butylamine functionalized MCM-41 mesoporous nanoparticles as drug carriers for the controlled release of cyclophosphamide anticancer drug

Mesoporous MCM-41 nanoparticles were synthesized and functionalized using 13-21% of tert-butylamine (TBA) and applied as efficient drug delivery systems (DDSs). The anticancer drug cyclophosphamide (CP) was loaded into the mesopores of the carriers. The surface area, pore volume and pore size of MCM-41 were measured to be 91.83 m2/g, 2.08 cm3/g and 106.35 Å whereas those of the TBA-functionalized MCM-41 samples were considerably smaller confirming the TBA molecules were attached to the pores and surfaces of these materials. The drug release was investigated within three diverse environments including acidic (pH=4), alkaline (pH=14) and neutral phosphate buffered saline (PBS, pH=7.4). The cyclophosphamide release was significantly increased (burst release) in about 24 h and then a sustained drug release was occurred within 7 days. Also, the greatest amount of drug release was occurred in alkaline environment, moderate amount in neutral medium and the lowest amount in acidic solution. The MTT assay proved that all MCM-41-x%TBA nanocarriers had high cell viabilities (very low cytotoxicity values) to the L929 murine fibroblast cells indicating these materials are favorable drug vehicles. The kinetics models for the drug release was investigated using the zero-order, first-order, Higuchi, Hixson-Crowel and Korsmeyer-Peppas models and it was found that the CP drug release from all carriers followed the Korsmeyer-Peppas model. Lastly, the MCM-41 nanomaterial functionalized with 17% TBA was suggested as the most desirable system due to they had satisfactory amounts of both drug loading and release.

Kinetic of Phenol Adsorption by Mesoporous MCM-41 Nanoparticles

In the present study application of MCM-41 for removal of phenol was investigated. MCM-41nano-adsorbent was synthesized and characterized by FTIR, XRD and SEM analysis. Adsorption isotherm experiment was performed in batch shake flask. The experimental data were analyzed using various isotherm models. Result revealsthat,Langmuir isotherm model fitted the data very well for the removal of phenol by the MCM-41 adsorbents. The calculated dimensionless separation factor, RL indicates that the adsorption of phenol onto MCM-41 was favorable. Pseudo-first order, pseudo-second order kinetic equations and intraparticle diffusion model were applied to analyze the adsorption kinetics of the MCM-41 at different initial phenol concentrations. It was found that the adsorption of phenol on to the MCM-41 follows the pseudo-second order kinetic. At an initial phenol concentration of 130 mgl-1, more than 99% phenol, 93% COD along with 96% of toxicity removal were achieved. Thus, the synthesized mesoporous MCM-41 proved to be a potential candidate for removal of phenol from industrial wastewater.

Photophysical Properties of Ir(III) Complexes Immobilized in MCM-41 via Templated Synthesis.

In the search for understanding and improving the luminescence of optical materials based on Ir(III) complexes, three [Ir(C∧N)2(dnbp)]+ (dnbp = 4,4'-dinonyl-2,2'-bipyridine) emitters were immobilized in MCM-41 mesoporous nanoparticles. By taking advantage of the amphiphilic nature of [Ir(C∧N)2(dnbp)]+, the complexes were mixed with an appropriate surfactant and the resulting micelles served as templates for the synthesis of mesoporous silica host materials in a one-step sol-gel route. The MCM-encapsulated [Ir(C∧N)2(dnbp)]+ complexes present intense emissions with prominent rigidochromic spectral changes that are substantially less affected by O2 as compared to methanolic solutions, with a thousand-fold decrease in quenching rate constants. These photophysical results points to a possible suitability of Ir(III)-complex-MCM-41 host-guest systems for possible future optoelectronic devices, rigidity optical sensors, or biological markers in different colors.

Lanthanide-doped mesoporous MCM-41 nanoparticles as a novel optical-magnetic multifunctional nanobioprobe.

To research and develop potential multifunctional nanoprobes for biological application, lanthanide-doped MCM-41 (Ln-MCM-41, Ln = Gd/Eu) silica nanoparticles with excellent pore structure and optical–magnetic properties were synthesized via a facile and economical sol–gel method. The microstructure and pore distribution of Ln-MCM-41 nanoparticles were obviously affected by the Ln-doping. As the Ln/Si mole ratio increased, the specific surface area and total pore volume of Ln-MCM-41 nanoparticles rapidly decreased. However, the Ln-MCM-41 nanoparticles still retained the typical well-ordered mesoporous structure, and exhibited excellent drug release behavior. Moreover, the drug release rate of Ln-MCM-41 was remarkably pH-dependent and increased gradually upon decreasing pH. Additionally, these nanoparticles also exhibit considerable photoluminescence properties, living cells photoluminescence imaging in vitro, and paramagnetism behavior at room temperature due to the Ln3+-ions doping. Our research shows the possibility of our Ln-MCM-41 nanoparticles as multifunctional nanoprobes for application in bioseparation, bioimaging, and drug delivery.

L-Arginine Encapsulated Mesoporous MCM-41 Nanoparticles: A Study on In Vitro Release as Well as Kinetics

L-Arginine Encapsulated Mesoporous MCM-41 Nanoparticles: A Study on<i> In Vitro</i> Release as Well as Kinetics

Synthesis of MCM-41 nanoparticles from stem of common reed ash silica and their application as substrate in electrooxidation of methanol

In this work, stem of common reed ash (SCRA) is introduced as a new source of silica in the preparation of mesoporous materials. Mesoporous silicate MCM-41 nanoparticles were synthesized hydrothermally using sodium silicate prepared from SCRA as a silica source. The characterization of MCM-41was carried out by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), N $$_{2}$$ adsorption/desorption (BET) and transmission electron microscopy (TEM). SEM shows that MCM-41 nanoparticles are sphere-like with size in the range of 30–50 nm with some degree of agglomeration. TEM image of the synthesized sample shows the open framework structure of MCM-41. A type IV isotherm can be observed from adsorption/desorption curves, which is the characteristic of mesoporous materials. The prepared MCM-41 nanoparticles were used as substrate to facilitate the oxidation of methanol through the modification with an electroactive species. The modification was achieved by impregnation of MCM-41 pores with $$\hbox {Ni}^{2+}$$ ions (Ni-doped MCM-41). A modified carbon paste electrode (CPE) was prepared by mixing Ni-doped MCM-41 with carbon paste (NiMCM-41CPE). Cyclic voltammetry of NiMCM-41CPE shows an increment in current density of methanol oxidation in comparison with CPE in alkaline solution. Moreover, a decrease in the overpotential of methanol oxidation occurred on the surface of modified electrode. The effects of some parameters such as scan rate and methanol concentration are also investigated on the behaviour of NiMCM-41CPE. Also, the heterogeneous electron transfer rate for the catalytic reaction (k) of methanol is calculated.

Electrochemical biointerfaces based on carbon nanotubes-mesoporous silica hybrid material: Bioelectrocatalysis of hemoglobin and biosensing applications

We are reporting a novel biosensing platform based on a hybrid nanomaterial that combines the advantages of Nafion-coated multiwalled carbon nanotubes (MWCNTs) and mesoporous silica MCM41 nanoparticles functionalized with hemoglobin (Hb). MWCNTs-MCM41-Hb hybrid bioconjugate was characterized by scanning electron microscopy (SEM), UV–vis spectroscopy and electrochemical techniques after deposition at glassy carbon electrodes (GCE). The combination of the high surface area, biocompatibility and protein loading capacity of MCM41 nanoparticles and the high surface area and catalytic properties of MWCNTs allowed the direct electron transfer (DET) between Hb and the electrode surface. The electron transfer rate constant (k) and the surface coverage of electroactive Hb (ΓHb) were 5.2 s−1 and 4.7 × 10−10 mol cm−2, respectively. The GCE modified with the nanostructured architecture (GCE/MWCNTs-MCM41-Hb) was successfully used as a third-generation biosensor for the highly sensitive and selective quantification of nitrite (NO2-) and trichloroacetic acid (TCA) by taking advantage of the excellent biocatalytic activity of Hb and the efficient direct charge transfer of the heme group.

Rice husk based MCM-41 nanoparticles loaded with Ag2S nanostructures by a green and room temperature method and its antimicrobial property

ABSTRACTIn this paper, we chose rice husk ash as raw material and synthesized successfully mesoporous MCM-41 nanoparticles loaded with silver sulfide nanoparticles by green, simple and cost-effective method. The synthesized nanocomposites were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The morphologies and sizes were characterized by SEM and TEM. The Ag2S nanoparticles were spherical in shape with an effective diameter size of 14 nm. The antibacterial properties of nanocomposite were evaluated against Gram-negative (E. coli) and Gram-positive (S. aureus). The diameters of the inhibition zone, which was obtained by the agar disc diffusion for microorganisms S. aureus and E. coli were about 11 mm.

Controlled release of metformin from chitosan–based nanocomposite films containing mesoporous MCM-41 nanoparticles as novel drug delivery systems

Biocompatible nanocomposite films based on blended chitosan and poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (BP) polymers containing metformin (MET) drug and MCM-41 or MCM-41-APS (APS=aminopropylsilane) nanoparticles (NPs) were designed and fabricated in order to prepare novel drug delivery systems which are useful for controlled drug release purposes. The total pore volume and mesopore volume of MCM-41 were measured equal to 1.08 and 1.05 cm3/g but those of MCM-41-APS were 0.54 and 0.26 cm3/g indicating smaller values for the APS functionalized material. The film thickness was the highest for CS-BP-G-10%MET (70μm) but it was the smallest for the CS-BP-G-4%MCM-41 (49μm). For all of the films, the swelling percent was the highest in acidic medium but it was decreased in PBS and the least water uptake occurred in the alkaline environment. The lowest and the highest water uptake was observed for the films incorporated with 4%MCM-41NPs and 4%MCM-41-APS-10%MET, respectively. The SEM micrographs of the films after three days water uptake in pH=4 medium exhibited that all of the films were stable against cracking and/or tearing. It was found that increasing the MCM-41 or MCM-41-APS amount within the films decreased the elongation at break but enhanced the tensile stress. The release of the MET was sharply increased within ∼22–24h (burst release) but after that the drug release was slowly enhanced during 15days (sustained release). Finally, it was concluded that the film 4% MCM-41-APS-10%MET NPs was the most promising drug delivery system because it had improved hydrophilicity, hydrolytic stability, biocompatibility, mechanical and drug release properties.

Polysulfide-Breathing/Dual-Conductive, Heterolayered Battery Separator Membranes Based on 0D/1D Mingled Nanomaterial Composite Mats.

Facile/sustainable utilization of sulfur active materials is an ultimate challenge in high-performance lithium-sulfur (Li-S) batteries. Here, as a membrane-driven approach to address this issue, we demonstrate a new class of polysulfide-breathing (capable of reversibly adsorbing and desorbing polysulfides)/dual (electron and ion) conductive, heterolayered battery separator membranes (denoted as "MEC-AA separators") based on 0D (nanoparticles)/1D (nanofibers) composite mats. The MEC-AA separator is fabricated through an in-series, concurrent electrospraying/electrospinning process. The top layer of the MEC-AA separator comprises close-packed mesoporous MCM-41 nanoparticles spatially besieged by multiwalled carbon nanotubes (MWNT) wrapped poly(ether imide) (PEI) nanofibers. The MCM-41 in the top layer shows reversible adsorption/desorption of polysulfides, and the MWNT-wrapped PEI nanofibers act as a dual-conductive upper current collector. Preferential deposition of the MWNTs along the PEI nanofibers and dispersion state of the separator components are elucidated theoretically using computational methods. The support layer, which consists of densely packed Al2O3 nanoparticles and polyacrylonitrile nanofibers, serves as a mechanically/thermally stable and polysulfide-capturing porous membrane. The unique structure and multifunctionality of the MEC-AA separator allow for substantial improvements in redox reaction kinetics and cycling performance of Li-S cells far beyond those achievable with conventional polyolefin separators. The heterolayered nanomat-based membrane strategy opens a new route toward electrochemically active/permselective advanced battery separators.

Assessing the potential of mesoporous MCM-41 nanoparticles for treatment of phenolic wastewater

In the present study, a highly mesoporous MCM-41 nano-adsorbent was synthesised, characterised using FTIR, SEM, EDS and XRD analysis and applied for treatment of phenolic wastewater. In order to enhance the phenol adsorption efficiency, adsorption parameters, such as pH, MCM-41 dosage and initial phenol concentration was optimised by employing central composite design (CCD) and response surface methodology (RSM). Result revealed that pH and adsorbent dose were found to have significant influence on phenol adsorption on to MCM-41. Further, among these significant factors adsorbent dose showed a large positive effect and pH showed strong negative effect on the phenol removal efficiency. Further, it was observed that interaction effect between pH and phenol dose had significant effects on phenol removal efficiency from the synthetic wastewater. At an optimum combination of pH 5.2, phenol dose 132 mgl–1 and 2.6 gl–1 of MCM-41 more than 99% phenol adsorption along with 96% of toxicity removal was achieved. Thus, mesoporous MCM-41 can be potentially employed for the treatment of industrial wastewater contaminated with phenol.

Assessing the potential of mesoporous MCM-41 nanoparticles for treatment of phenolic wastewater

Assessing the potential of mesoporous MCM-41 nanoparticles for treatment of phenolic wastewater

Evaluation of Stability of Mesoporous Silica Nanoparticles and Their Further Formulation in Tablet Form

Mesoporous silica nanoparticles have been widely investigated as drug delivery systems. The present study evaluated physical stability of indomethacin loaded mesoporous MCM-41 nanoparticles. The size, polydispersity index, zeta-potential, and drug loading degree of nanoparticles were determined immediately after their preparation and after 6 months storage at 25°C in dry state. The results showed insignificant changes in these parameters, suggesting high stability of nanoparticles and loaded indomethacin. The nanoparticles were formulated in tablets by direct compression. The low friability indicated good resistance during handling and storage. The formulation of the nanoparticles into tablets decreased the initial release of indomethacin.

Multifunctional enveloped mesoporous silica nanoparticles for subcellular co-delivery of drug and therapeutic peptide.

A multifunctional enveloped nanodevice based on mesoporous silica nanoparticle (MSN) was delicately designed for subcellular co-delivery of drug and therapeutic peptide to tumor cells. Mesoporous silica MCM-41 nanoparticles were used as the core for loading antineoplastic drug topotecan (TPT). The surface of nanoparticles was decorated with mitochondria-targeted therapeutic agent (Tpep) containing triphenylphosphonium (TPP) and antibiotic peptide (KLAKLAK)2 via disulfide linkage, followed by coating with a charge reversal polyanion poly(ethylene glycol)-blocked-2,3-dimethylmaleic anhydride-modified poly(L-lysine) (PEG-PLL(DMA)) via electrostatic interaction. It was found that the outer shielding layer could be removed at acidic tumor microenvironment due to the degradation of DMA blocks and the cellular uptake was significantly enhanced by the formation of cationic nanoparticles. After endocytosis, due to the cleavage of disulfide bonds in the presence of intracellular glutathione (GSH), pharmacological agents (Tpep and TPT) could be released from the nanoparticles and subsequently induce specific damage of tumor cell mitochondria and nucleus respectively with remarkable synergistic antitumor effect.

New method for preparation of delivery systems of poorly soluble drugs on the basis of functionalized mesoporous MCM-41 nanoparticles

MCM-41 silica with spherical morphology and small particle sizes (100nm) was synthesized and modified by post-synthesis method with amino and/or carboxylic groups. Solid state reaction was applied for the first time for loading of poorly soluble drug mesalazine (5-aminosalicylic acid – 5-ASA). The non-loaded and drug loaded mesoporous silicas were characterized by XRD, TEM, N2 physisorption, elemental analysis, thermal analysis, FT-IR and solid state NMR spectroscopy. Quantum-chemical calculations were used to predict the interactions between the drug molecule and the functional groups of the carrier. The nanoparticles were post-coated with sodium alginate and the coating modified the rate of mesalazine release from MCM-41NH2 and MCM-41NH2COOH particles. Cytotoxic evaluation on colon adenocarcinoma cell line revealed that the alginate coating reduced cytotoxicity of mesalazine loaded in the post-coated particles compared to the pure mesalazine. The functionalized, polymer coated mesoporous systems are suitable oral drug delivery systems providing an opportunity to modify drug release.

Tumor accumulation of neutron-activatable holmium-containing mesoporous silica nanoparticles in an orthotopic non-small cell lung cancer mouse model

Mesoporous silica MCM-41 nanoparticles containing the stable isotope holmium-165 (165Ho) were prepared by exposing the approximately 400nm particles to an aqueous solution of 165Ho acetylacetonate for 24h at room temperature; the obtained solid was subsequently irradiated in a PULSTAR nuclear reactor (reactor power=1MW; thermal neutron flux of approximately 5.5 or 7.7×1012n/cm2s) to produce holmium-166-containing mesoporous silica (166Ho-MCM-41) nanoparticles (20.8±1.9% w/w 166Ho). The 166Ho-MCM-41 nanoparticles were administered intravenously (i.v.) to orthotopic non-small cell lung cancer A549-luciferase tumor-bearing mice. After 24h, 4.5±3.9% initial dose per gram (ID/g) of tissue was detected in tumors and after 1week, this value increased to 58.8±34.7% ID/g. These results demonstrate that mesoporous silica MCM-41 nanoparticles can deliver significant amounts of a therapeutic radionuclide to tumors after i.v. injection.