Functionalized Mesoporous Silica Research Articles

Printing of In Situ Functionalized Mesoporous Silica with Digital Light Processing for Combinatorial Sensing.

Combinatorial sensing is especially important in the context of modern drug development to enable fast screening of large data sets. Mesoporous silica materials offer high surface area and a wide range of functionalization possibilities. By adding structural control, the combination of structural and functional control along all length scales opens a new pathway that permits larger amounts of analytes being tested simultaneously for complex sensing tasks. This study presents a fast and simple way to produce mesoporous silica in various shapes and sizes between 0.27-6mm by using light-induced sol-gel chemistry and digital light processing (DLP). Shape-selective functionalization of mesoporous silica is successfully carried out either after printing using organosilanes or in situ while printing through the use of functional mesopore template for the in situ functionalization approach. Shape-selective adsorption of dyes is shown as a demonstrator toward shape selective screening of potential analytes.

Investigation on the physicochemical properties of poly (ethylene-co-vinyl acetate)/mesoporous silica nanocomposites: Effects of content and surface functionalization

In this study, poly (ethylene-co-vinyl acetate)/mesoporous silica EVA/SBA-15 nanocomposites, containing 0.5, 1.5, and 2.5 wt% of unfunctionalized and functionalized SBA-15 were prepared by melt blending in an internal mixer. Mesoporous silica was synthesized through the sol-gel method and modified by hexadecyltrimethoxysilane (HDTMS). Several characterizations were performed; including Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), mechanical properties, dynamic mechanical analysis (DMA), and dielectric study to characterize the physicochemical properties of elaborated materials. The results revealed the successful synthesis and functionalization of mesoporous silica, as confirmed by the FTIR and SEM. The crystallinity of the nanocomposites decreased and the elastic modulus increased with the incorporation of the mesoporous silica. Measurement of tensile properties shows that the tensile strength of the nanocomposite content of 1.5 wt% F-SBA-15 is 17.2% is higher as compared to pure EVA. DMA analysis validates the improvement in mechanical properties of the EVA/SBA-15 samples. SEM images displayed well-dispersed F-SBA-15 nanoparticles and enhanced interfacial adhesion between the phases. TGA indicates the enhancement of the thermal stability of nanocomposites as compared with the pure EVA matrix. The surface functionalization presented an approach to preparing nanocomposites with enhanced thermal stability and a low dielectric constant.

Scaled-up microwave-assisted batch and flow synthesis and life cycle assessment of a silica mesoporous material: UVM-7

A novel scaled-up method for the preparation and functionalization of mesoporous silica.

High dispersibility ratiometric fluorescence sensor designed by functionalized mesoporous silica nanopraticles for sensing and imaging of hydrogen peroxide

Herein, a mesoporous silica nanoparticle (MSN) based ratiometric fluorescence nanosensor (MSN-BA-SiCD) with improved performance was designed for monitoring hydrogen peroxide (H2O2). Specifically, H2O2 response molecule (BA) with AIE feature was synthesized and encapsulated into MSN channel as the fluoresent recognition site. Afterwards, silane-modified carbon dot (SiCD) was covalently connected to the MSN surface which can effectively prevent the leakage of BA and improve the water dispersibility of the nanosensor. The presence of H2O2 could result in a “turn-on” fluorescence of BA as well as concurrent variation in the fluorescence resonance energy transfer (FRET) signal between SiCD and BA. MSN-BA-SiCD displays a specific blue-to-green resolved emission change in response to H2O2 and the detection limit can be as low as 4.78 × 10−6 M. In addition, the nanosensor exhibited enhanced photostability due to the protection of the material framework. Moreover, the nanosensing system was successfully applied to detect H2O2 in beer, orange juice and living cells. The excellent water dispersibility and photostability of the nanosensor, together with high specificity and biocompatibility, constituted an advanced set of characteristics among existing MSNs, which was expected to further promote the development of H2O2 sensors in the environmental and biological fields.

Experimental and theoretical investigations on Hg(II) removal by recyclable composite sorbents comprised of polymers bearing thiourea or amidoxime functional groups and mesoporous silica

It is extremely desirable but still challenging to skilfully manufacture highly efficient sorbents to remmediate, in a reversible manner, the water pollution with mercury. Herein, new sorbents for Hg(II) ions have been designed by the initial synthesis of polyacrylonitrile networks inside mesoporous SiO2 microparticles, followed by the chemical modification of acrylonitrile groups with thiourea or amidoxime moieties. The Hg(II) ions sorption properties of the new composites were compared with respect of initial solution pH, contact time, equilibrium concentration and impact of interfering metal ions. It was demonstrated that the sorbents containing thiourea groups exhibited superior sorption capacities (1.76 mmol Hg(II) g−1) compared to the ones containing amidoxime groups (1.68 mmol Hg(II) g−1), and also higher selectivity for Hg(II) ions separation from binary mixtures with Cu(II), Cd(II) or Pb(II) ions. Kinetic study and DFT results supported a combined sorption mechanism, both physical sorption and chem-isorption being possible. Following the elution of Hg(II) ions with 1 M HNO3 and the regeneration with 0.1 M NaOH, all sorbents exhibited around 90 % sorption capacity recovery after 4 reuse cycles.

Surface Functionalized Mesoporous Silica Nanoparticles for Enhanced Removal of Heavy Metals: A Review

Human health and environmental sustainability are strongly influenced by the contamination of water resources with hazardous heavy metal ions due to the accumulation in human body via food chains. Thereby, researchers’ attention has been paid on effective methods for heavy metal ion scavenging to prevent them releasing to environment. Notably, Mesoporous Silica Nanoparticles (MSNPs) with high surface area, massive surface area to volume ratio, large pore volume and uniform pore distribution play a crucial role in addressing this challenge. Additionally, researchers focus on novel surface functionalization methods of MSNPs with suitable organic and inorganic moieties to amplify the adsorption efficiency of heavy metals. MSNPs possess easily functionalizable surface which facilitates the modifications and enhanced removal of heavy metals. The review article summarizes the different moieties used for functionalization of MSNPs such as amino, thio, carboxyl, phenyl, cyano groups, different types of polymers, inorganic functional groups. Further, a comparison has been made between functional and unmodified MSNPs to elaborate how these modifications have enhanced the removal performance of heavy metals in water. Further, this review provides an overview on different synthesis routes and structure directing agent used in synthesis of MSNPs. Moreover, pH effect on adsorption andreusability of modified NPs, while illustrating the mechanism of adsorption on to modified MSNPs surface has also been elaborated. Maximum adsorption capacity of each functional moiety has been taken into consideration with the aim of supporting future advancements.
 Keywords: Adsorption, Mesoporous silica nanoparticles, Heavy metals, Functionalization, Maximum adsorption capacity

Fluorescent and ratiometric probe for tetracycline antibiotics based on metal-chelated functional mesoporous silica

The need to create efficient detection techniques for tetracycline antibiotics (TCs) is pressing, as their overabundance can be damaging to ecosystems and human health. In this work, phenylterpyridine and aminopropyl functionalized mesoporous silica (APT–SBA–15) was chelated with Zn2+, and the metal-chelated functional mesoporous silica material (APT–SBA–15@Zn2+) was successfully prepared. APT-SBA-15@Zn2+ was found to be a fluorescent and ratiometric probe with remarkable selectivity and sensitivity. In the presence of TCs, the fluorescence intensity of APT–SBA–15@Zn2+ at 447 nm quenched and a new fluorescence emission appeared at 521 nm (or 512 nm), which was due to the strong interaction between TCs and Zn2+ that led to the decomposing of APT–SBA–15@Zn2+ and the formation TCs-Zn2+ complexes. The fluorescent intensity ratio at 521 nm (or 512 nm) and 447 nm versus the concentration of tetracycline (or oxytetracycline) displayed good linear relationships, realizing the ratiometric detection of TCs which can avoid interferences from background and external factors. The detection of tetracycline and oxytetracycline was limited to 76.4 and 76.2 nM, respectively.

Functionalization of mesoporous silica with oligoisoprene brushes: Application as charge for elastomers reinforcement

The interfacial interaction between mesoporous silica nanoparticles (MSN) and natural rubber was successfully improved by surface modification of hydrophilic silica using oligoisoprene brushes. This approach involved grafting 3-aminopropyltriethoxy silane (APTES) onto the silica surface, achieving a grafting efficiency of 13.22 % and generating amine groups. The long polyisoprene chains of natural rubber were selectively cleaved using an optimized oxidative reaction, resulting in the formation of short oligomers with carbonyl chain ends known as Carbonyl Telechelic Natural Rubber (CTNR), having a molecular weight of 4100 g/mol. The CTNR oligomers were subsequently linked to APTES-modified silica via a Schiff's base reaction, imparting hydrophobicity to the silica surface and enhancing its compatibility and dispersion within the natural rubber matrix. Two conditions, MSN@CTNR1 and MSN@CTNR2, were investigated, exhibiting grafting efficiencies of 10.66 % and 4.70 %, respectively. The functionalized silica particles from MSN@CTNR1 were examined and incorporated at varying proportions into rubber latex, leading to the formation of thin films. Surprisingly, films containing 1 part per hundred rubber (phr) functionalized silica had better mechanical and thermal properties than films containing unmodified silica. This study underscores the potential of MSN, whose surfaces are modified by grafting oligoisoprene brushes, to enhance the crosslinking points and serve as innovative additives in the formulation of composite rubber films. Furthermore, these findings highlight the prospects of utilizing modified silica nanoparticles as coating additive materials, enabling the enhancement of properties and performance in rubber-based composites, thereby paving the way for the development of advanced coating applications in diverse industries.

Effects of Phospholipid Structure on the Acoustic Cavitation of Functionalized Mesoporous Silica Nanoparticles: Implications for Image-Guided Drug Delivery

Effects of Phospholipid Structure on the Acoustic Cavitation of Functionalized Mesoporous Silica Nanoparticles: Implications for Image-Guided Drug Delivery

Cu(II) and Mn(II) Anchored on Functionalized Mesoporous Silica with Schiff Bases: Effects of Supports and Metal-Ligand Interactions on Catalytic Activity.

New series of Cu(II) and Mn(II) complexes with Schiff base ligands derived from 2-furylmethylketone (Met), 2-furaldehyde (Fur), and 2-hydroxyacetopheneone (Hyd) have been synthesized in situ on SBA-15-NH2, MCM-48-NH2, and MCM-41-NH2 functionalized supports. The hybrid materials were characterized by X-ray diffraction, nitrogen adsorption-desorption, SEM and TEM microscopy, TG analysis, and AAS, FTIR, EPR, and XPS spectroscopies. Catalytic performances were tested in oxidation with the hydrogen peroxide of cyclohexene and of different aromatic and aliphatic alcohols (benzyl alcohol, 2-methylpropan-1-ol, and 1-buten-3-ol). The catalytic activity was correlated with the type of mesoporous silica support, ligand, and metal-ligand interactions. The best catalytic activity of all tested hybrid materials was obtained in the oxidation of cyclohexene on SBA-15-NH2-MetMn as a heterogeneous catalyst. No leaching was evidenced for Cu and Mn complexes, and the Cu catalysts were more stable due to a more covalent interaction of the metallic ions with the immobilized ligands.

L-lysine Functionalized Mesoporous Silica Hybrid Nanoparticles for pH-Responsive Delivery of Curcumin.

Stimuli-responsive controlled drug delivery systems have attracted the attention of researchers in recent decades due to their potential application in developing efficient drug carriers that are responsive to applied stimuli triggers. In this work, we present the synthesis of L-lysine (an amino acid that combines both amine and carboxylic acid groups in a single unit) modified mesoporous silica nanoparticles (MS@Lys NPs) for the delivery of the anticancer bioactive agent (curcumin, Cur) to cancer cells. To begin, mesoporous silica hybrid nanoparticles (MS@GPTS NPs) with 3-glycidoxypropyl trimethoxy silane (GPTS) were synthesized. The L-lysine groups were then functionalized onto the mesopore channel surfaces of the MS@GPTS NPs through a ring-opening reaction between the epoxy groups of the GPTS and the amine groups of the L-lysine units. Several instrumental techniques were used to examine the structural properties of the prepared L-lysine-modified mesoporous silica nanoparticles (MS@Lys NPs). The drug loading and pH-responsive drug delivery behavior of MS@Lys NPs were studied at different pH levels (pH 7.4, 6.5, and 4.0) using curcumin (Cur) as a model anticancer bioactive agent. The MS@Lys NPs' in vitro cytocompatibility and cell uptake behavior were also examined using MDA-MB-231 cells. The experimental results imply that MS@Lys NPs might be used in cancer therapy as pH-responsive drug delivery applications.

Adsorption and Removal of Tetrabromobisphenol A by Adsorption on Functionalized Mesoporous Silica Nanotubes: Isotherms, Kinetics, Thermodynamics, and Optimization via Box-Behnken Design.

In pursuit of environmental safety, a novel and efficient method-dispersive solid-phase extraction based on functionalized mesoporous silica nanotubes (FMSNT nanoadsorbent)-was developed to remove tetrabromobisphenol A (TBBPA) from water samples. Characterization and comprehensive analysis of the FMSNT nanoadsorbent, including maximum adsorption capacity of 815.85 mg g-1 for TBBPA and its water stability, confirmed its potential. Subsequent analysis revealed the impact of multiple factors, for instance pH, concentration, dose, ionic strength, time, and temperature, on the adsorption process. The findings revealed that the adsorption of TBBPA followed the Langmuir and pseudo-second-order kinetics models while primarily driven by hydrogen bond interactions between bromine ions or hydroxyl groups of TBBPA and amino protons around the cavity. The novel FMSNT nanoadsorbent showed high stability and efficiency even after five times of recycling. Moreover, the overall process was identified as chemisorption, endothermic, and spontaneous. Finally, the Box-Behnken design was applied to optimize the results, confirming good reusability even after five cycles.

Synthesis of Chitosan Oligosaccharide-Loaded Glycyrrhetinic Acid Functionalized Mesoporous Silica Nanoparticles and In Vitro Verification of the Treatment of APAP-Induced Liver Injury.

the study was to find a suitable treatment for acute drug-induced liver injury. The use of nanocarriers can improve the therapeutic effect of natural drugs by targeting hepatocytes and higher loads. firstly, uniformly dispersed three-dimensional dendritic mesoporous silica nanospheres (MSNs) were synthesized. Glycyrrhetinic acid (GA) was covalently modified on MSN surfaces through amide bond and then loaded with COSM to form drug-loaded nanoparticles (COSM@MSN-NH2-GA). The constructed drug-loaded nano-delivery system was determined by characterization analysis. Finally, the effect of nano-drug particles on cell viability was evaluated and the cell uptake in vitro was observed. GA was successfully modified to obtain the spherical nano-carrier MSN-NH2-GA (≤200 nm). The neutral surface charge improves its biocompatibility. MSN-NH2-GA has high drug loading (28.36% ± 1.00) because of its suitable specific surface area and pore volume. In vitro cell experiments showed that COSM@MSN-NH2-GA significantly enhanced the uptake of liver cells (LO2) and decreased the AST and ALT indexes. this study demonstrated for the first time that formulation and delivery schemes using natural drug COSM and nanocarrier MSN have a protective effect on APAP-induced hepatocyte injury. This result provides a potential nano-delivery scheme for the targeted therapy of acute drug-induced liver injury.

Increasing Bioavailability of Trans-Ferulic Acid by Encapsulation in Functionalized Mesoporous Silica

Two types of mesoporous materials, MCM-41 and MCM-48, were functionalized by the soft-template method using (3-aminopropyl)triethoxysilane (APTES) as a modifying agent. The obtained mesoporous silica materials were loaded with trans-ferulic acid (FA). In order to establish the morphology and structure of mesoporous materials, a series of specific techniques were used such as: X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Brunauer-Emmet-Teller (BET), Fourier Transform Infrared Spectroscopy (FTIR) and thermogravimetric analysis (TGA). We monitored the in vitro release of the loaded FA at two different pH values, by using simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). Additionally, Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853 and Candida albicans ATCC 10231 were used to evaluate the antimicrobial activity of FA loaded mesoporous silica materials. In conclusion such functionalized mesoporous materials can be employed as controlled release systems for polyphenols extracted from natural sources.

Functionalization of Mesoporous Silica with a G-A-Mismatched dsDNA Chain for Efficient Identification and Selective Capturing of the MutY Protein.

MUTYH adenine DNA glycosylase and its homologous protein (collectively MutY) are typical DNA glycosylases with a [4Fe4S] cluster and a helix-hairpin-helix (HhH) motif in its structure. In the present work, the binding behaviors of the MutY protein to dsDNA containing different base mismatches were investigated. The type and distribution of base mismatch in the dsDNA chain were found to influence the DNA-protein binding interaction greatly. The [4Fe4S] cluster of the MutY protein is able to identify a G-A mismatch in the dsDNA chain specifically by monitoring the anomalies of charge transport in the dsDNA chain, allowing the entrance of the identified dsDNA chain into the internal cavity of the MutY protein and the strong DNA-protein binding at the HhH motif of the protein through multiple H-bonds. The dsDNA chain with a centrally located G-A mismatch is thus functionalized on mesoporous silica (MSN) via amination reaction, and the obtained dsDNA(G-A)@MSN is used as a powerful sorbent for the selective capturing of the MutY protein from complex samples. By using 0.5% NH3·H2O (m/v) as a stripping reagent, efficient isolation of the MutY protein from different cell lines and bacteria is achieved and the recovered MutY protein is demonstrated to maintain favorable DNA adenine glycosylase activity.

A functional bimodal mesoporous silica nanoparticle with redox/cellulase dual-responsive gatekeepers for controlled release of fungicide

Integrating toxic fungicide into a functional stimuli-responsive nanosystem can effectively improve the fungus control specificity and reduce the effect on non-target organisms. We report here a redox and cellulase dual-responsive multifunctional nanoparticle based on bimodal mesoporous silica (BMMs) to deliver prochloraz (Pro) for the smart management of wilt disease (Pro-AC-SS-BMMs, known as P-ASB). The surface of the nanocarrier was modified with an aminosilane coupling agent, and Pro was encapsulated by physical adsorption using 2,2′-dithiodiacetic acid as a smart bridge and disulfide (SS) cross-linked aminocellulose (AC) as gatekeepers. P-ASB nanoparticles (NPs) had a spherical structure, and the size was 531.2 ± 4.9 nm. The loading rate of Pro was 28.5%, and the NPs possessed excellent redox/cellulase dual-responsive release characteristics in the presence of glutathione (GSH) and cellulase. The nanocarrier could effectively protect Pro against photodegradation and had better foliar wettability than the Pro technical. Fluorescence tracer results showed that the nanocarriers were taken up and activated by the mycelium. P-ASB NPs had better control efficacy against Rhizoctonia solani and had no significant toxicity to cells and bacteria. This study provides a new strategy for enhancing the environmental protection and promoting the development of green agriculture.

Research and Application of Functionalized Mesoporous Silica Supported Quaternary Ammonium Salt Nano-antibacterial Materials

Objective: Nano-mesoporous silica has the superior physical properties and special ordered mesoporous structure.It can be used to prepare a surface material with antibacterial activity. Methods: Nano-mesoporous silica has been prepared by TEOS as the silicon source and CTAB as template. In this study, mesoporous silica was synthesized by sol-gel method. In the last, amino surfactants were used as carriers to bind to long chain organic surfactants by surface modification. The mesoporous silica functionalized with long chain quaternary ammonium salt was characterized by infrared spectroscopy, laser particle size and Zeta potential test, and its antibacterial effect was tested. The results show that amino groups are introduced to the surface of mesoporous silica after removing the template, and then dodecyl hydroxyethyl dimethyl ammonium bromide is bound to the surface of mesoporous silica. The combined product has good water solubility and its particle size is about 240 nm.Zeta potential test shows that it can be ionized and has positive charge in pure water. The antimicrobial effect test showed that the material could inhibit the growth and reproduction of DH5α Escherichia coli obviously at room temperature(P<0.05), and had certain antimicrobial activity.

Characterization and antifungal applications of azole functional mesoporous and hollow silica nanocomposites

Bu çalışmada çok gözenekli (MSN) ve tek gözenekli (HSS) silika nanopartiküllerin yüzeyinde, viniltriazol (VTri) monomerinin polimerizasyon reaksiyonu ile amin grupları oluşturulmuştur. Hazırlanan nanokompozit yapıların karakterizasyonu ve antifungal özelliği incelenmiştir. Nanokompozitlerin karakterizasyonunda MSN ve HSS' nın viniltriazol ile etkileşimini, yüzeydeki azol gruplarının varlığını belirlemek için FTIR ve XRD analizi, termal özelliklerini incelemek için TGA analizi yapılmıştır. Nanokompozitlerin morfolojisini belirlemek için SEM analizi yapılmıştır. Nanokompozit yapıların antifungal özellikleri MİK yöntemi ile kanıtlanmıştır.

Co-Delivery System of Curcumin and Colchicine Using Functionalized Mesoporous Silica Nanoparticles Promotes Anticancer and Apoptosis Effects.

Many natural agents have a high anticancer potential, and their combination may be advantageous for improved anticancer effects. Such agents, however, often are not water soluble and do not efficiently target cancer cells, and the kinetics of their action is poorly controlled. One way to overcome these barriers is to combine natural agents with nanoparticles. Our aim in the current study was to fabricate an anticancer nanoformulation for co-delivery of two natural agents, curcumin (CR) and colchicine (CL), with a core-shell structure. Using cancer cell lines, we compared the anticancer efficacy between the combination and a nanoformulation with CL alone. For the single-drug nanoformulation, we used phosphonate groups to functionalize mesoporous silica nanoparticles (MSNs) and loaded the MSNs with CL. Additional loading of this nanoformulation with CR achieved the co-delivery format. To create the structure with a core shell, we selected a chitosan-cellulose mixture conjugated with targeting ligands of folic acid for the coating. For evaluating anticancer and apoptosis effects, we assessed changes in important genes and proteins in apoptosis (p53, caspase-3, Bax, Bcl-2) in several cell lines (MCF-7, breast adenocarcinoma; HCT-116, colon carcinoma; HOS, human osteosarcoma; and A-549, non-small cell lung cancer). Nanoformulations were successfully synthesized and contained 10.9 wt.% for the CL single-delivery version and 18.1 wt.% for the CL+CR co-delivery nanoformulation. Anticancer effects depended on treatment, cell line, and concentration. Co-delivery nanoformulations exerted anticancer effects that were significantly superior to those of single delivery or free CL or CR. Anticancer effects by cell line were in the order of HCT-116 &gt; A549 &gt; HOS &gt; MCF-7. The lowest IC50 value was obtained for the nanoformulation consisting of CL and CR coated with a polymeric shell conjugated with FA (equivalent to 4.1 ± 0.05 µg/mL). With dual delivery compared with the free agents, we detected strongly increased p53, caspase-3, and Bax expression, but inhibition of Bcl-2, suggesting promotion of apoptosis. Our findings, although preliminary, indicate that the proposed dual delivery nanoformulation consisting of nanocore: MSNs loaded with CL and CR and coated with a shell of chitosan-cellulose conjugated folic acid exerted strong anticancer and apoptotic effects with potent antitumor activity against HCT-116 colon cells. The effect bested CL alone. Evaluating and confirming the efficacy of co-delivery nanoformulations will require in vivo studies.

Dual functional mesoporous silica colloidal electrolyte for lithium-oxygen batteries

Dual functional mesoporous silica (mSiO2) colloidal electrolytes are promising to protect lithium anode and accelerate the reaction kinetics on cathode for lithium-oxygen batteries (LOBs).In this work, we achieved a significantly extended battery life (from 55 to 328 cycles) of LOB by using mSiO2 with a concentration of 80 mg L−1 in the colloidal electrolyte, compared with the one using conventional LiClO4/DMSO electrolyte. The rate performance and full-discharge capacity are also dramatically enhanced. The as-synthesized mSiO2 has a special ordered hexagonal mesoporous structure, with a high specific surface area of 1016.30 m2/g, which can form a stable colloid after mixing with 1.0 M LiClO4/DMSO. The side reactions of Li stripping/plating are suppressed, thus the cycling life performance of LOB is enhanced by relieving the attack of superoxide intermediates. The co-deposition of mesoporous mSiO2 and Li2O2 also effectively accelerated the decomposition of the discharge product by promoting the mass transfer at the cathode. This investigation of suppressing side reactions using non-aqueous electrolytes will shed a new light on the design and development of novel lithium metal batteries.