Search Results (82)

Mesoporous silica sieves have been prepared through sol–gel synthesis using diester gemini surfactants as pore templates, aiming to obtain new materials with potential use for water remediation. A series of mesoporous spherical silica particles of submicron size have been prepared in an alkali-catalyzed reaction, using a tetraethyl orthosilicate precursor and bis-quaternary ammonium gemini surfactants with diester spacers of varied lengths as pore-forming agents. The effect of the spacer length on the particle morphology was studied using nitrogen porosimetry, small-angle X-ray scattering (SAXS), ultra-small-angle neutron scattering, scanning, and transmission electron microscopy (SEM, TEM). The results revealed that for all spacer lengths, a long-range hexagonal pore ordering developed in the materials. The silica particles were nearly spherical, with sizes below 1 micrometer, and a weak dependence of the mean particle size on the spacer length could be observed. The template removal procedure had a strong influence on the porosity: calcination caused a moderate shrinkage of the pores while retaining the hexagonal structure, whereas treatment with acidified ethanol resulted in only partial removal of the surfactants; however, the hexagonal structure was severely destroyed. The applicability of the obtained calcined materials as adsorbents for heavy metal ions from water was studied with the example of Pb(II). A high sorption capacity of 110 mg/g was obtained in batch experiments, at pH 5 and 4 h contact time. Full article

Innovative nano fertilizers based on nanoparticles present great potential for agriculture since they can stimulate growth and development in different crops. However, the efficiency of nanoparticles directly depends on their physicochemical characteristics, such as composition, shape, size, and the type of plant species. In this work, a material formed by mesoporous silica and iron oxide (Fe₃O₄@MCM-48) was synthesized and used as a nano fertilizer for tomato crop. Materials with different percentages of iron (10, 20, 30, 40, and 50% by weight) were applied to study the effect of the amount of iron in the plants and compared with MCM-48 without iron and ferric chloride hexahydrate. Using X-ray diffraction (XRD), it was possible to identify the phases present in the system, and with Transmission Electron Microscopy (TEM), it was observed that the material is made up of a matrix of MCM-48 with embedded Fe₃O₄ nanoparticles with a size of 5 nm. Also, the results show that all treatments with nano fertilizers increased the content of photosynthetic pigments and carotenoids in leaves. The use of nano fertilizers can be a viable option to improve the crop growth and efficiency of nutrient use in plants. Full article

Bimetallic (Ta/Ti, V, Co, Nb) mesoporous MCM-41 nanoparticles were obtained by direct synthesis and hydrothermal treatment. The obtained mesoporous materials were characterized by XRD, XRF, N₂ adsorption/desorption, SEM, TEM, XPS, Raman, UV-Vis, and PL spectroscopy. A more significant effect was observed on the mesoporous structure, typically for MCM-41, and on optic properties if the second metal (Ti, Co) did not belong to the same Vb group with Ta as V and Nb. The XPS showed for the TaTi-MCM-41 sample that framework titanium is the major component. The new nanoparticles obtained were used as catalysts for oxidation with hydrogen peroxide of olefinic compounds (1,4 cyclohexadiene, cyclohexene, styrene) and photodegradation of organic pollutants (phenol, methyl orange) from water. The results showed improvementsin activity and selectivity in oxidation reactions by the addition of the second metal to the Ta-MCM-41 catalyst. The slow addition of H₂O₂ was also beneficial for the selectivity of epoxide products and the stability of the catalysts. The band gap energy values decreased in the presence of the second metal, and the band edge diagram evidenced positive potential for all the conduction bands of the bimetallic samples. The highestlevels of photocatalytic degradation were obtained for the samples with TaTi and TaV. Full article

Increased environmental pollution and the shortage of the current fossil fuel energy supply has increased the demand for eco-friendly energy sources. Hydrogen energy has become a potential solution due to its availability and green combustion byproduct. Hydrogen feedstock materials like sodium borohydride (NaBH₄) are promising sources of hydrogen; however, the rate at which the hydrogen is released during its reaction with water is slow and requires a stable catalyst. In this study, gold nanoparticles were deposited onto mesoporous carbon to form a nano-composite catalyst (AuNP-MCM), which was then characterized via transmission electron microscopy (TEM), powder X-ray diffraction (P-XRD), and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). The composite’s catalytic ability in a hydrogen evolution reaction was tested under varying conditions, including NaBH₄ concentration, pH, and temperature, and it showed an activation of energy of 30.0 kJ mol⁻¹. It was determined that the optimal reaction conditions include high NaBH4 concentrations, lower pH, and higher temperatures. This catalyst, with its stability and competitively low activation energy, makes it a promising material for hydrogen generation. Full article

Advanced breast cancer remains a significant oncological challenge, requiring new approaches to improve clinical outcomes. This study investigated an innovative theranostic agent using the MCM-41-NH₂-DTPA-Gd³⁺-MIH nanomaterial, which combined MRI imaging for detection and a novel chemotherapy agent (MIH 2.4Bl) for treatment. The nanomaterial was based on the mesoporous silica type, MCM-41, and was optimized for drug delivery via functionalization with amine groups and conjugation with DTPA and complexation with Gd³⁺. MRI sensitivity was enhanced by using gadolinium-based contrast agents, which are crucial in identifying early neoplastic lesions. MIH 2.4Bl, with its unique mesoionic structure, allows effective interactions with biomolecules that facilitate its intracellular antitumoral activity. Physicochemical characterization confirmed the nanomaterial synthesis and effective drug incorporation, with 15% of MIH 2.4Bl being adsorbed. Drug release assays indicated that approximately 50% was released within 8 h. MRI phantom studies demonstrated the superior imaging capability of the nanomaterial, with a relaxivity significantly higher than that of the commercial agent Magnevist. In vitro cellular cytotoxicity assays, the effectiveness of the nanomaterial in killing MDA-MB-231 breast cancer cells was demonstrated at an EC₅₀ concentration of 12.6 mg/mL compared to an EC₅₀ concentration of 68.9 mg/mL in normal human mammary epithelial cells (HMECs). In vivo, MRI evaluation in a 4T1 syngeneic mouse model confirmed its efficacy as a contrast agent. This study highlighted the theranostic capabilities of MCM-41-NH₂-DTPA-Gd³⁺-MIH and its potential to enhance breast cancer management. Full article

Alternative fuel sources are necessary in today’s economic and environmental climate. Hydrogen fuel arises as an environmentally friendly and energy dense option; however, the volatility of hydrogen gas makes it dangerous to store and utilize. The evolution of hydrogen from hydrogen feedstock materials may prove to overcome this safety barrier, but a catalyst for this reaction is necessary to optimize production. In this work, a composite catalyst comprised of palladium nanoparticles embedded on mesoporous carbon materials (Pd-MCM) was synthesized and characterized by Transmission Electron Microscope (TEM), Powder X-Ray diffraction (P-XRD), Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscope (EDS). Various reaction conditions such as concentration of reactant, temperature, and pH were applied in measuring the catalytic activity of Pd-MCM. Results show the catalytic activity of the Pd-MCM composite catalysts increased with increasing concentrations of sodium borohydride, increasing temperature, and lower pH. The reaction involving the Pd-MCM composite had an activation energy of 27.9 kJ mol⁻¹. Reusability trials showed the Pd-MCM composite remained stable for up to five consecutive trials. Full article

The growing population and increasingly competitive economic climate have increased the demand for alternative fuel sources, with hydrogen being one of the more viable options. Many metal hydrides, including sodium borohydride, are capable of releasing hydrogen stored within chemical bonds when reacted with water, but the rate of generation is slow and therefore necessitates a catalyst. Silver nanoparticles, which were chosen due to their known catalytic activity, were synthesized from sodium citrate and were embedded in mesoporous carbon to form a nano-composite catalyst (Ag-MCM). This composite was characterized via Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), and Scanning Electron Microscopy/Energy-Dispersive X-ray Spectroscopy (SEM/EDS). Catalytic testing showed that the catalytic activity for the Ag-MCM catalyst increased with increasing NaBH₄ concentration, low pH, and high temperatures. The Ag-MCM catalyst resulted in the activation energy at 15.6 kJ mol⁻¹, making it one of the lowest seen activation energies for inorganic catalysts. Lastly, the Ag-MCM catalysts showed stability, producing, on average, 20.0 mL per trial for five consecutive trials. This catalytic ability along with the cheap, carbon-based backbone that is made from readily available corn starch, makes it a promising catalyst for the hydrolysis of NaBH₄. Full article

The perpetually fluctuating economic and environmental climate significantly increases the demand for alternative fuel sources. The utilization of hydrogen gas is a viable option for such a fuel source. Hydrogen is one of the most energy-dense known substances; however, it is unfortunately also highly volatile, especially in the diatomic gaseous state most commonly used to store it. The utilization of a hydrogen feedstock material such as sodium borohydride (NaBH₄) may prove to mitigate this danger. When NaBH₄ reacts with water, hydrogen stored within its chemical structure is released. However, the rate of hydrogen release is slow and thus necessitates a catalyst. Platinum nanoparticles were chosen to act as a catalyst for the reaction, and to prevent them from conglomerating, they were embedded in a backbone of mesoporous carbon material (MCM) derived from a sustainable corn starch source. The nanocomposite (Pt-MCM) was characterized via transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). Pt-MCM underwent catalytic testing, revealing that the catalytic activity of the Pt-MCM composite catalysts increased with increasing quantities of sodium borohydride, lower pH levels, and higher temperatures. The activation energy of the catalyzed reaction was found to be 37.7 kJ mol⁻¹. Reusability experiments showed an initial drop off in hydrogen production after the first trial but subsequent stability. This Pt-MCM catalyst’s competitive activation energy and sustainable MCM backbone derived from readily available corn starch make it a promising option for optimizing the hydrogen generation reaction of NaBH₄. Full article

This work presents the green synthesis of iron oxide nanoparticles (IONPs) using Baccharis salicifolia extract and their incorporation in mesoporous silica MCM-41, obtaining an MCM-41@IONP composite. The MCM-41@IONP composite was characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), nitrogen adsorption and desorption, scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The use of the natural reducing agent Baccharis salicifolia resulted in nanoparticles with an average size of 31 nm. Furthermore, we showcase the application of the MCM-41@IONP nanocomposite in a metal–insulator–semiconductor (MIS) diode, which was fabricated at room temperature. The current–voltage and capacitance–voltage curves of the MIS diode were carefully measured and subjected to detailed analysis. The results demonstrate the potential utility of MCM-41@IONP nanocomposite-based MIS diodes, suggesting their applicability in the design of biosensors or as discrete components in electronic devices. Full article

The catalytic decomposition of CH₄ to H₂ and carbon nanotubes (CNTs) was investigated regarding Pt(1)-Fe(30)/MCM-41 and Fe(30)/MCM-41 using a fixed-bed flow reactor under an atmosphere. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscope (TEM), and Raman spectroscopy were used to characterize the behavior of Pt(1)-Fe(30)/MCM-41 and Fe(30)/MCM-41. The hydrogen yield of Pt(1)-Fe(30)/MCM-41 was 3.2 times higher than that of Fe(30)/MCM-41. When 1 wt% of Pt was added to Fe(30)/MCM-41(Mobil Composition of Matter No. 41), the atomic percentage of Fe2p increased from 13.39% to 16.14% and the core Fe2p_1/2 electron levels of Fe⁰ and Fe²⁺ chemically shifted to lower energies (0.2 eV and 0.1 eV, respectively) than those of Fe(30)/MCM-41. The Fe, Pt, Si, and O nanoparticles were uniformly distributed on the catalyst surface, and the average iron particle sizes of the Pt(1)-Fe(30)/MCM-41 and Fe(30)/MCM-41 were about 33.4 nm and 58.5 nm, respectively. This is attributed to the uniform distribution of the nano-sized iron particles on the MCM-41 surface, which was due to the suitable metal-carrier interaction (SMCI) between Fe, Pt, and MCM-41 and the high reduction degree of Fe due to the spillover effect of H₂ from Pt to Fe. Pt(1)-Fe(30)/MCM-41 produced multiwalled CNTs and bamboo-shaped CNTs with high crystallinity and graphitization degree using the tip-growth mechanism, with an I_D/I_G ratio of 0.93 and a C(101)/C(002) ratio of 0.64. Full article

Ivermectin (IVM), a widely used drug for parasitic infections, faces formulation and application challenges due to its poor water solubility and limited bioavailability. Pondering the impact of IVM’s high partition coefficient value (log P) on its drug release performance, it is relevant to explore whether IVM nanoencapsulation in organic or inorganic nanoparticles would afford comparable enhanced aqueous solubility. To date, the use of inorganic nanoparticles remains an unexplored approach for delivering IVM. Therefore, here we loaded IVM in mesoporous silica particles (IVM-MCM), as inorganic nanomaterial, and in well-known poly(ε-caprolactone) nanocapsules (IVM-NC). IVM-MCM had a well-organized hexagonal mesoporous structure, reduced surface area, and high drug loading of 10% w/w. IVM-NC had a nanometric mean size (196 nm), high encapsulation efficiency (100%), physicochemical stability as an aqueous dispersion, and drug loading of 0.1% w/w. Despite differing characteristics, both nanoencapsulated forms enhance IVM’s aqueous intrinsic solubility compared to a crystalline IVM: after 72 h, IVM-MCM and IVM-NC achieve 72% and 78% releases through a dialysis bag, whereas crystalline IVM dispersion achieves only 40% drug diffusion. These results show distinct controlled release profiles, where IVM-NC provides a deeper sustained controlled release over the whole experiment compared to the inorganic nanomaterial (IVM-MCM). Discussing differences, including drug loading and release kinetics, is crucial for optimizing IVM’s therapeutic performance. The study design, combined with administration route plans and safety considerations for humans and animals, may expedite the rational optimization of IVM nanoformulations for swift clinical translation. Full article

Hydrogels can offer many opportunities for drug delivery strategies. They can be used on their own, or their benefits can be further exploited in combination with other nanocarriers. Intelligent hydrogels that react to changes in the surrounding environment can be utilized as gatekeepers and provide sustained on-demand drug release. In this study, a hybrid nanosystem for temperature- and pH-sensitive delivery was prepared from MCM-41 nanoparticles grafted with a newly synthesized thermosensitive hydrogel (MCM-41/AA-g-PnVCL). The initial particles were chemically modified by the attachment of carboxyl groups. Later, they were grafted with agar (AA) and vinylcaprolactam (VCL) by free radical polymerization. Doxorubicin was applied as a model hydrophilic chemotherapeutic drug. The successful formulation was confirmed by FT-IR and TGA. Transmission electron microscopy and dynamic light scattering analysis showed small particles with negative zeta potential. Their release behaviour was investigated in vitro in media with different pH and at different temperatures. Under tumour simulating conditions (40 °C and pH 4.0), doxorubicin was almost completely released within 72 h. The biocompatibility of the proposed nanoparticles was demonstrated by in vitro haemolysis assay. These results suggest the possible parenteral application of the newly prepared hydrogel-functionalized mesoporous silica nanoparticles for temperature-sensitive and pH-triggered drug delivery at the tumour site. Full article

Non-small-cell lung cancer (NSCLC) mortality and new case rates are both on the rise. Most patients have fewer treatment options accessible due to side effects from drugs and the emergence of drug resistance. Bedaquiline (BQ), a drug licensed by the FDA to treat tuberculosis (TB), has demonstrated highly effective anti-cancer properties in the past. However, it is difficult to transport the biological barriers because of their limited solubility in water. Our study developed a UPLC method whose calibration curves showed linearity in the range of 5 ng/mL to 500 ng/mL. The UPLC method was developed with a retention time of 1.42 and high accuracy and precision. Its LOQ and LOD were observed to be 10 ng/mL and 5 ng/mL, respectively, whereas in the formulation, capmul MCM C10, Poloxamer 188, and PL90G were selected as solid lipids, surfactants, and co-surfactants, respectively, in the development of SLN. To combat NSCLC, we developed solid lipid nanoparticles (SLNs) loaded with BQ, whereas BQ suspension is prepared by the trituration method using acacia powder, hydroxypropyl methylcellulose, polyvinyl acrylic acid, and BQ. The developed and optimized BQ-SLN3 has a particle size of 144 nm and a zeta potential of (−) 16.3 mV. whereas BQ-loaded SLN3 has observed entrapment efficiency (EE) and loading capacity (LC) of 92.05% and 13.33%, respectively. Further, BQ-loaded suspension revealed a particle size of 1180 nm, a PDI of 0.25, and a zeta potential of −0.0668. whereas the EE and LC of BQ-loaded suspension were revealed to be 88.89% and 11.43%, respectively. The BQ-SLN3 exhibited insignificant variation in particle size, homogeneous dispersion, zeta potential, EE, and LC and remained stable over 90 days of storage at 25 °C/60% RH, whereas at 40 °C/75% RH, BQ-SLN3 observed significant variation in the above-mentioned parameters and remained unstable over 90 days of storage. Meanwhile, the BQ suspension at both 25 °C (60% RH) and 40 °C (75% RH) was found to be stable up to 90 days. The optimized BQ-SLN3 and BQ-suspension were in vitro gastrointestinally stable at pH 1.2 and 6.8, respectively. The in vitro drug release of BQ-SLN3 showed 98.19% up to 12 h at pH 7.2 whereas BQ suspensions observed only 40% drug release up to 4 h at pH 7.2 and maximum drug release of >99% within 4 h at pH 4.0. The mathematical modeling of BQ-SLN3 followed first-order release kinetics followed by a non-Fickian diffusion mechanism. After 24 to 72 h, the IC50 value of BQ-SLN3 was 3.46-fold lower than that of the BQ suspension, whereas the blank SLN observed cell viability of 98.01% and an IC50 of 120 g/mL at the end of 72 h. The bioavailability and higher biodistribution of BQ-SLN3 in the lung tumor were also shown to be greater than those of the BQ suspension. The effects of BQ-SLN3 on antioxidant enzymes, including MDA, SOD, CAT, GSH, and GR, in the treated group were significantly improved and reached the level nearest to that of the control group of rats over the cancer group of rats and the BQ suspension-treated group of rats. Moreover, the pharmacodynamic activity resulted in greater tumor volume and tumor weight reduction by BQ-SLN3 over the BQ suspension-treated group. As far as we are aware, this is the first research to look at the potential of SLN as a repurposed oral drug delivery, and the results suggest that BQ-loaded SLN3 is a better approach for NSCLC due to its better action potential. Full article

Functionalized polyethylene-based nanocomposites were prepared by in situ polymerization of ethylene with modified or neat MCM-41 nanoparticles (NMCM-41). Two different synthetic approaches were investigated to improve the compatibility between the hydrophobic HDPE matrix and the hydrophilic NMCM-41: (i) incorporation of UA into the polymeric matrix by copolymerization with ethylene, promoted by the zirconocene catalyst under homogeneous conditions, in the presence of pristine NMCM-41; (ii) use of undecenoic acid (UA) as an interfacial agent to obtain decorated NMCM-41 to be used as nanofiller for the in situ ethylene polymerization, catalyzed by Cp₂ZrCl₂/MAO under supported conditions. The strong polar character of the carboxylic group is expected to either increase the hydrophilicity of the HDPE chains (strategy i) or interact with the NMCM-41 surface and provide an additional link to the polymeric chains via copolymerization of the vinyl group under supported conditions (strategy ii). Although metallocene catalysts have been shown to copolymerize olefins with functional monomers, the presence of oxygen-containing compounds in the reaction media strongly affects the polymerization activity as a result of the interaction of functional groups with the electrophilic active center of the catalyst. Thus, UA was pre-contacted with tri(isobutyl)aluminum (TIBA) prior to its use in the polymerization to reduce the deactivating character of the carboxylic acid groups towards the zirconocene catalyst. The influence of the UA presence on the polymerization behavior of the protection step is discussed, and the polymerization activities observed for the different approaches are compared. In addition, the thermal behavior and structural details of the resulting materials have been characterized. The impact of using neat or functionalized NMCM-41 on the final dispersion within the polymeric matrix is also analyzed, which is correlated with the mechanical performance exhibited by these HDPE_UA_NMCM-41 nanocomposites. Full article

The vibrational dynamics in the sub-THz range of mesoporous silica nanoparticles (MSNs) having ordered cylindrical mesopores was investigated. MCM-41 and SBA-15 particles were synthesized, and their structure was determined using scanning electron microscopy (SEM), low-angle X-ray diffraction (XRD), N₂ physisorption analyses, and Raman scattering. Brillouin scattering measurements are reported and enabled determining the stiffness of the silica walls (speed of sound) using finite element calculations for the ordered mesoporous structure. The relevance of this approach is discussed based on the comparison between the numerical and experimental results and previous works reported in the literature. Full article