Application Of Silica Nanoparticles Research Articles

Structure, Properties, and Applications of Silica Nanoparticles: Recent Theoretical Modeling Advances, Challenges, and Future Directions.

Silica nanoparticles (SNPs), one of the most widely researched materials in modern science, are now commonly exploited in surface coatings, biomedicine, catalysis, and engineering of novel self-assembling materials. Theoretical approaches are invaluable to enhancing fundamental understanding of SNP properties and behavior. Tremendous research attention is dedicated to modeling silica structure, the silica-water interface, and functionalization of silica surfaces for tailored applications. In this review, the range of theoretical methodologies are discussed that have been employed to model bare silica and functionalized silica. The evolution of silica modeling approaches is detailed, including classical, quantum mechanical, and hybrid methods and highlight in particular the last decade of theoretical simulation advances. It is started with discussing investigations of bare silica systems, focusing on the fundamental interactions at the silica-water interface, following with a comprehensively review of the modeling studies that examine the interaction of silica with functional ligands, peptides, ions, surfactants, polymers, and carbonaceous species. The review is concluded with the perspective on existing challenges in the field and promising future directions that will further enhance the utility and importance of the theoretical approaches in guiding the rational design of SNPs for applications in engineering and biomedicine.

Proteomics revealed composition- and size-related regulators for hepatic impairments induced by silica nanoparticles

Along with the growing production and application of silica nanoparticles (SiNPs), increased human exposure and ensuing safety evaluation have progressively attracted concern. Accumulative data evidenced the hepatic injuries upon SiNPs inhalation. Still, the understanding of the hepatic outcomes resulting from SiNPs exposure, and underlying mechanisms are incompletely elucidated. Here, SiNPs of two sizes (60 nm and 300 nm) were applied to investigate their composition- and size-related impacts on livers of ApoE−/− mice via intratracheal instillation. Histopathological and biochemical analysis indicated SiNPs promoted inflammation, lipid deposition and fibrosis in the hepatic tissue, accompanied by increased ALT, AST, TC and TG. Oxidative stress was activated upon SiNPs stimuli, as evidenced by the increased hepatic ROS, MDA and declined GSH/GSSG. Of note, these alterations were more dramatic in SiNPs with a smaller size (SiNPs-60) but the same dosage. LC-MS/MS-based quantitative proteomics unveiled changes in mice liver protein profiles, and filtered out particle composition- or size-related molecules. Interestingly, altered lipid metabolism and oxidative damage served as two critical biological processes. In accordance with correlation analysis and liver disease-targeting prediction, a final of 10 differentially expressed proteins (DEPs) were selected as key potential targets attributable to composition- (4 molecules) and size-related (6 molecules) liver impairments upon SiNPs stimuli. Overall, our study provided strong laboratory evidence for a comprehensive understanding of the harmful biological effects of SiNPs, which was crucial for toxicological evaluation to ensure nanosafety.

Application of Silica Nanoparticles in Combination with Bacillus velezensis and Bacillus thuringiensis for Anthracnose Disease Control in Shallot.

<b>Background and Objective:</b> Anthracnose in shallot contributes to significant losses. To solve this issue, silica nanoparticles, in combination with <i>Bacillus velezensis</i> and <i>Bacillus thuringiensis</i> were used together. <b>Materials and Methods:</b> <i>In vitro</i> antagonistic test of <i>Bacillus velezensis</i> B-27 with <i>Colletotrichum gloeosporioides</i> was carried out using dual culture and co-culture methods. Treatment in greenhouse experiments was carried out using single application of silica, <i>B. thuringiensis</i>, <i>B. velezensis</i>, a combination of <i>B. thuringiensis</i> and <i>B. velezensis</i> and a combination of <i>B. thuringiensis</i>, <i>B. velezensis</i> and silica. Detection of <i>B. velezensis</i> in the roots of shallot plants was carried out by PCR using a pair of specific primers. <b>Results:</b> <i>Bacillus velezensis</i> was able to inhibit the growth of <i>C. gloeosporioides</i> mycelium <i>in vitro</i>, both in the dual culture and co-culture methods, by 62.8 and 77.17%, respectively. Treatment of <i>B. thuringiensis</i> and <i>B. velezensis</i>, either individually or in combination with silica, could reduce the intensity of anthracnose disease by 20% each and stimulate the growth of shallot plants. The PCR detection using specific primers on the roots of shallot plants showed that <i>B. velezensis</i> was detected with a DNA band length of ±576 bp. <b>Conclusion:</b> <i>Bacillus velezensis</i> can inhibit the growth of <i>C. gloeosporioides</i> mycelium <i>in vitro</i>. Applying <i>B. velezensis</i>, <i>B. thuringiensis</i> and silica can reduce the intensity of anthracnose disease, promote plant growth and increase plant productivity. Furthermore, <i>B. velezensis</i> was detected in the roots of shallot plants, revealing that the bacteria are well-established.

Synergetic Interfacial Tension Reduction Potential of Silica Nanoparticles and Enzyme

The co-existence of multiphase fluids in the hydrocarbon reservoir rock pores plays a fundamental role in oil recovery processes because of the strong effect of interfacial forces that exist at the interface of these immiscible fluids. In this study, the effects of enzyme and silica nanoparticles on crude oil-brine interfacial tension were investigated under varied brine salinities and brine compositions. The results showed that the application of silica nanoparticles alone in brines of varied compositions and salinities does not significantly modify the crude oil-brine IFT. The use of enzyme and combined enzyme-nanoparticles however significantly reduced crude oil-brines IFT but the contribution of silica nanoparticles to the IFT reduction was not significant. The result of this study is relevant to the design and applications of enzyme and nanoparticles enhanced oil recovery processes.

Fastness Improvement of a Crystalline Liquid Thermochromic Print on Cotton Fabric by the Application of Silica Nanoparticles from Rice-Husk

Most commercially available thermochromic dyes are not resistant to washing and rubbing when applied to textile materials. This is due to their low affinity for fibre. The addition of silica extracted from rice husk ash using the sol-gel method was performed to improve colour fastness and maintain the stability of thermochromic dyes printed on cotton fabrics. The rice husks used in this study were derived from the Baroma rice variety with silica content in ash and silica gel of 97.05% and 99.20%. The morphological structures and particle sizes of the silica obtained were analysed using a scanning electron microscope (SEM) and particle size analyser (PSA). The particle sizes of the silica product, thermochromic dye and silica-dye mixture were 53.64–60.66 nm, 2.603 nm and 5.827 nm, respectively. The printing process of silica: the dye mixture was applied to cotton fabric in a ratio of 1:1. Fluid of silica: the dye showed good stability until the seventh day of observation. Colour fastness to washing assessed using a staining scale was better with the addition of silica than without silica, i.e. 3–4 in the first washing and 3 in the third washing. Similarly, fastness to rubbing was also better with the addition of silica, i.e. 3–4 dry rubbings and 3 wet rubbings. Moreover, the combination of silica, binder, PDMS and dye (in a ratio of 1:1:1:1) gave the best colour fastness to washing and rubbing.

Facile Preparation and Characterization of Silica Nanoparticles from South Africa Fly Ash Using a Sol–Gel Hydrothermal Method

Silica nanoparticles (SNPs) consist of several applications which include lightweight aggregates, energy storage, and drug delivery. Nevertheless, the silica reagents used in SNP synthesis are both costly and hazardous. As a result, it is critical to look for other sources of silica. For this research, a simple sol–gel hydrothermal approach is used to make SNPs from South African fly ash (SAFA). SAFA is classified as fly ash class F according to X-ray fluorescence (XRF) analysis. The wide-angle X-ray diffraction (XRD) pattern reveals the structural composition of SAFA and the amorphous phase of extracted SNPs, while Fourier transform infrared (FTIR) examination reveals the presence of silanol and siloxane groups. Basic SNPs were generally spherical with diameters of about 60 nm, according to scanning electron microscopy (SEM) and transition electron microscope (TEM) studies. The presence of SiO2 is confirmed by energy-dispersive X-ray spectroscopy (EDX) spectrum analysis. Particle size assessment indicates particle sizes ranging from 48 nm to 87 nm in diameter, with a mean diameter of 67 nm. The application of SNPs in wastewater treatment demonstrated that they can be used to remove Cd2+ from an aqueous solution. This research offers new ideas for using South African fly ash in SNP manufacturing.

Silica nanoparticles activate defense responses by reducing reactive oxygen species under Ralstonia solanacearum infection in tomato plants

Silica nanoparticles (SNPs) play an important positive role in enhancing stress resistance of plants. However, their absorption and the mechanisms of resistance in plants are not yet fully understood. In this study, we investigated the uptake of SNPs in tomato plants and explored the physiological and molecular mechanisms of SNPs-mediated bacterial wilt resistance. Folia application of SNPs significantly increased silicon content in tomato leaves and roots by 5.4-fold and 1.8-fold compared with healthy control, respectively. Moreover, foliar-applied SNPs mainly accumulated in the shoots of plants. Interestingly, we found that SNPs significantly reduced wilt severity by 20.71%–87.97%. Under pathogen infection conditions, the Hydrogen peroxide (H2O2) levels and Malondialdehyde (MDA) content in SNPs treated leaves significantly decreased by 16.33%–24.84% and 22.15%–38.54%, respectively, compared to non-treated SNPs leaves. The application of SNPs remarkably increased peroxidase (78.56–157.47%), superoxide dismutase (46.02–51.68%), and catalase (1.59–1.64 fold) enzyme activities, as well as upregulated the expression of salicylic acid-related genes (PR-1, PR-5, and PAL) in tomato leaves. Taken together, our findings demonstrate that SNPs function as important nanoparticles to maintain ROS homeostasis in plants by increasing antioxidant enzyme activity in tomato plants and enhancing plant tolerance to bacterial wilt disease by regulating the expression of salicylic acid-related genes. This study expands our understanding of how plants utilize these nanoparticles to deal with pathogen infection.

Application of Silica Nanoparticles in Combination with Two Bacterial Strains Improves the Growth, Antioxidant Capacity and Production of Barley Irrigated with Saline Water in Salt-Affected Soil.

Exploitation of low-quality water or irrigation of field crops with saline water in salt-affected soil is a critical worldwide challenge that rigorously influences agricultural productivity and sustainability, especially in arid and semiarid zones with limited freshwater resources. Therefore, we investigated a synergistic amendment strategy for salt-affected soil using a singular and combined application of plant growth-promoting rhizobacteria (PGPR at 950 g ha−1; Azotobacter chroococcum SARS 10 and Pseudomonas koreensis MG209738) and silica nanoparticles (SiNPs) at 500 mg L−1 to mitigate the detrimental impacts of irrigation with saline water on the growth, physiology, and productivity of barley (Hordum vulgare L.), along with soil attributes and nutrient uptake during 2019/2020 and 2020/2021. Our field trials showed that the combined application of PGPR and SiNPs significantly improved the soil physicochemical properties, mainly by reducing the soil exchangeable sodium percentage. Additionally, it considerably enhanced the microbiological counts (i.e., bacteria, azotobacter, and bacillus) and soil enzyme activity (i.e., urease and dehydrogenase) in both growing seasons compared with the control. The combined application of PGPR and SiNPs alleviated the detrimental impacts of saline water on barley plants grown in salt-affected soil compared to the single application of PGPR or SiNPs. The marked improvement was due to the combined application of PGPR and SiNPs, which enhanced the physiological properties (e.g., relative chlorophyll content (SPAD), relative water content (RWC), stomatal conductance, and K/Na ratio), enzyme activity (superoxide dismutase (SOD), catalase (CAT), and peroxidase (POX)), and yield and yield-related traits and nutrient uptake (N, P, and K) of barley plants. Moreover, the Na+ content, hydrogen peroxide (H2O2) content, lipid peroxidation (MDA), electrolyte leakage (EL), and proline content were reduced upon the application of PGPR + SiNPs. These results could be important information for cultivating barley and other cereal crops in salt-affected soil under irrigation with saline water.

Effect of silica nanoparticles on cell membrane fluidity: The role of temperature and membrane composition

The increasing production and application of silica nanoparticles (SiO2 NPs) raise public concern regarding their environmental and health risks. The fluidity of the cell membrane is essential for supporting membrane proteins and regulating membrane transport. Changes in membrane fluidity inevitably influence the physiological activities of cells and even cause biological effects. In this study, the effect of SiO2 NPs on membrane fluidity was studied at 25 °C and 37 °C, and the role of membrane components in SiO2 NP-membrane interactions was investigated using giant plasma membrane vesicles (GPMVs) isolated from RBL-2H3 cells. SiO2 NPs cause a more serious membrane fluidity decrease at 37 °C than at 25 °C, which is revealed by the shift of Laurdan fluorescence emission and further quantified via forster resonance energy transfer (FRET) experiments. In addition, after the removal of 75 % cholesterol from the membrane, SiO2 NPs caused a greater extent of membrane gelation. These results indicate that SiO2 NPs prefer to interact with membranes that are more dynamic and less densely packed. Moreover, fluorescent experiments confirmed that the existence of phosphatidyl ethanolamine (PE) and phosphoinositide (PI) can mitigate NP-induced membrane gelation. Molecular dynamics simulation further demonstrated that SiO2 NPs form hydrogen bonds with the terminal of PE or PI but with the -PO4−- group in the middle of phosphatidylcholine (PC). The bonding that occurs in the terminal gives less restriction of phospholipid movement and a weaker effect on membrane fluidity. This research provides both evidence and mechanisms of SiO2 NP-induced membrane fluidity changes, which are helpful for understanding cell membrane damage and the biological effects of NPs.

Silica Nanoparticle Acute Toxicity on Male Rattus norvegicus Domestica: Ethological Behavior, Hematological Disorders, Biochemical Analyses, Hepato-Renal Function, and Antioxidant-Immune Response.

With extensive production and various applications of silica nanoparticles (SiNPs), there is a controversy regarding the ecotoxicological impacts of SiNPs. Therefore, the current study was aimed to assess the acute toxicity of silica nanoparticles in male Rattus norvegicus domestica after 24 and 96 h. Hematological, serum biochemical, stress biomarker, and immune-antioxidant parameters were addressed. Chemical composition, crystal structure, and the particle shape and morphology of SiNPs were investigated using XRD, FTIR, BET, UV-Vis, and SEM, while TEM was used to estimate the average size distribution of particles. For the exposure experiment, 48 male rats were divided into four groups (12 rat/group) and gavaged daily with different levels of zero (control), 5, 10, and 20 mg of SiNPs corresponding to zero, 31.25, 62.5, and 125 mg per kg of body weight. Sampling was carried out after 24 and 96 h. Relative to the control group, the exposure to SiNPs induced clear behavioral changes such as inactivity, lethargy, aggressiveness, and screaming. In a dose-dependent manner, the behavior scores recorded the highest values. Pairwise comparisons with the control demonstrated a significant (p < 0.05) decrease in hematological and immunological biomarkers [lysozymes and alternative complement activity (ACH50)] with a concomitant reduction in the antioxidant enzymes [catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD)] in all exposed groups to SiNPs. On the contrary, there was a noticeable increase in biochemical parameters (glucose, cortisol, creatinine, urea, low-density lipoproteins (LDL), high-density lipoproteins (HDL), total protein, and albumin) and hepato-renal indicators, including alkaline phosphatase (ALP), alanine aminotransferase (ALT), and aspartate aminotransferase (AST), of all SiNP-exposed groups. It was observed that SiNPs induced acute toxicity, either after 24 h or 96 h, post-exposure of rats to SiNPs evidenced by ethological changes, hepato-renal dysfunction, hyperlipemia, and severe suppression in hematological, protein, stress, and immune-antioxidant biomarkers reflecting an impaired physiological status. The obtained outcomes create a foundation for future research to consider the acute toxicity of nanoparticles to preserve human health and sustain the environment.

A Comprehensive Review of Synthesis, Applications and Future Prospects for Silica Nanoparticles (SNPs)

Silica nanoparticles (SNPs) have shown great applicability potential in a number of fields like chemical, biomedical, biotechnology, agriculture, environmental remediation and even wastewater purification. With remarkably instinctive properties like mesoporous structure, high surface area, tunable pore size/diameter, biocompatibility, modifiability and polymeric hybridizability, the SNPs are growing in their applicable potential even further. These particles are shown to be non-toxic in nature, hence safe to be used in biomedical research. Moreover, the molecular mobilizability onto the internal and external surface of the particles makes them excellent carriers for biotic and non-biotic compounds. In this respect, the present study comprehensively reviews the most important and recent applications of SNPs in a number of fields along with synthetic approaches. Moreover, despite versatile contributions, the applicable potential of SNPs is still a tip of the iceberg waiting to be exploited more, hence, the last section of the review presents the future prospects containing only few of the many gaps/research extensions regarding SNPs that need to be addressed in future work.

Application of DLVO Modeling to Study the Effect of Silica Nanofluid to Reduce Critical Salt Concentration in Sandstones

Critical salt concentration (CSC) is the minimum salt concentration of injected water used for different oil recovery operations, below which fines migration initiates within sandstone reservoirs having clay contents and could be one of the potential causes of formation damage. This paper estimated CSC for Berea sandstone-NaCl brine system experimentally and by using DLVO modeling based on Van der Waals and electric double layer (EDL) surface forces. Furthermore, the effectiveness of silica nanofluid to reduce CSC and control fines migration was investigated. At different salinities of the injected fluid, the experimental CSC was determined by performing corefloods and analyzing effluent turbidity and absorbance. Attractive (van der Waals) and repulsive (EDL) forces were estimated by DLVO theory to predict the value of CSC. The experimental data were used to validate the model. The application of silica nanoparticles (NPs) was studied by injecting 0.1 wt% silica nanofluid and the resultant reduction in CSC was observed. During the injection of brines at different salinities ranging from 0.2 M to 0.05 M into the sandstone porous media, fines production was detected in the effluent after the injection of 0.1M NaCl solution, indicating that the CSC was 0.1M for this sand-fine-brine (SFB) system. The zeta potentials for SFB systems of different salinities were measured by zeta-sizer and were in the range of -32 mV to -24 mV. DLVO model based on attractive and repulsive forces was then used to predict the CSC, at which the total DLVO energy shifts from negative to positive and was around 0.1M for NaCl solution. The model prediction was in close agreement with the experimental results. Both the experiment and DLVO model showed the efficiency of silica nanofluid to mitigate fines migration as no fines production was observed for 0.1M NaCl case after the treatment with nanofluid. The estimation of CSC is critical to avoid formation damage during many oil recovery processes, included but not limited to low salinity waterflooding and alkaline flooding. The utilization of nanofluid provided promising results in controlling fines migration and reducing CSC. The proposed model based on DLVO theory can work as a useful tool to predict CSC without the need for extensive experimental work.

The alterations of miRNA and mRNA expression profile and their integration analysis induced by silica nanoparticles in spermatocyte cells

Air pollution and the application of Silica nanoparticles (SiNPs) have increased the risk of human exposure to SiNPs. SiNPs are known to induce cytotoxicity in spermatocyte cells (GC-2spd cells) of mice and male reproductive system damage. However, the expression profiles of miRNA and mRNA and the molecular mechanism of miRNA-mRNA integration in reproductive toxicity induced by SiNPs in GC-2spd cells are still unclear. Therefore, GC-2spd cells were divided into 0 μg/mL and 5 μg/mL SiNPs groups, and the cells were collected and analyzed after passaging for 30 generations using miRNA microarray and Illumina high-throughput sequencing (Illumina HiSeq) for the integrated analysis of miRNA and mRNA expression. Both miRNA Microarray and Illumina Hiseq identified 15 significant differentially expressed miRNAs and 1648 significant differentially expressed mRNAs. Gene Ontology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, and miRNA-gene-pathway-network analysis revealed 15 significant differentially expressed miRNAs that could regulate the DNA replication and the fatty acid metabolism, respectively. Furthermore, the mRNA-mRNA regulatory network analysis revealed that Pkfl (phosphofructokinase, liver, B-type) and DHCR24 (24-dehydrocholesterol reductase) were highly expressed, but also affected DNA replication and fatty acid metabolism in SiNPs-treated GC-2spd cells. Additionally, miRNA-mRNA integration analysis revealed that miRNA-138-1-3p might have a regulatory relationship with fatty acid metabolism and DNA replication. It is confirmed that SiNPs could decrease the expression of 10 miRNAs and increase the expression of 5 miRNAs. These findings suggest that the cytotoxicity of GC-2spd cells induced by SiNPs depends on the deregulation of multiple miRNAs, which regulate the DNA replication and fatty acid metabolism. Our results are the first to establish an integrated analysis of miRNA–mRNA interactions and mRNA-mRNA and defines multiple pathways involved in SiNPs-treated GC-2spd cells.

Combined foliar and soil application of silica nanoparticles enhances the growth, flowering period and flower characteristics of marigold (Tagetes erecta L.)

In recent years, the utilization of nanoparticles, especially in agricultural sector, has been intensively gained the interest of policymakers and the public. Most of these nanoparticles are applied singularly through foliar or soil applications. However, no reports are highlighting the interaction between foliar and soil application of nanoparticles, particularly silica nanoparticles (SiNPs). This study reports the differences between the singular and combined (foliar and soil) applications of SiNPs on the ornamental model marigold (Tagetes erecta L.) using different concentrations of amorphous SiNPs in pot experiments carried out under open field conditions during two consecutive seasons (2017 and 2018). The results proved the potentiality of SiNPs on plant growth where all the treated plants, regardless of the SiNPs concentration and delivery technique, displayed higher values for all the measured parameters compared to the control plants. Moreover, results demonstrated that the soil application of 200 mg L−1 resulted in higher values of plant height, number of branches, and root length than the foliar application of the same SiNPs concentration. On the other hand, the foliar application of 200 mg L−1 significantly increased flower’s traits over the soil application. The enhancement effect of SiNPs on plant biometrics, physiology, and properties of flower strongly linked to the Si content in plant leaves. The highest Si content corresponded to the combined foliar and soil application. Consequently, the higher number of flowers, flower's diameter, fresh and dry masses of flower, flowering period, and days taken to first bud initiation linked to plants received jointly 200 and 600 mg L−1 through foliar and soil application, respectively.

Silica nanoparticles induce mitochondrial pathway-dependent apoptosis by activating unfolded protein response in human neuroblastoma cells.

The application of silica nanoparticles (SiNPs) in areas of agriculture and medicine has raised great concerns for the potential adverse effects of SiNPs. The increasing toxicological studies focused mainly on the lung and cardiovascular system, but the adverse effects of SiNPs on nervous system have not been well explored. This study aimed to evaluate the role and mechanism of unfolded protein reaction (UPR) in SiNPs-induced cell injury on nerve cells in vitro. We investigated the UPR-mediated apoptosis caused by SiNPs in human neuroblastoma (SH-SY5Y) cell line. The size of SiNPs and its effect on cell ultrastructure were observed by transmission electron microscopy (TEM). Cell growth, mitochondrial membrane potential (MMP), calcium ion (Ca2+ ), apoptosis rate, and the expression level of related proteins were evaluated using MTT, flow cytometry, and western blot in SH-SY5Y cells exposed to SiNPs. The results showed that with the increase of SiNPs concentration, cell viability decreased, MMP decreased, active oxygen (ROS), and Ca2+ levels increased in a dose-dependent manner. In addition, protein expression of PERK, GRP78, and other related proteins in the unfolded protein response increased in a dose-response manner together with the expression of apoptosis proteins. Conclusively, this study confirmed that SiNPs can affect the neural system by interfering structure and functional and inducing apoptosis in nerve cells through unfolded protein response.

Plant-derived silica nanoparticles and composites for biosensors, bioimaging, drug delivery and supercapacitors: a review.

Silica nanoparticles have rapidly found applications in medicine, supercapacitors, batteries, optical fibers and concrete materials, because silica nanoparticles have tunable physical, chemical, optical and mechanical properties. In most applications, high-purity silica comes from synthetic organic precursors, yet this approach could be costly, polluting and non-biocompatible. Alternatively, natural silica sources from biomass are often cheap and abundant, yet they contain impurities. Silica can be extracted from corn cob, coffee husk, rice husk, sugarcane bagasse and wheat husk wastes, which are often disposed of in rivers, lands and ponds. These wastes can be used to prepare homogenous silica nanoparticles. Here we review properties, preparation and applications of silica nanoparticles. Preparation includes chemical and biomass methods. Applications include biosensors, bioimaging, drug delivery and supercapacitors. In particular, to fight the COVID-19 pandemic, recent research has shown that silver nanocluster/silica deposited on a mask reduces SARS-Cov-2 infectivity to zero.

Application of Silica Nanoparticles in the Determination of Herbicides in Environmental Water Samples Using Liquid Chromatography-Mass Spectroscopy

Background: Herbicides are very beneficial in the crop yield with the aid of controlling weeds within the agriculture, but several herbicides are chronic in soil. Objective: In this study, nanoparticles and the packages of synthesized novel silica nanoparticles were studied for the preconcentration of herbicides. Methods: These nanoparticles prepared by the Stöber mechanism were purified and functionalized. Nanoparticles thus prepared successfully were used as supporting material for the preconcentration of residues of herbicides in the water. Results: Preconcentration was achieved by preparing the silica-based solid-phase-extraction cartridges. Nanoparticles used for this purpose were within the range of 50-250 nm. An SPE cartridge was prepared by packing 200 mg of silica nanoparticle in the empty cartridge of diameter 5.5 cm and length 0.6 cm in between PTFE frits. Aqueous solutions of 0.1 μg/ml of herbicides were prepared separately, and 10 ml of the solution was passed through the cartridge at the rate of 0.2 ml/min. After passing 10 ml volume of the aqueous solution, residues adsorbed on the cartridge were eluted using 2 ml of acetonitrile. The eluate was injected to determine the herbicide residue adsorbed on the SPE cartridge. Conclusion: In the study, it was found that greater than 90% of the herbicide residues were trapped on silica nanoparticle-based SPE cartridge. An analytical method was developed for the simultaneous determination of these herbicides. The residues were quantified by LC-MS/MS with ESI mode.

Silica Nanoparticles in Transmucosal Drug Delivery.

Transmucosal drug delivery includes the administration of drugs via various mucous membranes, such as gastrointestinal, nasal, ocular, and vaginal mucosa. The use of nanoparticles in transmucosal drug delivery has several advantages, including the protection of drugs against the harsh environment of the mucosal lumens and surfaces, increased drug residence time, and enhanced drug absorption. Due to their relatively simple synthetic methods for preparation, safety profile, and possibilities of surface functionalisation, silica nanoparticles are highly promising for transmucosal drug delivery. This review provides a description of silica nanoparticles and outlines the preparation methods for various core and surface-functionalised silica nanoparticles. The relationship between the functionalities of silica nanoparticles and their interactions with various mucous membranes are critically analysed. Applications of silica nanoparticles in transmucosal drug delivery are also discussed.

Assessing the effects of different gas types on stability of SiO2 nanoparticle foam for enhanced oil recovery purpose

Application of silica nanoparticles (SiO2-NPs) as a foamer in CO2 foams has been widely investigated. Investigating the role of SiO2-NPs on making and stabilizing foams created by various gas types is still ongoing. This research attempted to experimentally determine and compare the impacts of SiO2-NPs on the stability of foams created by various available gas types including Nitrogen (N2), Methane (CH4), and carbon dioxide (CO2). For this purpose, 0.12 wt% Sodium dodecyl sulfate was solved in NaCl solution 0.1 wt% and then SiO2-NPs at concentrations from 0.001 to 0.1 wt% were added to the solution. N2, CH4, and CO2 gases were injected to the NPs suspensions with a flow rate of 50 mL/min and the stability of generated foams was determined through measuring half-life time. Once the optimum NP concentration was found for each gas type, that foam was flooded to a sandpack to find and compare the amount of oil recoveries. The optimum concentration of SiO2-NPs in terms of foam stability was achieved 0.01 wt% for all the applied gas. The half-life time of CH4, N2, and CO2 foams at 0.01 wt% SiO2-NPs were achieved 1054, 1720, and 62 min, respectively. Besides that, the amounts of incremental oil recoveries by NP-CH4, NP-N2, and NP-CO2 foams were obtained 25%, 31%, and 19%, respectively that 2 to 6% were higher than foam flood tests without NPs. According to the obtained results, it is generally can be concluded that utilizing N2 and CH4 gases in foam flooding for EOR purpose is more efficient than CO2.

Application of surface-modified silica nanoparticles with dual silane coupling agents in bitumen for performance enhancement

Bitumen is a black and highly viscous liquid that holds stone aggregate together in road pavement. Oxidation aging of bitumen can accelerate overall pavement deterioration and shorten pavement service life. Use of silica nanoparticles (SNPs) have been promoted as a sustainable construction practice to delay bitumen oxidation. Nonetheless, adequate dispersion of SNPs in bitumen has been a challenge since their first employment. Surface functionalization of SNPs with (3-aminopropyl) triethoxysilane (APTES) has demonstrated its efficiency to improve dispersion of SNPs in bitumen at relatively high loading of SNPs with low mechanical energy input. As the amount of APTES increases in the process of surface modification of SNPs, however, average size of the resultant SNPs and their agglomeration in bitumen also increase due to APTES self-condensation reaction on SNP surface. This research investigated surface modification of SNPs with other silane coupling agents including 3-(trihydroxysilyl) propyl methylphosphonate (THPMP) and (3-glycidyloxypropyl) trimethoxysilane (GPTMS) as well as dual silane combinations: APTES with THPMP and APTES with GPTMS. The intention was to minimize agglomeration of SNPs in bitumen and to further improve overall performance of SNP-containing bitumen. The comparative experimental results indicated that the surface-modified SNPs with dual silanes (APTES-GPTMS) outperformed the sole APTES-modified SNPs regarding dispersion in bitumen, resulting in bitumen with more enhanced anti-aging and low temperature properties. The results of this study inform and promote the application of SNPs in road pavement with enhanced performance and sustainability.