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The study aimed to apply biosilica nanoparticles from renewable resources for improving soil quality as a type of fertilizer carier. The silica particles having a purity of about 98 % were extracted from rice husk at the calcination temperatures of 550 °C, 600 °C, 650 °C, and 700 °C. The required materials properties were investigated by advanced measurement techniques. All samples showed the amorphous structure with Si–O–Si bond and the particles' agglomeration with the average size of 10–50 nm and principle electronic structures with the typical spectra of Si and O 2. When the synthesized silica was used as the medium to release absorbed nutrients in a controlled manner, surface properties, including the Brunauer–Emmett–Teller area and the average pore diameter were evaluated between 179 m2/g to 570 m2/g, and 4 nm–40 nm, respectively. The measured electrokinetic potential of the synthesized particles was between −20 mV and −36 mV guaranteeing the stability when they are dispersed in the aqueous environment. The experimental results showed that the silica particles calcinated at 650 °C had the best properties. [ABSTRACT FROM AUTHOR]

Gelatin methacrylate (GM) and sodium alginate (SA) are two biomaterials that have been widely employed in tissue engineering, particularly in 3D bioprinting. However, they have some drawbacks including undesirable physico‐mechanical properties and printability, hindering their application. This work developed an interpenetrating polymeric network (IPN) of GM and SA reinforced with silica nanoparticles (SNPs) to deal with hydrogels’ drawbacks. Besides, for cross‐linking, visible light is used as an alternative to UV light to prevent disruptions in cellular metabolism and immune system reactions. Four GM/SA/SNP hydrogels different in SNPs concentration (0, 0.5, 1, and 2 w/w%) are studied. The performance of the hydrogels is evaluated in terms of physico‐mechanical properties (viscoelasticity, compressive modulus, degradation, and swelling), rheological properties, and biological properties (fibroblast cell growth and adhesion, and MTT assay). The results demonstrated that the GM/SA/SNP hydrogel with 1% SNPs provided desirable physical (645% swelling and 59.3% degradation), mechanical strength (270 kPa), rheological (tan δ of almost 0.14), and biological performances (≈98% viability after 3 days) while maintaining appropriate printability. The findings suggest that the GM/SA/SNP hydrogel holds great potential for applications in soft tissue regeneration. [ABSTRACT FROM AUTHOR]

By using piezoelectric materials, it is possible to convert clean and renewable energy sources into electrical energy. In this paper, the effect on the piezoelectro-elastic response of piezoelectric-fiber-reinforced nanocomposites by adding silica nanoparticles into the polyimide matrix is investigated by a micromechanical method. First, the Ji and Mori–Tanaka models are used to calculate the properties of the nanoscale silica-filled polymer. The nanoparticle agglomeration and silica–polymer interphase are considered in the micromechanical modeling. Then, considering the filled polymer as the matrix and the piezoelectric fiber as the reinforcement, the Mori–Tanaka model is used to estimate the elastic and piezoelectric constants of the piezoelectric fibrous nanocomposites. It was found that adding silica nanoparticles into the polymer improves the elastic and piezoelectric properties of the piezoelectric fibrous nanocomposites. When the fiber volume fraction is 60%, the nanocomposite with the 3% silica-filled polyimide exhibits 39%, 31.8%, and 37% improvements in the transverse Young's modulus E T , transverse shear modulus G T L , and piezoelectric coefficient e 31 in comparison with the composite without nanoparticles. Furthermore, the piezoelectro-elastic properties such as E T , G T L , and e 31 can be improved as the nanoparticle diameter decreases. However, the elastic and piezoelectric constants of the piezoelectric fibrous nanocomposites decrease once the nanoparticles are agglomerated in the polymer matrix. A thick interphase with a high stiffness enhances the nanocomposite's piezoelectro-elastic performance. Also, the influence of volume fractions of the silica nanoparticles and piezoelectric fibers on the nanocomposite properties is studied. [ABSTRACT FROM AUTHOR]

Given the inevitable human exposure owing to its increasing production and utilization, the comprehensive safety evaluation of silica nanoparticles (SiNPs) has sparked concerns. Substantial evidence indicated liver damage by inhaled SiNPs. Notwithstanding, few reports focused on the persistence or reversibility of hepatic injuries, and the intricate molecular mechanisms involved remain limited. Here, rats are intratracheally instilled with SiNPs in two regimens (a 3‐month exposure and a subsequent 6‐week recovery after terminating SiNPs administration) to assess the hepatic effects. Nontargeted lipidomics revealed alterations in lipid metabolites as a contributor to the hepatic response and recovery effects of SiNPs. In line with the functional analysis of differential lipid metabolites, SiNPs activated oxidative stress, and induced lipid peroxidation and lipid deposition in the liver, as evidenced by the elevated hepatic levels of ROS, MDA, TC, and TG. Of note, these indicators showed great improvements after a 6‐week recovery, even returning to the control levels. According to the correlation, ROC curve, and SEM analysis, 11 lipids identified as potential regulatory molecules for ameliorating liver injury by SiNPs. Collectively, the work first revealed the reversibility of SiNP‐elicited hepatotoxicity from the perspective of lipidomics and offered valuable laboratory evidence and therapeutic strategy to facilitate nanosafety. [ABSTRACT FROM AUTHOR]

A concept to prepare a highly hydrophobic composite with self-healing properties has been designed and verified. The new material is based on a composite of a crystalline hydrophobic fluoro wax, synthesized from montan waxes and perfluoroethylene alcohols, combined with spherical silica nanoparticles equipped with a hydrophobic shell. Highly repellent layers were prepared using this combination of a hydrophobic crystalline wax and silica nanoparticles. The novel aspect of our concept was to prepare a ladder-like structure of the hydrophobic shell allowing the inclusion of a certain share of wax molecules. Wax molecules trapped in the hydrophobic structure during mixing are hindered from crystallizing; therefore, these molecules maintain a higher mobility compared to crystallized molecules. When a thin layer of the composite material is mechanically damaged, the mobile wax molecules can migrate and heal the defects to a certain extent. The general preparation of the composite is described and XRD analysis demonstrated that a certain share of wax molecules in the composite are hindered to crystallize. Furthermore, we show that the resulting material can recovery its repellent properties after surface damage. [ABSTRACT FROM AUTHOR]

Hollow silica nanoparticles (HSNPs) have hygroscopic properties because of their high specific surface area and surface hydroxyl groups. However, compared with other hygroscopic materials, their hygroscopic properties are relatively weak, which limits the further application of HSNPs. One feasible method to enhance their hygroscopic properties is by combining highly hygroscopic materials with hollow silica nanoparticles. To take advantage of the high hygroscopicity of polyacrylic acid (PAA) when combined with the high specific surface area of the hollow particles, PAA was coated on the inner and outer surfaces of the silica shell of the nanoparticles in this study to prepare hollow nanoparticles with a PAA/silica/PAA multilayer structure. The size of the PAA/silica/PAA multi-layer nanoparticles is about 85 nm, and the shell thickness is 25 nm. The specific surface area of the multi-layer nanoparticles is 58 m2/g. The water vapor adsorption capacity of multi-layer structure hollow nanoparticles was increased by 160% compared with the HSNPs (increased from 45.9 cm3/m2 to 109.1 cm3/m2). Meanwhile, at the same content of PAA, the PAA/silica/PAA-structured particles will adsorb 9% more water vapor than the PAA/silica-structured particles. This indicates that the high specific surface area structure of the hollow particles will enhance the adsorption ability of PAA toward water vapor. This novel structure of PAA-HSNPs is expected to be used as a humidity-regulating material for filler in environmental and architectural applications. [ABSTRACT FROM AUTHOR]

Background: Silica nanoparticles (SNPs) have immense potential in biomedical research, particularly in drug delivery and imaging applications, owing to their stability and minimal interactions with biological entities such as tissues or cells. Results: With synthesized and characterized cyanine-dye-doped fluorescent SNPs (CSNPs) using cyanine 3.5, 5.5, and 7 (Cy3.5, Cy5.5, and Cy7). Through systematic analysis, we discerned variations in the surface charge and fluorescence properties of the nanoparticles contingent on the encapsulated dye-(3-aminopropyl)triethoxysilane conjugate, while their size and shape remained constant. The fluorescence emission spectra exhibited a redshift correlated with increasing dye concentration, which was attributed to cascade energy transfer and self-quenching effects. Additionally, the fluorescence signal intensity showed a linear relationship with the particle concentration, particularly at lower dye equivalents, indicating a robust performance suitable for imaging applications. In vitro assessments revealed negligible cytotoxicity and efficient cellular uptake of the nanoparticles, enabling long-term tracking and imaging. Validation through in vivo imaging in mice underscored the versatility and efficacy of CSNPs, showing single-switching imaging capabilities and linear signal enhancement within subcutaneous tissue environment. Conclusions: This study provides valuable insights for designing fluorescence imaging and optimizing nanoparticle-based applications in biomedical research, with potential implications for targeted drug delivery and in vivo imaging of tissue structures and organs. [ABSTRACT FROM AUTHOR]

Silica nanoparticles (SiNPs) and graphene oxide (GO) are two promising nanomaterial that have attracted considerable attention for their unique properties and applications. However, the conventional synthesis methods of SiNPs and GO often involve hazardous chemicals and high energy consumption, which pose environmental and economic challenges. Therefore, green and sustainable synthesis methods of SiNPs and GO are highly desirable. In this review, we summarize the recent advances in the green synthesis of SiNPs and GO using various natural sources, such as plants, fungi, bacteria, algae, clay, etc. We also discuss the functionalization of SiNPs and GO with acrylic resin to form hybrid nanocomposites for anti-corrosion applications. The advantages and challenges of these green methods are highlighted, and the future prospects are outlined. This review aims to provide a comprehensive overview of the current state-of-the-art in the green synthesis of SiNPs and GO-based nanocomposites for anti-corrosion applications, and to inspire further research in this emerging field. [ABSTRACT FROM AUTHOR]

A new strategy for a catalytic C−C bond forming cascade reaction comprising acetal hydrolysis and Knoevenagel condensation is presented here. The heterogeneous nanocatalyst is prepared by immobilizing an ionic liquid on the surface of highly monodisperse silica nanoparticles. This work is the first example of showing that there is no need to use bifunctional acid‐base catalysts for a cascade reaction including the hydrolysis of benzaldehyde dimethyl acetal to benzaldehyde and the subsequent Knoevenagel condensation of the resulting benzaldehyde with malononitrile. It is shown here that these reactions can proceed smoothly with a mono‐functional heterogeneous catalyst that contains a neutral ionic liquid. It has been proposed that such a neutral ionic liquid can "switch on" to an acidic catalyst in conjunction with water. The selected ionic liquid has potentially biodegradability characteristics, which is an important issue to achieve a sustainable catalyst. The simple procedure for preparing both the ionic liquid and the monodisperse silica nanoparticles provides opportunities for a large‐scale synthesis of the catalyst. This work introduces a breakthrough in the design and synthesis of heterogeneous catalysts for acid/base catalyzed cascade organic reactions. [ABSTRACT FROM AUTHOR]

In this study, Taylor-vortex reactor was adopted to synthesize silica nanoparticles from sodium silicate solution and carbon dioxide. The outstanding advantages of the reactor have been demonstrated by comparing the synthesis results of silica nanoparticles by Erlenmeyer reactor. The results showed that silica particles synthesized from Taylor-vortex reactor are smaller in size than silica particles synthesized from the Erlenmeyer reactor. SEM images and histogram of particle size distribution obtained from experiments clearly exhibited that the concentration of SiO2 in the solution, reaction temperature, and rotation speed of the cylinder significantly affected morphology as well as size of the silica particles. [ABSTRACT FROM AUTHOR]

This work reports the fabrication of a large‐sized hydrogel sheet with enhanced mechanical and adhesive properties. The fabrication involves the introduction of carboxymethyl‐modified cellulose nanofibers (m‐CNFs) and solid silica nanoparticles (SSNs) as physical cross‐linkers into acrylic acid monomer (AA), followed by bar coating and photopolymerization. The addition of the nanomaterials to the monomer solution renders it viscous, enabling the fabrication of A4‐sized hydrogel sheets with uniform thickness and enhanced mechanical and adhesive properties. Interestingly, the combined incorporation of both the nanomaterials generates a synergistic effect to improve the properties much more, which results from the hierarchical rupture of the multiple hydrogen‐bonded interactions among the poly(acrylic acid) (PAA) matrix, m‐CNFs, and SSNs. Under optimal conditions, the hydrogel sheet incorporated with the dual crosslinkers exhibits a sevenfold higher toughness and a sixfold increased peel strength than plain PAA, together with good biocompatibility. Furthermore, when mesoporous silica nanoparticles (MSNs) with active agent loading into their pores are incorporated instead of SSNs, the active agent can be released from the hydrogel sheet in a sustained or temperature‐sensitive manner, indicating that the system is potentially applicable to transdermal drug delivery system with no additional adhesive. [ABSTRACT FROM AUTHOR]

[Display omitted] We have learned from the recent COVID-19 pandemic that the emergence of a new virus can quickly become a global health burden and kill millions of lives. Antiviral drugs are essential in our fight against viral diseases, but most of them are virus-specific and are prone to viral mutations. We have developed broad-spectrum antivirals based on multivalent nanoparticles grafted with ligands that mimic the target of viral attachment ligands (VALs). We have shown that when the ligand has a sufficiently long hydrophobic tail, the inhibition mechanism switches from reversible (virustatic) to irreversible (virucidal). Here, we investigate further how ligand density and particle size affect antiviral efficacy, both in terms of half-inhibitory concentration (IC 50) and of reversible vs irreversible mechanism. We designed antiviral silica nanoparticles modified with 11-mercaptoundecane-1-sulfonic acid (MUS), a ligand that mimics heparan sulfate proteoglycans (HSPG) and we showed that these nanoparticles can be synthesized with different sizes (4–200 nm) and ligand grafting densities (0.59–10.70 /nm2). By testing these particles against herpes simplex virus type 2 (HSV-2), we show that within the size and density ranges studied, the antiviral IC 50 is determined solely by equivalent ligand concentration. The nanoparticles are found to be virucidal at all sizes and densities studied. [ABSTRACT FROM AUTHOR]

[Display omitted] The adsorption of proteins on nanoparticles (NPs) largely decides the fate and bioeffects of NPs in vivo. However, bio-fluids are too complicated to directly study in them to reveal related mechanisms, and current studies on model systems often ignore some important biological factors, such as metal ions. Herein, we evaluate the effect of Ca2+ at physiological concentrations on the protein adsorption on negatively-charged silica NP (SNP50). It is found that Ca2+, as well as Mg2+ and several transition metal ions, significantly enhances the adsorption of negatively-charged proteins on SNP50. Moreover, the Ca2+-induced enhancement of protein adsorption leads to the reduced uptake of SNP50 by HeLa cells. A double-chelating mechanism is proposed for the enhanced adsorption of negatively-charged proteins by multivalent metal ions that can form 6 (or more) coordinate bonds, where the metal ions are chelated by both the surface groups of NPs and the surface residues of the adsorbed proteins. This mechanism is consistent with all experimental evidences from metal ions-induced changes of physicochemical properties of NPs to protein adsorption isotherms, and is validated with several model proteins as well as complicated serum. The findings highlight the importance of investigating the influences of physiological factors on the interaction between proteins and NPs. [ABSTRACT FROM AUTHOR]

Recently, silica nanoparticles (NPs) have attracted considerable attention as biocompatible and stable templates for embedding noble metals. Noble-metal-embedded silica NPs utilize the exceptional optical properties of novel metals while overcoming the limitations of individual novel metal NPs. In addition, the structure of metal-embedded silica NPs decorated with small metal NPs around the silica core results in strong signal enhancement in localized surface plasmon resonance and surface-enhanced Raman scattering. This review summarizes recent studies on metal-embedded silica NPs, focusing on their unique designs and applications. The characteristics of the metal-embedded silica NPs depend on the type and structure of the embedded metals. Based on this progress, metal-embedded silica NPs are currently utilized in various spectroscopic applications, serving as nanozymes, detection and imaging probes, drug carriers, photothermal inducers, and bioactivation molecule screening identifiers. Owing to their versatile roles, metal-embedded silica NPs are expected to be applied in various fields, such as biology and medicine, in the future. [ABSTRACT FROM AUTHOR]

Foam stability tests were performed using sodium dodecyl sulfate (SDS) surfactant and SiO2 nanoparticles as foaming system at different asphaltene concentrations, and the half-life of CO2 foam was measured. The mechanism of foam stability reduction in the presence of asphaltene was analyzed by scanning electron microscope (SEM), UV adsorption spectrophotometric concentration measurement and Zeta potential measurement. When the mass ratio of synthetic oil to foam-formation suspension was 1:9 and the asphaltene mass fraction increased from 0 to 15%, the half-life of SDS-stabilized foams decreased from 751 s to 239 s, and the half-life of SDS/silica-stabilized foams decreased from 912 s to 298 s. When the mass ratio of synthetic oil to foam-formation suspension was 2:8 and the asphaltene mass fraction increased from 0 to 15%, the half-life of SDS-stabilized foams decreased from 526 s to 171 s, and the half-life of SDS/silica-stabilized foams decreased from 660 s to 205 s. In addition, due to asphaltene-SDS/silica interaction in the aqueous phase, the absolute value of Zeta potential decreases, and the surface charges of particles reduce, leading to the reduction of repulsive forces between two interfaces of thin liquid film, which in turn, damages the foam stability. [ABSTRACT FROM AUTHOR]

The preparation of bulk-fused silica glass using stimuli-responsive silica nanoparticle (SiNP) aggregation methods is a promising research topic. For instance, the use of a SiNP/polyethylene glycol (PEG)/polyvinyl butyral (PVB) system for thermoplastic nanocomposite preparation, followed by heat-treatment sintering, has emerged as a highly precise and scalable method for obtaining fused silica glass with a short processing time. In this study, transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), and rheological analysis were used to investigate the dispersion of SiNPs in water, ethanol, water/ethanol, and water/ethanol/PEG mixtures. Furthermore, we investigated the effect of the different solvents on regulating external stimuli in the preparation of a SiNP slurry. Our results indicate that water/ethanol mixtures have a greater ability to obtain dispersed and thin slurries than water or ethanol alone, while the inclusion of PEG can further enhance this effect.The feedstocks obtained by this method is favorable for obtaining defect-free fused silica glass. In addition, agglomerates formed by SiNPs in a liquid environment can be rearranged and partially disassembled under the action of mechanical (shear) forces. Finally, optical profilometry tests showed that the sintered fused silica glass exhibited good surface quality replication, with a roughness Sa of only 148 nm. The finding in this study provides an idea for the preparation of commercial slurry for sintering fused silica glass. [ABSTRACT FROM AUTHOR]

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In recent years, the use of nanotechnology-based methods has become widespread in the treatment of ocular diseases. Silica nanoparticles (SiO 2 NPs) are most common used NPs in medical field due to their physicochemical properties. SiO 2 NPs can easily cross biological membranes and interact with basic biological structures, causing structural and functional changes in cells. In this study, it was aimed to investigate the dose dependent effect of SiO 2 NPs on retinal pigment epithelium (RPE) in vitro using electrobiophysical, biochemical and histological methods. A commercially purchased human RPE (hARPE-19) cell line was used in this study. Cells were divided into four groups as control, 50 μg/mL SiO 2 , 100 μg/mL SiO 2 and 150 μg/mL SiO 2 groups. Cell index, apoptotic activity, cell cycle and oxidative stress markers were measured in all groups. Findings in the present study showed that SiO 2 nanoparticles reduced cell proliferation, increased oxidative stress, apoptosis and arrest in the G 0 /G 1 phase of the cell cycle as dose dependent manner in ARPE-19 cells. In conclusion, SiO 2 exposure can induce cytotoxic effects in RPE cell line. The results of this study provide clues that exposure to SiO 2 nanoparticles may impair visual function and reduce quality of life. However, further studies are needed in this regard. • SiO 2 nanoparticles are used as drug carriers in the treatment of many eye diseases. • SiO 2 nanoparticles have toxic effects that should not be ignored. • SiO 2 nanoparticles reduce cell proliferation in hARPE19 cells. • SiO 2 nanoparticles induce apoptosis and Go/G1 arrest in hARPE19 cells. • SiO 2 nanoparticles cause induce oxidative stress leading to cell death in hARPE19 cells. [ABSTRACT FROM AUTHOR]

Oil-based drilling fluids for deep well drilling should have stability and high temperature resistance, and water-in-oil inverse emulsions are a good choice as oil-based drilling fluids. In deep well drilling, high temperature will cause polymer surfactants to degrade and phase separation occurs. The octadecyltrimethoxysilane modified silica nanoparticles are used to form a stable water-in-oil inverse emulsion in a drilling fluid model, so that the emulsion fluid forms 60 µm water droplets. In addition, rheology shows that the use of hydrophobic silica nanoparticles can obtain stable water-in-oil inverse emulsions, the properties of which can be modified by adjusting the properties and content of the nanoparticles. The aging test at 120 °C shows that it has good stability at high temperatures and is suitable for deep well drilling operations. [ABSTRACT FROM AUTHOR]

In this study, we were able to create highly dispersed silica nanoparticles with diameters of less than one nm by changing the sol-gel technique. During the poly-condensation process, a strong magnetic field was applied to the silica sol to control particle size. The size of silica nanoparticles has a substantial impact on preparation elements such pH, magnetic field intensity, and exposure time. These parameters can be changed in a systematic manner to reduce or increase particle size. A dynamic light scattering test was also used to investigate the effect of a magnetic field on the particle size and dispersion of silica dust. Despite the fact that silica is naturally diamagnetic, the magnetic field has a considerable impact on their size growth. Magnetic fields altered the typical influence on silicon structure, resulting in crystal formation in the silicon sample under consideration. Many applications require small particle sizes and/or a narrow particle size dispersion. The building blocks of nanotechnology are usually made of low-dimension particles. The experts concluded that additional research into such strange phenomena will be required in the future. [ABSTRACT FROM AUTHOR]

Bleeding complications are associated with substantial tissue morbidities and mortalities. Biomimetic composite materials that possess the ability to sufficiently stimulate and augment different physiological mechanisms of hemostasis are highly desirable to reduce bleeding-related casualties, which, however, are still largely under-explored. This study aims to develop a composite hemostatic system by combining collagen hydrogel with tissue factor (TF)-integrated liposome and silica nanoparticle, which could integrate the platelet plug-promoting capacity of collagen with the abilities of the latter two components to activate the extrinsic and intrinsic pathways of coagulation respectively. Several hydrogel compositions were synthesized and characterized. We show that lipidated TF and silica were evenly distributed in the collagen-based hydrogels, while exhibiting tunable release kinetics in simulated body fluid. Time-to-coagulation test revealed that each component in the TF-liposome/silica/collagen ternary hydrogels was hemostasis-active, and their combination showed enhanced and potent procoagulant performance, without detectable cytotoxicity against NIH/3T3 model cells. These results suggest that collagen hydrogels with embedded TF-liposome and silica nanoparticle may serve as a platform for an effective hemostatic composite that incorporates all the basic known pathways of coagulation. [ABSTRACT FROM AUTHOR]

In this study, we have prepared silica nanoparticles (SiNPs) from biomass (rice husk) and organic precursor (TEOS) by sol‐gel precipitation method and compared their efficacy for theranostics applications. In the preparation of SiNPs, we have studied the effects of different parameters such as solvent, catalyst, temperature, water and precursor on the shape and size of SiNPs. It shows that the size of SiNPs was increased with an increase in the concentration of ethanol and acid catalyst; the particle size was decreased with an increase in reaction temperature and precursor. To develop the drug for photodynamic therapy against the target tumor cells, protoporphyrin (PpIX), an efficient photosensitizer is functionalized on the surface of SiNPs. The drug loading potential was studied by the conjugation of 5‐Fluorouracil on the surface of functionalized SiNPs. From the results, we suggest that the functionalized SiNPs will be used for combined therapeutic and diagnostic in biomedical applications. [ABSTRACT FROM AUTHOR]

Agro-waste can provide a non-metallic, environmentally friendly bio-precursor for the production of green silica nanoparticles. To manufacture silica nanoparticles from rice husk, biogenic silica nanoparticles were generated using an alkaline precipitation approach. Rice husk as a source of silica nanoparticles is environmentally and economically valuable because it is a plentiful lower price agricultural derivative that can be used to help with waste management. During the synthesis process, the dose of rice husk ash was used at 5 g at pH 7, alkali dose concentration of 0.5 M, reaction period of 3.5 h, and temperature of 90°C that produced maximum silica nanoparticles with a yield of 88.5%. To optimize the silica nanoparticle production from rice husk ash Box Behnken Design (BBD) a subcategory of the response surface methodology (RSM) was accomplished. BBD model was successfully matched, as evidenced by the high correlation values of adjusted R2 0.9989 and predicted R² 0.9977. Silica nanoparticles' amorphous form generated from rice husk ash is indicated by XRD analysis 2θ peak at 22.12° and UV-Vis Spectroscopy absorbance peak at 312 nm. The amorphous shape of silica is amorphous and crystalline defined through XRD. nanoparticles generated from rice husk ash is indicated by FESEM analysis and EDX analysis, confirming that the SiO2 elemental configuration comprises the highest concentration of Si and O. The existence of a siloxane group in the produced compound was revealed by FTIR spectra stretching vibrations at 803.69 and 1089.05 cm-1. [ABSTRACT FROM AUTHOR]

Elastin-like polypeptides (ELPs) are attractive materials for the green preparation of silica nanoparticles via biomimetic silicification. However, the critical factors affecting the ELP-mediated silicification remain unclear. Herein, the role of tunable amino acid residues of ELPs in silicification was studied using three ELPs (ELPs[V9F-40], ELPs[KV8F-40], and ELPs[K5V4F-40]) and their fusion proteins (ELPs[V9F-40]-SpyCatcher, ELPs[KV8F-40]-SpyCatcher, and ELPs[K5V4F-40]-SpyCatcher) with different contents of lysine residues. Bioinformatics methods were employed for the first time to reveal the key physicochemical parameters correlated with silicification. The specific activity of ELPs was increased with the promotion of lysine content with a high correlation coefficient (R = 0.899). Furthermore, exogenous acidic protein SpyCatcher would hinder the interactions between the silica precursors and ELPs, leading to the significantly decrease in specific activity. The isoelectric point (p I) of ELPs presented the highest correlation to silicification with a coefficient of 0.963. The charges of the ELPs [K5V4F-40] at different pH were calculated based on the sequence or structure. Interestingly, the excellent correlation between charges based on structure and specific activity was obtained. Collectively, the novel methods developed here may pave a new way for rational design of ELPs or other peptides for efficient and green preparation of silica nanomaterials for biomedicine, biocatalysis, and biosensor. [ABSTRACT FROM AUTHOR]

Membrane distillation (MD) is a promising technology for wastewater treatment, but often faces significant challenges of scaling and wetting. Development of advanced omniphobic membranes has been the core research for mitigating scaling and wetting in MD. In this study, a novel fluorinated multi-scale silicon nanoparticle grafted corrugated (FSiC-PVDF) membrane (water contact angle 179.5 ± 0.3°) was prepared and explored for enhancement of anti-scaling performance by calcium sulfate and anti-wetting performance by sodium dodecylsulfate (SDS). Silica nanoparticles (SiNPs) were synthesized and covalently bonded to the surface of the corrugated membrane and the surface energy was further reduced via chemical fluorination. Flat-sheet membrane (F-PVDF) and corrugated membrane (C-PVDF) were compared. Results showed that compared to the previous study of grafting SiNPs on flat membranes directly, FSiC-PVDF exhibited superior flux (21.1 kg/(m2·h)), and it can consistently demonstrate stable water flux and quality even at high calcium sulfate and SDS concentrations. The F-PVDF experienced significant declines in performance, and the C-PVDF showed limited improvement in scaling and wetting resistance. Corrugation pattern contributed to a larger evaporation area and higher velocity near the membrane surface, thus reducing crystal deposition and heterogeneous nucleation on the surface. The combination of corrugation and SiNPs resulted in a stable Cassie-Baxter wetting state, reduced solid-liquid interface areas, and created slippage conditions that minimized the impact of contaminants on MD performance. These findings indicated that FSiC-PVDF membranes offer significant advantages for MD processes, enhancing operational stability and efficiency. [Display omitted] • SiNPs grafted multi-scale corrugation patterned superhydrophobic membrane was prepared. • SiNPs grafted on corrugated PVDF membranes enhanced scaling and wetting resistance. • High flow velocity and re-entrant structure contributed to exceptional resistance to scaling and wetting. [ABSTRACT FROM AUTHOR]

Nanoparticles have useful functions due to the characteristics conferred on them by an increase in their specific surface area, and they have already been put into practical use in products in various industrial fields. Although exposure to nanoparticles in daily life is unavoidable for pregnant women, studies that evaluate the toxicity of nanoparticles in pregnant women are lacking. To redress this, we have focused on the placenta and have previously revealed that nanoparticles can show placental toxicity. However, there is still little knowledge regarding the behavior of nanoparticles within placental cells, which would enable us to understand their mode of action. Here, we tried to clarify the intracellular localization of silica nanoparticles in placental cells and how this affects placental toxicity. We analyzed the uptake of silica nanoparticles with a diameter of 10 nm (nSP10) into JEG-3 cells, a human choriocarcinoma cell line. Flow cytometry analysis showed that nSP10 labelled with red fluorescence were taken up into JEG-3 cells, and that pre-treatment with the endocytosis inhibitor cytochalasin D inhibited their uptake, suggesting that nSP10 are taken up into JEG-3 cells by the endocytic pathway. Moreover, confocal microscopy revealed that nSP10 are prominently localized in lysosomes. Staining with LysoTracker showed that nSP10 treatment increased the acidic compartment of JEG-3 cells, suggesting lysosome accumulation and swelling. These results indicate that nSP10 taken into placental cells are transferred to lysosomes and may cause lysosomal dysfunction. • 10-nm silica nanoparticles were taken up into JEG-3 cells via the endocytic pathway. • 10-nm silica nanoparticles were localized in lysosomes in JEG-3 cells. • 10-nm silica nanoparticles increased the number of lysosomes in JEG-3 cells. [ABSTRACT FROM AUTHOR]

Herein, a facile, scalable, and cost‐effective method was used to fabricate eco‐friendly superhydrophobic UV‐curable polyurethane‐silica nanocomposite coating with promising physicomechanical properties. Fluorinated UV‐curable polyurethane dispersion was synthesized and used as the binder of the superhydrophobic coating along with hydrophobically modified silica nanoparticles as textured topography. The chemical structures of the employed silica nanoparticles, prepared UV‐curable polymer, and superhydrophobic coating were thoroughly studied by FTIR analysis. It has been revealed that the prepared SH coating possesses well‐defined micro/nano‐scale roughness, high contact angle (159°), and low sliding angle (1.5°), which can be applied onto various substrates. Also, the exceptional durability of the fabricated coating against sandpaper abrasion (over 80 m) without losing its superhydrophobicity revealed the high capability of the prepared waterborne coating to be used in harsh practical applications. Additionally, due to the highly cross‐linked structure of the prepared SH coating, the applied coating could maintain its integrity even after 30 days of immersion in different organic solvents. Moreover, the prepared coatings showed substantial potential for use in self‐cleaning and oil/water separation fields (> 98% efficiency after 15 cycles of oil/water separations). We are convinced that the prepared hybrid coating could offer a practical approach for fabricating of superhydrophobic materials as promising nominates for disparate fields. [ABSTRACT FROM AUTHOR]

In this study, we have developed a synthetic method which can precisely and conveniently manipulate the morphologies of silica nanoparticles at the molecular level. The reaction system contains cationic cetyltrimethylammonium bromide (CTAB), fatty acid salts, modulating molecules, silica precursor, and water. No additional alkaline catalysts and organic solvents are needed. Fatty acid salts, acting as the catalytic co-surfactants and the shaping agents as well, form uniform self-assembly templates with cationic CTAB. All the synthetic silica nanoparticles are characterized using TEM, SEM and N 2 sorption experiments. Results show that the generated nanoparticles are highly dispersed and demonstrate a variety of surface morphologies such as solid, porous, spokewise, sponge-like, walnut-like, Swiss roll-like appearance. The morphology transitions can be tuned by changing the aliphatic lengths (C2 to C18) of catalytic fatty acid salts, the concentration of silica precursor, and the combination of the fatty acid salts with different carbon chains. In the case of all the porous nanoparticles, the pore size (from ∼2.5 nm to > 100 nm, from single-pore type to dual-pore type) can be obtained by the adjustment of above parameters. In addition, the silica nanoparticles can also be transformed to extremely small granulates（∼8 nm to the lowest）and hollow shells via introducing specific compounds (called modulating molecules) that regulate the molecular interactions within the reaction system. The developed reaction system is environment-friendly. The current work could be applied to the engineering of preparing other nanomaterials via the sol-gel method. [ABSTRACT FROM AUTHOR]

Long‐term exposure to respirable silica particles causes pulmonary inflammation and fibrosis primarily promoted by cytokines released from alveolar macrophages, yet the underlying mechanism is still unclear. From the perspective of nuclear factor kappa B (NF‐κB), we studied the mechanism of IL‐1β biosynthesis and release. Utilizing BAY 11‐7082, an NF‐κB specific inhibitor, we showed the alteration of macrophage viability and examined the expression of both IL‐1β and NF‐κB in vitro. We found that silica nanoparticles (SiNPs) were internalized by macrophages and caused damage to cell integrity. The immunofluorescence assay showed that SiNPs exposure enhanced the expression of IL‐1β and NF‐κB, which could be effectively suppressed by BAY 11‐7082. Besides, we built silica exposure mouse model by intratracheally instilling 5 mg of SiNPs and checked the effect of silica exposure on pulmonary pathological changes. Consistently, we found an upregulation of IL‐1β and NF‐κB after SiNPs exposure, along with the aggravated inflammatory cell infiltration, thickened alveolar wall, and enhanced expression of collagens. In conclusion, SiNPs exposure causes pulmonary inflammation and fibrosis that is regulated by NK‐κB through upregulating IL‐1β in alveolar macrophages. [ABSTRACT FROM AUTHOR]

This article describes about feasibility of silica modified Candelilla wax (CW)/thermoplastic polyurethane (TPU) coating for hydrophobic textiles. CW/TPU blend solutions at different ratio (10:1, 10:3 and 10:5) were studied for rheological properties at different temperature and shear rates. The blend solutions were coated on the surface of cotton, polyester and nylon fabric. Water contact angle and stiffness properties of the coated fabrics were evaluated in order to optimize the blend ratio. The optimized blend ratio CW/TPU (10:5) was further modified with different weight percentage of Silica nanoparticles (0.5 to 2 wt. %) and coated on the cotton, polyester and nylon fabrics. The water contact angle of 2.0% silica modified CW/TPU coating was found to be 147°, 144° and 140° for cotton, polyester and nylon respectively. The surface morphology of coated fabrics was evaluated through scanning electron microscopy. Silica modified CW/TPU fabric showed textured surface. Coated fabrics were evaluated for properties such as thickness, weight gain and stiffness. [ABSTRACT FROM AUTHOR]

• A new type of phosphorescent material without metal or organic fluorophores. • Carbon-related defects leading the intersystem crossing-based phosphorescence. • The rigid silica network ensuring the longevity of the phosphorescent emission. • Time-gated afterglow imaging system eliminating the tissue-autofluorescence. • Clear visualization-based diagnosis of subcutaneous tumors by high-contrast imaging. Room-temperature phosphorescence (RTP) has tremendous potential in optics and photonics. Unlike fluorescence, RTP has substantial afterglow signals even after the excitation light is removed, which allows for extended acquisition times and higher signal-to-noise ratio under time-gated bioimaging. However, conventional RTP materials, both metal-containing and metal-free organic compounds, typically have limited photostability and inherent toxicity, making them unsuitable for long-term biological applications. Here, we report metal- and organic fluorophore-free silica nanoparticles (SNPs) that facilitate long-lived phosphorescence and exhibit RTP for high-contrast bioimaging. Polycondensation of silicon precursors and silyl biphenyls forms biphenyl-doped SNPs (bSNPs), and thermal decomposition of biphenyl moieties generates optically active defects in the biphenyl-bonded silicate network. The calcined bSNPs (C-bSNPs) have RTP-related biphenyl defects composed of carbon impurities, corresponding to spectroscopic measurements and ab initio calculations. Facile surface functionalization of defect-engineered C-bSNPs with tumor-targeting peptides while maintaining long-lived RTP allows for tissue autofluorescence-free in vivo bioimaging for cancer diagnosis, surpassing the limitations of continuous-wave imaging. [ABSTRACT FROM AUTHOR]

[Display omitted] • CS-coated FMSNs allow sustained, pH-dependent anti-cancer camptothecin release. • NDDS exhibited remarkable efficacy in vitro and in vivo without any side effects. • Addition of CpG ODN to NDDS further amplifies its therapeutic effect. The therapeutic efficacy of camptothecin (CPT), a potent antitumor alkaloid, is hindered by its hydrophobic nature and instability, limiting its clinical use in treating cutaneous squamous cell carcinoma (SCC). This study introduces a novel nano drug delivery system (NDDS) utilizing functionalized mesoporous silica nanoparticles (FMSNs) for efficient CPT delivery. The FMSNs were loaded with CPT and subsequently coated with chitosan (CS) for enhanced stability and bioadhesion. Importantly, CpG oligodeoxynucleotide (CpG ODN) was attached onto the CS-coated FMSNs to leverage the immunostimulatory properties of CpG ODN, augmenting the chemotherapy's efficacy. The final formulation FMSN-CPT-CS-CpG displayed an average size of 241 nm and PDI of 0.316 with an encapsulation efficiency of 95 %. Comprehensive in vitro and in vivo analyses, including B16F10 cells and DMBA/TPA-induced SCC murine model, demonstrated that the FMSN-CPT-CS-CpG formulation significantly enhanced cytotoxicity against B16F10 cells and induced complete regression in 40 % of the in vivo subjects, surpassing the efficacy of standard CPT and FMSN-CPT treatments. This study highlights the potential of combining chemotherapeutic and immunotherapeutic agents in an NDDS for targeted, efficient skin cancer treatment. [ABSTRACT FROM AUTHOR]

In this work, we present two methodologies to prepare nano compounds derived from a mixture of metals oxides supported in biogenic silica nanoparticles. Cobalt, copper, and zinc salts were used to impregnate the silica nanoparticles by two different methods. In the first method, called, Direct method, the rice husks were impregnated with salts solutions of the metals of interest and then thermally treated and sintered to obtain the respective silica nanocomposite, in the second method, the Indirect method, silica nanoparticles were prepared from biogenic materials and then were impregnated with the metal solution and sintered. Samples obtained by both methods were characterized by SEM, DLS, and AFM, the composition was determined by LiBS and their optical properties by Uv–vis, FTIR and the variations in the bandgap of the metal oxides and the effect of the metal oxide's confinement within the nanoparticle structure were studied. The bandgap values obtained for the samples correspond to those of oxide nanoparticles of the corresponding metals, with small variations due to confinement by being embedded in the SiO2 matrix. [ABSTRACT FROM AUTHOR]

Silica nanoparticles (SiO2 NPs) are increasingly investigated for their potential in drug delivery systems. However, the neurotoxicity of SiO2 NPs remains to be fully clarified. Previously SiO2 NPs have been reported to be detected in the central nervous system, especially in the dopaminergic neurons which are deeply involved in Parkinson's disease (PD). In this article, we characterized the effects of SiO2 NPs on inducing PD-like pathology both in vitro and in vivo. Results showed that SiO2 NPs promote more severe hyperphosphorylation and aggregation of α-synuclein, mitochondria impairment, oxidative stress, autophagy dysfunction, and neuronal apoptosis in the α-Syn A53T transgenic mice intranasally administrated with SiO2 NPs compared with the control group. Our findings provide new evidence supporting that SiO2 NPs exposure might have a strong capability of promoting the initiation and development of PD. [ABSTRACT FROM AUTHOR]

Mixed matrix membranes (MMMs) owing to the tunable characteristics and functionalization ability can effectively substitute the highly intensive conventional membranes for industrial‐scale CO2 separation. Further, to strengthen the interfacial polymer‐filler interaction, an interfacial design strategy incorporating active functional groups in the filler surface can be demonstrated. In this study, as‐synthesized silica nanoparticles (SNPs) was surface functionalized by (3‐aminopropyl) trimethoxysilane silica modifier (AFSNP). The CO2 separation of poly (vinyl alcohol)/polyethylene glycol based MMM infused with surface‐functionalized SNP (AFSNP) was conducted. The comparative study highlighted in‐depth analysis of intrinsic physicochemical properties of as‐synthesized membranes and nanoparticles. Detailed characterization such as advanced microscopic analysis, X‐ray photoelectron spectroscopy (XPS) analysis and ninhydrin assay validated the successful grafting of amino groups onto the silica surface. The morphological inspection corroborated the consistent dispersion ability of the nanoparticles in the membrane matrix. The effect of the operating conditions on the membrane selectivity and CO2 permeance were statistically analyzed by ANOVA. The CO2 permeation result (CO2 permeance and CO2/N2 selectivity) exhibited many fold increment with surface functionalization of SNPs compared to undoped silica MMM. The defect‐free, performance‐oriented CO2‐selective membrane thus opened up the possibility of this combination as a prospective contender for large‐scale carbon capture studies. [ABSTRACT FROM AUTHOR]

The rapid development of nanotechnology has greatly benefited modern science and engineering and also led to an increased environmental exposure to nanoparticles (NPs). While recent research has established a correlation between the exposure of NPs and cardiovascular diseases, the intrinsic mechanisms of such a connection remain unclear. Inhaled NPs can penetrate the air–blood barrier from the lung to systemic circulation, thereby intruding the cardiovascular system and generating cardiotoxic effects. In this study, on-site cardiovascular damage was observed in mice upon respiratory exposure of silica nanoparticles (SiNPs), and the corresponding mechanism was investigated by focusing on the interaction of SiNPs and their encountered biomacromolecules en route. SiNPs were found to collect a significant amount of apolipoprotein A-I (Apo A-I) from the blood, in particular when the SiNPs were preadsorbed with pulmonary surfactants. While the adsorbed Apo A-I ameliorated the cytotoxic and proinflammatory effects of SiNPs, the protein was eliminated from the blood upon clearance of the NPs. However, supplementation of Apo A-I mimic peptide mitigated the atherosclerotic lesion induced by SiNPs. In addition, we found a further declined plasma Apo A-I level in clinical silicosis patients than coronary heart disease patients, suggesting clearance of SiNPs sequestered Apo A-I to compromise the coronal protein’s regular biological functions. Together, this study has provided evidence that the protein corona of SiNPs acquired in the blood depletes Apo A-I, a biomarker for prediction of cardiovascular diseases, which gives rise to unexpected toxic effects of the nanoparticles. [ABSTRACT FROM AUTHOR]

A hyperbranched hybrid curing agent (CSD) for epoxidized novolac resin (ENR) was prepared by grafting silica nanoparticles modified with poly(amidoamine) (PAMAM) dendritic structure (SD) to carbon nanotube (CNT) using an esterification reaction between the amino functional groups of SD and carboxylic acid functionalities of oxidized CNT. ENR was prepared by a reaction between novolac resin and epichlorohydrin. Curing of ENR was carried out with two different contents of CSD as the hyperbranched hybrid curing component of the epoxidized matrix. The amino-rich structure of CSD could result in its high dispersion in the ENR matrix and consequently high thermal stability of the hybrid composites. Fourier-transform infrared spectroscopy and thermal gravimetric analysis (TGA) showed successful modification of silica nanoparticles and CNT with the PAMAM dendritic structure and SD, respectively. Structure of the resulting hybrid curing agents (SD and CSD) was investigated by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Thermal investigation of the resulted composites by TGA showed that the cured ENR with higher content of CSD has high thermal properties with a char residue of 44.4% among the other hybrid composites. [ABSTRACT FROM AUTHOR]

The rapid development of gene therapy and genome editing techniques brings up an urgent need to develop safe and efficient nanoplatforms for nucleic acids and CRISPR genome editors. Herein we report a stimulus-responsive silica nanoparticle (SNP) capable of encapsulating biomacromolecules in their active forms with a high loading content and loading efficiency as well as a well-controlled nanoparticle size (~50 nm). A disulfide crosslinker was integrated into the silica network, endowing SNP with glutathione (GSH)-responsive cargo release capability when internalized by target cells. An imidazole-containing component was incorporated into the SNP to enhance the endosomal escape capability. The SNP can deliver various cargos, including nucleic acids (e.g., DNA and mRNA) and CRISPR genome editors (e.g., Cas9/sgRNA ribonucleoprotein (RNP), and RNP with donor DNA) with excellent efficiency and biocompatibility. The SNP surface can be PEGylated and functionalized with different targeting ligands. In vivo studies showed that subretinally injected SNP conjugated with all- trans -retinoic acid (ATRA) and intravenously injected SNP conjugated with GalNAc can effectively deliver mRNA and RNP to murine retinal pigment epithelium (RPE) cells and liver cells, respectively, leading to efficient genome editing. Overall, the SNP is a promising nanoplatform for various applications including gene therapy and genome editing. [Display omitted] [ABSTRACT FROM AUTHOR]

Superhydrophobic cotton fabrics with water contact angle of 160.8° was fabricated based on fluorinated alternating copolymer grafted silica nanoparticle, which demonstrated durable and excellent resistance to varying organic solvents, acids, alkalis, hot water, sonication and mechanical abrasion, as well as high separation efficiency (maximum 99.6 %) and satisfying reusability for continuous separation of oil/water mixtures. [Display omitted] • Superhydrophobic cotton fabrics based on fluorinated polymer and silica nanoparticle are prepared. • The cotton fabrics as prepared show excellent stability and resistance to extreme conditions. • High efficiency and reusability for continuous separation of oil/water mixtures are achieved. The development of superhydrophobic materials has attracted great attention due to their promising potential in a variety of areas including oil–water separation. In this work, durable and robust superhydrophobic cotton fabrics based on fluorinated alternating copolymer and silica nanoparticle are prepared. Silica nanoparticles are in-situ produced and immobilized onto the surface of poly dopamine (PDA) wrapped cotton fabrics, then modified by fluorinated block copolymer (AB2) n A- b -PIPMSA m , followed by removing the iodine on the polymers, to prepare superhydrophobic cotton fabrics with water contact angle up to 160.8°. The prepared cotton fabrics are durable, displaying excellent resistance to varying organic solvents, acids, alkalis, hot water, sonication and mechanical abrasion. High separation efficiency (maximum 99.6 %) and satisfying reusability for continuous separation of oil/water mixtures are achieved. The separation efficiency for trichloromethane/water mixtures is still as high as 94 % even after 50 times of repetitive separation. In addition, water-in-oil emulsion can be also efficiently handled, displaying high practical application potential. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cellulose nanofibers (CNF)/silica nanoparticles were successfully prepared for hydrophobic coating. • The addition of CNF effectively improved the viscosity of the coating solution and the dispersion stability of silica nanoparticles. • The durability of the coating is improved due to the strong hydrogen bonding between the added CNFs and the wood surface. Hydrophobization of wood is pivotal for enhancing the utility of wood products. Traditional hydrophobic coatings, primarily petrochemical-based, are now being replaced by environmentally friendly silane-coupled inorganic nanoparticles. However, these alternatives face challenges like poor dispersion stability and weak wood surface adhesion. Our research introduces cellulose nanofibers (CNFs) into the condensation process of silica nanoparticles, creating a CNFs/silica nanoparticle composite. This composite exhibits remarkable dispersion stability and adjustable viscosity, leading to an improved hydrophobic silica/CNFs coating. Its versatility allows for various application methods, including spray, dip, and brush coating. Remarkably, the composite maintains a water contact angle of about 151°, demonstrating excellent water repellency, even with hydrophilic CNFs. The CNFs also enhance the interaction with wood surfaces, boosting the durability of the coating. This innovative approach not only improves storage stability and workability but also ensures uniform hydrophobicity and durable coating formation. Our findings suggest that CNFs derived from lignocellulosic biomass could ultimately be incorporated into environmentally friendly wood coating materials, significantly improving the shortcomings of conventional hydrophobic coatings while reducing dependence on petroleum-based products. [ABSTRACT FROM AUTHOR]

Staphylococcal enterotoxins are one of the most important causative agents of food poisoning. These molecules function as both gastrointestinal toxins and superantigens (SAgs) which can simultaneously bind MHC-II and T cell receptor leading to a non-specific polyclonal T cell activation and massive proinflammatory cytokine release. Common symptoms include vomiting and diarrhea; however, in more severe cases, systemic dissemination may result in toxic shock syndrome and can be lethal in a few hours. Only small amounts of these heat-stable toxins are needed to cause the disease. Therefore, it is highly important to detect quickly low concentrations of SAgs in biological samples. In this work, we report a surface plasmon resonance (SPR)-based capture immunoassay for the detection of the SAg SEG. We analyzed the use of different amplification strategies. The SPR-based double-antibody sandwich approach could detect picomolar levels of SEG. The use of antibody-coated silica nanoparticles (AbSiNPs) as an alternative enhancing reagent also detected SEG in the picomolar range. Although AbSiNPs did not improve the limit of detection, for the same amount of SAg tested, AbSiNPs gave a higher response level than free antibodies. This work highlights the suitability of silica nanoparticles for signal amplification in SPR-based biosensors. Overall, SPR biosensors offer the capability for continuous real-time monitoring and high sensitivity that can be befitting for the detection of enterotoxins in food industries, laboratories and regulatory agencies. [Display omitted] • SPR biosensors are useful tools for Staphylococcal enterotoxins detection. • SPR-based double-antibody sandwich assay could detect picomolar levels of SEG. • Antibody-coated silica nanoparticles can amplify the signal in SPR-based methods. • SEG detection in the picomolar range was achieved with AbSiNPs. • AbSiNPs gave higher binding responses than free antibodies for SEG detection. [ABSTRACT FROM AUTHOR]

Background: As the application of silica nanomaterials continues to expand, increasing chances of its exposure to the human body and potential harm are anticipated. Although the toxicity of silica nanomaterials is assumed to be affected by their physio-chemical properties, including size and surface functionalization, its molecular mechanisms remain unclear. We hypothesized that analysis of intracellular localization of the particles and subsequent intracellular signaling could reveal a novel determinant of inflammatory response against silica particles with different physico-chemical properties. Results: We employed a murine intratracheal instillation model of amorphous silica nanoparticles (NPs) exposure to compare their in vivo toxicities in the respiratory system. Pristine silica-NPs of 50 nm diameters (50 nm-plain) induced airway-centered lung injury with marked neutrophilic infiltration. By contrast, instillation of pristine silica particles of a larger diameter (3 μm; 3 μm-plain) significantly reduced the severity of lung injury and neutrophilic infiltration, possibly through attenuated induction of neutrophil chemotactic chemokines including MIP2. Ex vivo analysis of alveolar macrophages as well as in vitro assessment using RAW264.7 cells revealed a remarkably lower cellular uptake of 3 μm-plain particles compared with 50 nm-plain, which is assumed to be the underlying mechanism of attenuated immune response. The severity of lung injury and neutrophilic infiltration was also significantly reduced after intratracheal instillation of silica NPs with an amine surface modification (50 nm-NH2) when compared with 50 nm-plain. Despite unchanged efficacy in cellular uptake, treatment with 50 nm-NH2 induced a significantly attenuated immune response in RAW264.7 cells. Assessment of intracellular redox signaling revealed increased reactive oxygen species (ROS) in endosomal compartments of RAW264.7 cells treated with 50 nm-plain when compared with vehicle-treated control. In contrast, augmentation of endosomal ROS signals in cells treated with 50 nm-NH2 was significantly lower. Moreover, selective inhibition of NADPH oxidase 2 (NOX2) was sufficient to inhibit endosomal ROS bursts and induction of chemokine expressions in cells treated with silica NPs, suggesting the central role of endosomal ROS generated by NOX2 in the regulation of the inflammatory response in macrophages that endocytosed silica NPs. Conclusions: Our murine model suggested that the pulmonary toxicity of silica NPs depended on their physico-chemical properties through distinct mechanisms. Cellular uptake of larger particles by macrophages decreased, while surface amine modification modulated endosomal ROS signaling via NOX2, both of which are assumed to be involved in mitigating immune response in macrophages and resulting lung injury. [ABSTRACT FROM AUTHOR]

Enhanced oil recovery (EOR) processes are applied to recover trapped or residual oil in the reservoir rocks after primary and secondary recovery methods. Changing the wettability of the rock from oil-wet to water-wet is named wettability alteration. It is an important factor for EOR. Due to their unique properties, nanoparticles have gained great attention for improving oil recovery. Despite the promising results, the main challenges of applying nanoparticles are related to the colloidal stability of the nanofluids in the harsh conditions of the reservoirs. In recent years, polymer-grafted nanoparticles have been considered as novel promising materials for EOR. The obtained results showed that adding a hydrophobic agent trimethoxy (propyl) silane on the surface of modified silica nanoparticles with polyethylene glycol methyl ether has an effective role in improving retention and wettability alteration, especially in the oil-wet substrate due to hydrophobic interaction. The modified silica nanoparticle by mixed polyethylene glycol methyl ether (Mn ~ 5000) and trimethoxy (propyl) silane showed a proper performance at a concentration of 1000 ppm and a salinity range of 2000–40,000 ppm. The obtained findings can help for a better understanding of the silica nanofluid modification with both hydrophilic and hydrophobic agents for the EOR application of near-wellbore. [ABSTRACT FROM AUTHOR]

Multidrug resistance (MDR) of chemotherapy is one of the significant concerns in cancer therapy. Here in our study, cisplatin (DDP) and oleanolic acid (OA) were co‐loaded in mesoporous silica nanoparticles (Nsi) to construct DDP/OA‐Nsi and solve the DDP‐resistance in lung cancer therapy. The cytotoxicity and apoptosis assays demonstrated that in DDP‐resistant A549/DDP cells, the cytotoxicity of DDP/OA‐Nsi was significantly higher than that of free DDP or DDP single delivery system (DDP‐Nsi). The intracellular drug accumulation study revealed that the intracellular DDP concentration in the DDP/OA‐Nsi group was also higher than that in free DDP and DDP‐Nsi groups. In the A549/DDP xenograft tumor model, DDP/OA‐Nsi showed the best anticancer effect. In summary, DDP/OA‐Nsi was a promising drug delivery system to solve MDR in lung cancer therapy. [ABSTRACT FROM AUTHOR]

A multi-step homogenization approach is presented to predict the off-axis creep response of hybrid polymer matrix composites (HPMCs) reinforced with unidirectional carbon fibers and silica nanoparticles. The first step deals with evaluating the viscoelastic properties of silica nanoparticle-polymer nanocomposite using the Mori-Tanaka micromechanical model. Two essential features affecting the behavior, including silica nanoparticle agglomeration and interphase region generated due to the interaction between the nanoparticle and polymer are taken into account. In the second step, the off-axis viscoelastic behavior of HPMCs is extracted from the homogenized nanocomposite and carbon fiber properties using a unit cell-based micromechanical model. Some comparative studies between the predictions and available experiment are directed to verify the homogenization process. All the model predictions are in good agreement with the experimental data. The results indicate that with increasing the fiber off-axis angle from 0° to 90°, the presence of silica nanoparticles leads to a reduction in the HPMC creep compliance. Also, the proposed multi-step homogenization approach is applied to investigate the effects of volume fraction, size and agglomeration degree of silica nanoparticles; thickness and material properties of the interphase region; and off-axis angle and volume fraction of the carbon fiber on the HPMC creep response. [ABSTRACT FROM AUTHOR]

The aim of this study was to experimentally determine the effect of silica nanoparticles (NS) on the buckling characteristics of Kevlar/epoxy fiber reinforced composite laminates. The composite samples with different weight fractions of NS particles, namely 0.0, 0.5, 1.0, 1.5 and 2.5 wt%, were prepared by vacuum assisted resin transfer molding (VARTM) and subjected to axial and lateral buckling tests. Additionally, the buckling tests were performed on the samples with different lengths (125, 150, 175, 200 and 225 mm) to analyze in more detail the influence of NS fractions on axial and lateral buckling performances. Morphology and failure mechanisms of the samples were analyzed using scanning electron microscopy images of critical regions of each sample. The results showed that the incorporation of NS particles led to higher critical buckling load values for both axial and lateral buckling. The highest critical buckling load values for both axial and lateral buckling events were observed for 1.5 wt% NS particle content in Kevlar/epoxy composite laminates. Further increasing of NS resulted with the decrements in critical buckling loads because of poor interfacial bonding between NS particles and epoxy resin, primarily due to onset of agglomeration. As it is expected the decreases in length of samples resulted with significant increases in both the axial and lateral buckling characteristics. The results of this research can be used to design composites with high buckling resistance, especially for applications where loading may compromise structural stability and functionality, such as tall buildings, structural bridges and roofs, rail tracks. [ABSTRACT FROM AUTHOR]

We report a highly sensitive approach for detecting microRNA-21 (miR-21) in cancer cells and human serum by using Au@Si nanocomposite labeled lateral flow assay. The Au@Si nanocomposite was prepared by coating numerous 3–5 nm gold nanoparticles (GNP) on a silica nanoparticle (SiNP) with a diameter of 150 nm and used as colored label on the lateral flow assay for signal amplification. TEM results show there are around 1000 GNPs coated on the SiNP surface. The principle of miR-21 detection is based on on-strip DNA-microRNA hybridization reactions to form DNA-miR-21-DNA-Au@Si complexes, which are captured on the test zone of the lateral flow test strip and produce a visible red band. A thiol-modified detecting DNA probe (Det-DNA) and a biotin-modified capturing DNA probe (Cap-DNA), which are complementary to miR-21, were used to prepare the lateral flow test strips. After systematic optimization, the method can detect a minimum concentration of 1.0 pM miR-21, which is 60 times lower than that of the GNP-based lateral flow assay (Gao et al. Biosens & Bioelectro, 2014, 54, 578–584). The method was applied to detect miR-21 in cancer cells and spiked human serum with satisfactory results. Gold nanoparticles coated silica nanosphere as colored label for sensitive lateral flow microRNA-21 assay. Image 1 • Gold@Silica nanocomposite was prepared by loading around one thousand 3–5 nm gold nanoparticles on a silica nanosphere with a diameter of 150 nm. • Lateral flow microRNA-21 assay was developed by using the gold@Silica nanocomposite as colored tag for signal amplification. • A minimum concentration of 1.0 pM microRNA-21 can be detected visually within 20 min. • The detection limit is 60 folds lower than that of gold nanoparticle based lateral flow microRNA assay. • The assay was applied to detect microRNA-21 in cancer cells and human serum with satisfied results. [ABSTRACT FROM AUTHOR]