Synthesis Of Silica Nanoparticles Research Articles

Concept Design, Development and Preliminary Physical and Chemical Characterization of Tamoxifen-Guided-Mesoporous Silica Nanoparticles.

Conventional chemotherapies used for breast cancer (BC) treatment are non-selective, attacking both healthy and cancerous cells. Therefore, new technologies that enhance drug efficacy and ameliorate the off-target toxic effects exhibited by currently used anticancer drugs are urgently needed. Here we report the design and synthesis of novel mesoporous silica nanoparticles (MSNs) equipped with the hormonal drug tamoxifen (TAM) to facilitate guidance towards estrogen receptors (ERs) which are upregulated in breast tumours. TAM is linked to the MSNs using a poly-ʟ-histidine (PLH) polymer as a pH-sensitive gatekeeper, to ensure efficient delivery of encapsulated materials within the pores. XRD, HR-TEM, DLS, SEM, FT-IR and BET techniques were used to confirm the successful fabrication of MSNs. The MSNs have a high surface area (>1000 m2/g); and a mean particle size of 150 nm, which is an appropriate size to allow the penetration of premature blood vessels surrounding breast tumours. Successful surface functionalization was supported by FT-IR, XPS and TGA techniques, with a grafting ratio of approximately 29%. The outcomes of this preliminary work could be used as practical building blocks towards future formulations.

Photocatalytic degradation of dyes using one-step synthesized silica nanoparticles

Schematic route diagram of one step synthesis of Silica nanoparticles. • Synthesis of silicon oxide based employing sol–gel method. • Degradation of dye methylene blue and methyl orange. Silica nanoparticles are synthesized by one step simple, rapid and cost effective sol–gel method using methyltrimethoxysilane (MTMS) as precursor. Synthesized silica nanoparticles are characterized by UV–Visible spectroscopic techniques, XRD and FE-SEM. From UV curve the maximum absorbance observed was at the wavelength 297 nm which indicates formation of silica nanoparticles. The FE-SEM analysis showed the larger size of nanoparticles is due to agglomeration of silica nanoparticles. The X-ray diffraction pattern indicate the structure of the silica nanoparticles. FT-IR spectra of silica nanoparticles are indicative of the stretching vibration of Si-O-Si bonds and Si-OH vibration respectively. TGA indicates the final degradation temperature of silica nanoparticles are near about 515 °C temperature. Photo degradation process is carried out by employing different dyes along with UV irradiating at pH-7. Photodegradation of both (10 ppm) methylene blue and methyl orange with 1.5 g/dm 3 SiO 2 photocatalyst dose accomplished around 98 and 95% degradation in 90 min at 25 °C with pH-7. Finally, it can be concluded that silica nanoparticles support to the photo degradation of methylene blue and methyl orange. Hence nanoparticles synthesized using sol–gel method can be used for degradation of various industrial pollutants dyes.

Synthesis of mesoporous silica nanoparticles derived from rice husk and surface-controlled amine functionalization for efficient adsorption of methylene blue from aqueous solution

Mesoporous silica nanoparticles (MSN) were synthesized using rice husk (RH) as the raw material via sol-gel pathway using cetyltrimethylammonium bromide (CTAB) as the structure directing agent. Silica nanoparticles were successfully functionalized with 3-aminopropyl triethoxysilane (APTES) via in-situ and post functionalization methods. Synthesized nanoparticles were characterized by X-Ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and Brunauer-Emmett-Teller (BET) surface area analysis. The amorphous silica nanoparticles were of 50–60 ​nm in diameter with a surface area of 150 ​m2/g, pore volume of 0.237 ​cm3/g and average pore size of 3.62 ​nm. Morphology and textural parameters were changed upon functionalization. The equilibrium adsorption capacity of MSN-A (4.94 ​mg/g) to adsorb 10 ​mg/L methylene blue (MB), was higher than in amine functionalized silica nanoparticles. The influence of experimental factors such as pH, adsorbent dosage, and initial MB concentration on adsorption of MB to MSN-A were studied. The equilibrium data for MB adsorption on mesoporous silica nanoparticles well fitted to Langmuir equation, with a maximum monolayer capacity of 19.26 ​mg/g. The adsorption of MB could be best described by the pseudo-second order model. The results indicate that MSN-A is a potential mesoporous material fabricated by cheap natural resources to remove MB from aqueous solutions.

Silica Nanoparticles.

Silica consists of one silicon atom and two oxygen atoms (SiO2) and iscommonly used in various aspects of dailylife. For example, it has been used as glass, insulator, and so on. Nowadays, silica is used as core reagents for fabricating and encapsulating nanoparticles(NPs). In this chapter, the usage of silica in nanotechnology is described. Synthesis and surface modification of silica nanoparticles (SiNPs), including via the Stöber method, reverse microemulsion method, and modified sol-gel method,areillustrated. Then, various NPs with silica encapsulation are explained. At last, the biological applications of those mentioned NPs are described.

Immobilization of green fluorescence and lipase proteins in porous silica nanoparticles to improve their bioluminescence and catalytic activity

Introduction: The GFP and lipase proteins have been immobilized in the aminated silica nanoparticles through encapsulation and ionic interaction. The synthesis of porous silica nanoparticles and amination of silica surface were simultaneously performed in a water-in-oil emulsion. Methods: The materials have been characterized by zeta potential measurements, electron transmission microscopy, and fluorescence spectroscopy. The reaction mixture was analyzed by gas chromatography equipped with a mass selective detector. Results: The aminated-silica nanoparticles with a positive zeta potential interact with GFP having a negative zeta potential via ionic force. GFP immobilized by the aminated silica nanoparticles greatly enhances (ca. 2 times) the bioluminescence intensity compared to free GFP. The lipase/aminated-silica nanoparticles catalyzed the transesterification reaction of 1-hexanol and ethyl acetate. This catalyst shows better activity than free lipase and remains catalytic activity over at least eight catalytic cycles in an organic solvent. Conclusion: The result shows that the immobilization of proteins in the aminated-silica nanoparticles improves their bioluminescence and catalytic activity.

Gear-shaped micromixer for synthesis of silica particles utilizing inertio-elastic flow instability.

Mixing in microscale flows, where turbulence is inherently difficult to generate, has been a challenging issue owing to its laminar flow characteristics. Either the diffusion-based mixing process, or the convective mixing based on the cross-stream secondary flow, has been exploited as a passive mixing scheme that does not require any external force field. However, these techniques suffer from insufficient mixing or complicated channel design step. In this study, we propose an efficient mixing scheme by combining inertio-elastic flow instability in a viscoelastic dilute polymer solution and a modified serpentine channel, termed a gear-shape channel, which has side wells along the serpentine channel. We achieved highly efficient mixing in the gear-shaped channel for a significantly wider range of flow rates than in a conventional serpentine channel. Further, we applied our novel mixing scheme to the continuous synthesis of silica nanoparticles, which demonstrated the synthesis of nanoparticles with more uniform size distribution and regular shape, than those in a Newtonian fluid. In addition, the adsorption of inorganic materials on the channel walls was significantly suppressed by the flow instability of the viscoelastic dilute polymer solution in the gear-shaped channel.

Synthesis and characterization of novel binders free high hydrophobic silica nano particles spray

Among various nano materials, Silica is quite interesting in hydrophobic applications due to its non-toxic, hydrophobic and eco-friendly nature. A cost effective Sol-Gel method is employed to synthesize Silica nanoparticles followed by calcination (650 °C). In contrast to conventional Ethanol in various reports, here Tetrahydrofuran is used as a solvent with controlled reaction time, pH and temperature. UV–Visible Absorption Spectroscopy, X – Ray Diffraction, Dynamic Light Scattering, Energy Dispersive X-Ray Analysis, Scanning Electron Microscopy and Optical Goniometer are used to characterize the material. A portable-cost effective binder free spray with high transparency coating was obtained with 116.4° contact angle.

Large scale synthesis of self-assembled shuttlecock-shaped silica nanoparticles with minimized drag as advanced catalytic nanomotors

• Large scale synthesis of shuttlecock-shaped silica nanoparticles (SSNs) were reported. • Assembly behavior of two surfactants were finely controlled to direct the growth. • SSNs exhibited minimized drag force in motion in fluid. • SSNs based nanomotors showed high diffusibility and lipid degradation activity. The catalytic performance of nanomotors is highly dependent on their interaction with substrates, for which the motion dynamics of the nanomotors needs to be carefully manipulated via materials design. Herein, we report a facile one-step self-assembly strategy for hundred-gram scale synthesis of shuttlecock-shaped silica nanoparticles as advanced catalytic nanomotors. These asymmetric nanoparticles have a streamline conical morphology with ultra-large opening in one side. The shuttlecock-mimetic morphology endows the nanoparticles with minimized drag force during fluid motion and consequently high diffusibility, while the large open cavity ensures efficient encapsulation of lipase (a model enzyme) to provide propulsive force. These unique features collectively result in superior diffusibility, leading to significantly improved catalytic performance compared with conventional large pore mesoporous silica nanoparticles with a spherical morphology. This research provides a new conceptual design and synthetic strategy to develop high-performance nanomotors.

Effects of process variable on synthesis and characterization of amorphous silica nanoparticles using sodium silicate solutions as precursor by sol–gel method

The recent rapid urban growth has resulted into high demand for virgin materials thus causing more accumulation of solid wastes (urban mines). As a result, efforts are now geared towards urban mining approach based on re-using and recycling in order to ensure sustainability and environmental protection. In this regard, the present work synthesized pure amorphous silica nanoparticles using sodium silicate solutions produced from recycled glass powder under varying process parameter. In this work, the process variable used was NaOH concentration (3.0, 4.0 and 5.0 mol/L). 20 g of glass powder was reacted with 160 ml of 3.0, 4.0 and 5.0 mol/L NaOH solutions respectively in a 250 ml Erlenmeyer flask placed on a heating plate connected with a reflux condenser to maintain the volume of the mixture and stirred continuously at a speed of 60 rpm for 180 mins under reaction temperature of 200 °C. The solutions were filtered to obtain a sodium silicate solution (SSLS) samples. Hydrochloric acid (3 mol/L) was added gently into the respective SSLS while continuously stirred to obtain a white gel mixture. The gel was left to age for 18 h at room temperature (25 °C), then filtered and washed repeatedly using deionized water until a neutral pH is reached; then dried in an electric-powered oven at 80 °C for 12 h to obtain highly pure white silica powder. The results showed that the nano-size range between 0.025 μm (25 nm) to 0.067 μm (67 nm).

Synthesis, structural properties, biosafety and applications of chiral mesoporous silica nanostructures

• Synthesis and applications of chiral mesoporous silica nanoparticles are reviewed. • A discussion on structural properties and chirality mechanism is presented. • The potential applications as a drug delivery system are discussed in depth. • Biosafety including cytotoxicity, biocompatibility and degradability is evaluated. • A discussion concerning emerging trends and challenges is undertaken. Chiral mesoporous silica nanoparticles (CMSNs) are important members of mesoporous silica nanoparticles (MSNs) family. They not only exhibit prominent physicochemical properties as MSNs, being effective and tunable for drug loading and releasing, but also have specific functions and unique biological behavior advantages due to the presence of helical architectures at both the molecular and macroscopic scale. Accordingly, CMSNs show extensive and promising applications in several fields (e.g., chiral catalysis, chiral selectivity, chiral recognition, separation and drug delivery). Moreover, they have turned out to be a hotspot in medical research. For the past two decades, considerable studies on CMSNs have been conducted, and synthesis, chirality origination mechanisms, structural properties, as well as practical applications have been substantially progressed. In the present study, the experimental and theoretical studies on synthesizing strategies and chirality origination mechanisms of CMSNs are summarized and assessed, especially the synthesizing methods and mechanisms of surfactants as templates. Furthermore, the typical applications of CMSNs, especially in drug delivery system are elaborated. In view of the in vivo utilization of CMSNs, we also evaluate the biosafety of CMSNs. Thus, this study also discusses the research status, development prospects and future challenges of CMSNs. Undoubtedly, CMSNs with unique functionalities are capable of facilitating the application of nanoporous silica and presenting novel insights into the development of pharmaceutical science and other relevant fields.

Self-Assembled Surfactant-Templated Synthesis of Porous Hollow Silica Nanoparticles: Mechanism of Formation and Feasibility of Post-Synthesis Nanoencapsulation.

SiO2 is bioinert and highly functionalizable, thus making it a very attractive material for nanotechnology applications such as drug delivery and nanoencapsulation of pesticides. Herein, we synthesized porous hollow SiO2 nanoparticles (PHSNs) by using cetyltrimethylammonium bromide (CTAB) and Pluronic P123 as the structure-directing agents. The porosity and hollowness of the SiO2 structure allow for the protective and high-density loading of molecules of interest inside the nanoshell. We demonstrate here that loading can be achieved post-synthesis through the pores of the PHSNs. The PHSNs are monodisperse with a mean diameter of 258 nm and a specific surface area of 287 m2 g-1. The mechanism of formation of the PHSNs was investigated using 1-D and 2-D solid-state nuclear magnetic resonance (SS-NMR) and Fourier-transform infrared spectroscopy (FTIR). The data suggest that CTAB and Pluronic P123 interact, forming a hydrophobic spherical hollow cage that serves as a template for the porous hollow structure. After synthesis, the surfactants were removed by calcination at 550 °C and the PHSNs were added to an Fe3+ solution followed by addition of the reductant NaBH4 to the suspension, which led to the formation of Fe(0) NPs both on the PHSNs and inside the hollow shell, as confirmed by transmission electron microscopy imaging. The imaging of the formation of Fe(0) NPs inside the hollow shell provides direct evidence of transport of solute molecules across the shell and their reactions within the PHSNs, making it a versatile nanocarrier and nanoreactor.

Design and synthesis of a new topical agent for halting blood loss rapidly: A multimodal chitosan-gelatin xerogel composite loaded with silica nanoparticles and calcium

Uncontrolled hemorrhage often causes death during traumatic injuries and halting exsanguination topically is a challenge. Here, an efficient multimodal topical hemostat was developed by (i) ionically crosslinking chitosan and gelatin with sodium tripolyphosphate for (ii) fabricating a robust, highly porous xerogel by lyophilization having 86.7 % porosity, by micro-CT and large pores ∼30 μm by SEM (iii) incorporating 0.5 mg synthesized silica nanoparticles (SiNPs, 120 nm size, −22 mV charge) and 2.5 mM calcium in xerogel composite that was confirmed by FTIR analysis with peaks at 3372, 986 and 788 cm−1, respectively. XPS analysis displayed the presence of SiNPs (Si2p peak for silicon) and calcium (Ca2p1, Ca2p3 transition peaks) in the composite. Interestingly, in silico percolation simulation for composite revealed interlinked 800 μm long-conduits predicting excellent absorption capacity and validated experimentally (640 % of composite dry weight). The composite achieved >16-fold improved blood clotting in vitro than commercial Celox and Gauze through multimodal interaction of its components with RBCs and platelets. The composite displayed good platelet activation and thrombin generation activities. It displayed high compressive strength (2.45 MPa) and withstood pressure during application. Moreover, xerogel composite showed high biocompatibility. In vivo application of xerogel composite to lethal femoral artery injury in rats achieved hemostasis (2.5 min) significantly faster than commercial Celox (3.3 min) and Gauze (4.6 min) and was easily removed from the wound. The gamma irradiated composite was stable till 1.5 yr. Therefore, the xerogel composite has potential for application as a rapid topical hemostatic agent.

The Synthesis of silica nanoparticles from Vietnamese rice husk - Application for adsorption of heavy metals in industrial wastewater

Heavy metals are known to be toxic, even at low content (ppm), for living organisms[1,2]. The presence of heavy metals and other pollutants in water continues to be a major concern and the removal of such contaminants is considered as an important solution for environmental remediation[3,4]. In this paper, we study the ability adsorption of Pb2+ and Cd2+ heavy ionic metal on silica nanomaterials which was extracted and purified from Vietnamese rice husk. The structure of the materials was investigated by X-ray diffraction (XRD) and FT-IR spectroscopy. By Adsorption Atomic Spectroscopy (AAS) analysis, the results have demonstrated the time taken for attaining equilibrium adsorption is about 1.5 hours for both cases, and the adsorption capacity of Pb2+ and Cd2+ on silica are 21 and 24 mg/L, respectively.

Recent Trends in Morphology-Controlled Synthesis and Application of Mesoporous Silica Nanoparticles.

The outstanding journey towards the investigation of mesoporous materials commences with the discovery of high surface area porous silica materials, named MCM-41 (Mobil Composition of Matter-41) according to the inventors’ name Mobile scientists in the United States. Based on a self-assembled supramolecular templating mechanism, the synthesis of mesoporous silica has extended to wide varieties of silica categories along with versatile applications of all these types in many fields. These silica families have some extraordinary structural features, like highly tunable nanoscale sized pore diameter, good Brunauer–Emmett–Teller (BET) surface areas, good flexibility to accommodate different organic and inorganic functional groups, metals etc., onto their surface. As a consequence, thousands of scientists and researchers throughout the world have reported numerous silica materials in the form of published articles, communication, reviews, etc. Beside this, attention is also given to the morphology-oriented synthesis of silica nanoparticles and their significant effects on the emerging fields of study like catalysis, energy applications, sensing, environmental, and biomedical research. This review highlights a consolidated overview of those morphology-based mesoporous silica particles, emphasizing their syntheses and potential role in many promising fields of research.

Controlled synthesis of mesoporous silica nanoparticles with tunable architectures via oil-water microemulsion assembly process

Mesoporous silica nanoparticles (MSNs) have received extensive attention owing to their fascinating properties in recent years. However, the controllable synthesis of MSNs with different morphologies and the transformation of various structures by using simple oil-water microemulsion assembly methods remains a challenge. Herein, a facile microemulsion assembly approach has been developed to fabricate MSNs with various morphologies, tunable particle diameter (135–280 nm), and pore size (2.8–32.8 nm). In the same reaction system, the evolution of walnut-like MSNs to mulberry-like MSNs has been easily achieved. The amount of pentanol not only plays an important role in the evolution of pore sizes but also significantly affects the interfacial interaction between soft templates and silica precursors, which is critical to the morphology of the resulting particles. As a result, wrinkle-like, dendritic-like, walnut-like, and mulberry-like mesoporous nanospheres can be synthesized. More importantly, MSNs with visible voids in the center can be successfully obtained during the synthesis process when the appropriate pentanol is employed. Other experimental parameters, such as the amount of isopropanol, the concentration of surfactant, and the concentration of alkali, were also investigated. A possible mechanism is proposed to account for the formation and growth of MSNs. The Au@NH2-MSNs composite nanostructures can be used as a catalyst for the reduction of 4-nitrophenol by NaBH4 into 4-aminophenol and exhibit superior catalytic performance.

Robust synthesis of mono-dispersed spherical silica nanoparticle from rice husk for high definition latent fingermark development

Silica is one of the most functional metalloid oxides with a widespread application as semiconductor, fillers, silicone and ceramic primarily due to its structural versatility. In this work, a robust step-wise thermochemical treatment was successfully formulated for the controlled fabrication of high-purity mono-dispersed spherical silica nanoparticle from rice husk. The silica nanoparticle with the desired morphology was formed in two stages; thermal-assisted seed particle formation followed by particle growth through acidification of the solvent modified sodium silicate solution. The obtained powder was characterised, and the effectiveness of the powder for latent fingermark development across varied donors and surfaces was tested at the introductory level. The formed spherical particles were in the range of 200 to 400 nm, as confirmed by FESEM and HRTEM analysis. Minimising the degree of silica nanoparticle agglomeration notably affected their selectivity to fingermark residue. There was a striking improvement in the selectivity of the silica nanoparticle to fingermark residue. The improvement was attributed to the strong interaction between the silica nanoparticle and the lipid components in the fingermark residue, as compared to the commercial white powder that works solely based on mechanical adherence. Additionally, the size and morphology of the fabricated silica nanoparticle were optimised to enhance the clarity of the developed fingermark. Findings of this study could improve quality of fingermarks obtained in a crime scene due to considerably lower background interference without compromising the effectiveness of fingermark development.

Facile approach for the synthesis of spherical mesoporous silica nanoparticles from sodium silicate

We developed a facile synthetic method for the preparation of spherical mesoporous silica nanoparticles from a sodium silicate solution. Spherical mesoporous silica with an overall size of several hundreds of nanometers was obtained through a simple sol–gel process using acetic acid and polyethylene glycol (PEG) as a pH adjuster and morphology directing agent, respectively. In this method, PEG is an essential component that affects the shape of silica particles and that leads to the formation of mesopores on silica. Additionally, the size of the mesopores could be easily controlled by changing the reaction temperature. Thus, we successfully synthesized spherical silica nanoparticles with tunable mesopores ranging from 3 to 40 nm. This synthetic method can be valuable in developing customized porous silica nanoparticles using an inexpensive silica resource.

Droplet-based Microfluidic Device for the Synthesis of Silica Nanoparticles

Microfluidic reactors are advantageous for nanomaterial synthesis due to their capability to provide controlled reaction environment. In this work, a droplet based microfluidic reactor is designed for the synthesis of silica nanoparticles. The synthesis is carried out in a very controlled environment and a uniform size and shape distribution is achieved. The classical synthesis protocol for silica nanoparticles is modified to use nonpolar solvents in the reaction so that this platform can later be used for coating hydrophobic nanomaterials. Therefore, this study not only presents a new device but also a new synthesis method. The results are compared with conventional batch wise synthesis methods and the obtained nanoparticles showed better size distribution.

Synthesis and application of rice husk silica nanoparticles for chemical enhanced oil recovery

Silica (SiO2) nanoparticles were synthesized from rice husk (RH) via wet milling method and evaluated for enhanced oil recovery (EOR) applications. Physical properties of RH-SiO2 nanoparticles (RH-SNP) with its size distribution were explored through field emission scanning electron microscopy (FESEM) and dynamic light scattering (DLS). Stability, functional groups and purity of RH-SNP were determined by zeta potential, Fourier-transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD), respectively. Effect of RH-SNP on the precipitation and thermal degradation of oilfield polyacrylamide (HPAM) was studied using Brookfield RST rheometer. Interfacial tension (IFT) properties of RH-SiO2 polymeric nanofluid (RH-SPNF) at interface of oil and water (O/W) were investigated using Easy-Dyne KRUSS tensiometer. Subsequently, oil displacement efficiency of RH-SPNF was determined and compared with oilfield HPAM at reservoir conditions using Fars EOR high-pressure high-temperature (HPHT) core flooding equipment. The wet milling method was effective in producing RH-SNP of size ranges 43.9–59.5 nm with a purity of 98% through the mechanism of nucleation, Brownian motion and coalescence. Rheological results show that RH-SNP inhibited the precipitation and thermal degradation of oilfield HPAM. IFT of RH-SPNF showed a monotonic tendency as temperature increased. HPAM and RH-SPNF flooding showed an incremental oil recovery of approximately 10% and 24%, respectively. Emulsion generated using RH-SPNF shows higher stability and resistance to coalescence. Finally, mobility ratio of water flooding approaches unity faster, compared to HPAM and RH-SPNF. Overall, the low energy utilization, use of low-cost and benign raw material make RH-SNP and the extraction method an appropriate substitute to commercially available SiO2 nanoparticles.

Advances in Methods for Recovery of Ferrous, Alumina, and Silica Nanoparticles from Fly Ash Waste

Fly ash or coal fly ash causes major global pollution in the form of solid waste and is classified as a “hazardous waste”, which is a by-product of thermal power plants produced during electricity production. Si, Al, Fe Ca, and Mg alone form more than 85% of the chemical compounds and glasses of most fly ashes. Fly ash has a chemical composition of 70–90%, as well as glasses of ferrous, alumina, silica, and CaO. Therefore, fly ash could act as a reliable and alternative source for ferrous, alumina, and silica. The ferrous fractions can be recovered by a simple magnetic separation method, while alumina and silica can be extracted by chemical or biological approaches. Alumina extraction is possible using both alkali- and acid-based methods, while silica is extracted by strong alkali, such as NaOH. Chemical extraction has a higher yield than the biological approaches, but the bio-based approaches are more environmentally friendly. Fly ash can also be used for the synthesis of zeolites by NaOH treatment of variable types, as fly ash is rich in alumino-silicates. The present review work deals with the recent advances in the field of the recovery and synthesis of ferrous, alumina, and silica micro and nanoparticles from fly ash.