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Hypothesis We developed a geometrical model to determine the theoretical maximum number of proteins that can pack as a monolayer surrounding a spherical nanoparticle. We applied our new model to study the adsorption of receptor binding domain (RBD) of the SARS-CoV-2 spike protein to silica nanoparticles. Due to its abundance and extensive use in manufacturing, silica represents a reservoir where the virus can accumulate. It is therefore important to study the adsorption and the persistence of viral components on inanimate surfaces. Experiments We used previously published datasets of nanoparticle-adsorbed proteins to validate the new model. We then used integrated experimental methods and Molecular Dynamics (MD) simulations to characterise binding of the RBD to silica nanoparticles and the effect of such binding on RBD structure. Findings The new model showed excellent fit with existing datasets and, combined to new RBD-silica nanoparticles binding data, revealed a surface occupancy of 32% with respect to the maximum RBD packing theoretically achievable. Up to 25% of RBD’s secondary structures undergo conformational changes as a consequence of adsorption onto silica nanoparticles. Our findings will help developing a better understanding of the principles governing interaction of proteins with surfaces and can contribute to control the spread of SARS-CoV-2 through contaminated objects.

Otsubo, M., Terao, K. Kinetics of the complex formation of silica nanoparticles with collagen. Polym J 53, 1481–1484 (2021). https://doi.org/10.1038/s41428-021-00553-4., Time-resolved small-angle X-ray scattering measurements were made for a mixed solution of negatively charged silica nanoparticles (SiNPs) and positively charged atelocollagen (AC) in buffers at pH = 3 and 4 at 25 °C, in which the scattering intensity from the AC molecules was very weak in the investigated q (magnitude of the scattering vector) range. The scattering intensity from the SiNPs at the low q end and middle q range gradually increased and decreased, respectively, and reached asymptotic values approximately 5–20 min after rapid mixing of the two solutions of SiNPs and AC. This clearly shows that the structural formation of the SiNP–AC complex is on the time scale of minutes. Furthermore, the structure factor at 30 min after mixing is consistent with the previously investigated data for SiNPs and triple helical AC at 15 °C. The obtained time scale to form the complex can be important information to control the aggregating structure of SiNPs with the aid of collagen molecules.

Waterborne polyurethane (WPU) is widely applied in many fields; however, it is limited by its drawback of low mechanical strength and short lifespan. Polymer nanocomposites have been developed for many years to enhance the mechanical behavior of materials. Nevertheless, obtaining nanofillers with even dispersion to obtain improved mechanical performance is difficult. To solve the above problems, silica nanoparticles modified by furfuryl (furan@SiO2) were synthesized according to the sol–gel process. By introducing furan@SiO2 into a maleimide-terminated waterborne polyurethane matrix, a self-healing system was constructed through a DA/retro-DA process among furan groups and maleimide-terminated waterborne polyurethane, and a series of WPU films with different furan@SiO2 (WMPUS-x) contents were prepared. The structure of furan@SiO2 was clearly corroborated by TEM, SEM, FTIR, etc. Moreover, confirmed by tensile tests, the mechanical properties of all WPU samples were significantly improved due to the addition of rigid furan@SiO2, and their first self-healing efficiencies were all higher than 88%. In this article, a series of thermo-driven self-healable organic/inorganic nanohybrid polyurethane (WMPUS-x) films were prepared with different addition amount of furfuryl modified silica nanoparticles (furan@SiO2). The self-healable system was constructed via a DA/retro-DA process among furan@SiO2 and maleimide-terminated waterborne polyurethane. The results exhibited the addition of furan@SiO2 enhanced the mechanical behavior of all WPU samples.

Protein fouling on critical biointerfaces causes significant public health and clinical ramifications. Multiple strategies, including superhydrophobic (SHP) surfaces and coatings, have been explored to mitigate protein adsorption on solid surfaces. SHP materials with underwater air plastron (AP) layers hold great promise by physically reducing the contact area between a substrate and protein molecules. However, sustaining AP stability or lifetime is crucial in determining the durability and long-term applications of SHP materials. This work investigated the effect of protein on the AP stability using model SHP substrates, which were prepared from a mixture of silica nanoparticles and epoxy. The AP stability was determined using a submersion test with real-time visualization. The results showed that AP stability was significantly weakened by protein solutions compared to water, which could be attributed to the surface tension of protein solutions and protein adsorption on SHP substrates. The results were further examined to reveal the correlation between protein fouling and accelerated AP dissipation on SHP materials by confocal fluorescent imaging, surface energy measurement, and surface robustness modeling of the Cassie-Baxter to Wenzel transition. The study reveals fundamental protein adsorption mechanisms on SHP materials, which could guide future SHP material design to better mitigate protein fouling on critical biointerfaces.

We describe an in situ facile synthetic approach to prepare carbon quantum dot (CQD) fluorescent markers (FMs) for polyethylene (PE) in the presence of agglomerated silica nanoparticles (SiO2 NPs) under mild reaction conditions. First SiO2 NPs, prepared by the Stöber method, were dispersed in toluene. This dispersion was added to a PE solution in toluene. After heating (either in air or under Ar) a fluorescent mixture was obtained. After drying, PE films were obtained by compression molding, which showed strong blue fluorescence, attributed to CQDs. SiO2 NPs loading values varied between 0.5 and 4 wt %. Subsequent to isolation, the fluorescent CQDs were characterized by TEM, UV-vis, and fluorescence spectroscopy. TEM imaging unveiled a lattice spacing value of 0.21 nm of the isolated fluorescent particles which is typical for (100) graphite plane lattice spacing in CQDs. UV spectroscopy and fluorescence measurements show characteristic absorption and excitation spectra for the aromatic core and oxidized surface defects typically observed for CQDs. The emission maximum for PE/CQD samples increased from 394 to 408 nm when the reaction temperature was decreased from 110 to 90 °C, which is attributed to increasing oxygen content in the reaction mixture upon decreasing the reaction temperature. When the reaction was performed under Ar, the PE/CQD samples emitted in the ultraviolet region (286 nm). Finally, we demonstrated that PE samples marked with CQDs can be easily visually identified upon irradiating with 367 nm light. Thus, the marked PE can be used, for example, as a labeling ingredient in master batches for component identification and in recycling.

We study the slowing down of polymer dynamics in canonical nanocomposites made of strongly interacting mixtures of poly-2-vinyl pyridine and silica nanoparticles (radius R = 7 ± 2 nm) by means of l...

The use of silica nanoparticles (SNPs) has shown promising results in providing higher foam stability in chemically enhanced oil recovery (cEOR). In this study, hydrophobic SNPs stabilized in a car...

Self‐assembly processes guide disordered molecules or particles into long‐range organized structures due to specific supramolecular interactions among the building entities. Herein, we report a unique evaporation‐induced self‐assembly (EISA) strategy for four different silica nanoparticle systems obtained through peptide functionalization of the particle surface. First, covalent peptide‐silica coupling was investigated in detail, starting with the grafting of a single amino acid (L‐serine) and expanded to specific small peptides (up to four amino acids) and transferred to different particle types (MCM‐48‐type MSNs, solid nanoparticles, and newly developed virus‐like nanoparticles). These materials were investigated regarding their ability to undergo EISA, which was shown to be independent of particle type and amount of peptide anchored to their surface. This EISA‐based approach provides new possibilities for the design of future advanced drug delivery systems, engineered hierarchical sorbents, and nanocatalyst assemblies., Evaporation‐induced self‐assembly of a bioconjugate is reported. The formation of ring‐like structures was independent of different silica particle types and the amount of peptide conjugated to the material. This novel approach paves the way for further production of functional materials for separation, catalysis, and medical applications.

The present work reported the synthesis and characterisation of β-cyclodextrin (βCD) grafted into silica (SiO2@βCD) nanoparticles (NPs). Morphology analysis shows that the prepared NPs have a spher...

In the present study, several polypropylene/silica nanocomposites (PP/SiO2), containing 3 and 5 wt.% of untreated silica nanoparticles in presence of stearic acid (SA) as modifier agent, were prepa...

A multifunctional hybrid curing component (GSD) for epichlorohydrin-modified novolac resin (ENR) was synthesized via grafting poly(amidoamine) (PAMAM)-modified silica nanoparticles (SD) on graphene...

The insertion of nanoparticles into smart hydrogels can diversify their functionalities by a synergistic combination of the components properties within the hydrogels. While these hybrid systems are attractive to the biomaterials field, careful design and control of their properties are required since the new interactions between the polymer and the nanoparticles can result in changes or the loss of hydrogels stimuli response. In order to understand the physicochemical aspects of the thermoresponsive systems, nanocomposites of poly(N-vinylcaprolactam) (PNVCL) and silica nanoparticles with different sizes and concentrations were synthesized. The UV-vis and DLS techniques showed that the PNVCL has a sharp phase transition at 34 °C, while the nanocomposites have a diffuse transition. The nanocomposites showed an initial coil-globule transition before the phase transition takes place. This was identified by the evolution of the hydrodynamic diameter of the nanocomposite globules before the cloud point temperature (Tcp), which remained constant for PNVCL. This new transition profile can be described by two stages in which microscopic volume transitions occur first, followed by the macroscopic transition that forms the hydrogel. These results show that the proposed nanocomposites can be designed to have tunable stimuli response to smaller temperature variations with the formation of intermediate globule states.

The Pickering emulsion polymerization of styrene (St), divinylbenzene (DVB) as a crosslinking agent, and sodium 4-vinyl benzene sulfonate (VBS) used for in situ surface-modification of silica nanoparticles (SNps) was investigated. At 1.0 wt% DVB, amphiphilic SNps with hydrophobic patches were formed, further self-assembling into copolymer-SNps clusters occurred. Subsequently, these clusters grow by monomer swelling to finally lead to the formation of core-shell polymer microspheres. Unlike the hydrophilic patchy SNps, at 2.0 and 3.0 wt% DVB, surface-patterned SNps with higher effective hydrophobicity do not self-assemble in the water phase but rather lead to the formation of monoliths. The polymerization mechanisms related to the formation of polymer silica-coated microspheres hybrid-materials, or percolated monoliths with bi-continuous porosity, formed by interfacially jammed emulsion gel (bijels) templates, are discussed herein.

We investigate the crystallization-induced ordering of C18 grafted 14 nm diameter spherical silica nanoparticles (NPs) in a short chain (Mw = 4 kDa, ĐM ≈ 2.3) polyethylene and a commercial high-den...

The typical method for minimizing serum protein adsorption in biological settings and prolonging blood circulation time of nanoparticles, is to anchor hydrophilic polymers (e.g., poly(ethylene glycol), PEG) on the particle surface, which is most often done by covalent attachment (PEGylation). Herein, different PEGylation methods were realised and compared to functionalize mesoporous silica nanoparticles (MSNs). First, reactive groups were installed using post-grafting procedures with different functional silanes. Further, PEGs carrying a functional group and having different chain lengths and termini, were used. The grafting efficacy as well as the structural and physicochemical characteristics of the resulting particles were determined. Finally, the serum protein adsorption behaviour of these functionalized particles was investigated using thermogravimetric analysis. The type of selected coupling method was shown to strongly influence the grafting efficiency as well as the resulting protein adsorption. The results highlight the importance of the right choice of the linking chemistry when aiming at surface functionalization of nanoparticles.

We present a facile method to produce silica nanoparticles as a superhydrophobic material which has been successfully synthesized by mechanical milling and the sol–gel method. The powder obtained was characterized using scanning electronic microscopy, X-Ray Diffraction, particle size distribution, and zeta potential. The effects of alcohol solvents on synthesis, such as on particle size, particle size distribution, and zeta potential, were examined thoroughly. To evaluate the surface modification of silica nanoparticles from hydrophilic to hydrophobic properties, IR spectra was applied. Surface modification was conducted prior to the evaluation of the superhydrophobic properties of silica nanoparticles on the glass substrate. In this study, silica nanoparticles in the ethanol solvent achieved optimum results with a particle size of 170.3 ± 14.3 nm and the highest zeta potential of −50.4 ± 0.3 mV, which is the best superhydrophobic effect on the glass substrate. In addition, the superhydrophobic effect of the silica nanoparticles was also applied to the bitumen, as both coating and mixing with the water contact angle was increased to 149.2° and 148.1° compared to the bitumen without silica nanoparticles. Due to their simplicity and low-cost, modified silica nanoparticles show great potential for industrial applications as superhydrophobic material on the bitumen.

Nanosilica was prepared from sugarcane bagasse ash (SCBA) and used as additive to the diatomaceous earth (DE). Nanosilica was characterized using laser light scattering (LS), scanning electron micr...

Superhydrophobic silica (SHS) nanoparticles (NPs) with fluoro- or alkyl-surface functionalization are explored for a wide range of potential applications. Here, the aqueous synthesis of SHS NPs fro...

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 ...

The development of a practical synthetic method to functionalize hollow mesoporous silica with organic groups is of current interest for selective adsorption and energy storage applications. Herein, a facile and controllable one-pot approach for the synthesis of monodisperse amino-functionalized hollow mesoporous silica nanoparticles is presented. A novel solid-to-hollow structural transformation procedure of the silica nanoparticles is presented. The structural transformation is easily designed, as observed through transmission electron microscopy, by tailoring the HCl and N-lauroylsarcosine sodium molar ratio and the water content in the sol-gel. Ordered and radially oriented in situ amino-functionalized mesochannels were successfully introduced into the shells of the hollow silica nanoparticles. A formation mechanism for the hollow mesoporous silica materials is discussed.

Nanofluid is well known as smart fluid which has high ability to recover oil. Therefore, it gains more significant effect in oil and gas industry. With the low concentration of nanofiller in nanofluid is used to enhance the numerous characteristics for oil recovery applications. Then, the main feature is the size of reinforcing agent and properties along matrix medium. Nano dimensional particles suspension in polymeric matrix have major advantages are stable sedimentation, optical, mechanical, electrical, and rheological properties that can be affected during the synthesis of nanofluids. Therefore nanoparticles/polymeric nanofluid have exceptional characteristics over the conventional fluid. Mixed nanoparticles/polymeric nanofluid in the presence of surfactant have effective interfacial tension and wettability which is evident for the development of nanofluids for oil recovery. In this context, the designed experimental study of silica/PVP nanofluids is synthesized via two step methods and characterized by SEM, TG/DTA, contact angle measurement, centrifugal effect and sedimentation test intended for Enhanced Oil Recovery (EOR) system.

Four different consolidants for adobe buildings conservation were synthetized and evaluated. Adobe bricks materials tested from several Mining Haciendas of the seventeenth and eighteenth centuries located in Guanajuato, Mexico; these materials were characterized using XRD analysis, granulometry, porosity, moisture content, and mechanical resistance. The four consolidants synthetized are formulations based on TEOS (F1); TEOS with silica nanoparticles (F2); TEOS with PDMS-OH (F3) and hybrid consolidant formed by TEOS, PDMS, and nanoparticle silica (F4). The consolidants were tested and evaluated by porosity changes, absorption, and durability. The results show that colloidal silica improves the fulfill porosity by TEOS gels and the PDMS improves the flexibility on TEOS gel avoiding the crack. Thus, the addition of both components to TEOS gel results as an excellent consolidant treatment to adobe materials.

We systematically examine the role of the self-assembly state of polymer-grafted silica nanoparticles (GNPs) on the spherulitic growth kinetics of a poly(ethylene oxide) (PEO) matrix. The nanoparti...

Inorganic/polymer hybrid hydrogels generally exhibit excellent mechanical properties, while extra function include luminescence are extremely explored due to the further application in sensors and optoelectronic devices. Herein, we report the rare-earth (RE) complex/silica nanoparticles (SNs) luminescent hybrid polyethylene glycol (PEG) hydrogels showing stable luminescence. The hybrid hydrogels coordinated with RE (Eu3+) complex are fabricated via a convenient in situ photocrosslinked procedure. The coordination polymers showed red luminescent color under the 365 nm UV irradiation. Furthermore, the hybrid hydrogel exhibited long luminescence lifetime. These properties of hybrid luminescent hydrogel gave rise to a great improvement in the potential applications as a soft material.

Surface modification of nanoparticles is often utilized to tailor the interfacial properties in dielectric nanocomposites. Introducing different functional groups to the nanoparticles’ surface may induce localized states (traps) that can enhance the dielectric performance of the material depending on their density and energy levels. Furthermore, surface modification of the filler can affect the dispersion quality and crystallization of the nanocomposites which can ultimately alter the dielectric response of the material. In this study, functionalization of silica nanoparticles is demonstrated using 3-(trimethoxysilyl)propyl methacrylate (TMPM) and 1-[3-(trimethoxysilyl)propyl]urea (TMPU) as modifying agents. The effect of such modifications on the crystallization behavior, dispersion quality of the nanoparticles, as well as charge trapping and transport under a medium DC field is studied in nanocomposites based on polypropylene (PP)/ethylene-octene-copolymer (EOC) blends at 1% and 5% of filler concentrations. The results show that both ureido and methacrylate functional groups introduce localized states, but with different energy levels. Nitrogen containing ureido groups in TMPU tend to introduce deeper traps to the filler-polymer interfaces, compared to the methacrylate silane modification. Comparing the two types of surface functionalization, the ureido-functionalized silica resulted in a suppression of space charge formation at the interfaces under a medium DC electric field, despite the relatively larger mean cluster size of nanoparticles. publishedVersion

Bombyx (B.) mori silk's water-responsive actuation correlates to its high β-sheet crystallinity. In this research, we demonstrated that stiff silica nanoparticles can mimic the role of dispersed β-sheet nanocrystals and dramatically increase amorphous silk's water-responsive actuation energy density to ∼700 kJ m−3.

Lipase-loaded hollow colloidosomes are prepared for Pickering interfacial biocatalysis (PIB). Unlike in other systems, colloidosomes are self-assembled by lipases and silica nanoparticles, achieving a high enzyme-loading process without chemical crosslinking, and can stabilize Pickering emulsion due to the amphiphilic lipase confined in the porous shell. Remarkably, the enzyme encapsulation rate is 95.2%, which is better than other enzyme-loaded carriers in PIB reported so far. This system maintains 80.4% of the initial enzyme activity after 10 cycles, which provides a powerful and green platform for interfacial biocatalysis.

This work reports the preparation, characterization, and a drug release study of mesoporous silica nanoparticles (MNPSiO2) functionalized with folic acid (FA) and loaded with Cis-Pt as a targeted release system to kill glioblastoma cancer cells. The MNPSiO2 were synthesized by the Stöber method using hexadecyltrimethylammonium bromide as the templating agent, which was finally removed by calcination at 550°C. The folic acid was chemically anchored to the silica nanoparticles surface by a carbodiimide reaction. Several physicochemical techniques were used for the MNPSiO2 characterization, and a triplicate in vitro Cis-Pt release test was carried out. The release Cis-Pt experimental values were fitted to different theoretical models to find the Cis-Pt release mechanism. The cytotoxicity evaluation of the MNPSiO2 was performed using LN 18 cells (human GBM cells). Homogeneous and well-defined nanoparticles with well-distributed and homogeneous porosity were obtained. The spectroscopic results show the proper functionalization of the mesoporous nanoparticles; besides, MNPSiO2 showed high surface area and large pore size. High correlation coefficients were obtained. Though the best fitted was the Korsmeyer-Peppas kinetic model, the Higuchi model adjusted better to the results obtained for our system. The MNPSiO2-FA were highly biocompatible, and they increased the cytotoxic effect of Cis-Pt loaded in them.

This article is devoted to adhesion forces of polymers modified with silica nanoparticles, as well as studying changes in the surface relief of polymers modified with nanopowders of silicon dioxide, using the atomic force microscope. Enhancement of adhesion forces of nanocomposite samples of polymers containing 1 and 3% of silica nanoparticles was observed despite the non-modified nature of the samples.

Low-permeability reservoirs are characterized by small pore size and a complex strata structure that present challenges and opportunities in recovering petroleum. In this study, a new nanofluid com...

CO2 mobility control in porous media is crucial to geological sequestration of CO2 and enhanced oil recovery (EOR). Although aqueous foam has been widely used to control the mobility of CO2, bubble...

Incorporating drugs into silica matrices by the melting method can be applied to obtain drug delivery systems because they are governed by electrostatic type interactions, hydrogen bonding and hydrophilic-hydrophobic interactions between the drug and the silica surface. the melting method is an environmentally correct tool since it is free of organic solvent, low cost and with easy execution for the incorporation of drugs in silicas. Drugs delivery systems are very important for improving the treatment of chronic diseases. Topiramate (TPM) is a potent antiepileptic used in high daily doses as it has low bioavailability. In this context, silica nanoparticles (NPS) were used as an inorganic matrix for TPM transport in (