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•Silica nanoparticles-covered graphene oxide (SiO2-GO) nanohybrids were synthesized.•Fine nanometric SiO2 particles (<20nm) covered the surface of GO sheets.•SiO2-GO nanohybrids ...significantly enhanced the barrier properties of epoxy coating.•SiO2-GO nanohybrids significantly enhanced GO dispersion in epoxy coating.
This study reports two facile routes for the synthesis and characterization of silica nanoparticles-decorated graphene oxide (SiO2-GO) nanohybrids by a two-step in-situ sol-gel process using a mixture of 3-Aminopropyl triethoxysilane and Tetraethylorthosilicate in water–alcohol solution. Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and thermal gravimetric analysis (TGA) were employed for the SiO2-GO nanohybrids characterization. Field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM) were employed to characterize the SiO2 nanoparticles precipitation on the surface of GO sheets. FT-IR, XPS, AFM, FE-SEM and TGA analyses revealed that fine nanometric SiO2 particles (<20nm) covered the surface of GO sheets. X-ray diffraction and FE-SEM analyses showed better dispersion of SiO2-GO nanohybrids in the epoxy coating than pure GO. The effect of SiO2-GO nanohybrids on the corrosion protection and barrier performance of the epoxy coating was investigated by electrochemical impedance spectroscopy (EIS). Results revealed that SiO2-GO nanohybrids significantly enhanced the barrier and corrosion protection properties of the epoxy coating. It was also shown that SiO2-GO nanohybrids significantly reduced the cathodic delamination rate of epoxy coating.
Oral ingestion remains as the most convenient route of administration for the application of pharmaceuticals since it is non-invasive and does not require trained personnel to administer the drugs. ...Despite significant progress in novel oral drug delivery platforms over the past few decades, the oral delivery of macromolecules (particularly for peptides and proteins) is one of the major challenges faced by the biopharmaceutical industry. This is even more important since a large number of biologic drugs have been available in the past decade which typically require intravenous administration. Recently, silica nanoparticles have emerged as multifunctional, biocompatible and biodegradable inorganic nanocarriers with enormous potential as an oral drug delivery platform for various therapeutics including macromolecules. Their unique structural composition facilitates the loading of large therapeutic payloads at desired loading capacities for a controlled and site-specific oral delivery. Here, we review first the physiological challenges for oral delivery of peptides and proteins. Next, we discuss silica-based functional materials for oral delivery of macromolecules and highlight their evolving role not only as an encapsulant but as a permeation enhancer as well. Lastly, we also discuss potential strategies for future translation of these novel materials to the clinic.
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•Copper ions chelated mesoporous silica nanoparticles via dopamine chemistry was developed.•Copper ions and polydopamine could endow azoxystobin pH-responsive release profiles by ...coordination bonding.•Azoxystrobin-loaded nanoparticles exhibited better fungicidal activity against P. oryzae.•PDA coating could improve deposition efficiency toward cucumber leaves.
Controlled release of pesticide is highly desirable for improving efficacy and reducing side effects. Hydrophobic, hydrogen bonding, and ionic interactions have been widely investigated to control the release of pesticides. However, metal coordination bonding is yet to be fully explored for controlled release of pesticides. In this study, copper ions (Cu2+) chelated mesoporous silica nanoparticles (MSNs) via dopamine chemistry (AZOX@MSNs-PDA-Cu) for controlled azoxystrobin (AZOX) release have been developed. The chemical properties and morphological features of the nanoparticles were characterized by SEM, TEM, FT-IR, TGA, XPS, and N2 adsorption/desorption. The coordination bonding interaction between copper ions and AZOX slows down the release of AZOX to the surrounding environment. Moreover, copper chelation could endow cargo molecules with pH-responsive release profiles because of the competitive coordination of protons to polydopamine (PDA) layers or hydroxide ions to Cu2+ to break down the coordination bonding architecture of “PDA–Cu2+–AZOX”. AZOX@MSNs-PDA-Cu exhibited better fungicidal activity against Pyricularia oryzae than AZOX technical under the same dose of active ingredient applied. Dynamic contact angle measurement demonstrated that the PDA coating could improve adhesion ability and deposition efficiency toward crop leaves. This strategy opens up a facile but powerful avenue for the design of pH-responsive systems and new opportunities for their application in pesticide delivery.
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•“Dry amine” solid CO2 sorbents were synthesized within 60 s.•“Dry amine” sorbents are cost-effective due to cheap support.•“Dry amine” sorbents show excellent CO2 capture performance ...due to the open structure.
The low cost and facile preparation of CO2 sorbents are extremely important for the practical CO2 capture application. In this study, we demonstrate a facile preparation of “dry amine” CO2 sorbents through a cost-effective and environmental friendly pathway. Commercially available mass-produced SiO2 nanoparticles were used as the support of “molecular basket” sorbents. Tetraethylenepentamine (TEPA) was quickly (60 s) loaded on the surface of SiO2 nanoparticles through high-speed mechanical mixing (22000 rpm) method. Compared with the conventional wet impregnation method, no solvent is required. Although this new pathway is simple, timesaving, cost-effective and environmental friendly, the prepared sorbents present excellent CO2 capture performance. The results show that with the increase of the TEPA loading, the CO2 adsorption amount of the TEPA/SiO2 sorbent increases first and then decreases. The 50TEPA/SiO2 sorbent shows much higher CO2 uptake (3.98 mmol/g) than SBA-15 based sorbent (2.45 mmol/g) prepared through the same method. And it also displays lower mass transfer resistance due to the small particle size and the open structure while 50TEPA/SBA-15 shows larger mass transfer resistance due to the channel structure. The results also show that 50TEPA/SiO2 has good reproducibility. Due to the low cost and facile preparation, the dry amine sorbents may also show the potential application for urgent use, such as SO2 leak or H2S leak.
The rapid emergence of drug resistance continues to outpace the development of new antibiotics in the treatment of infectious diseases. Conventional therapy is currently limited by drug access issues ...such as low intracellular drug accumulations, drug efflux by efflux pumps and/or enzymatic degradation. To improve access, targeted delivery using nanocarriers could provide the quantum leap in intracellular drug transport and retention. Silica nanoparticles (SiNPs) with crucial advantages such as large surface area, ease-of-functionalization, and biocompatibility, are one of the most commonly used nanoparticles in drug delivery applications. A porous variant, called the mesoporous silica nanoparticles (MSN), also confers additional amenities such as tunable pore size and volume, leading to high drug loading capacity. In the context of bacterial infections, SiNPs and its variants can act as a powerful tool for the targeted delivery of antimicrobials, potentially reducing the impact of high drug dosage and its side effects. In this review, we will provide an overview of SiNPs synthesis, its structural proficiency which is critical in loading and conjugation of antimicrobials and its role in different antimicrobial applications with emphasis on intracellular drug targeting in anti-tuberculosis therapy, nitric oxide delivery, and metal nanocomposites. The role of SiNPs in antibiofilm coatings will also be covered in the context of nosocomial infections and surgical implants.
Mesoporous silica nanoparticles functionalized with peptides are developed for sequential drug delivery. The RGD peptide is used for vasculature/cell membrane targeting and the TAT peptide for ...nuclear targeting. Using this delivery strategy, a tumor in a murine xenograft model is successfully regressed.
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•An epoxy-silica nanocomposite was developed to fabricate durable superhydrophobic coatings.•The fabrication technique is facile, economic, and scalable.•An amino-functionalized ...polysiloxane was used to modify the epoxy.•The coating is suitable for different substrate materials such as metals, glass, wood, or fabrics.•The coating demonstrated exceptional durability against peeling, abrasion, corrosion, and high temperature tests.
The extensive research and interest in superhydrophobic surfaces have not yet resulted in their widespread utilization. Limitations include high cost, complex fabrication techniques, and poor durability. Herein, we report a facile, economic, and scalable spray-coating fabrication technique that utilizes an epoxy-silica nanocomposite to create robust and durable superhydrophobic coatings. To overcome its inherent high surface energy, the epoxy was modified using an amino-functionalized polysiloxane. The newly developed nanocomposite coating demonstrated excellent water repellency with contact angles of ~165° and sliding angles of ~3° for different substrate materials such as metals, wood, glass, and textile. Our results revealed that a nanocomposite coating with a silica concentration of ~28 wt% provides an optimum balance between superhydrophobicity and durability. We also investigated the effect of solvent volatility on the hierarchical structure and superhydrophobicity of the coated samples, which is rarely considered in the literature. It was found that a spray emulsion with lower solvent volatility results in an enhanced surface microstructure that improves water repellency. Moreover, the coated samples demonstrated excellent robustness and durability against peeling, abrasion, corrosion (pH 1 to 13), and high temperature (up to 150 °C) environments exposure tests. The outcome of our efforts confirms that the epoxy modification process leads to enhanced superhydrophobicity without compromising the robustness and durability of the coating. This remarkable performance offers a great potential for large-scale production of superhydrophobic surfaces operating in harsh working conditions.
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•ZIF-8 was used as a multifunctional gatekeeper for HMSN-BTA.•HMSN-BTA@ZIF-8 was well-dispersed in epoxy matrix.•HMSN-BTA@ZIF-8 notably improved anticorrosion performance for epoxy ...coating.•HMSN-BTA@ZIF-8/epoxy coatings exhibited excellent self-healing performance.
Zeolitic imidazole framework-8 (ZIF-8) with porous structure, pH-response and facile synthesis characteristics, as a molecule delivery and stimulus-response nanomaterial, has been widely investigated over the past decades. Here, we report for the first time a new corrosion inhibitor-encapsulated nanocontainer (denoted as HMSN-BTA@ZIF-8), successfully synthesized using ZIF-8 as self-sacrificial template, pH-responsive gatekeeper and interfacial compatibility assistant for hollow mesoporous silica nanoparticle (HMSN). Corrosion inhibitors of benzotriazole (BTA) are encapsulated in the cavity and mesopores of HMSN. The results demonstrate that there are outstanding pH-triggered activities to both acidic and alkaline conditions for HMSN-BTA@ZIF-8. Rather than physically dispersing nanocontainers in the coating matrix, the synthesized HMSN-BTA@ZIF-8 can covalently interact with epoxy resin, resulting in superior compatibility and more uniform dispersion behavior of nanocontainers in the coatings. Interestingly, the epoxy composite coating with HMSN-BTA@ZIF-8 exhibits excellent corrosion protection and outstanding self-healing performances, which are well characterized by potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), salt spray test and Scanning Kelvin Probe (SKP) technique. The outstanding anticorrosion and impressive self-healing properties are attributed to the good compatibility of HMSN-BTA@ZIF-8, the hydrophobicity of ZIF-8, higher crosslinking densities, and the controllable release of BTA in the epoxy composite coating. It is believed that this work is very helpful for extending the service life of various anticorrosion coatings.
Owing to the limitations of conventional cancer therapies, cancer immunotherapy has emerged for the prevention of cancer recurrence. To provoke adaptive immune responses that are antigen-specific, it ...is important to develop an efficient antigen delivery system that can enhance the activation and maturation of the dendritic cells (DCs) in the human body. In this study, we synthesize hollow mesoporous silica nanoparticles with extra-large mesopores (H-XL-MSNs) based on a single-step synthesis from core–shell mesoporous silica nanoparticles with a core composed of an assembly of iron oxide nanoparticles. The hollow void inside the mesoporous silica nanoparticles with large mesopores allows a high loading efficiency of various model proteins of different sizes. The H-XL-MSNs are coated with a poly(ethyleneimine) (PEI) solution to provide an immune adjuvant and change the surface charge of the particles for loading and slow release of a model antigen. An in vitro study using a cancer vaccine based on the PEI-coated H-XL-MSNs with the loading of the model antigen showed an enhanced activation of the DCs. An in vivo study demonstrated that the resulting cancer vaccine increased the antigen-specific cytotoxic T cells, enhanced the suppression of tumor growth, and improved the survival rate after challenging cancer to mice. These findings suggest that these hollow MSNs with extra-large pores can be used as excellent antigen carriers for immunotherapy.
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