Gas-phase synthesis of magnetic metal/polymer nanocomposites

Magnetic nanoparticles incorporation into different substrates for dyes and heavy metals removal-A Review

Substantial discharge of hazardous substances, especially dyes and heavy metal ions to the environment, has become a global concern due to many industries neglecting the environmental protocols in waste management. A massive discharge of contaminantsfrom different anthropogenic activities, can pose alarming threats to living species and adverse effect to the ecosystem stability. In the process of treating the polluted water, various methods and materials are used. Hybrid nanocomposites have attained numerous interest due to the combination of remarkable features of the organic and inorganic elements in a single material. In this regards, carbon and polymer based nanocomposites have gained particular interest because of their tremendous magnetic properties and stability. These nanocomposites can be fabricated using several approaches that include filling, template, hydrothermal, pulsed-laser irradiation, electro-spinning, detonation induced reaction, pyrolysis, ball milling, melt-blending, and many more. Moreover, carbon-based and polymer-based magnetic nanocomposites have been utilized for an extensive number of applications such as removal of heavy metal and dye adsorbents, magnetic resonance imaging, and drug delivery. This review emphasized mainly on the production of magnetic carbon and polymer nanocomposites employing various approaches and their applications in water and wastewater treatment. Furthermore, the future opportunities and challenges in applying magnetic nanocomposites for heavy metal ion and dye removal from water and wastewater treatment plant.

Nanoparticles for Biomedicine: Coagulation During Synthesis and Applications

Nanoparticle-based systems offer fascinating possibilities for biomedicine, but their translation into clinics is slow. Missing sterile, reproducible, and scalable methods for their synthesis along with challenges in characterization and poor colloidal stability of nanoparticles in body fluids are key obstacles. Flame aerosol technology gives proven access to scalable synthesis of nanoparticles with diverse compositions and architectures. Although highly promising in terms of product reproducibility and sterility, this technology is frequently overlooked, as its products are of fractal-like aggregated and/or agglomerated morphology. However, coagulation is a widely occurring phenomenon in all kinds of particle-based systems. In particular, protein-rich body fluids encountered in biomedical settings often lead to destabilization of colloidal nanoparticle suspensions in vivo. We aim to provide insights into how particle–particle interactions can be measured and controlled. Moreover, we show how particle coupling effects driven by coagulation may even be beneficial for certain sensing, therapeutic, and bioimaging applications.

Engineering the Bioactivity of Flame-Made Ceria and Ceria/Bioglass Hybrid Nanoparticles

Despite its use as a highly efficient and reusable catalyst in research and industrial settings, cerium oxide nanoparticles or nanoceria have yet to gain a foothold in the biomedical field. A variety of beneficial effects of nanoceria have been demonstrated, including its use as an inorganic nanoenzyme to mimic antioxidant enzymes, to protect mammalian cells, and to suppress microbial growth. While these properties are of high interest for wound-management applications, the literature offers contradicting reports on toxicity and enzymatic activity of nanoceria. These discrepancies can be attributed to differences between synthesis methods and insufficient physicochemical characterization, leading to incomparable studies. The activity of nanoceria is mostly governed by its Ce³⁺/Ce⁴⁺ ratio which needs to be controlled to compare different nanoceria systems. In this work, we demonstrate that liquid-feed flame spray pyrolysis offers excellent control over the oxidation state in a one-step synthesis of nanoceria. This control allows a comprehensive comparison of different types of ceria nanoparticles. We connect physicochemical characteristics to biomedically relevant properties such as superoxide dismutase and catalase mimicry, human monocyte and macrophage protection, and antimicrobial activity. Furthermore, we demonstrate how the synthesis method also allows tailoring the properties of ceria/bioglass hybrid nanoparticles, thus creating nanoparticles with manifold biomedical prospects.

Single-Step Fabrication of Polymer Nanocomposite Films

Polymer nanocomposites are employed in (micro)electronic, biomedical, structural and optical applications. Their fabrication is challenging due to nanoparticle (filler) agglomeration and settling, increased viscosity of blended solutions and multiple tedious processing steps, just to name a few. Often this leads to an upper limit for filler content, requirements for filler⁻polymer interfacial chemistry and expensive manufacturing. As a result, novel but simple processes for nanocomposite manufacture that overcome such hurdles are needed. Here, a truly single-step procedure for synthesis of polymer nanocomposite films, structures and patterns at high loadings of nanoparticles (for example, >24 vol %) for a variety of compositions is presented. It is highly versatile with respect to rapid preparation of films possessing multiple layers and filler content gradients even on untreated challenging substrates (paper, glass, polymers). Such composites containing homogeneously dispersed nanoparticles even at high loadings can improve the mechanical strength of hydrogels, load-bearing ability of fragile microstructures, gas permeability in thin barriers, performance of dielectrics and device integration in stretchable electronics.

Au–Ir nanoalloy nucleation during the gas-phase condensation: a comprehensive MD study including different effects

The number of formed clusters and their size increases with the increasing temperature and pressure, which is in good agreement with the experimental results.

Developing a tissue glue by engineering the adhesive and hemostatic properties of metal oxide nanoparticles

Despite decades of research, wound complications remain a major cause of postoperative mortality, especially in the face of multiple comorbidities. Addressing the issue of anastomotic leakages and impaired wound healing from a new angle is of great interest with the prospect of having direct impact on patient outcome. Recently, aqueous suspensions of silica and iron oxide nanoparticles have been employed to connect biological tissue by serving as an adhesive layer eventually leading to macroscopic gluing of tissue. In this work, we explore the prospects of this effect by introducing bioactive tissue adhesives composed of nanoparticles produced via scalable and sterile flame spray pyrolysis. We investigate six different metal oxides on cytocompatibility, hemostatic activity and adhesive properties in a small intestine lap joint model. While bioglass nanoparticles show exceptionally strong procoagulant and adhesive properties, the cell membrane integrity is impaired at high particle concentrations. Interestingly, when bioglass is combined with ceria, a material that has well-documented cytoprotective effects, the resulting hybrid particles exhibit the same beneficiary effects as bioglass while featuring superior cytocompatibility. Taken together, we demonstrate highly modular synthesis of nanoparticles expressing adhesive properties in conjunction with tailored bioactivity. Such bioactive nanoparticles as adhesion nuclei in wound healing have a wide range of potential applications in surgical wound care and regenerative medicine.

Silica-Coated Nonstoichiometric Nano Zn-Ferrites for Magnetic Resonance Imaging and Hyperthermia Treatment

Large-scale and reproducible synthesis of nanomaterials is highly sought out for successful translation into clinics. Flame aerosol technology with its proven capacity to manufacture high purity materials (e.g., light guides) up to kg h^-1 is explored here for the preparation of highly magnetic, nonstoichiometric Zn-ferrite (Zn_0.4 Fe_2.6 O₄ ) nanoparticles coated in situ with a nanothin SiO₂ layer. The focus is on their suitability as magnetic multifunctional theranostic agents analyzing their T2 contrast enhancing capability for magnetic resonance imaging (MRI) and their magnetic hyperthermia performance. The primary particle size is closely controlled from 5 to 35 nm evaluating its impact on magnetic properties, MRI relaxivity, and magnetic heating performance. Most importantly, the addition of Zn in the flame precursor solution facilitates the growth of spinel Zn-ferrite crystals that exhibit superior magnetic properties over iron oxides typically made in flames. These properties result in strong MRI T2 contrast agents as shown on a 4.7 T small animal MRI scanner and lead to a more efficient heating with alternating magnetic fields. Also, by injecting Zn_0.4 Fe_2.6 O₄ nanoparticle suspensions into pork tissue, MR-images are acquired at clinically relevant concentrations. Furthermore, the nanothin SiO₂ shell facilitates functionalization with polymers, which improves the biocompatibility of the theranostic system.

Scalable hybrid chemical manufacture to photothermal therapy: PEG-capped phototransducers

Ag-TiO2@polyethylene glycol (PEG) nanoparticles were continuously obtained in a single-pass configuration by appropriately reacting freshly flame-synthesized TiO2 with Ag formed in an ultrasonic aqueous medium containing PEG. When the proposed synthesis was kept constant, the production rate for Ag-TiO2@PEG nanoparticles reached approximately 3 g/h while only using a combination of a lab-scale inverse-diffusion flame (16 mm head diameter) and an ultrasonic Ag(I) cell (50 mL). The synthesized nanoparticles were employed as inducers for in vitro photoinduced therapy to kill cancer cells at different light wavelengths. Measurements of the nanoparticle cytotoxicity revealed that PEG incorporation with the Ag-TiO2 particles significantly decreased the cytotoxicity (cell viability of more than ~91% at 200 μg mL(-1) particle concentration) of Ag, and this was comparable with that of TiO2 particles (cell viability of more than ~90%). When 632 nm and 808 nm light was applied to the nanoparticles in the HeLa cells, the viability of the cells was significantly affected [decreased to ~4% (632 nm) and ~26% (808 nm) at 200 μg mL(-1), 5 min irradiation time] by surface plasmon resonance heating and photothermal therapy.