Synthesis,characterisation and potential biomedical applications of magnetic core–shell structures: carbon‐, dextran‐, SiO2 ‐ and ZnO‐coated Fe3 O4 nanoparticles

Due to the strong effect of nanoparticles'' size and surface properties on cellular uptake and bio‐distribution, the selection of coating material for magnetic core–shell nanoparticles (CSNPs) is very important. In this study, the effects of four different biocompatible coating materials on the physical properties of Fe₃ O₄ (magnetite) nanoparticles (NPs) for different biomedical applications are investigated and compared. In this regard, magnetite NPs are prepared by a simple co‐precipitation method. Then, CSNPs including Fe₃ O₄ as a core and carbon, dextran, ZnO (zincite) and SiO₂ (silica) as different shells are synthesised using simple one‐ or two‐step methods. A comprehensive study is carried out on the prepared samples using X‐ray diffraction, vibrating sample magnetometry, transmission electron microscopy and Fourier transform infrared spectroscopy analyses. According to the authors'' findings, it is suggested that carbon‐ and dextran‐coated magnetite NPs with high M _s have great potential in the application of magnetic resonance imaging contrast agents. Moreover, silica‐coated magnetite NPs with high coercivity are potentially suitable candidates for hyperthermia and ZnO‐coated Fe₃ O₄ is potentially suitable for photothermal therapy.Inspec keywords: iron compounds, carbon, silicon compounds, zinc compounds, nanomedicine, biomedical materials, nanofabrication, nanoparticles, magnetic particles, coatings, X‐ray diffraction, magnetometry, transmission electron microscopy, Fourier transform spectra, infrared spectra, biomedical MRI, hyperthermia, radiation therapyOther keywords: biomedical applications, magnetic core‐shell nanoparticles, CSNP, cellular uptake, biodistribution, coating material, biocompatible coating materials, co‐precipitation, dextran, zincite, silica, X‐ray diffraction, vibrating sample magnetometry, transmission electron microscopy, Fourier transform infrared spectroscopy, magnetic resonance imaging contrast agents, hyperthermia, photothermal therapy, SiO₂ ‐Fe₃ O₄ , ZnO‐Fe₃ O₄      

Synthesis of porous GdF3 :Er3+, Yb3+ –COOH core–shell structured bi‐functional nanoparticles for drug delivery

The authors synthesised porous GdF₃ :Er³⁺, Yb³⁺ –COOH core–shell structured bi‐functional nanoparticles through a one‐step hydrothermal route during which ethylene diamine tetraacetic acid) was bound to the surface of the nanoparticles. It has high up‐conversion emission intensity for monitoring the drug release process and magnetisation saturation value (10.2 emu/g) for drug targeting under foreign magnetic fields. Moreover, porous GdF₃ :Er³⁺, Yb³⁺ as drug carriers with a high drug‐loading efficiency. cis‐Dichlorodiammineplatinum(II) (cisplatin, CDDP)‐loaded GdF₃ :Er³⁺, Yb³⁺ nanoparticles (GdF₃ :Er³⁺, Yb³⁺ –CDDP) were characterised by the Fourier transform infrared spectra, and CDDP was loaded in the form of electrostatic interaction and hydrogen bonds. Compared with CDDP alone, GdF₃ :Er³⁺, Yb³⁺ –CDDP nanoparticles increase concentration of CDDP in the target site and enhance its anticancer efficiency. Therefore, the as‐prepared GdF₃ :Er³⁺, Yb³⁺ –COOH nanoparticles allow simultaneous targeted drug delivery and monitoring as promising anti‐cancer theranostic agents.Inspec keywords: gadolinium compounds, erbium, ytterbium, organic compounds, nanoporous materials, core‐shell nanostructures, drug delivery systems, Fourier transform infrared spectra, electrostatics, hydrogen bonds, magnetisation, nanofabrication, nanomedicine, spectrochemical analysisOther keywords: porous core–shell structured bifunctional nanoparticles, drug delivery, one‐step hydrothermal route, ethylene diamine tetraacetic acid, magnetisation saturation value, up‐conversion emission intensity, cis‐Dichlorodiammineplatinum(II), Fourier transform infrared spectra, electrostatic interaction, hydrogen bonds, anticancer theranostic agents     

Green synthesised iron and iron‐based nanoparticle in environmental and biomedical application: – a review

Owing to the development of nanotechnology and its influence in various fields, the development of efficient and environmental friendly technique for the synthesis of nanomaterials is important. Among the various traditional and conventional methods available for the synthesis, plant‐mediated synthesis seems to be a very attractive and environmental friendly method, attributing to its simple methodology and eco‐friendly approach. The synthesis rate and stability of the nanoparticle synthesised are good when compared to the other methods of synthesis and it is proved to be efficient in various fields of application. Hence, the present review article deals with furnishing information about the plant sources used so far and details about the environmental and biomedical applications of the synthesised nanoparticles.Inspec keywords: nanoparticles, reviews, nanomedicine, nanofabrication, antibacterial activity, ironOther keywords: environmental application, biomedical application, iron‐based nanoparticle, environmental friendly technique, traditional methods, plant‐mediated synthesis, environmental friendly method, simple methodology, eco‐friendly approach, synthesis rate, nanoparticle stability, green synthesis, nanotechnology, nanomaterials, conventional methods, Fe     

Protective agent-free synthesis of Ni–Ag core–shell nanoparticles

Ni–Ag core–shell nanoparticles have been prepared by successive hydrazine reduction in ethylene glycol in the absence of protective agents. TEM analysis indicated the product was very fine and the thickness of Ag nanoshells could be controlled by the added silver nitrate concentration. The analyses of electron diffraction pattern and XRD revealed that both Ni cores and Ag shells had a fcc structure. The surface composition analysis by XPS indicated that Ni cores were fully covered by Ag nanoshells. Because of the absence of protective agent, the appropriate nickel concentration for the coating of Ag nanoshells should be less than 1.0 mM to avoid particle agglomeration. The product possessed the surface character of Ag and the magnetic property of Ni, and may have many potential applications in optical, magnetic, catalytic, biochemical, and biomedical fields.     

Preparation and characteristics of core–shell structure cobalt/silica nanoparticles

The silica nanolayer with different thickness was coated on the spherical cobalt nanoparticles (an average diameter of 67 nm) to form core–shell structure by the controlled hydrolysis and condensation of tetraethyl orthosilicate (TEOS). This coating process was based on the use of silane coupling agent 3-mercaptopropyltrimethoxysilane (HS-(CH₂)₃Si(OCH₃)₃, MPTS) as a primer to render the cobalt surface vitreophilic, thus rendering cobalt surface compatible with silica. The control over the silica coating layer thickness can be achieved by varying the reaction time. The cobalt nanoparticles and the cobalt coated with silica shell were confirmed by transmission electron microscopy (TEM). X-ray photoelectron spectroscopy (XPS) was used to gain insight into the way in which the MPTS is bound to the surface of the cobalt nanoparticles. Result of the thermogravimetric analysis (TGA) and differential thermal analysis (DTA) indicate that the thermal stability of cobalt/silica is better than that of pure cobalt nanoparticles. Magnetic properties of these powders have been evaluated. These cobalt/silica core–shell nanoparticles can be utilized as precursors for making property-tunable magnetic nanoparticles, thin films, and multilayered core–shell structure nanocomposites.     

Medicinal plants mediated the green synthesis of silver nanoparticles and their biomedical applications

The alarming effect of antibiotic resistance prompted the search for alternative medicine to resolve the microbial resistance conflict. Over the last two decades, scientists have become increasingly interested in metallic nanoparticles to discover their new dimensions. Green nano synthesis is a rapidly expanding field of interest in nanotechnology due to its feasibility, low toxicity, eco‐friendly nature, and long‐term viability. Some plants have long been used in medicine because they contain a variety of bioactive compounds. Silver has long been known for its antibacterial properties. Silver nanoparticles have taken a special place among other metal nanoparticles. Silver nanotechnology has a big impact on medical applications like bio‐coating, novel antimicrobial agents, and drug delivery systems. This review aims to provide a comprehensive understanding of the pharmaceutical qualities of medicinal plants, as well as a convenient guideline for plant‐based silver nanoparticles and their antimicrobial activity.     

Bioengineered and biocompatible silver nanoparticles from Thalictrum foliolosum DC and their biomedical applications

Bioengineered nanoparticles display unique characteristics at the cellular, atomic, and molecular levels with their geometric shapes dictating suitable actions and use. In the present study, bioengineered and bio-compatible silver nanoparticles (AgNPs) were obtained from Thalictrum foliolosum leaf extract which served as a capping and reducing agent. The effects of different parameters, such as varying concentrations of silver nitrate (0.2, 0.5, 1.0, and 2.0 mM), leaf extract (24.5, 24, 23.5, and 23 mL), pH (2, 4, 6, 7, and 8), and temperature (20, 40, 60, and 80 °C) were examined on the synthesis of T. foliolosum-assisted silver nanoparticles (TF@AgNPs) and their characterization accomplished by UV–visible and Fourier transform infrared spectroscopy, X-ray diffraction, Transmission, and Scanning electron microscopy, and Zeta potential analyses. X-ray and microscopy results revealed that TF@AgNPs were spherical with?~?18.27?±?3.9 nm size. The biological studies indicate potential antifungal, antioxidant, and anticancer properties besides hydrogen peroxide sensing, for the ensued TF@AgNPs suggesting their numerous biomedical appliances. A clean, cost-effective, and safer method for the procurement of bioengineered TF@AgNPs that precludes the use of any hazardous elements with no adverse effects is some additional sustainable attributes.

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Strategies for area-selective deposition of metal nanoparticles on carbon nanotubes and their applications: a review

Journal of Materials Science - Carbon nanotubes (CNTs) have a common use as a nanostructured substrate to support and stabilize metal nanoparticles (MNPs), generating hybrid materials whose...     

Preparation of manganese-based perovskite nanoparticles using a reverse microemulsion method: biomedical applications

In this study, La_0.7Sr_0.3Mn_0.98Ti_0.02O₃ (LSMTO) nanoparticles with a perovskite structure and an average particle size of 23.5 nm were synthesized using a reverse microemulsion method. In this method, cetyltrimethylammonium bromide (CTAB) was used as a surfactant, 1-butanol as a co-surfactant, n-hexane as a continuous oil phase, and an aqueous solution containing metal cations or precipitating agent as a dispersed aqueous phase. The aqueous nanodroplets of microemulsions were used for the formation of perovskite precursor. The obtained precursor was then calcined at 700 ^° C for 4 h to convert the precursor to the perovskite phase. In addition, the heating ability of the LSMTO nanoparticles was evaluated under a safe alternating magnetic field used in magnetic hyperthermia therapy. The results showed the fast magneto-temperature response of the prepared sample with sufficient heat loss at the therapeutic temperature range, indicating the LSMTO nanoparticles can be used as a self-regulated heating agent in the magnetic hyperthermia therapy.     

Emerging biomedical sensing technologies and their applications

Recent progress in biomedical sensing technologies has resulted in the development of several novel sensor products and new applications. Modern biomedical sensors developed with advanced microfabrication and signal processing techniques are becoming inexpensive, accurate, and reliable. A broad range of sensing mechanisms has significantly increased the number of possible target measurands that can be detected. The miniaturization of classical "bulky" measurement techniques has led to the realization of complex analytical systems, including such sensors as the BioChemLab-on-a-Chip. This rapid progress in miniature devices and instrumentation development will significantly impact the practice of medical care as well as future advances in the biomedical industry. Currently, electrochemical, optical, and acoustic wave sensing technologies have emerged as some of the most promising biomedical sensor technologies. In this paper, important features of these technologies, along with new developments and some of the applications, are presented.     

CuAg and AuAg bimetallic nanoparticles for catalytic and heat transfer applications

Clean Technologies and Environmental Policy - Bimetallic nanoparticles (BNPs) have drawn significant attention due to their numerous applications. They demonstrate enhanced optical, electrical,...     

Synthesis and sintering of biomimetic hydroxyapatite nanoparticles for biomedical applications

Synthesis of monodisperse nanoparticles with uniform morphology and narrow size distribution as achieved by nature is a challenge to materials scientists. Mimicking the process of biomineralization has led to the development of biomolecules mediated synthesis of nanoparticles that overcomes many of the problems associated with nanoparticle synthesis. Termed as biomimetics this paradigm shift in the philosophy of synthesis of materials is very advantageous for the design-based synthesis of nanoparticles. The effect of concentration of a protein named bovine serum albumin on particle size, morphology and degree of crystallinity of biomimetically synthesized hydroxyapatite particles, has been studied. Results establish 0.5% protein as the required concentration to produce 30–40 nm sized hydroxyapatite particles with an optimum degree of crystallinity as required for biomedical applications. These particles synthesized under certain stringent conditions are found to have stoichiometric calcium:phosphorus ratio of 1.67 and exhibit restricted grain growth during sintering.     

Protein-based nanomaterials and nanosystems for biomedical applications: A review

Advanced protein-based nanomaterials and nanosystems (PNNS) have attracted considerable scientific interest in recent decades due to their potential in bio-applications. Nowadays, the constructed PNNS exhibit different properties for various special applications based on the characteristics of different proteins. Herein, in this review article, a systematic summary and discussion focusing on designing multi-functional PNNS are presented. The latest developments in unique synthesis strategies and detailed classification of PNNS are reviewed. The functions of proteins in PNNS for biomedical applications, such as targeting proteins, carriers, enzymes, and fluorescent indicators, are summarized. Finally, the challenges and forward-looking perspectives of PNNS research are provided.     

Synthesis and physical characterization of magnetite nanoparticles for biomedical applications

Iron oxide nanoparticles for biomedical applications in the size range of 15–130 nm were prepared by either oxidative hydrolysis of ferrous sulfate with KOH or precipitation from ferrous/ferric chloride solutions. The magnetite particle size is controlled by variation of pH and temperature. The synthesized magnetite nanoparticles are partially oxidized as signaled by ferrous concentrations of below 24 wt% Fe²⁺ and lattice parameters of a₀ ≤ 8.39 Å which are smaller compared to 8.39 Å for stoichiometric magnetite. The extend of oxidation increases with decreasing particle size. Heating at 150–350 °C topotactically transforms the magnetite nanoparticles into stoichiometric tetragonal maghemite (ferrous ion concentration c_Fe²⁺=0 and a₀ = 8.34 Å) without significant particle growth. The magnetite–maghemite transformation is studied with thermal analysis, XRD and IR spectroscopy. The saturation magnetizations of the magnetite and maghemite particles decrease with decreasing particle size. The variation of M_s with particle size is interpreted using a magnetic core–shell particle model. Magnetite particles with d ≤ 16 nm show superparamagnetic behavior at room temperature whereas particles with diameter >16 nm display hysteresis behavior. These particles are candidates for biomedical applications, e.g. controlled drug release or hyperthermia.     

Fungal xylanases‐mediated synthesis of silver nanoparticles for catalytic and biomedical applications

Green synthesis of nanoparticles has fuelled the use of biomaterials to synthesise a variety of metallic nanoparticles. The current study investigates the use of xylanases of Aspergillus niger L3 (NEA) and Trichoderma longibrachiatum L2 (TEA) to synthesise silver nanoparticles (AgNPs). Characterisation of AgNPs was carried out using UV–Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy, while their effectiveness as antimicrobial, antioxidant, catalytic, anticoagulant, and thrombolytic agents were determined. The colloidal AgNPs was brownish with surface plasmon resonance at 402.5 and 410 nm for NEA‐AgNPs and TEA‐AgNPs, respectively; while FTIR indicated that protein molecules were responsible for the capping and stabilisation of the nanoparticles. The spherical nanoparticles had size of 15.21–77.49 nm. The nanoparticles significantly inhibited the growth of tested bacteria (63.20–88.10%) and fungi (82.20–86.10%), and also scavenged DPPH (37.48–79.42%) and hydrogen peroxide (20.50–96.50%). In addition, the AgNPs degraded malachite green (78.97%) and methylene blue (25.30%). Furthermore, the AgNPs displayed excellent anticoagulant and thrombolytic activities using human blood. This study has demonstrated the potential of xylanases to synthesise AgNPs which is to the best of our knowledge the first record of such. The present study underscores the relevance of xylanases in nanobiotechnology.Inspec keywords: visible spectra, catalysis, ultraviolet spectra, silver, microorganisms, antibacterial activity, transmission electron microscopy, surface plasmon resonance, nanoparticles, nanofabrication, colloids, blood, Fourier transform infrared spectra, particle sizeOther keywords: Ag, fungal xylanases‐mediated synthesis, silver nanoparticles, catalytic applications, biomedical applications, green synthesis, metallic nanoparticles, Trichoderma longibrachiatum L2, transmission electron microscopy, antimicrobial agents, antioxidant agents, catalytic agents, thrombolytic agents, surface plasmon resonance, spherical nanoparticles, FTIR spectra, anticoagulant agents, colloidal nanoparticles, biomaterials, Aspergillus niger L3, UV‐vis spectroscopy, Fourier transform infrared spectroscopy, protein molecules, DPPH, hydrogen peroxide, malachite green, methylene blue, human blood, nanobiotechnology     

生物医用磁性纳米颗粒的制备与表面改性

磁性纳米颗粒目前是生物医用纳米材料领域异常活跃的方向之一.不同方法制备的磁性纳米颗粒经不同聚合物或分子表面改性后具有多方面的生物医学应用.本文综合评述了磁性纳米颗粒的制备方法,如共沉淀法、溶胶-凝胶法、微乳剂法等;总结了磁性纳米颗粒表面改性技术,包括改性物质与改性方法;概括了磁性纳米颗粒在生物医学领域的应用,主要涉及磁靶向制剂、细胞分离、肿瘤细胞的过热治疗、MR I衬度增强剂四方面.磁性纳米颗粒还有很大的发展空间和广阔的应用前景.     

Biosynthesis of γ ‐Fe2 O3 @CuO core–shell nanoclusters using aqueous extract of Sesbania grandiflora Linn fresh leaves,its characterisation,and antimicrobial activity studies against Staphylococcus aureus strains

The present study reports an eco‐friendly and rapid method for the synthesis of core–shell nanoclusters using the modified reverse micelle method. It is a green synthetic method which uses Sesbania grandiflora Linn extract which acts as a reducing and capping agent. It is observed that this method is very fast and convenient and the nanoclusters are formed with 5–10 min of the reaction time without using harsh conditions. The core–shell nanoclusters so prepared were characterised using UV–Vis spectroscopy, scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, and X‐ray photoelectron spectroscopy. Further, their effective antibacterial activity towards the gram‐positive bacteria Staphylococcus aureus was found to be due to their smaller particle size.Inspec keywords: iron compounds, copper compounds, nanoparticles, particle size, nanofabrication, nanomedicine, biomedical materials, core‐shell nanostructures, antibacterial activity, ultraviolet spectra, visible spectra, microorganisms, reduction (chemical), scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, X‐ray photoelectron spectraOther keywords: biosynthesis, γ‐Fe₂ O₃ ‐CuO core‐shell nanoclusters, aqueous extract, Sesbania grandiflora Linn fresh leaves, antimicrobial activity, Staphylococcus aureus strains, eco‐friendly method, modified reverse micelle method, green synthetic method, reducing agent, capping agent, UV‐visible spectroscopy, scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, X‐ray photoelectron spectroscopy, antibacterial activity, gram‐positive bacteria Staphylococcus aureus, particle size, time 5 min to 10 min, Fe₂ O₃ ‐CuO