Magnetic core-shell Fe3 O4 @TiO2 nanocomposites for broad spectrum antibacterial applications.

The authors have synthesised a core-shell Fe3 O4 @TiO2 nanocomposite consisting of Fe3 O4 as a magnetic core, and TiO2 as its external shell. The TiO2 shell is primarily intended for use as a biocompatible and antimicrobial carrier for drug delivery and possible other applications such as wastewater remediation purposes because of its known antibacterial and photocatalytic properties. The magnetic core enables quick and easy concentration and separation of nanoparticles. The magnetite nanoparticles were synthesized by a hydrothermal route using ferric chloride as a single-source precursor. The magnetite nanoparticles were then coated with titanium dioxide using titanium butoxide as a precursor. The core-shell Fe3 O4 @TiO2 nanostructure particles were characterized by XRD, UV spectroscopy, and FT-IR, TEM, and VSM techniques. The saturation magnetization of Fe3 O4 nanoparticles was significantly reduced from 74.2 to 13.7 emu/g after the TiO2 coating. The antibacterial studies of magnetic nanoparticles and the titania-coated magnetic nanocomposite were carried out against gram+ve, and gram-ve bacteria (Staphylococcus aureus, Pseudomonas aeruginosa, Shigella flexneri, Escherichia coli, and Salmonella typhi) using well diffusion technique. The inhibition zone for E. coli (17 mm after 24 h) was higher than the other bacterial strains; nevertheless, both the uncoated and TiO2 -coated magnetite nanocomposites showed admirable antibacterial activity against each of the above bacterial strains.

Magnetic and optical properties of green synthesized nickel ferrite nanoparticles and its application into photocatalysis.

Spinel NiFe2O4nanoparticles have been synthesized via hydrothermal route usingMangifera indicaflower extract (MIFE) as a green surfactant and reducing agent. X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy techniques have been used to determine the structure and morphology. The formation of single-phase, monodispersed NiFe2O4with mixed morphology, the predominant shape being of equi-axed nanoparticles having an average particle size ≲45 nm, is observed. The thermal magnetization of as-synthesized NiFe2O4nanoparticles shows ferromagnetic to paramagnetic phase transition atTc âˆ¼ 825 K. These nanoparticles show a very high saturation magnetization (Ms) value of 55 emu g-1close to the bulk material and amongst the highest reported values for green synthesized NiFe2O4 nanoparticles. This material has a coercivity (Hc) of 0.15 kOe and remanent magnetization (Mr) of 8.5 emu g-1. The as-synthesized NiFe2O4nanoparticles show bandgap energy of 2.02 eV, derived from UV-vis absorption measurement, which is suitable for effective solar photocatalytic reactions. When exposed to sunlight in the presence of as-synthesized NiFe2O4nanoparticles, 93% of MB-dye degradation is measured in 80 min, indicating excellent photocatalytic properties. Based on the as-synthesized NiFe2O4nanoparticles' observed properties, the effectiveness of MIFE as an environmentally friendly surfactant, and the low-cost dye-degradation prospects of green synthesized NiFe2O4nanoparticles are affirmed.

Magnetically recyclable copper doped core-shell Fe3O4@TiO2@Cu nanocomposites for wastewater remediation.

The smart magnetic nanocomposites have been doped to diminish the energy bandgap of the photocatalyst and to permit recovering of the photocatalyst after the wastewater treatment. The core-shell Fe3O4@TiO2 nanocomposite was synthesised by the hydrothermal method using titanium butoxide as a precursor. The nanocomposites were examined by XRD, VSM, UV-Vis, and TEM techniques. The energy band gap of core-shell Fe3O4@TiO2 nanocomposite is 3.5 eV. Doping of copper with a concentration of 1, 2, and 3 wt% into TiO2 shell was done to increase the performance of photocatalyst. The Fe3O4/PVP@TiO2@Cu photocatalyst was used for dye wastewater treatment. The energy bandgap decreased to 2.2 eV after copper doping into the TiO2 shell specified that copper-doped nanocomposite could be an outstanding photocatalyst. The photocatalytic activity was carried out using methylene blue(MB) and methyl orange (MO) under sunlight. About 65% of methylene blue and 85% of methyl orange degradation was done using Cu (3wt %) doped Fe3O4@TiO2 nanocomposite. These photocatalysts can be easily withdrawn with a magnetic field. The Fe3O4/PVP@TiO2@Cu photocatalyst has been demonstrated to be very functional or effective for the degradation of MB and MO dyes using solar illumination.

Fast removal of heavy metals from water and soil samples using magnetic Fe3O4 nanoparticles.

Heavy metal discharge from anthropogenic sources on open soil surfaces and in natural water bodies poses serious environmental and health concerns. In addition to the contamination reduction of metals at the source, post-discharge removal of metals using nanoparticles is one of the remediation technologies being explored nowadays due to its cost-effectiveness, being environment-friendly, and easy application as a technique. In this work, magnetic iron oxide (Fe3O4) nanoparticles were synthesized chemically and then used for the removal of heavy metals (Cd, Cr, Cu, Fe, Ni, Pb, and Zn) from water and soil samples. The heavy metal removal efficiency of these iron oxide nanoparticles for different metals in water was best observed at a pH of 4.5 and varied between 63.5 and 98.3%. However, the removal efficiency of these nanoparticles from the soil sample was only measured at a pH of 0.7, and heavy metal removal efficiency varied between 69.6 and 99.6%. In both soil and water samples, the most efficient remediation time was less than 20 min, after which desorption and even dissolution of the nanoparticles can occur at a highly acidic pH. Among all selected metals for removal, lead showed the best adsorption and hence removal efficiency. The nanoparticles were characterized using the TEM, XRD, and FTIR techniques. The adsorption efficiency of various metals was estimated by using atomic absorption spectroscopy. The results suggest that the removal efficiency and stability of adsorbed products can further be improved by adjusting the pH higher towards 7 and also perhaps by modifying the nanoparticles with functional groups. The primary advantage of the magnetic un-coated nanoparticles is easy and efficient removal of the nanoparticles from the treated solutions by using an ordinary magnet.

Comprehensive Survey on Nanobiomaterials for Bone Tissue Engineering Applications.

One of the most important ideas ever produced by the application of materials science to the medical field is the notion of biomaterials. The nanostructured biomaterials play a crucial role in the development of new treatment strategies including not only the replacement of tissues and organs, but also repair and regeneration. They are designed to interact with damaged or injured tissues to induce regeneration, or as a forest for the production of laboratory tissues, so they must be micro-environmentally sensitive. The existing materials have many limitations, including impaired cell attachment, proliferation, and toxicity. Nanotechnology may open new avenues to bone tissue engineering by forming new assemblies similar in size and shape to the existing hierarchical bone structure. Organic and inorganic nanobiomaterials are increasingly used for bone tissue engineering applications because they may allow to overcome some of the current restrictions entailed by bone regeneration methods. This review covers the applications of different organic and inorganic nanobiomaterials in the field of hard tissue engineering.

Fabrication and in-vitro biocompatibility of freeze-dried CTS-nHA and CTS-nBG scaffolds for bone regeneration applications.

The thought of biodegradable organic-inorganic composites composed of natural polymer chitosan and ceramic nanoparticles (hydroxyapatite and bioglass) can be considered as a solution for hard tissue engineering. In this paper, we described a comparative assessment of chitosan-nanohydroxyapatite (CTS-nHA) and chitosan-nano-bioglass (CTS-nBG) scaffolds. The dispersion of nanoscaled hydroxyapatite (nHA) and bioglass (nBG) in chitosan remained satisfactory. The freeze-dried composite based CTS-nHA and CTS-nBG scaffolds shown porous structure. The physiochemical and morphological analysis of all samples has been performed through X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The SEM image confirmed the presence of spherically shaped nHA particles of 4.20 µm and irregularly shaped nBG particles of 6.89 µm. The TEM analysis revealed the existence of 165.52 to 255.17 nm sized nHA particles and 167.35 to 334.69 nm sized nBG particles. TEM analysis also showed the interconnected structure of CTS-nHA and CTS-nBG nanocomposites. After seven days' incubation period, the CTS-nHA and CTS-nBG scaffolds shown good mineralization behavior in simulated body fluid (SBF). The CTS-nHA scaffolds exhibited enhanced compressive strength and elastic modulus compared with the CTS-nBG sample. The cell culture experiment revealed that fabricated scaffolds had good compatibility with fibroblast cells (L929, ATCC) and MG-63 which are able to adhere, proliferate, and migrate through the porous structure. All the obtained results clearly recommend that pre-loaded hydroxyapatite and bioglass nanoparticles can enhance the apatite formation. The scaffolds with chitosan, bioglass, and hydroxyapatite have better biomechanical characteristics and allow cell growth. Therefore, these scaffolds can be perfect candidates for various hard tissue engineering applications such as bone regeneration.

Ibuprofen-Loaded CTS/nHA/nBG Scaffolds for the Applications of Hard Tissue Engineering

Background: This study addressed the development of biodegradable and biocompatible scaffolds with enhanced biomechanical characteristics. The biocompatibility and the cationic nature of chitosan (CTS) make it more effective as a bone grafting material. Methods: The hydroxyapatite nanoparticles (nHA) were synthesized by hydrothermal method, and bioglass (nBG) (50% SiO2-45% CaO-5% P2O5) was synthesized using sol-gel method. The ibuprofen-loaded CTS/nHA and CTS/nBG scaffolds were fabricated by using freeze-drying method. Results: Transmission electron microscopy image of nHA and nBG revealed the particles of less than 200 nm. The scanning electron microscopy (SEM) images of CTS/nHA and CTS/nBG scaffolds showed pore sizes ranging from 84-190 µm. The physiochemical characteristics of synthesized ceramic nanoparticles and scaffolds analyzed by XRD were confirmed by ICDD 9-432. The porosity of scaffolds was measured by using SEM, Brunauer-Emmett-Teller method, and Archimedes' principle. The open porosities of CTS/nBG and CTS/nHA samples were 29% and 31%, respectively. The compressive strength of scaffolds was evaluated by stress vs. strain curve. The CTS/nHA scaffold revealed 4% more water retention capacity than CTS/nBG scaffold. In the presence of lysozyme, CTS/nBG scaffold degraded 32.8%, while CTS/nHA degraded 26.1% in PBS solution at pH 7.4. The density of all scaffolds was found (1.9824 g/cm-3 and 1.9338 g/cm-3) to be nearly similar to that of the dry bone (0.8-1.2 g/cm-3). Fibroblast cells multiplied two times in the sample medium of CTS/nBG after 14 days. After 72 h, CTS/nBG and CTS/nHA scaffolds demonstrated 52% and 46% drug release, respectively. Conclusion: Based on our findings, ibuprofen-loaded scaffolds could be an effective drug delivery system for tissue engineering applications.