Iranian Journal of Materials Science and Engineering

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This study focuses on the physical, magnetic, biological and antibacterial behaviour of cobalt-doped HAp powder samples. Pure and Cobalt- doped HAp nanoparticles were synthesized by hydrothermal method. Calcium nitrate, di- ammonium hydrogen phosphate and cobalt nitrate were used as precursor materials.  The synthesized powders were characterized using x-ray diffraction pattern (XRD), fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), vibrating sample magnetometer (VSM), Raman spectroscopy as well as MTT assay and cell adhesion test. Disc diffusion method was used to investigate antibacterial activity of the samples. The results confirmed the substitution of Ca by Co ions in the HAp lattice. In addition, this substitution induced size reduction and morphology change in HAp particles. All cobalt substituted HAp powder samples displayed paramagnetic properties, as opposed to the diamagnetic behaviour observed in the pure HAp samples. In addition, these nanoparticles exhibited cell adhesion, biocompatibility and antibacterial activity against S.aureus bacteria.
This study focuses on the physical, magnetic, biological and antibacterial behaviour of cobalt-doped HAp powder samples. Pure and Cobalt- doped HAp nanoparticles were synthesized by hydrothermal method. Calcium nitrate, di- ammonium hydrogen phosphate and cobalt nitrate were used as precursor materials.  The synthesized powders were characterized using x-ray diffraction pattern (XRD), fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), vibrating sample magnetometer (VSM), Raman spectroscopy as well as MTT assay and cell adhesion test. Disc diffusion method was used to investigate antibacterial activity of the samples. The results confirmed the substitution of Ca by Co ions in the HAp lattice. In addition, this substitution induced size reduction and morphology change in HAp particles. All cobalt substituted HAp powder samples displayed paramagnetic properties, as opposed to the diamagnetic behaviour observed in the pure HAp samples. In addition, these nanoparticles exhibited cell adhesion, biocompatibility and antibacterial activity against S.aureus bacteria.

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The Nano Hydroxyapatite (HAp), HAp/PEG and HAp/PVP powders derived from both Gastropod shell (natural source) and chemical precursor by the precipitation method were characterized through various characterization techniques such as FT-IR, XRD, SEM-EDX, TEM, Antibacterial activity and SBF analysis. Based on the structural, chemical, morphological and biological characteristics, HAp/PVP from natural and chemical precursors have been compared successfully. Calculated structural parameters, crystallinity index, C/P ratio, morphology, antibacterial activity and SBF analysis of the products show that HAp/PVP-S (derived from a natural source) exhibits good mechanical property, rod like morphology, good antibacterial activity and apatite formation ability at 14 days. EDX analysis also shows the presence of carbon and sodium in HAp/PVP-S. Comparative analysis reveals that characteristics of HAp/PVP-S such as high carbonate content, low crystallite size, poor crystalline nature, presence of trace metal, non-stoichiometric elemental composition and rod like crystals which are matched with the characteristics of biological apatite. Thus, the HAp/PVP-S has the ability to form bone apatite.

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Researchers have increasingly investigated hybrid nanocomposites that mix physical and chemical properties of carbonaceous materials and metal/metal oxides. In this work, a nanocomposite composed of reduced graphene oxide and silver (I) oxide, rGO@Ag₂O, was prepared using ascorbic acid as a green reducing agent. The Ag₂O nanoparticles were synthesized by means of a controlled precipitation process in water. The carbonaceous material of rGO was obtained through a modified Hummers' approach. After being combined with a solvent, the Ag₂O and rGO in ethanol were dried with heat. The resultant nanocomposite was structurally and optically examined using different characterization techniques.  
The results showed that GO has been successfully reduced, Ag₂O revealed a crystalline structure, and Ag₂O nanostructures were found on the surface of rGO sheets. Disk diffusion assay was adopted in order to evaluate antibacterial activity of nanocomposite against both Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacteria. The Ag₂O nanostructures in the composite form exhibited inhibition zone with higher diameter compared to their uncomposited counterparts. Higher antibacterial activity of rGO@Ag₂O was attributed to the role of negatively charged oxygen-containing groups present on the surface of rGO in slightly improvement in the stability of Ag₂O nanostructures.
Our findings show that rGO@Ag₂O could be a useful antimicrobial material for biomedical surfaces, as a coating, and in systems that clean water. It could be a good option for future research in nano-enabled antimicrobial technology because it can destroy bacteria, is made in an environmentally benign way, and could be made on a larger scale.
 

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The copper oxide nanoparticles were synthesized using a precipitation method, recognized for its significance in antibacterial applications. This study reports the synthesis of pure CuO and CuO:Cd nanoparticles at two different concentrations, and explores their structural properties and antibacterial activity. The structural characteristics of the prepared powders were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). Raman spectra were also examined using a 543 nm laser wavelength. XRD analysis confirmed that the as-synthesized samples exhibit a face-centered monoclinic structure, with crystallite size decreasing as dopant concentration increases, as estimated using the Scherrer method. The obtained crystallite sizes ranged from 7.13 to 11.72 nm, likely due to the larger atomic radius of Cd compared to Cu. The major Raman lines observed included Au2 (156 cm^-1), Ag (∼294 cm^-1), Bu2 (∼598 cm^-1), and lines at 1100 cm^-1 and 1420 cm^-1. The antibacterial activity of the synthesized CuO and CuO:Cd specimens was evaluated using the Kirby-Bauer disk diffusion method against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria. The antibacterial activity increased with higher Cd concentrations and smaller particle sizes, resulting in larger inhibition zones and higher percentage inhibition ratios for both types of bacteria.
The copper oxide nanoparticles were synthesized using a precipitation method, recognized for its significance in antibacterial applications. This study reports the synthesis of pure CuO and CuO:Cd nanoparticles at two different concentrations, and explores their structural properties and antibacterial activity. The structural characteristics of the prepared powders were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). Raman spectra were also examined using a 543 nm laser wavelength. XRD analysis confirmed that the as-synthesized samples exhibit a face-centered monoclinic structure, with crystallite size decreasing as dopant concentration increases, as estimated using the Scherrer method. The obtained crystallite sizes ranged from 7.13 to 11.72 nm, likely due to the larger atomic radius of Cd compared to Cu. The major Raman lines observed included Au2 (156 cm^-1), Ag (∼294 cm^-1), Bu2 (∼598 cm^-1), and lines at 1100 cm^-1 and 1420 cm^-1. The antibacterial activity of the synthesized CuO and CuO:Cd specimens was evaluated using the Kirby-Bauer disk diffusion method against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria. The antibacterial activity increased with higher Cd concentrations and smaller particle sizes, resulting in larger inhibition zones and higher percentage inhibition ratios for both types of bacteria.
 

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In the current study, titanium dioxide (TiO₂) nanoparticles were synthesized and subsequently combined with chitosan (CS) and silver (Ag) to augment their antimicrobial effectiveness. The synthesized TiO₂, TiO₂-CS, and TiO₂-CS-Ag nanocomposites were subjected to various characterization analyses in order to thoroughly assess their structural, morphological, and compositional attributes. XRD analysis substantiated the phase transition from anatase to rutile consequent to incorporation of chitosan and silver, accompanied by a diminution in nanoparticle dimensions. FTIR spectra corroborated the existence of functional groups linked to chitosan and silver, while FESEM illustrated morphological modifications, notably the emergence of polygonal nanostructures within the TiO₂-CS-Ag composite. The antibacterial efficacy of the synthesized nanocomposites was evaluated against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Although pure TiO₂ demonstrated minimal antibacterial properties, the TiO₂-CS and TiO₂-CS-Ag composites exhibited substantial inhibition zones, with the most pronounced efficacy recorded for the TiO₂-CS-Ag composite attributable to the synergistic interaction between chitosan and silver nanoparticles. BET analysis revealed that the augmented antimicrobial activity was associated with the increased surface area of the TiO₂-CS-Ag nanocomposite.