Electro-deposition of bactericidal and corrosion-resistant hydroxyapatite nanoslabs

Different solvents and organic modifiers for the control of crystallographic parameters in nano-crystallite hydroxyapatite for amplification of photocatalytic activity

In this research, HAp nanocrystals were synthesized using conventional wet chemical precipitation methods using various organic modifiers, including urea, palmitic acid, and naphthalene. Ethanol and isopropyl alcohol (IPA) were used as solvents in this process. Different characterization techniques, namely X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-vis absorption spectroscopy, were employed to ascertain the formation of HAp nanocrystals. Numerous structural parameters, including lattice parameters, unit cell size, volume of the unit cell, specific surface area, degree of crystallinity, dislocation density, macrostrain, and crystallinity index, were assessed using XRD data. The linear straight-line method of Scherrer's equation, Monshi-Scherrer's method, the Williamson-Hall method, the size-strain plot method, the Halder-Wagner method, and Sahadat-Scherrer's model were applied to compute the crystallite size of the synthesized HAp samples. All the synthesized HAp has crystalline structures within the permissible range of 1-150 nm which were estimated from the XRD data using the mentioned models. However, the values for strain (from -3 × 10-4 to 6.4 × 10-3), strain (from -9.599 × 104 to 7 × 1010 N m-2), and energy density (from -11 × 1011 to 2 × 107 J m-3) were also calculated for the synthesized samples. In addition, the optical band gap energy of the synthesized HAp was computed (5.89 to 6.19 eV). The synthesis media have a control on the crystallographic planes, e.g. in the case of the ethanol medium, the (110) plane exhibited significant intensity (which could potentially serve as a driving force for enhancing photocatalytic activity). The use of 100% ethanol HAp yields the most favorable outcome regarding both the degradation percentage (91.79%) and degradation capacity (7%) for the Congo red dye.

Synthesis and characterization of nano crystallite plaster of Paris prepared from waste eggshells and exploration of cytotoxicity, hemolysis and antimicrobial properties

Plaster of Paris, a well-known biomaterial, was synthesized from waste eggshells, which were chosen as an available bio-source of calcium. The produced plaster of Paris was characterized by X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), Raman spectroscopy, UV-Vis spectroscopy, and SEM images along with a few crystallographic parameters such as crystallite size (Scherrer equation and different model equations), lattice parameters, crystallinity index, the volume of the unit cell, microstrain, dislocation density, growth preference, and residual stress from the XRD-sin² Ψ technique. The biomedical competency of the prepared plaster of Paris was evaluated utilizing the cytotoxicity, hemolysis, and antimicrobial activity of E. coli and S. aureus. The cytotoxicity assessment has revealed that the percentages of viable cells were 93-98% and a highly hemocompatible nature (<5%) was exerted by the sample. The plaster of Paris only revealed antimicrobial properties against Gram-positive bacteria (S. aureus), and no effect was noticed for Gram-negative bacteria (E. coli).

Crystallographic characterization and application of copper doped hydroxyapatite as a biomaterial

Cu-doped hydroxyapatite is synthesized from eggshell and its suitability as a potential biomaterial is examined via cytotoxicity, haemolysis and antibacterial activity.

Adsorptive removal of Acid Blue 113 using hydroxyapatite nanoadsorbents synthesized using Peltophorum pterocarpum pod extract

The present work reports the study on the green synthesis of hydroxyapatite (HAP) nanoadsorbents using Peltophorum pterocarpum pod extract. HAP nanoadsorbents were characterized by using FESEM, EDS, TEM, XRD, FTIR, XPS, and BET analyses. The results highlighted the high purity, needle-like aggregations, and crystalline nature of the prepared HAP nanoadsorbents. The surface area was determined as 40.04 m²/g possessing mesopores that can be related to the high adsorption efficiency of the HAP for the removal of a toxic dye, - Acid Blue 113 (AB 113) from water. Central Composite Design (CCD) was used for optimizing the adsorption process, which yielded 94.59% removal efficiency at the optimum conditions (dose: 0.5 g/L, AB 113 dye concentration: 25 ppm, agitation speed: 173 rpm, and adsorption time: 120 min). The adsorption kinetics followed the pseudo-second-order model (R²:0.9996) and the equilibrium data fitted well with the Freundlich isotherm (R²:0.9924). The thermodynamic parameters indicated that the adsorption of AB 113 was a spontaneous and exothermic process. The highest adsorption capacity was determined as 153.85 mg/g, which suggested the promising role of green HAP nanoadsorbents in environmental remediation applications.

Constructions of ROS-responsive titanium-hydroxyapatite implant for mesenchymal stem cell recruitment in peri-implant space and bone formation in osteoporosis microenvironment

To solve the issue of unsatisfactory recruitment of mesenchymal stem cells (MSCs) around implant in osteoporotic fractures, we fabricated a ROS-responsive system on titanium surface through hydroxyapatite coating and biomolecule grafting. The porous hydroxyapatite and phosphorylated osteogenic growth peptides (p-OGP) were introduced onto titanium surface to synergistically improve osteogenic differentiation of MSCs. After the p-OGP-promoted expression of osteogenic related proteins, the calcium and phosphate ions were released through the degradation of hydroxyapatite and integrated into bone tissues to boost the mineralization of bone matrix. The ROS-triggered release of DNA aptamer (Apt) 19S in the osteoporotic microenvironment guides MSC migration to implant site due to its high affinity with alkaline phosphatase on the membrane of MSCs. Once MSCs reached the implant interface, their osteogenic differentiation potential was enhanced by p-OGP and hydroxyapatite to promote bone regeneration. The study here provided a simple and novel strategy to prepare functional titanium implants for osteoporotic bone fracture repair.

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ROS-responsive system was constructed on Titanium surface.

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Aptamer 19S boosted the migration of MSC to the injury site.

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Hydroxyapatite and OGP synergistically promoted the biomineralized of MSC.

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Osseointegration was improved in osteoporotic fracture site.

Synthesis of nano-crystallite gypsum and bassanite from waste Pila globosa shells: crystallographic characterization

For the first time, in this work, waste Pila globosa shells have been used to synthesize two industrially valuable materials, gypsum and bassanite. In the first stage, gypsum was synthesized using a wet chemical precipitation method. Subsequently, bassanite was produced by the heat treatment of gypsum at a certain temperature (200 °C), which was chosen after TGA and DSC analysis. The synthesized gypsum and bassanite phases were confirmed by XRD with the assistance of FTIR spectroscopy. Various crystallographic parameters of gypsum and bassanite were investigated, such as the crystallite size (a number of models were employed along with the Scherrer equation), crystallinity index, lattice parameters, unit cell volume, dislocation density, relative intensity, preference growth, specific surface area, microstrain (models were also engaged), and residual stress using the XRD-sin² Ψ technique.

For the first time, in this work, waste Pila globosa shells have been used to synthesize two industrially valuable materials, gypsum and bassanite.

Magnesium Doped Hydroxyapatite-Based Coatings Obtained by Pulsed Galvanostatic Electrochemical Deposition with Adjustable Electrochemical Behavior

The aim of this study was to adapt the electrochemical behavior in synthetic body fluid (SBF) of hydroxyapatite-based coatings obtained by pulsed galvanostatic electrochemical deposition through addition of Mg in different concentrations. The coatings were obtained by electrochemical deposition in a typical three electrodes electrochemical cell in galvanic pulsed mode. The electrolyte was obtained by subsequently dissolving Ca(NO3)2·4H2O, NH4H2PO4, and Mg(NO3)2·6H2O in ultra-pure water and the pH value was set to 5. The morphology consists of elongated and thin ribbon-like crystals for hydroxyapatite (HAp), which after the addition of Mg became a little wider. The elemental and phase composition evidenced that HAp was successfully doped with Mg through pulsed galvanostatic electrochemical deposition. The characteristics and properties of hydroxyapatite obtained electrochemically can be controlled by adding Mg in different concentrations, thus being able to obtain materials with different properties and characteristics. In addition, the addition of Mg can lead to the control of hydroxyapatite bioactive ceramics in terms of dissolution rate.