Abstract
The study highlighted, that a new approach in biomaterials as a therapeutic material in bone engineering and prosthetics, which is a new type of bone differentiation by converting wastes into value-added products will clear the way for more efficient waste management and contribute significantly to sustainable economic development eggshell waste into hydroxyapatite “Ca10(PO4)6(OH)2” nanoparticles” HAPn”. Part one Calcium oxide was a precursor to synthesize HAPn using the chemical precipitation technique. Chemical treatment and microwave radiation form a novel strategy to create a graphene oxide nanosheet” GNS” that decorates carbon crystal nanostructures from graphite. This approach is proven to be eco-friendly and low-cost.
The structural investigation X-ray diffraction (XRD), test showed that eggshell powder was calcite a stable polycrystalline hexagonal structure calcium carbonate. CaO has a polycrystalline nature with a cubic structure. The XRD analysis results for the hexagonal hydroxyapatite structure also showed that the other main phases, CaO and β-Tricalcium phosphate (β-TCP), appeared as shown for strong peaks. The crystalline size of the prepared materials was calculated using Scherrer’s formula, where the crystalline size values were (44.15, 10,35.4) nm for the eggshell powder, CaO, hydroxyapatite, and β-Tricalcium phosphate. In addition, XRD findings indicated that graphene oxide nanosheet had a hexagonal shape and exhibited a wide peak. The d-spacing of the graphene oxide nanosheet has been measured to be 0.9 nm.
Fourier Transform Infrared Instruments (FTIR), a strong bond between materials prepared materials and their precursors indicated that the bonding bands were compatible. The D and G bands of the graphene oxide nanosheet were seen in the Raman spectra. A peak shift with a strengthening of the 960 cm-1 peak has also been seen in hydroxyapatite Raman spectra. Eggshell had a sharp peak at (280 nm) in UV-vis, whereas CaO and hydroxyapatite had a peak at 320 nm and 207 nm.
Field Emission-Scanning Electron Microscope (FESEM) images have revealed that the eggshell was a nano calcite structure with porous particles of various sizes. Moreover, hydroxyapatite nanoparticles vary in size and shape but are always porous and irregular. Energy Dispersive X-ray spectroscopy (EDS) mapping has shown high C and Ca eggshell nanoparticles. The Ca/P ratio of 1.68 is identical to that of human cortical bone in hydroxyapatite nanoparticles, of 1.67. The FESEM images reveal a porous network with dense layers from a few nanometers to 30nm and visible three-dimensional characteristics.
Using the transmission electron microscopy (TEM) technique, which was developed to determine the size of nanoparticles produced, it was seen that the eggshell nano calcite sample had very aggregated particles with spherical forms and average sizes below 100 nm. While, the hydroxyapatite nanoparticle granules take on a variety of forms before eventually coming together to create a single, bigger one; their particle size is less than 30 nanometers. The TEM images have shown graphene oxide nanosheet monolayers arranged in many survey flakes with a limited number of layers. The nanosheets are characterized by well-identified edges and sharp corners. Graphene oxide nanosheet has aggregative carbon nanoparticles, whose carbon nanoparticles decorated represent promising novel carbon-based structures.
Part two included testing HAP and GNS’s biological antibacterial activity two different genus —Pseudomonas aeruginosa, a Gram-negative bacteria, and Staphylococcus aureus, gram-positive bacteria. incubated with GNS at concentrations of (15, 30, 45, and 60) µg/ml, and HAP at (50, 100, 150, and 200) µg /ml. The MTT test, a quantitative technique for evaluating cytotoxicity in vitro, shows that porous HAPn and GNS-decorated nanomaterials do not have any detrimental effects on the MG-63 cell line. The blue fluorescent signals indicate that the HAPn and GNS have been labeled with a fluorescent dye or probe, allowing their localization and distribution within the MG-63 cells to be visualized under a fluorescence microscope.
part three included the production of the below-knee prosthesis. four laminate composites were used for fabricated below-knee prostheses by a vacuum-forming process. The matrix consisted of polymethyl methacrylate (PMMA) and was reinforced with several layers of fibers (carbon, glass, and perlon) with a weight fraction of 30 %. The best concentration in biological activity was chosen to add to the resin for the other three laminated prosthetic limb materials.
Part three included performing a mechanical test, specifically focusing on tensile and hardness properties. The HAPn/GNS hybrid laminated socket exhibited optimal properties according to tensile strength, Young’s modulus, and hardness, with 9 GPa, 115 MPa, and 96 Shore-D values. The theoretical components of this study include simulations of the theoretical parameters related to safety and interface pressure. Continuous monitoring of muscle and bone pressure was conducted inside the prosthesis. Both laminates in the numerical analysis exhibited a maximum equivalent contact pressure of 1.87 kPa. The Von Mises stress observed in all instances remained constant at 7.9 MPa. The maximum interface pressure value obtained in practical use was 219 kPa.
Part four included the osseointegration approach an alternative to traditional socket-based prosthetics, which rely on a socket that fits over the residual limb. In this work, a combination of HAP/GNS- Polyvinylpyrrolidon (PVP) nanocomposite coatings was constructed for osseointegration on a stainless steel 316L alloy substrate using an electrophoretic deposition (EPD) technique. The composition of the alloy (316L) was verified by energy-dispersive X-ray fluorescence (ED-XRF). The mechanical properties of the alloy (316L) were studied by tensile, impact, and hardness testing where, the results showed Young’s modulus was 213 MPa the impact resistance was 5.4J/m2, and the hardness value was 290 HB. The biological behavior of the coated samples was investigated using the contact angle test. The results indicated that the samples had good wetting characteristics.
FESEM with quantitative and qualitative energy dispersive EDS is used to examine the layer composition and the cross-section related to coating and atomic force microscopy (AFM) to characterize the roughness of the surface morphology. The tape technique was also used to assess the adhesion test results of the EPD layers with the 316L alloy substrate. Additionally, the antibacterial test of nanocomposite coating demonstrated effective inhibition of bacterial growth. Furthermore, in vitro experiments, performed over two weeks, showed that the coating layers could form apatite crystals on their surfaces in simulated body fluid (SBF), indicating high osteoconductivity.
