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In vitro bioactivity and biocompatibility of femtosecond laser-modified Ti6Al4V alloy
摘要： The present work investigates bioactivity and biocompatibility of femtosecond (fs) laser surface-modified Ti6Al4V alloy (Ti-alloy). Self-aligned conical surface features were generated on Ti-alloy when laser irradiated employing a Ti:sapphire pulsed fs laser of wavelength 800 nm. Modification of surface chemical composition resulting from fs-laser irradiation of Ti-alloy was examined using Grazing incidence X-ray diffraction (GIXRD) technique and micro-Raman spectroscopy. Sub-oxide phase of titanium was detected on Ti-alloy surface post-fs-laser irradiation leading to increased oxygen vacancies on sample surface. For in vitro bioactivity tests, untreated and fs-laser-treated samples were immersed in simulated body fluid for 2 weeks. Evidence of hydroxyapatite deposition on both untreated Ti-alloy, as well as, fs-laser-treated Ti-alloy surfaces after in vitro tests were provided by scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), GIXRD, Fourier transform infrared spectroscopy (FTIR), and micro-Raman spectroscopy. Superior growth of HAP was observed on fs-laser-modified Ti-alloy surface in comparison with untreated surface. Biocompatibility of the laser-treated Ti-alloy was investigated by studying anchoring and growth of human osteosarcoma cell line (U2OS) on it. Using MTT assay technique in vitro cell viability and growth potential in the presence of untreated and laser-treated Ti-alloy samples were assessed. MTT test results demonstrated that, neither cell viability, nor growth were affected in the presence of either the untreated or laser-treated sample surfaces. In addition, in comparison with the untreated Ti-alloy surface, the fs-laser-treated Ti-alloy surface showed more efficient cellular attachment when examined under confocal microscope.
关键词： Biocompatibility,Hydroxyapatite,Surface modification,Ti6Al4V alloy,Femtosecond laser,Bioactivity
更新于2025-11-21 11:08:12
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Increased UV absorption properties of natural hydroxyapatite-based sunscreen through laser ablation modification in liquid
摘要： Sunfilters based on hydroxyapatite (HAp) and iron-containing compounds (Fe2O3 and calcium iron phosphates) are of increasing interest, as they show UV absorption without generating health endanger free radicals (usually observed when other inorganic sunscreens are used). In this paper, laser ablation of solids in liquids has been applied to improve the UV absorption properties of a HAp based Fe-containing sunscreen powder derived from cod fish bones. Two different laser wavelengths were explored (532 and 1064 nm, green and infrared respectively); an improved experimental device was used, to allow a fine control of the volume of the irradiated particles. Results show an increased UV absorbance for the laser-treated powders in comparison with the untreated ones; this can be explained considering the smaller particle size and increased surface area; the higher iron concentration in the powders may also be determinant. Enhanced absorption was also observed in the near-infrared range, making the powders even more suitable for sunscreen applications. The green laser was more effective than the infrared one. Overall, laser ablation showed to be a powerful technique to control the size of the sunscreen particles and tailor their optical properties.
关键词： hydroxyapatite,Liquid laser ablation,UV protection,sunscreen
更新于2025-11-14 15:25:21
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Laser synthesis of iron nanoparticle for Fe doped hydroxyapatite coatings
摘要： Thin films of iron doped hydroxyapatite have been prepared by nanosecond Pulsed Laser Deposition (PLD). The composite target used for the deposition has been obtained by mixing commercial hydroxyapatite powder with iron-based nanoparticles produced by femtosecond laser ablation in liquid (LAL) (4% of iron nanoparticles). In fact, LAL technique allows to obtain metallic nanostructures without any toxic chemicals and reagents, with a green approach that is crucial for application in biological and medical technologies. Films have been prepared with substrate temperature growing from room temperature (RT) to 500 °C. The effect of deposition temperature on morphology, composition and structural properties of coatings has been investigated. Films deposited at higher temperature result dense and crystalline, they present microscale and nanoscale structures, an average surface roughness of 0.3 μm and magnetic properties suitable for biomedical applications.
关键词： PLD,Iron doped hydroxyapatite,Laser ablation in liquid,Regenerative orthopedic applications
更新于2025-09-23 15:23:52
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Optical and Magnetic Properties of Cobalt Ions Doped Calcium Phosphate by Ultrasonication
摘要： Background: Hydroxyapatite (HAp) is a remarkable member of the calcium phosphate family. It resembles natural bone in both structure and chemical composition. Owing to its bioactive and chemical properties, it has been used as a biocompatible osteogenesis and energy materials as discussed in patents. Objective: To study the structural, optical properties and magnetic properties of hydroxyapatite and cobalt ions doped hydroxyapatite for biomedical application. Method: Hydroxyapatite and cobalt ions doped hydroxyapatite were synthesized by ultrasonication assisted wet chemical synthesis. Results: X-ray diffraction analysis confirmed the phase and crystallite size of hydroxyapatite. There was a 12% decrease in crystallite size compared to pristine. The functional groups and vibrational assignments of the samples were observed in infra-red and Raman spectra. Optical properties of the samples were analyzed by Diffuse Reflectance Spectroscopy, ultraviolet-visible and photoluminescence emission spectroscopy. Doped samples showed paramagnetic in nature. Conclusion: Therefore, the cobalt doped samples could be employed in biomedical applications.
关键词： optical,luminescence,hyperthermia,bioceramics,Cobalt ions,magnetic,hydroxyapatite
更新于2025-09-23 15:23:52
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Conventionally Sintered Hydroxyapatite–Barium Titanate Piezo-Biocomposites
摘要： The central goal of this initial effort is to develop and characterize distinctive piezo-biocomposites as load-bearing orthopedic implants. The motivation is derived from the fact that mammalian bone is a piezoelectric material and this property is helpful in the natural healing of fractured bone. We have employed a cost-effective and industrially viable technique—conventional sintering to consolidate specific compositions of hydroxyapatite (HA) and barium titanate (BT). HA is the primary mineral constituent of mammalian bone but is not piezoelectric. On the contrary, BT is well known for its piezoelectric properties. Their combination creates piezo-biocomposites. The sintering is reactive in nature as BT decomposes into several compounds. Average grain sizes of piezo-biocomposites lie in the range of 1.75–1.9 μm. Interestingly, 15% compressive strength enhancement is noted in the case of HA-40 wt% BT as compared to HA. In vitro examinations reveal favorable bioactivity and biocompatible nature of the composites. These results show that conventionally sintered HA-BT piezo-biocomposites can qualify as candidate materials for load-bearing implants at affordable prices.
关键词： Orthopedic implants,Conventional sintering,Hydroxyapatite,Barium titanate
更新于2025-09-23 15:22:29
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Synthesis and characterization of nickel free titanium–hydroxyapatite composite coating over Nitinol surface through in-situ laser cladding and alloying
摘要： In this study, a high power fibre laser was used to synthesize titanium hydroxyapatite composite coating over biomedical-grade Nitinol surface through laser in-situ formation, cladding and alloying processes. The laser fluence is varied in the range of 2 kJ/cm2 to 8 kJ/cm2 in view of establishing a relationship between various in-situ phase-formation characteristics along with the rate of diffusion of the base material in the cladding zone with molten pool temperature. The alloying with base Nitinol material and subsequent diffusion of titanium to the in-situ formed calcium phosphate cladding layer are observed in the samples treated with laser fluence of 4 kJ/cm2 or above. Double layer configuration of the solidified molten pool is mostly found in all the cladding samples. At the fluence of 6 kJ/cm2 or above, the top layer primarily comprises segregated titanium-hydroxyapatite phase along with diffusion of titanium from the base material. Whereas, the bottom part of the molten pool is dominated with titanium-rich nickel–titanium intermetallic reinforced with nano particles. The steady-state variations of calcium and elemental presence of titanium through the cladding cross-section along with no nickel or oxide presence are confirmed through EDS line scans. The spherical and lamellar structures of formation of titanium-hydroxyapatite on the top surface also help to improve the overall corrosion resistance properties as compared to the bare surface. The modulus of elasticity is controlled by the variation of the top layer and intermediate layer composition and thickness, which varies with laser fluence. It falls in the range of 6–30 GPa which is similar to natural bone. Thus this nickel-free alloying and cladding layer of titanium-hydroxyapatite can serve as one of the potential candidates for use as a coating over the load bearing Nitinol implants to arrest the nickel release phenomena.
关键词： Titanium–calcium coating,Biocompatible functional coating,Hydroxyapatite,Nitinol surface modification,Laser cladding and alloying
更新于2025-09-23 15:22:29
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Nanostructured apatites grown by laser floating zone
摘要： Apatites (AP) ceramics are important due to their application in the orthopaedics field as bioceramic material. Several processes to produce apatites such as oxyapatite (OAP) and hydroxyapatite (HA) materials are used to apply as a temporary substitute for human bone. In the present work, AP powders were prepared by high-energy ball milling and then by laser floating zone (LFZ) technique to transform into a dense cylinder (fibre). The effect of LFZ processing conditions was assessed by structural and electric characterization. Fibres present strong densification and a uniform polycrystalline microstructure, which could favour the use for natural bone treatments and as bio-sensors. However, further work must be assessed to optimize laser processing conditions.
关键词： Bioceramic,Apatites,Laser floating zone,Bio-sensors,Bone treatment,Hydroxyapatite,Oxyapatite
更新于2025-09-23 15:21:01
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A salt-resistant Janus evaporator assembled from ultralong hydroxyapatite nanowires and nickel oxide for efficient and recyclable solar desalination
摘要： Solar energy-driven interfacial water evaporation is a promising energy utilization technology in the field of seawater desalination and water purification. However, the accumulation of salt on the heating surface severely impairs the water evaporation performance and long-time stability. Herein, we demonstrate a new kind of photothermal paper comprising a high-temperature-resistant paper made from ultralong hydroxyapatite nanowires and glass fibers and black nickel oxide (NiO) nanoparticles for solar energy-driven desalination. Owing to the high photothermal conversion ability, fast water transportation in the air-laid paper, and good heat insulation, the hydrophilic HN/NiO photothermal paper can achieve efficient, stable and recyclable water evaporation performance. In addition, a Janus HN/NiO photothermal paper based on hydrophobic sodium oleate-modified ultralong hydroxyapatite nanowires has been developed, and it has a high water evaporation efficiency of 83.5% under 1 kW m?2 irradiation. In particular, with the bottom hydrophobic ultralong hydroxyapatite nanowire layer and water-transporting channels in the air-laid paper to facilitate salt exchange, the as-prepared Janus evaporator exhibits no salt accumulation on the surface, high performance and long-time stable desalination using simulated seawater (3.5 wt% NaCl). Furthermore, the Janus evaporator with the hydrophobic ultralong hydroxyapatite nanowire substrate can be extended to support other photothermal materials such as black titanium oxide (Ti2O3) and Ketjen black carbon. The as-prepared Janus HN/Ti2O3 and Janus HN/KB photothermal paper also exhibit salt-resistant desalination function. The as-prepared Janus salt-resistant photothermal paper with efficient, stable and recyclable merits has great potential in solar energy-driven desalination and water purification.
关键词： desalination,interfacial water evaporation,water purification,solar energy-driven,photothermal paper,ultralong hydroxyapatite nanowires,nickel oxide
更新于2025-09-23 15:19:57
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Ultrasound-Assisted Synthesis and Characterization of Heparin-Coated Eu3+ Doped Hydroxyapatite Luminescent Nanoparticles
摘要： Herein, the heparin-coated Eu3+ doped hydroxyapatite luminescent nanoparticles were synthesized by an ultrasound-assisted coprecipitation method followed with steam sterilization at 121 °C. The effects of ultrasound treatment, steam sterilization, sodium heparin (SH) concentration and Eu doping content on the formation of heparin-coated Eu3+ doped hydroxyapatite nanoparticles (SH-Eu:nHAP) were investigated. The sterilized and suspended Eu-nHAP with improved luminescence and stability was simultaneously achieved in a process of about 2 h due to the combined effect of ultrasonic sonochemistry and stabilization function of SH. The obtained SH-Eu:nHAP suspension shows good stability in water and biological media. Moreover, the SH-Eu:nHAP shows no hemolysis and cytotoxicity, and can be ingested by cells and emit characteristic luminescence in cells. In summary, this study provides an improved method for the synthesis of SH-Eu:nHAP suspension that is helpful for promoting the application of rare earth doped nHAP as bioimaging agent.
关键词： Heparin,Hydroxyapatite nanoparticles,Europium,Luminescence,Bioimaging
更新于2025-09-19 17:15:36
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Visualizing different crystalline states during the infrared imaging of calcium phosphates
摘要： Methods utilizing relatively simple mathematical operations during physical analyses to enable the visualization of otherwise invisible correlations and effects are of particular appeal to researchers and students in pedagogical settings. At the same time, discerning the amorphous phase from its crystalline counterpart in materials is challenging with the use of vibrational spectroscopy and is nowhere as straightforward as in phase composition analytical methods such as X-ray diffraction. A method is demonstrated for the use of first- and second-order differentiation of Fourier transform infrared spectra of calcium phosphates to distinguish their amorphous states from the crystalline ones based on the exact line positioning rather than on comparatively vaguer band broadening and splitting effects. The study utilizes a kinetic approach, focusing on the comparison of spectral features of amorphous precursors annealed in air at different temperatures or aged for different periods of time in an aqueous solution until transforming to one or a mixture of crystalline phases, including hydroxyapatite and α- and β-tricalcium phosphate. One of the findings challenges the concept of the nucleation lag time preceding the crystallization from amorphous precursors as a “dead” period and derives a finite degree of constructive changes occurring at the atomic scale in its course. The differential method for highlighting spectral differences depending on the sample crystallinity allows for monitoring in situ the process of conversion of the amorphous calcium phosphate phase to its crystalline analogue(s). One such method can be of practical significance for synthetic solid state chemists testing for the chemical stability and/or concentration of the reactive amorphous phase in these materials, but also for biologists measuring the maturity of bone and medical researchers evaluating its phase composition and, thus, the state of metabolic and mechanical stability.
关键词： Hydroxyapatite,XRD,Derivative method,Crystallization,Amorphous,FTIR,Tricalcium phosphate
更新于2025-09-19 17:13:59