Resorbable Bone-Fixation Materials: Synthesis, Physical-Chemical and Biological Properties

Synthesis and Investigation into Apatite-forming Ability of Hydroxyapatite/Chitosan-based Scaffold

Effect of formulation ingredients on the physical characteristics of salmeterol xinafoate microparticles tailored by spray freeze drying

The authors aimed to impart the apatite-forming ability to 50 wt% carbon fiber-polyetheretherketone composite (50C-PEEK), which has more suitable mechanical properties as artificial bone materials than pure PEEK. First, the 50C-PEEK was treated with sulfuric acid in a short time to form pores on the surface. Second, the surface of the 50C-PEEK was treated with oxygen plasma to improve the hydrophilicity. Finally, fine particles of calcium phosphate, which the authors refer to as “apatite nuclei”, were precipitated on the surface of the 50C-PEEK by soaking in an aqueous solution containing multiple inorganic ions such as phosphate and calcium (modified-SBF) at pH 8.20, 25 °C. The 50C-PEEK without the modified-SBF treatment did not show the formation of apatitic phase even after immersion in simulated body fluid (SBF) for 7 days. The 50C-PEEK treated with the modified-SBF showed the formation of apatitic phase on the entire surface within 1 day in the SBF. The apatite nuclei-precipitated 50C-PEEK will be expected as a new artificial bone material with high bioactivity that is obtained without complicated fabrication processes.

Effect of particle size on the in vitro bioactivity, hydrophilicity and mechanical properties of bioactive glass-reinforced polycaprolactone composites

Developing smart scaffolds with drug release capability is one of the main approaches to bone tissue engineering. The current study involves the fabrication of novel gelatin (G)-hydroxyapatite (HA)-/vitamin D (VD)-loaded graphene oxide (GO) scaffolds with different concentrations through solvent-casting method. Characterizations confirmed the successful synthesis of HA and GO, and VD was loaded in GO with 36.87 ± 4.87% encapsulation efficiency. Physicochemical characterizations showed that the scaffold containing 1% VD-loaded GO had the best mechanical properties and its porosity percentage and density was in the range of natural spongy bone. All scaffolds were degraded after 1-month, subjecting to phosphate buffer saline. The release profile of VD did not match any mathematical kinetics model, porosities and the degradation rate of the scaffolds were dominant controlling factors of release behavior. Studies on the bioactivity of scaffolds immersed in simulated body fluid indicated that VD and HA could encourage the formation of secondary apatite crystals in vitro. Buccal fat pad-derived stem cells (BFPSCs) were seeded on the scaffolds, MTT assay, alkaline phosphatase activity as an indicator of osteoconductivity, and cell adhesion were conducted in order to evaluate in vitro biological responses. All scaffolds highly supported cell adhesion, MTT assay indicated better cell viability in 0.5% VD-loaded GO containing scaffold, and the scaffold enriched with 2% VD-loaded GO performed the most ALP activity. The results demonstrated the potential of these scaffolds to induce bone regeneration. Developing smart scaffolds with drug release capability is one of the main approaches to bone tissue engineering. The current study involves the fabrication of novel gelatin (G)-hydroxyapatite (HA)-/vitamin D (VD)-loaded graphene oxide (GO) scaffolds with different concentrations through solvent-casting method. Characterizations confirmed the successful synthesis of HA and GO, and VD was loaded in GO with 36.87 ± 4.87% encapsulation efficiency. Physicochemical characterizations showed that the scaffold containing 1% VD-loaded GO had the best mechanical properties and its porosity percentage and density was in the range of natural spongy bone. All scaffolds were degraded after 1-month, subjecting to phosphate buffer saline. The release profile of VD did not match any mathematical kinetics model, porosities and the degradation rate of the scaffolds were dominant controlling factors of release behavior. Studies on the bioactivity of scaffolds immersed in simulated body fluid indicated that VD and HA could encourage the formation of secondary apatite crystals in vitro. Buccal fat pad-derived stem cells (BFPSCs) were seeded on the scaffolds, MTT assay, alkaline phosphatase activity as an indicator of osteoconductivity, and cell adhesion were conducted in order to evaluate in vitro biological responses. All scaffolds highly supported cell adhesion, MTT assay indicated better cell viability in 0.5% VD-loaded GO containing scaffold, and the scaffold enriched with 2% VD-loaded GO performed the most ALP activity. The results demonstrated the potential of these scaffolds to induce bone regeneration.

Porous silicon as a substrate for hydroxyapatite growth

In recent years, there has been a great demand for artificial materials for biomedical applications, especially to bone growth. In the present study, the in vitro bioactivity of chitosan-acetylated jute blended film was investigated through biomimitic growth of bone-like apatite layer formation in simulated body fluid (SBF) on the surface of the film. Chitosan was prepared from crab shells and the blended film was prepared by solvent casting method using 10 % formic acid aqueous solution of in-house chitosan and mercerized, acetylated jute fiber. Water absorption characteristics (swelling test) and tensile strength (Universal testing machine) of the films were determined. Thermal behavior of the films were examined by TGA analysis. The biocompatibility of the chitosan-acetylated jute (CAJ) film was indicated by the formation of hydroxy apatite (HAp) bone-like layer formed on the surface when soaked in SBF solution for 14 days. The topography of the film was characterized by scanning electron microscope (SEM) and Ca/P ratio of the apatite layer was confirmed to be 50:50 by EDX analysis. The results showed that the CAJ film will be a promising bone substituting material.

This research focuses on the interaction between fish bone extracted hydroxyapatite and polyvinyl alcohol as the composite material of a scaffold with the ions presented in a simulated body condition to study on the composite’s bioactivity and biodegradability. This was achieved by synthesizing scaffold with different amount of hydroxyapatite particles using the solvent casting method and with that done, the scaffolds were soaked in simulated body fluid for 7 and 14 days. Studies and investigations were done based on the weight difference before and after immersion of samples in simulated body fluid and the FTIR characterization of the samples before and after immersion. The weight analysis of the samples showed that along with degradation of the scaffolds as time passes, degradation of scaffold material and formation of deposits were present. The degradation of materials is due to the bioactivity reaction between the simulated body fluid and the scaffold where PVA is resorbed by the water contents and ions in relation to apatite in the fluid bonded onto the HAp contents in the scaffold. The most optimum composition for a long period of degradation and regeneration of apatite amongst the compositions studied was determined to be that with 100 phr PVA and 10 phr HAp. The FTIR results obtained also showed that the functional groups of both PVA and HAp exist in the samples before and after immersion as the absorption band for both the materials were present. The bands shifted had clearly shown that the amount of HAp related bonds had increased in amount. All in all, the results showed that fish bone extracted hydroxyapatite formed composite with PVA is a low cost biocomposite which could be a potential substitute of metal in bone grafting and a potential development in bone tissue engineering.

Biodegradable metal alloys may be successfully used to support bone repair, avoiding second surgery commonly needed when inert metal alloys are used. Combining a biodegradable metal alloy with a suitable pain relief agent could improve patient quality of life. AZ31 alloy was coated using a poly(lactic-co-glycolic) acid (PLGA) polymer loaded with ketorolac tromethamine using the solvent casting method. The ketorolac release profile from the polymeric film and the coated AZ31 samples, the PLGA mass loss of polymeric film, and the cytotoxicity of the optimized coated alloy were assessed. The coated sample showed a ketorolac release that was prolonged for two weeks, which was slower than that of just the polymeric film, in simulated body fluid. PLGA mass loss was complete after a 45-day immersion in simulated body fluid. The PLGA coating was able to lower AZ31 and ketorolac tromethamine cytotoxicity observed in human osteoblasts. PLGA coating also prevents AZ31 cytotoxicity, which was identified in human fibroblasts. Therefore, PLGA was able to control ketorolac release and protect AZ31 from premature corrosion. These characteristics allow us to hypothesize that the use of ketorolac tromethamine-loaded PLGA coating on AZ31 in the management of bone fractures can favor osteosynthesis and relief pain.

Polymer has been widely applied in the biomedical field. In this study, degradable polylactic complex yarns are twisted and braided by a 16-spindle braid machine; therefore, a polylactic complex braid fabric, an artificial bone material, was prepared. Different experimental parameters were conducted to examine the complex braid fabric’s mechanical property. chitosan was coated onto the polylactic braid as a membrane. The modified chitosan produced a functional group existing on its surface. This polylactic complex braid was immersed in the simulated body fluid to observe Hap. When the modified chitosan/polylactic complex braid was immersed in the simulated body fluid for 21 days, the overall hydroxyapatite was in sphere shape as previous studies had argued.

In the present work, silk fiber (SF) and methylcellulose (MC) composites were fabricated by solvent casting method and characterized in detail. The interactions between SF/MC composites were studied in detail by Fourier transform infrared (FT-IR) spectroscopy and powder X-ray diffraction (XRD). The surface morphology and thermal stability were studied. Viscosity, thickness, folding endurance, tensile strength and antioxidant activity were analyzed for different ratios of SF/MC composite. Antimicrobial activity, in vitro biomimetic mineralization, hemocompatibility and cell viability of the SF/MC composite were studied. The deposition of calcium and phosphorus ions from simulated body fluid (SBF) onto SF/MC composite surface was evidenced from XRD, FT-IR and SEM–EDS. Inductively coupled plasma-optical emission spectrometry analysis (ICP-OES) was utilized to analyze leaching of Ca and P ions from the SBF. Hemolytic assay proves that the composites were compatible with blood and hemolytic ratio is found to be less than 5%. The MTT assay test against MG-63 suggests that the SF/MC composites are promising biomaterials for bone tissue engineering applications.

Composite film combining bioactive particles with natural and synthetic polymer has received greater attention for enhanced cytocompatibility properties. The current study aimed to determine human mesenchymal stem cells (HMSC) responses towards different concentration of bioactive glass/poly-Ɛ-caprolactone/chitosan (BG/PCL/CS) films conditioned medium extract using Alamar Blue assay. The samples were incubated in simulated body fluid (SBF) and the pH was assessed during the 21 days of incubation. Briefly, BG/PCL/CS at optimize weight percentages in acetic acid solution were prepared using solvent casting method and left to dry under fume hood for 48 h. The BG/PCL/CS films were incubated in culture medium at 200 mg/ml for 24 h at 37 ℃ and was serially diluted until 0.78 mg/ml with culture medium and supplemented before exposure to HMSC. The effects of the conditioned mediums are not consistent and not in dose dependent order towards HMSC cell’s viability and proliferation. Higher conditioned medium extracts concentration tends to reduce cell proliferation. The pH of the samples tends to approach equilibrium at pH 7 for 21 days duration when incubated in SBF that may be contributed by the sample’s compositions. Thus, suitable concentration or dose ratio of the samples is important to reduce cytotoxicity before further biocompatibility assessment is conducted.KeywordsBioactive glassPoly-Ɛ-caprolactoneChitosan

As we all know poly(lactic acid), cellulose nanofibrils and poly (ethylene glycol) possess good biocompatibility. Also, PLA/cellulose nanofibrils/PEG ternary composite materials have a good developmental prospect. These composite materials in medical field have a potential application. Nanocomposites of poly(lactic acid) (PLA) reinforced with cellulose nanofibrils compatibilized with different molecular weight of poly(ethylene glycol) (PEG) were prepared for the first time. The composites obtained by solvent casting methods from N, N-Dimethylacetamide (DMAc) were characterized by biodegrade in simulated body fluid (SBF), atomic force microscope (AFM), scanning electron microscope (SEM). The effects of the molecular weight of PEG on the degradation properties of three kinds of composite materials after soaking in SBF were detected. The results showed that with the addition of the PEG (4 wt%), the weight loss of the composites with low molecular weight of PEG was higher distinctly than the others, which was verified by performing SEM and AFM.

Hip resurfacing arthroplasty is associated with increased frictional moments compared to standard heads owing to their large diameter. High frictional moments may harbor the risk of the implant loosening if the frictional moments exceed the fixation stability of the hip resurfacing arthroplasty. Therefore, the aim of this experimental study was to evaluate the fixation stability of ceramic hip resurfacing implants through a turn-off test. The test specimens, made of alumina toughened zirconia (ATZ) ceramics with an inner titanium-coated surface and square base bodies for better application to the test setup, were pushed on artificial bone materials until a predefined seating depth was achieved. Thereafter, the specimens were turned off from the artificial bone material by using a lever-arm and the turn-off moments were calculated. The density of the artificial bone material utilized (15 and 25 pcf), the press-fit (0.4 and 0.8 mm) and the size of the test specimens varied. The push-on forces ranged from 0.6 ± 0.1 kN to 5.6 ± 0.5 kN depending on the press-fit and artificial bone material. The turn-off moments relied on the respective press-fit, artificial bone material and size of the specimen. They belonged between the range of 8.5 ± 0.4 Nm and 105.4 ± 0.2 Nm. Most of the previously described frictional moments are lower compared to the turn-off moments determined in this study. However, in the worst-case scenario, the turn-off moments of the hip resurfacing implants may be reduced, especially when the adjacent bone stock has a low mineral density.

In this study, This study report the preparation of alumina matrix coated with hydroxyapatite and their evaluation as biomaterials. The first hydroxyapatite powder is made by Dry Method. And then hydroxyapatite sol is made by attrition mill due to decreasing the size of hydroxyapatite. the second prepared alumina was coated with HAp sol for 10-50 seconds. And then, the structures tested their mechanical and biological properties. First, Compressive strength and hardness evaluates as measuring the mechanical properties. According to adding the HAp, Compressive strength shows increased tendency and indicates up to a maximum value of 122 MPa in this study. However, hardness indicates low value which is that of Monolithic alumina, because this hardness value is measured HAp located on the surface of alumina. Second, measuring the biological properties is observed Calcium growth on the structure surface. When bathed in simulated body fluid (SBF), calcium growth was observed for both structures. Notably, MC3T3-E1 pre-osteoblastic cells grew on disks made up the alumina matrix coated with HAp and cell proliferation enhancements were similar to pure hydroxyapatite. These results suggest that structure is potentially useful as an artificial bone material.