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Design and synthesis of materials with better properties and performance are essential requirements in the field of biomaterials science that would directly improve patient quality of life. For this purpose, in situ silica-coated silicate and carbonate co-doped hydroxyapatite (Sc/S.C.HA) nanopowder was synthesized via the sol–gel method. Characterisation of the prepared nanopowder was carried out by XRD, FTIR, TEM, SEM, EDX, ICP, zeta potential, acid dissolution test, and cell culture test. The substitution of the silicate and carbonate ions into hydroxyapatite structure was confirmed by FTIR analysis. XRD analysis showed that silica is an amorphous phase, which played a role in covering the surface of the S.C.HA nanoparticles as confirmed by acid dissolution test. Low thickness and low integrity of the amorphous silica surface layer facilitated ions release from S.C.HA nanoparticles into physiological saline solution. Zeta potential of the prepared nanopowder suspended in physiological saline solution was − 27.3 ± 0.2 mV at pH 7.4. This negatively charged surface, due to the presence of amorphous silica layer upon the S.C.HA nanoparticles, not only had an accelerating effect on in vitro biomineralization of apatite, but also had a positive effect on cell attachment. [ABSTRACT FROM AUTHOR]

A silk fibroin-chondroitin sulfate-sodium alginate (SF-CHS-SA) porous scaffold containing chitosan nanoparticles (NPs) was investigated. The proliferation of adipose-derived stem cells (ASCs) was studied by SEM, fluorescent microscopy, alcian blue staining, dimethylmethylene blue assay, and real-time polymerization chain reaction. The results showed that incorporation of NPs into the scaffold improved compressive modulus (5.6 ± 0.15 MPa). The amount of glycosaminoglycan expression of the ASCs was reached to 8.9 ± 0.3 µg/mL. The gene expressions of aggrecan, collagen II, and SOX9 of the ASCs were significantly improved. This study revealed that the prepared scaffold can be used as a substrate for cartilage tissue engineering. [ABSTRACT FROM PUBLISHER]

The main aim of this research was the preparation of the forsterite (Mg 2 SiO 4 ) coating on the surface of 316L stainless steel (316L SS) substrate. For this purpose, the nanostructured forsterite was coated on the 316L SS substrate using the sol–gel dip coating technique. Structural characterization techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDX) were utilized to investigate the phase structure, morphology and elemental composition of the uncoated and coated samples. Corrosion properties of samples were studied using the electrochemical measurements in simulated body fluid (SBF). The in vitro bioactivity evaluation of the forsterite coated samples was conducted by soaking the samples in the SBF at the temperature of 37 °C. The results showed that, a crack-free and homogeneous forsterite coating with the crystallite size of around 40 nm was successfully achieved on the surface of 316L SS substrate. The corrosion current density of the forsterite coated samples was lesser than that of the uncoated ones indicating the improvement of corrosion resistance of the metallic substrate using the forsterite coating. Deposition of Ca and P-contained products on the surface of coated samples during the incubation in the SBF solution confirmed the bioactivity behavior of the forsterite coated samples. Consequently, the 316L SS substrate coated with nanostructured forsterite may be an appropriate selection for dental and orthopedic implant applications. [ABSTRACT FROM AUTHOR]

ABSTRACT The inflammation and pain associated with osteoarthritis are treated with nonsteroidal anti-inflammatory drugs (NSAIDs). This treatment is accompanied by several side effects; therefore local intra articular (IA) NSAID injection can be more efficient and safe than systemic administration or topical use. In this study, alginate−chitosan−pluronic nanoparticles were considered as a new vehicle for IA meloxicam delivery. These novel nanoparticles were prepared using an ionotropic gelation method and were optimized for variables such as alginate to chitosan mass ratio, pluronic concentration, and meloxicam concentration using a 3-factor in 3-level Box-Behnken design. To optimize the formulation, the dependent variables considered were particle size, zeta potential, entrapment efficiency, and mean dissolution time (MDT). The nanoparticles morphology was characterized by FESEM and AFM. The potential interactions of the drug-polymers were investigated by ATR-FTIR and DSC, and the delivery profile of meloxicam from the nanoparticles was obtained. The average particle size of the optimized nanoparticles was 283 nm, the zeta potential was −16.9 mV, the meloxicam entrapment efficiency was 55%, and the MDT was 8.9 hours. The cumulative released meloxicam amount from the composite nanoparticles was 85% at pH 7.4 within 96 h. The release profile showed an initial burst release followed by a sustained release phase. The release mechanism was non-Fickian diffusion. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42241. [ABSTRACT FROM AUTHOR]

Magnesium (Mg) alloys have been recently introduced as a biodegradable implant for orthopedic applications. However, their fast corrosion, low bioactivity, and mechanical integrity have limited their clinical applications. The main aim of this research was to improve such properties of the AZ91 Mg alloy through surface modifications. For this purpose, nanostructured fluoridated hydroxyapatite (FHA) was coated on AZ91 Mg alloy by micro-arc oxidation and electrophoretic deposition method. The coated alloy was characterized through scanning electron microscopy, transmission electron microscopy, X-ray diffraction, in vitro corrosion tests, mechanical tests, and cytocompatibility evaluation. The results confirmed the improvement of the corrosion resistance, in vitro bioactivity, mechanical integrity, and the cytocompatibility of the coated Mg alloy. Therefore, the nanostructured FHA coating can offer a promising way to improve the properties of the Mg alloy for orthopedic applications. [ABSTRACT FROM AUTHOR]

ABSTRACT The development of porous biodegradable scaffolds is of great interest in tissue engineering. In this regard, exploration of novel biocompatible materials is needed. Silk fibroin-chondroitin sulfate-sodium alginate (SF-CHS-SA) porous hybrid scaffolds were successfully prepared via lyophilization method and crosslinked by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide-ethanol treatment. According to the scanning electron microscopy studies, mean pore diameters of the scaffolds were in the range of 60-187 μm. The porosity percentage of the scaffold with SF-CHS-SA ratio of 70 : 15 : 15 (w/w/w %) was 92.4 ± 3%. Attenuated total reflectance Fourier transform infrared spectroscopy, X-ray diffraction, and differential scanning calorimetry results confirmed the transition from amorphous random coil to crystalline β-sheet in treated SF-CHS-SA scaffold. Compressive modulus was significantly improved in hybrid scaffold with SF-CHS-SA ratio of 70 : 15 : 15 (3.35 ± 0.15 MPa). Cytotoxicity assay showed that the scaffolds have no toxic effects on chondrocytes. Attachment of chondrocytes was much more improved within the SF-CHS-SA hybrid scaffold. Real-time polymerase chain reaction analyses showed a significant increase in gene expression of collagen type II, aggrecan, and SOX9 and decrease in gene expression of collagen type I for SF-CHS-SA compared with SF scaffold. This novel hybrid scaffold can be a good candidate to be utilized as an efficient scaffold for cartilage tissue engineering. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41048. [ABSTRACT FROM AUTHOR]

The effect of the fluorine content and nano-structure of fluoridated hydroxyapatite (FHA) on human osteoblast-like (HO) cell behavior were investigated. FHA nanopowders and bulk nanostructured FHA, produced via mechanical alloying and two-step sintering, respectively, were used. The cytotoxicity of FHA nanopowders was assessed by MTT. Cell attachment to the surface of the bulk nanostructured FHA was evaluated by culturing of HO cells. Although HO cells proliferated 10 % more in contact with FHA nanopowders compared to culture medium without FHA nanopowders, an increase in the fluorine content of FHA caused a delay in the cell proliferation by about 2 days. Cell attachment on the bulk nanostructured FHA did not change the fluorine content. [ABSTRACT FROM AUTHOR]

Abstract: Magnesium and its alloys have been recently investigated as biodegradable metallic biomaterials for bone implants. However, rapid corrosion rate and low bioactivity have been two limiting factors for their biomedical applications. In this work we aimed to improve these two properties for AZ91 magnesium alloy using the nanostructured bredigite (Ca7MgSi4O16) coating made by micro-arc oxidation and electrophoretic deposition methods. The results indicated that this surface treatment enhanced both corrosion resistance and the bioactivity of AZ91 substrate, making it suitable for biomedical applications. [Copyright &y& Elsevier]

Abstract: Magnesium (Mg) alloys have been introduced as new generation of biodegradable orthopedic materials in recent years since it has been proved that Mg is one of the main minerals required for osseous tissue revival. The main goal of the present study was to establish a desired harmony between the necessities of orthopedic patient body to Mg2+ ions and degradation rate of the Mg based implants as a new class of biodegradable/bioresorbable materials. This prospect was followed by providing a sol–gel derived nanostructured hydroxyapatite (n-HAp) coating on AZ91 alloy using dip coating technique. Phase structural analysis, morphology study, microstructure characterization, and functional group identification were performed using X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. The prepared samples were immersed in simulated body fluid in order to study the formation of apatite-like precipitations, barricade properties of the n-HAp coating, and to estimate the dosage of released Mg2+ ions within a specified and limited time of implantation. Electrochemical polarization tests were carried out to evaluate and compare the corrosion behavior of the n-HAp coated and uncoated samples. The changes of the in vitro pH values were also evaluated. Results posed the noticeable capability of n-HAp coating on stabilizing alkalization behavior and improving the corrosion resistance of AZ91 alloy. It was concluded that n-HAp coated AZ91 alloy could be a good candidate as a type of biodegradable implant material for biomedical applications. [Copyright &y& Elsevier]

Magnesium (Mg) alloys as a new group of biodegradable metal implants are being extensively investigated as a promising selection for biomaterials applications due to their apt mechanical and biological performance. However, as a foremost drawback of Mg alloys, the high degradation in body fluid prevents its clinical applications. In this work, a bioceramic composite coating is developed composed of diopside, bredigite, and fluoridated hydroxyapatite on the AZ91 Mg alloy in order to moderate the degradation rate, while improving its bioactivity, cell compatibility, and mechanical integrity. Microstructural studies were performed using a transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray diffraction (XRD) analysis, and energy dispersive spectroscopy (EDS). The degradation properties of samples were carried out under two steps, including electrochemical corrosion test and immersion test in simulated body fluid (SBF). Additionally, compression test was performed to evaluate the mechanical integrity of the specimens. L-929 fibroblast cells were cultured on the samples to determine the cell compatibility of the samples, including the cell viability and attachment. The degradation results suggest that the composite coating decreases the degradation and improves the bioactivity of AZ91 Mg alloy substrate. No considerable deterioration in the compression strength was observed for the coated samples compared to the uncoated sample after 4 weeks immersion. Cytotoxicity test indicated that the coatings improve the cell compatibility of AZ91 alloy for L-929 cells. [ABSTRACT FROM AUTHOR]

Because of the superior chemical and mechanical properties of titanium, many surface treatments have been developed to alleviate its bioactivity limitations. Among all these, the procedures involving the modification of the surface of the titanium using liquid media have received more attention, because of their ability to modify all outer and inner pores of porous titanium implants. In this research, both rigid and porous titanium implants were surface treated using hydrogen peroxide and the effects of treatment on surface morphology and the weight change of the rigid implant and the mechanical properties of the porous implant were investigated using scanning electron microscope (SEM), balance, and compression tests, respectively. The results indicated that although this procedure was a corrosive phenomenon leading to the surface roughening of rigid samples and influencing cell adhesion positively, it also resulted in about 34% reduction in the mechanical properties of the porous titanium implant. [ABSTRACT FROM AUTHOR]