Biomimetic Mineralization and Bioactivity of Phosphorylated Chitosan

2005 ◽  
Vol 288-289 ◽  
pp. 429-432 ◽  
Author(s):  
Zhi Qing Chen ◽  
Quan Li Li ◽  
Quan Zen ◽  
Gang Li ◽  
Hao Bin Jiang ◽  
...  

Phosphorylated chitosans were synthesized as templates to manipulate hydroxyapatite (HA) crystal nucleation, growth and microstructure. Two kinds of insoluble phosphorylated chitosan were soaked in saturated Ca(OH)2 solution for 4 d and in 1.5× SBF (simulated body fluid) solutions for 14 d at 37 °C for biomimetic mineralization. A lower [P]-content of phosphorylated chitosan promoted greater mineralization than higher [P]-content. Phosphorylated chitosan inhibited osteoblast proliferation and differentiation in vitro, while calcium phosphate phosphorylated chitosan composites did not.

2015 ◽  
Vol 23 (1) ◽  
pp. 1-14
Author(s):  
Sudirman Sahid ◽  
◽  
Nor Shahida Kader Bashah ◽  
Salina Sabudin ◽  
◽  
...  

2007 ◽  
Vol 342-343 ◽  
pp. 701-704
Author(s):  
Li Ming Fang ◽  
Yang Leng ◽  
Ping Gao

Bioactivity of hydroxyapatite reinforced ultrahigh molecular weight polyethylene (HA/UHMWPE) nanocomposites with HA volume content of 10~50 % was evaluated by simulated body fluid (SBF) immersion. The effect of HA content on the capability for calcium phosphate (Ca- P) induction was studied. It was found that Ca-P deposition covered the whole surface of the composite with 30 vol. % of HA after immersion for 1 day and the layer grew to around 10 0m thick in one-week immersion, while there was few nucleus formed for composites with HA content lower than 30 vol. % after one-week immersion. The Ca-P structure was identified as octacalcium phosphate (OCP) by SEM, TEM, and ToF-SIMS.


2011 ◽  
Vol 493-494 ◽  
pp. 582-587 ◽  
Author(s):  
Marziyeh Abbasi-Shahni ◽  
Saeed Hesaraki ◽  
Ali Asghar Behnam-Ghader ◽  
Masoud Hafezi-Ardakani

In this study, nanocomposites based on of β-tri calcium phosphate (β-TCP) and 2.5-10 wt% merwinite nanoparticles were prepared and sintered at 1100-1300°c.The mechanical properties were investigated by measuring compressive strength and fracture toughness. Structural properties were evaluated by XRD, TEM and SEM analysis, and the in vitro bioactivity was studied by soaking the samples in simulated body fluid (SBF). The mechanical strength of the sintered samples wereincreased, by increasing the amount of merwinite phase up to 5 wt%, whereas it decreased when the samples were sintered at 1100 and 1200°c. Nanostructured calcium phosphate layer was formed on the surfaces of the nanocomposites within 1 day immersion in simulated body fluid. Because of appropriate mechanical properties the composite is suggested to be used as substitute for hard tissue.


2013 ◽  
Vol 334-335 ◽  
pp. 297-302 ◽  
Author(s):  
A.L.A. Escada ◽  
João Paulo Barros Machado ◽  
Roberto Zenhei Nakazato ◽  
Ana Paula Rosifini Alves Claro

Titanium and its alloys are widely used as biomaterials due to their mechanical, chemical and biological properties. To enhance the biocompatibility of titanium alloys, various surface treatments have been proposed. In particular, the formation of titanium oxide nanotubes layers has been extensively examined. Among the various materials for implants, calcium phosphates and hydroxyapatite are widely used clinically. In this work, titanium nanotubes were fabricated on the surface of Ti-7.5Mo alloy by anodization. The samples were anodized for 20 V in an electrolyte containing glycerol in combination with ammonium fluoride (NH4F, 0.25%), and the anodization time was 24 h. After being anodized, specimens were heat treated at 450 °C and 600°C for 1 h to crystallize the amorphous TiO2 nanotubes and then treated with NaOH solution to make them bioactive, to induce growth of calcium phosphate in a simulated body fluid. Surface morphology and coating chemistry were obtained respectively using, field-emission scanning electron microscopy (FEG-SEM), AFM and X-ray diffraction (XRD). It was shown that the presence of titanium nanotubes induces the growth of a sodium titanate nanolayer. During the subsequent in-vitro immersion in a simulated body fluid, the sodium titanate nanolayer induced the nucleation and growth of nanodimensioned calcium phosphate. It was possible to observe the formation of TiO2 nanotubes on the surface of Ti-7.5Mo. Calcium phosphate coating was greater in the samples with larger nanotube diameter. These findings represent a simple surface treatment for Ti-7.5Mo alloy that has high potential for biomedical applications.


2012 ◽  
Vol 16 ◽  
pp. 63-68 ◽  
Author(s):  
A.L.A. Escada ◽  
João Paulo Barros Machado ◽  
Sandra G. Schneider ◽  
Roberto Zenhei Nakazato ◽  
Ana Paula Rosifini Alves Claro

Many materials with different surfaces have been developed for dental and orthopedics implants. Among the various materials for implants, titanium and bioactive ones such as calcium phosphates and hydroxyapatite, are widely used clinically. When these materials are inserted into bone several biological reactions occur. Thes processes can be associated with surface properties (topography, roughness and surface energy). In this work, ingots were obtained from titanium and molybdenum by using an arc-melting furnace. They were submitted to heat treatment at 1100°C for one hour, cooled in water and cold worked by swaging. Titanium nanotubes were fabricated on the surface of Ti-7,5Mo alloy by anodization, and then treated with NaOH solution to make them bioactive, to induce growth of calcium phosphate in a simulated body fluid. . It is shown that the presence of titanium nanotubes induces the growth of a sodium titanate nanolayer. During the subsequent in-vitro immersion in a simulated body fluid, the sodium titanate nanolayer induced the nucleation and growth of nano-dimensioned calcium phosphate. These titanium nanotubes can be useful as a well-adhered bioactive surface layer on Ti implant metals for orthopedic and dental implants.


2010 ◽  
Vol 21 (6) ◽  
pp. 1817-1828 ◽  
Author(s):  
Ashok Priya ◽  
Shekhar Nath ◽  
Krishanu Biswas ◽  
Bikramjit Basu

2003 ◽  
Vol 254-256 ◽  
pp. 7-10 ◽  
Author(s):  
Chun Lin Deng ◽  
Y. Tan ◽  
C.Y. Bao ◽  
Q. Zhang ◽  
Hong Song Fan ◽  
...  

2016 ◽  
Vol 33 (2) ◽  
pp. 38
Author(s):  
X.V Bui ◽  
T.D Thang

The main goal of this study is to elaborate and evaluate the physicochemical properties of the synthetic biphasic calcium phosphate (BCP) powder: an associate compound of hydroxyapatite (HA): Ca10(PO4)6(OH)2 and beta-tricalcium phosphate (β-TCP): Ca3(PO4)2. The new compound BCP has two advantages: high bioactivity (HA) and fast biodegradation (β-TCP). The obtained powder of BCP was prepared by the precipitate method. XRD analysis confirmed the synthetic material contained both HA and β-TCP crystalline phases. SEM images showed that the small particles of HA attached to bigger particles of β-TCP in the structure morphology of BCP. The in vitro experiment was carried out in static condition by soaking of a series of 50 mg BCP powder in 100 ml of simulated body fluid solution at different period of soaking time. The XRD and SEM methods studied the microstructureand chemical bond after soaking. The obtained results confirmed the bioactivity of synthetic BCP material by the formation of a new apatite layer on its surface.


Scanning ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Yichang Su ◽  
Yingchao Su ◽  
Wei Zai ◽  
Guangyu Li ◽  
Cuie Wen

In order to decrease the degradation rate of magnesium (Mg) alloys for the potential orthopedic applications, manganese-calcium phosphate coatings were prepared on an Mg-Ca-Zn alloy in calcium phosphating solutions with different addition of Mn2+. Influence of Mn content on degradation behaviors of phosphate coatings in the simulated body fluid was investigated to obtain the optimum coating. With the increasing Mn addition, the corrosion resistance of the manganese-calcium phosphate coatings was gradually improved. The optimum coating prepared in solution containing 0.05 mol/L Mn2+ had a uniform and compact microstructure and was composed of MnHPO4·3H2O, CaHPO4·2H2O, and Ca3(PO4)2. The electrochemical corrosion test in simulated body fluid revealed that polarization resistance of the optimum coating is 36273 Ωcm2, which is about 11 times higher than that of phosphate coating without Mn addition. The optimum coating also showed the most stable surface structure and lowest hydrogen release in the immersion test in simulated body fluid.


2007 ◽  
Vol 22 (3) ◽  
pp. 621-626
Author(s):  
M. Hamdi ◽  
Ari Ide-Ektessabi ◽  
J.A. Toque

Calcium phosphate coatings prepared using the technique of electron beam deposition were immersed in a simulated body fluid for different periods of time to determine their response in vitro. The amorphous as-deposited coatings dissolved completely after a few days of immersion. After annealing in air at 700 °C, the dissolution of a small amount of amorphous phase in the crystalline coatings promotes the precipitation of bonelike apatite on the recessed regions by increasing the local supersaturation of calcium and phosphate ions. Formation of apatite was confirmed by the x-ray diffraction peaks at (200), (211), and (203) planes which grew after immersion in simulated body fluid. Fourier transform infrared results conformed to this with the increase in intensity of the absorption band at 1450 cm−1, signifying the increase in carbonate content. Scanning electron microscopy results showed spherical-shaped apatite nucleated on dissolved surface after 8 days of immersion. Sixteen days after immersion, almost 80% of the surface area was covered with apatite formation and grew to coalesce between neighboring particles forming an integrated platelike layer after 28 days. No obvious detachment between the grown layer and the underlying coating was observed.


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