Behavior In Simulated Body Fluid Research Articles

Preparation, characterization, and in vitro cytotoxicity of chitosan hydrogels containing silver nanoparticles

Hydrogels, chitosan as well as silver nanoparticles become in recent years materials characterized by a great interest. In present paper hydrogel based on chitosan and containing mentioned type of nano-sized particles have been synthesized by means of photopolymerization. Sorption capacity in selected liquids as well as behavior in simulated body fluid (such as Ringer’s liquid) have been determined. Particularly attention was paid to the studies on toxicity of the hydrogels in relation to the epidermal cells as well as on their impact on growth of selected strain of bacteria (Escherichia coli). Furthermore, impact of introduction of nanosilver into hydrogel matrix on its properties has also been defined. Surface morphology of attained hydrogels by means of SEM analysis and chemical structure using spectroscopy have been checked. The most interesting conclusion is the fact that proposed chitosan based hydrogels modified with nanosilver do not affect negatively on epidermal cells. However, they inhibit a growth of E. coli. These two observations make them very interesting from the medical point of view.

A highly bioactive poly (amido amine)/70S30C bioactive glass hybrid with photoluminescent and antimicrobial properties for bone regeneration

The field of tissue engineering constantly calls for novel biomaterials that possess intrinsically multifunctional properties such as bioactivity, bioimaging ability and antibacterial properties. In this paper, poly (amido amine) generation 5/bioactive glass inorganic-organic hybrids have been developed through direct hybridization by 3-glycidoxypropyltrimethoxysilane (GPTMS) as coupling agent. Results indicated that the degree of covalent coupling by GPTMS and the weight percent of inorganic and organic constituents highly influence hybrids properties. It was found that nanoscale integration of inorganic and organic chains by GPTMS significantly endows hybrids with high thermal stability. Furthermore, hybrids exhibited photoluminescent ability (emission 400–600nm and 700nm) without incorporating of any organic dyes or quantum dots. In addition, hydrophilicity of our hybrids indicated good cell/material interaction. The biological apatite was formed on the surface of calcium containing hybrids when soaked in simulated body fluid (SBF) for 1week. Hybrids also showed linear biodegradation behavior in SBF that could be controlled by the degree of covalent crosslinking which was indicative of their stable biodegradation ability. High inherent antibacterial properties against Staphylococcus aureus was also observed from poly (amido amine)/silica hybrids. No adverse cytotoxicity for human gingival fibroblast cell lines (HGF) was detected after 4days. It is envisaged that our novel multifunctional hybrid system will confer intriguing potential in advancing the field of tissue engineering.

Microstructure and corrosion behavior of laser surface-treated AZ31B Mg bio-implant material.

Although magnesium and magnesium alloys are considered biocompatible and biodegradable, they suffer from poor corrosion performance in the human body environment. In light of this, surface modification via rapid surface melting of AZ31B Mg alloy using a continuous-wave Nd:YAG laser was conducted. Laser processing was performed with laser energy ranging from 1.06 to 3.18J/mm2. The corrosion behavior in simulated body fluid of laser surface-treated and untreated AZ31B Mg alloy samples was evaluated using electrochemical technique. The effect of laser surface treatment on phase and microstructure evolution was evaluated using X-ray diffraction and scanning electron microscopy. Microstructure examination revealed grain refinement as well as formation and uniform distribution of Mg17Al12 phase along the grain boundary for laser surface-treated samples. Evolution of such unique microstructure during laser surface treatment indicated enhancement in the corrosion resistance of laser surface-treated samples compared to untreated alloy.

Effective role of CaO/P2O5 ratio on SiO2-CaO-P2O5 glass system

In the present work, the effect of the CaO/P2O5 ratio on the composition of sol-gel synthesized 58SiO2-(19−x)P2O5–(23+x)CaO (x=0, 5, 10 and 15mol%) glass samples was studied. Further, the effect of NBO/BO ratio on hydroxy carbonated apatite layer (HCA) forming ability based on dissolution behavior in simulated body fluid (SBF) solution was also investigated. CaO/P2O5 ratios of synthesized glass samples were 1.2, 2, 3.6, and 9.5, respectively. NBO/BO ratios were obtained using Raman spectroscopic analysis as 0.58, 1.20, 1.46, and 1.78, respectively. All samples were soaked in the SBF solution for 7days. The calculated weight losses of these samples were 58%, 64%, 83%, and 89% for corresponding NBO/BO ratios. The increase in CaO/P2O5 ratio increases the NBO/BO ratios. However, the increase in NBO/BO ratio increases HCA forming ability of SBF treated samples. The HCA crystalline layer formation was confirmed through X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Raman and Infrared spectroscopic analysis. Higher CaO/P2O5 ratio favors the increase in HCA formation for SBF treated calcium phospho silicate glasses.

The effective role of alkali earth/alkali ratio on formation HCA nano particles for soda lime phospho silicate glass system

In the present work, we report on the effect of the CaO/Na2O ratio on Non-Bridging Oxygen/Bridging Oxygen (NBO/BO) ratio for sol-gel synthesised 58SiO2-(38-x)CaO-xNa2O-4P2O5 glasses and establish the correlation between Hydroxy Carbonated Apatite layer (HCA) forming ability and the dissolution behaviour in simulated body fluid (SBF) solution. Thermal stabilities were calculated as 221, 135, 153 and 77°C respectively. It is inferred that thermal stabilities varied nonlinearly with CaO/Na2O ratio. Similarly NBO/BO ratios were obtained using Raman spectroscopic analysis as 0.6293, 0.7917, 0.2264 and 0.3513, respectively. All samples were soaked in the SBF solution for 7 days. The calculated weight losses of these samples were 55.32, 69.13, 18.09 and 20.08 for the corresponding NBO/BO ratios. The decrease in CaO/ Na2O ratio led to nonlinear variation of the NBO/BO ratios. Consequently the non linear variation in NBO/BO ratio led to the nonlinear variation of HCA forming ability of SBF treated samples.

Synthesis of Biphasic Calcium Phosphate and its Behaviour in Simulated Body Fluid

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.

Fabrication and characterization of strontium incorporated 3-D bioactive glass scaffolds for bone tissue from biosilica

Bioactive glass scaffolds that contain silica are high viable biomaterials as bone supporters for bone tissue engineering due to their bioactive behaviour in simulated body fluid (SBF). In the human body, these materials help inorganic bone structure formation due to a combination of the particular ratio of elements such as silicon (Si), calcium (Ca), sodium (Na) and phosphorus (P), and the doping of strontium (Sr) into the scaffold structure increases their bioactive behaviour. In this study, bioactive glass scaffolds were produced by using rice hull ash (RHA) silica and commercial silica based bioactive glasses. The structural properties of scaffolds such as pore size, porosity and also the bioactive behaviour were investigated. The results showed that undoped and Sr-doped RHA silica-based bioactive glass scaffolds have better bioactivity than that of commercial silica based bioactive glass scaffolds. Moreover, undoped and Sr-doped RHA silica-based bioactive glass scaffolds will be able to be used instead of undoped and Sr-doped commercial silica based bioactive glass scaffolds for bone regeneration applications. Scaffolds that are produced from undoped or Sr-doped RHA silica have high potential to form new bone for bone defects in tissue engineering.

An investigation on pulsed DC plasma electrolytic oxidation of cp-Ti and its corrosion behaviour in simulated body fluid

Titania coating was produced on commercially pure titanium by a pulsed DC plasma electrolytic oxidation (PEO) process in an aqueous electrolyte containing 5 g/l trisodium orthophosphate and 2 g/l potassium hydroxide. Four different PEO coatings were fabricated with two different duty cycles (10% and 95%) and two different current frequencies (50 Hz and 1000 Hz) while maintaining a constant current density and process time of 150 mA/cm2 and 8 min, respectively. The phase composition, roughness, thickness, surface morphology and cross-sectional microstructure of the coating were assessed using X-ray diffraction (XRD), optical profilometer, eddy current thickness gauge and scanning electron microscope (SEM). The scratch resistance of the coating was assessed by a scratch test. The corrosion behaviour of the coating was studied in a Kokubo 7.4 pH simulated body fluid (SBF) solution by open circuit potential (OCP) measurement, potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) with equivalent circuit modelling and EIS curve fitting. Among the coatings, the coating produced at 10% duty–50 Hz frequency had a lower thickness, poor corrosion resistance (icorr, 1.9 × 10− 4 mA/cm2) and poor scratch resistance (Lc, 15 N) while the coating produced at 95% duty–1000 Hz frequency showed higher corrosion resistance (icorr, 3.3 × 10− 6 mA/cm2), higher scratch resistance (Lc, 26 N) and had a dense coating. The coating with highest corrosion resistance also showed good wettability (contact angle, 61 ± 3°) and apatite forming ability under bioactivity test.

Influence of bicarbonate concentration on the conversion layer formation onto AZ31 magnesium alloy and its electrochemical corrosion behaviour in simulated body fluid

The electrochemical corrosion behaviour of a magnesium carbonate conversion layer-coated AZ31 magnesium alloy was evaluated in simulated body fluid (SBF) solution.

In vitro biodegradability and biocompatibility of porous Mg-Zn scaffolds coated with nano hydroxyapatite via pulse electrodeposition

The biodegradability and biocompatibility of porous Mg-2Zn (mass fraction, %) scaffolds coated with nano hydroxyapatite (HAP) were investigated. The nano HAP coating on Mg-2Zn scaffolds was prepared by the pulse electrodeposition method. The as-deposited scaffolds were then post-treated with alkaline solution to improve the biodegradation behavior and biocompatibility for implant applications. The microstructure and composition of scaffold and nano HAP coating, as well as their degradation and cytotoxicity behavior in simulated body fluid (SBF) were investigated. The post-treated coating is composed of needle-like HAP with the diameter less than 100 nm developed almost perpendicularly to the substrate, which exhibits a similar composition to natural bone. It is found that the products of immersion in SBF are identified to be HAP, (Ca, Mg)3(PO4)2 and Mg(OH)2. The bioactivity, biocompatibility and cell viabilities for the as-coated and post-treated scaffold extracts are higher than those for the uncoated scaffold. MG63 cells are found to adhere and proliferate on the surface of the as-coated and post-treated scaffolds, making it a promising choice for medical application. The results show that the pulse electrodeposition of nano HAP coating and alkaline treatment is a useful approach to improve the biodegradability and bioactivity of porous Mg-Zn scaffolds.

Improving of in vitro Biodegradation Resistance in a Chitosan Coated Magnesium Bio-composite

A magnesium base composite with a chitosan coating was prepared to study its in vitro degradation behavior in simulated body fluid. The in vitro test results show that the immersion corrosion rate, the pH values of the simulated body fluids and the released metal ion concentration of the chitosan coated composite are all lower than those of the uncoated magnesium composite. The in vitro cytotoxicity test indicates that the chitosan coated specimen is safe for cellular applications with a toxic grade of zero. The chitosan coating is an effective corrosion resistant layer that reduces the hydrogen release of the implant composite, thereby decreasing the damage of the corrosion products of magnesium composite as an implant material.

Composite biodegradable biopolymer coatings of silk fibroin – Poly(3-hydroxybutyric-acid-co-3-hydroxyvaleric-acid) for biomedical applications

Composite silk fibroin–poly(3-hydroxybutyric-acid-co-3-hydroxyvaleric-acid) (SF–PHBV) biodegradable coatings were grown by Matrix Assisted Pulsed Laser Evaporation on titanium substrates. Their physico-chemical properties and particularly the degradation behavior in simulated body fluid at 37°C were studied as first step of applicability in local controlled release for tissue regeneration applications.SF and PHBV, natural biopolymers with excellent biocompatibility, but different biodegradability and tensile strength properties, were combined in a composite to improve their properties as coatings for biomedical uses.FTIR analyses showed the stoichiometric transfer from targets to coatings by the presence in the spectra of the main absorption maxima characteristic of both polymers. XRD investigations confirmed the FTIR results showing differences in crystallization behavior with respect to the SF and PHBV content. Contact angle values obtained through wettability measurements indicated the MAPLE deposited coatings were highly hydrophilic; surfaces turning hydrophobic with the increase of the PHBV component. Degradation assays proved that higher PHBV contents resulted in enhanced resistance and a slower degradation rate of composite coatings in SBF. Distinct drug-release schemes could be obtained by adjusting the SF:PHBV ratio to controllably tuning the coatings degradation rate, from rapid-release formulas, where SF predominates, to prolonged sustained ones, for larger PHBV content.

Influence of homogenization treatment on the degradation behavior of Zn–3 Mg alloy in simulated body fluid solution

This paper reports a degradation study of Zn–(3 wt%) Mg alloy proposed for biodegradable medical implants. The alloy was cast from high-purity raw materials and homogenized at 370 ℃ for 15 h under vacuum and water quenched. The effect of homogenization on microstructure and degradation behavior in simulated body fluid was investigated. Results showed that homogenization transformed the star-like dendritic Zn-rich shape into a network of precipitate phase along eutectic colony and dispersed Mg2Zn11 phase. The homogenized alloy showed higher degradation resistance compared to the as-cast alloy, pure Zn, and pure Mg samples. The relationship between microstructure and degradation behavior discussed further in this paper.

Effect of Gd/Nd ratio on mechanical and biocorrosion properties of as-extruded Mg–Nd–Gd–Sr–Zn–Zr alloys

Mg–(4–x)Nd–x Gd–0·3Sr–0·2Zn–0·4Zr (wt.-%, x = 0, 1, 2, and 3) alloys with various Gd/Nd ratios were prepared by gravity casting, solution-treated and then hot extruded. The microstructures, mechanical properties at room temperature, corrosion behaviour in simulated body fluid of the as-extruded alloys were studied. The as-extruded alloys undergo partially dynamic recrystallisation, and the equiaxed grains become coarse with increasing Gd/Nd ratio. The strength of the alloys increases first and then decreases with increasing the Gd/Nd ratio; however, the elongation of the alloys increases apparently with increasing Gd/Nd ratio. Both immersion test and polarisation test indicate that the corrosion rate of the as-extruded alloys is reduced with increasing the Gd/Nd ratio, and the alloys exhibit relatively uniform corrosion morphologies.

Investigation of the Surface Modification on Biomedical Magnesium Alloy

In this work, the green chemistry conversion coating on AZ31 magnesium alloy surface was made and studied by means of Ce (SO4)2·2(NH4)2SO4·4H2O and MnSO4 as inhibitor, H2O2 as oxidant, NaCl as accelerator, CH3COOH as stabilizer. The coating was evaluated in simulated body fluid (SBF) with pH=7.4 at 37°C by using electrochemical impedance spectroscopy (EIS). The results show the conversion coating resistance, for the untreated or treated alloy, is 0.75 kΩ·cm2 and 3.28 kΩ·cm2 respectively. It indicates the conversion coating treated surface presents better corrosion behaviour in SBF than the original material surface. The morphologies and composition the coating were examined by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) respectively. The result indicates that the Ce-Mn conversion coating was made on magnesium alloy surface. Biocompatibility of conversion coating was investigated by use of cell toxicity. Cell culture has shown that the magnesium alloy has good cytocompatibility.

Evaluation of Sr- and/or Mg-Containing Hydroxyapatite Behavior in Simulated Body Fluid

The main goal of this study was to evaluate the behavior of Sr- and/or Mg-containing hydroxyapatite (HAp) bioceramics in simulated body fluid (SBF). Sr-and/or Mg-containing HAp powders were synthesized by modified wet chemical precipitation method. Sr-and/or Mg-containing HAp bioceramics were prepared by uniaxial pressing of the precipitated powders and subsequent sintering at 1100 °C for 1 h. The synthesis products were characterized in terms of chemical, phase and molecular composition. Influence of the substitutions on thermal stability, morphology and microstructure of the HAp products were evaluated. Results suggest that incorporation of Sr (up to 1.45 wt.%) in HAp structure induced an increasing of particle sizes, but incorporation of Mg (up to 1.05 wt.%) led to a reduction of particle sizes of the HAp powders. The ability to simultaneously release bioactive ions and the apatite-formation ability of the Sr-and/or Mg-containing HAp bioceramics were evaluated through immersing the samples in SBF for different time periods. Ca ions release and apatite-formation ability on the surfaces of the Sr-and/or Mg-containing HAp bioceramics in SBF depends on Sr and/or Mg concentration in the samples.

Diamond-like carbon electrochemical corrosion resistance by addition of nanocrystalline diamond particles for biomedical applications

Combining chemical and mechanical properties of diamond-like carbon (DLC) films opens the possibilities for its use in electrochemical applications. DLC electrochemical corrosion behavior is heavily dependent on deposition techniques and precursor gas. In this paper, nanocrystalline diamond (NCD) particles were incorporated into DLC films to study NCD-DLC electrochemical corrosion resistance in biomedical area. The films were grown over 316L stainless steel using plasma enhanced chemical vapor deposition. NCD particles were incorporated into DLC during the deposition. Raman scattering spectroscopy and scanning electron microscopy characterized NCD-DLC structure and morphology. Electrochemical Impedance Spectroscopy and potentiodynamic method investigate NCD-DLC electrochemical corrosion behavior in simulated body fluid. The presence of NCD particles increases the DLC corrosion resistance. However, as the NCD concentration increases, the disorder also increases. Therefore, DLC films at lower concentration of NCD particles had the maximum corrosion resistance. From these results, NCD-DLC films can be considered a potential candidate for an anticorrosion material in biomedical applications.

Effect of different processings on mechanical property and corrosion behavior in simulated body fluid of Mg-Zn-Y-Nd alloy for cardiovascular stent application

The biomagnesium alloys have been considered to be one of the most potential biodegradable metal materials due to its good mechanical compatibility, biological compatibility, biological security and biodegradable characteristics. However, the two major problems of high degradation rates in physiological environment and low mechanical properties prevent the development of biomagnesium alloys. In the present work, the samples of Mg-Zn-Y-Nd alloy were prepared by cyclic extrusion compression (CEC) and equal channel angular pressing (ECAP). The microstructures, mechanical properties of alloy and its corrosion behavior in simulated body fluid (SBF) were evaluated. The results reveal that Mg-Zn-Y-Nd alloy consists of equiaxial fine grain structure with the homogeneous distribution of micrometer size and nano-sized second phase, which was caused by the dynamic recrystallization during the ECAP and CEC. The corrosion resistance of alloy was improved. The tensile and corrosion resistance were improved, especially the processed alloy exhibit uniform corrosion performances and decreased corrosion rate. This will provide theoretical ground for Mg-Zn-Y-Nd alloy as vascular stent application.

Formation of stacking faults for improving the performance of biodegradable Mg–Ho–Zn alloy

A novel Mg–6Ho–1Zn alloy was successfully prepared, which had a good combination of mechanical properties and corrosion resistance due to the formation of profuse nano-spaced basal plane stacking faults (SFs). The ultimate tensile strength (UTS), tensile yield strength (TYS) and elongation were 325MPa, 224MPa and 17%, respectively. More importantly, the alloy with SFs presented a uniform corrosion behavior in simulated body fluid (SBF) with a low corrosion rate of about 0.5mm/year, which could avoid rapid reduction in mechanical integrity. The performance of the alloy with SFs could be further improved by optimizing the microstructure. The investigation suggests that the alloys with SFs are promising biodegradable implant materials.

Effect of heat treatment on the microstructure and corrosion behaviour of Mg–Zn alloys

Microstructure and corrosion behaviour in simulated body fluid of as‐cast and heat treated Mg–xZn (x = 3 and 6) alloys for different heat treatment times were studied. The results revealed that as‐cast Mg–3Zn alloys consist of Mg12Zn13 phase and α‐Mg matrix, while Mg–6Zn is composed of Mg51Zn20, Mg12Zn13 compounds and α‐Mg matrix. After heat treatment of Mg–6Zn alloy at 340 °C, the Mg51Zn20 phase decomposed to the matrix and Mg12Zn13 while, the microstructure of Mg–3Zn remained unchanged. The results also indicated that heat treatment at 340 °C has little influence on the corrosion behaviour of Mg–3Zn. In contrast, heat treatment improved the corrosion resistance of the Mg–6Zn alloy as the decomposition of the Mg51Zn20 phase decreased micro‐galvanic corrosion. The corrosion resistance of both as‐cast Mg–3Zn and Mg–6Zn alloys marginally improved with increasing heat treatment times.