Days Of Soaking In Simulated Body Fluid Research Articles

Fabrication and characterization of 3D-printed composite scaffolds of coral-derived hydroxyapatite nanoparticles/polycaprolactone/gelatin carrying doxorubicin for bone tissue engineering

In this study, nanocomposite scaffolds of hydroxyapatite (HA)/polycaprolactone (PCL)/gelatin (Gel) with varying amounts of HA (42–52 wt. %), PCL (42–52 wt. %), and Gel (6 wt. %) were 3D printed. Subsequently, a scaffold with optimal mechanical properties was utilized as a carrier for doxorubicin (DOX) in the treatment of bone cancer. For this purpose, HA nanoparticles were first synthesized by the hydrothermal conversion of Acropora coral and characterized by using different techniques. Also, a compression test was performed to investigate the mechanical properties of the fabricated scaffolds. The mineralization of the optimal scaffold was determined by immersing it in simulated body fluid (SBF) solution for 28 days, and the biocompatibility was investigated by seeding MG-63 osteoblast-like cells on it after 1–7 days. The obtained results showed that the average size of the synthesized HA particles was about 80 nm. The compressive modulus and strength of the scaffold with 47 wt. % HA was reported to be 0.29 GPa and 9.9 MPa, respectively, which was in the range of trabecular bones. In addition, the scaffold surface was entirely coated with an apatite layer after 28 days of soaking in SBF. Also, the efficiency and loading percentage of DOX were obtained as 30.8 and 1.6%, respectively. The drug release behavior was stable for 14 days. Cytotoxicity and adhesion evaluations showed that the fabricated scaffold had no negative effects on the viability of MG-63 cells and led to their proliferation during the investigated period. From these results, it can be concluded that the HA/PCL/Gel scaffold prepared in this study, in addition to its drug release capability, has good bioactivity, mechanical properties, and biocompatibility, and can be considered a suitable option for bone tumor treatment.Graphical

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

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

Use of epoxypropoxy-propyl-trimethoxysilane in the fabrication of bioactive gelatin microspheres using an emulsification method

Gelatin microspheres (GMs) using various concentrations of epoxypropoxy-propyl-trimethoxysilane (EPPTMS) as a crosslinking agent were prepared. Since the crosslinking agent content and manufacturing conditions are crucial factors in the characteristics of the microspheres, this study was carried out to evaluate the effect of processing variables on morphology, and in vitro behavior of GMs using acellular simulated body fluid (SBF). It was found that the best morphology was acquired in terms of both shape and uniformity for the GMs containing a certain concentration of EPPTMS (20wt%), whereas other concentrations yielded rambling spheres. The results revealed that the size of microspheres became smaller when both the oil-to-water ratio and agitation rate were increased. Moreover, the density of the crosslinking agent was also dependent on the above-mentioned factors in 20wt% EPPTMS. Different morphologies of hydroxyapatite deposits on the surface of GMs were observed after 14 days of soaking in SBF. These in vitro acellular studies were confirmed by SEM, FTIR, and XRD analyses. According to the results of UV–Vis spectroscopy, the GMs were released into the SBF solution in a time-dependent manner; however, the fastest rate of release occurred for the largest GM.

Wollastonite - Tricalcium Phosphate Glass-Ceramics of Eutectic Composition Synthesized by the Glass-Crystallization Method

ABSTRACTGlass-ceramics of eutectic composition in the wollastonite [W, CaO⋅SiO2]- tricalcium phosphate [TCP, β-Ca3(PO4)2] binary system were synthesized by using the glass-crystallization method. The parent glass was crystalized at 800-1300 °C for 0.5-5 h. The in vitro bioactivity of the synthesized glass-ceramics was tested in Kokubo’s Simulated Body Fluid (SBF) for 7-21 days, at pH = 7.4 and 37 °C. All materials were characterized by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM/EDS). The results showed that metastable Apatite phase [Ap, Ca10(PO4)6O], plus W and TCP phases expected according to the binary phase diagram, were formed. Ap was the first phase formed at 900 °C/0.5 h, which was followed by formation of W phase at 900 °C/2 h and of TCP phase at 1200 °C/0.5 h. The relative proportion of the formed crystalline phases was a function of heat treatment temperature and time. A eutectic microstructure was obtained for the materials heat-treated at 1300 °C for 2 or 5 h. All glass-ceramics showed the formation of a hydroxyapatite (HAp)-like layer during the in vitro bioactivity tests. After 21 days of soaking in SBF, the samples treated at 1300 °C/5 h showed a behavior similar to that typically shown by Bioeutectic® material, while the materials heat-treated at lower temperatures tended to form denser HAp-like layers, with similar thicknesses but with higher Ca/P molar ratios.

Feasibility, tailoring and properties of polyurethane/bioactive glass composite scaffolds for tissue engineering

This research work aims to propose highly porous polymer/bioactive glass composites as potential scaffolds for hard-tissue and soft-tissue engineering. The scaffolds were prepared by impregnating an open-cells polyurethane sponge with melt-derived particles of a bioactive glass belonging to the SiO(2)-P(2)O(5)-CaO-MgO-Na(2)O-K(2)O system (CEL2). Both the starting materials and the composite scaffolds were investigated from a morphological and structural viewpoint by X-ray diffraction analysis and scanning electron microscopy. Tensile mechanical tests, carried out according to international ISO and ASTM standards, were performed by using properly tailored specimens. In vitro tests by soaking the scaffolds in simulated body fluid (SBF) were also carried out to assess the bioactivity of the porous composites. It was found that the composite scaffolds were highly bioactive as after 7 days of soaking in SBF a HA layer grew on their surface. The obtained polyurethane/CEL2 composite scaffolds are promising candidates for tissue engineering applications.

Apatite Wollastonite–Titanium Biocomposites: Synthesis and In Vitro Evaluation

The present paper discusses the consolidation of apatite wollastonite (AW) glass ceramic/titanium composites with various percentages of Ti (5–40 wt%) in an argon atmosphere, and, evaluation of the sintered properties and bioactivity in simulated body fluid (SBF). The sintered density of the composites was found to increase with an increase in Ti content and was found to be in the range of 2.25 (5 wt% Ti)–2.70 g/cm3 (40 wt%) as compared with those of sintered AW (2.06 g/cm3) and Ti (4.5 g/cm3). Biaxial flexural strength of the composites was found to be in the range of 13–45 MPa. X‐ray diffraction studies of the sintered AW/Ti composites showed Ti phases (TiPO4+CaTiO3+Ti2O3) and wollastonites (CaSiO3+MgSiO3+CaMgSiO4) as dominating phases. In vitro bioactivity of the composites was studied by soaking the composites in SBF for 7, 14, and 21 days, and the sample surfaces as well as the remaining SBF were analyzed to study the interaction between the material and SBF. The results indicated that the growth of phosphates increased in about 7 days of soaking in SBF, after which a steady state was reached, confirming the samples to be bioactive.

Amorphous Calcium Silicate Coating on Metallic Titanium

Amorphous calcium silicate coating on a metallic titanium substrate for hard tissue replacement was prepared by a sol-gel method. Calcium silicate film was deposited on a titanium substrate by a spin-coating technique and subsequently heated at 500°C for 2 h in air. The deposited film, which was dense, had thickness of about 800 nm and strongly adhered to the substrate. Biomimetic apatite-forming ability of the deposited films was examined by soaking in simulated body fluid (SBF). Thin film X-ray diffractometry and scanning electron microscopy showed the formation of apatite on the surface after 10 days of soaking in SBF.

In vitro bioactivity of akermanite ceramics

In this study, the bone-like apatite-formation ability of akermanite ceramics (Ca2MgSi2O7) in simulated body fluid (SBF) and the effects of ionic products from akermanite dissolution on osteoblasts and mouse fibroblasts (cell line L929) were investigated. In addition, osteoblast morphology and proliferation on the ceramics were evaluated. The results showed that akermanite ceramics possessed bone-like apatite-formation ability comparable with bioactive wollastonite ceramics (CaSiO3) after 20 days of soaking in SBF and the mechanism of bone-like apatite formation on akermanite ceramics is similar to that of wollastonite ceramics. The Ca, Si, and Mg ions from akermanite dissolution at certain ranges of concentration significantly stimulated osteoblast and L929 cell proliferation. Furthermore, osteoblasts spread well on the surface of akermanite ceramics, and proliferated with increasing the culture time. The results showed that akermanite ceramics possess bone-like apatite-formation ability and can release soluble ionic products to stimulate cell proliferation, which indicated good bioactivity.

In situ formation of bioactive titanium coating using reactive plasma spraying

In vitro nucleation of apatite was studied on surface-modified Ti coatings prepared by reactive plasma spraying (RPS). The in situ surface modification of Ti particles was conducted by making use of plasma-enhanced reactions between the Ti particles and the reactive gaseous species in the plasma flame during RPS. Surface-modified Ti coatings were deposited on Ti substrates by rf-RPS using a thermal plasma of Ar gas containing 1%–6% N2 and/or 1%–6% O2. As a means of surface modification, Ti powders impregnated with 0.05–0.2mol% Ca were also sprayed. Compositional changes in the coatings’ surface after soaking in simulated body fluid (SBF) were evaluated by Fourier transform infrared spectroscopy and thin-film x-ray diffraction analyses (TF-XRD). The Ti coatings prepared with Ar-O2 and Ar-N2-O2 plasma formed bone-like apatite after three days of soaking in SBF. On the other hand, no compositional change was observed in the surface of the Ti coatings sprayed with Ar-N2 plasma, even after seven days of soaking in SBF. In the TF-XRD patterns for the Ti coatings sprayed with oxygen-containing plasma, TiO2 (anatase and rutile phase) were commonly observed. In SBF tests, we observed a retardation of apatite deposition for the Ca-added Ti coatings prepared with Ar-O2 and Ar-N2-O2 plasmas. Analyses by x-ray photoelectron spectroscopy indicated that the Ca impregnated in the RPS-Ti coatings formed a Ca-O compound.

In Vitro Apatite Formation on Surface-Modified Titanium Coatings Prepared by Reactive Plasma Spraying

In vitro nucleation of apatite was studied over surface-modified Ti coatings prepared by reactive plasma spraying (RPS). An in-situ surface-modification of Ti particles is conducted by making use of plasma-enhanced reactions between the Ti particles and the reactive gaseous species in the plasma flame during plasma spraying. Surface-modified Ti coatings were deposited on Ti substrates by radio-frequency (rf)-RPS using a thermal plasma of Ar gas containing 1-6% N2 and/or 1-6% O2 at an input power of 16 kW. As a means of surface modification, Ti powders impregnated with 0.05-0.2 mol% Ca were also sprayed. Compositional changes in the coatings' surface after soaking in simulated body fluid (SBF) were examined by Fourier transform infrared spectroscopy (FT-IR) and thin film X-ray diffraction (TF-XRD). The Ti coatings prepared with Ar-O2 and Ar-N2-O2 plasma formed apatite after 3 days of soaking in SBF. On the other hand, no compositional change was observed in the surface of the Ti coatings sprayed with Ar-N2 plasma, even after 7 days of soaking in SBF. In SBF tests, we observed a retardation of apatite deposition for the Ca-added Ti coatings prepared with Ar-O2 and Ar-N2-O2 plasmas. Analyses by X-ray photoelectron spectroscopy indicated that the Ca impregnated in the RPS-Ti coatings formed a Ca-O compound.

Hydoxyapatite/titanium composite coating prepared by hydrothermal–electrochemical technique

To improve the bonding strength of HA coating, hydroxyapatite(HA)/titanium(Ti) composite coatings were successfully prepared by modifying hydrothermal–electrochemical (HTEC) technique. The effect of Ti additions on the phase composition, microstructure, thermal stability and the bonding strength of the HA/Ti composite coatings was studied. The results show that HA and Ti particles are relatively well distributed in the coating, and the addition of Ti reduces the HA crystallite size. The bonding strength of HA/Ti composite coatings increases with addition of Ti, and the bonding strength of the Ti reinforced HA increases with increase of Ti content in the coatings. The bioactivity of HA/Ti composite coating was investigated by immersion of coating in simulated body fluid (SBF). A bone-like apatite layer form on the coating surface after 7 days of soaking in SBF, indicating good bioactivity for HA/Ti composite coating.

Enhancement of Biomimetic Apatite Forming Ability of Calcium Phosphate Glass-Ceramic by a Hydrothermal Treatment

60CaO·30P2O5·7Na2O·3TiO2 glass-ceramic, which consists of crystalline β-Ca3(PO4)2 and β-Ca2P2O7 phases with a small amount of glassy calcium phosphate phase including sodium and titanium ions, has an apatite-forming ability in simulated body fluid (SBF) at 37°C; on the glass-ceramic, the bonelike apatite forms after 20 days of soaking in SBF. In the present work, the apatite-forming ability in SBF of the glass-ceramic was enhanced by a hydrothermal treatment in water at 140°C for 1h; the glass-ceramic was completely covered with bonelike apatite after 10 days of soaking. The phosphate glassy phase around the surface dissolved drastically during the treatment but almost no titanium ion dissolved. X-ray photoelectron spectroscopic analysis implied that the hydrated titania groups, which may induce nucleation of the apatite, form newly around the surface during the treatment.

Correlation between microstructure and properties of biocomposite coatings

A SiO2–CaO–Na2O (SCN) based bioactive glass was used to prepare glass–matrix/Ti particle composite coatings (SCNT). The coatings were obtained by vacuum plasma spray (VPS) on Ti–6Al–4V substrates. Two different deposition methods have been compared: (a) VPS of powders obtained by ball milling of sintered composites; (b) in situ plasma spray of mixed titanium and glass powders. For comparative purposes, pure SCN glass coatings were produced. The coating morphology and microstructure were observed by optical and scanning electron microscopy, compositional analyses by energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). Comparative mechanical tests were carried out by shear tests and by Vickers indentations at the interface between the substrate and the coatings. The bioactivity of glass- and composite coatings was investigated in vitro by soaking them in a simulated body fluid (SBF) with the same ion concentration of the human plasma. All the layers retain their starting composition. The composite coatings obtained by VPS of the powdered presintered composites showed a better mechanical behaviour with respect both to the composite coatings obtained by the in situ method and to the pure glass coatings. Both the glass- and the two kind of composite coatings revealed to be bioactive by the growth of a thick apatite layer after 30 days of soaking in SBF. The electrochemical behaviour of the SCNT coatings was evaluated by means of potentiodynamic anodic polarization curves and free corrosion potential measurements in Ringer solution at 25 °C. For comparative purposes the same analyses were performed on analogous bioactive glass-matrix/Ti particle composite coated samples, based on the system TiO2–SiO2–CaO–B2O3 (TSCB), and obtained both by the in situ and by presintering method as well. The results of the electrochemical tests showed a better corrosion behaviour of the samples coated by VPS of powdered sintered composites with respect to those coated by in situ VPS composites.