Formation Of Apatite-like Layer Research Articles

<i>In Vitro</i> Study: Bioactivity, Biocompatibility and Antibacterial Behavior for Polyetheretherketone Composites

Polyetheretherketone (PEEK) as alternate biomaterial to traditional metallic implant materials has become greater important. At the same time have greater chemical resistance, mechanical properties, biocompatibility and radiolucency, making it convenient for use as dental and orthopedic implants. In the present study the biological behavior was evaluated of polymer composites based polyetheretherketone combined with various nano hydroxyapatite and nano titanium dioxide blending up to (1.5 wt%). The bioactivity of the specimens was evaluated by investigation apatite formation after immersion for 7 days and 14 days in simulated body fluid (SBF). XRD and SEM were used to approve the bioactivity of the specimens. Cell viability, proliferation, and the cell attachment activity of L929 mouse fibroblast cells was evaluated after (1, 3 & 5) days by MTT assay. Antibacterial property of the specimens versus S. aureus was observed with optical density methods. The results detected that the apatite-like layer formation was clearly observed on specimens after immersion for different period in simulated body fluid (SBF). Moreover, Results of MTT assay recorded the PEEK specimens excited the activity of fibroblasts and therefore a high cytocompatibility was noticed and specimens showed antibacterial properties against S. aureus.

Hydroxyapatite nucleation and growth modulated by amino acid-capped gold nanoparticles: An in vitro study

Surface modification of biomaterials significantly influences implantable materials' surface reactivity to induce an apatite-like layer formation. This study observed the bioactivity and surface reactivity of modified biomaterials (calcium-deficient hydroxyapatite [CDHA] on amino acid-capped AuNPs [AA-AuNPs]) through immersion in simulated body fluid (SBF). AuNPs capped with eight different amino acids (AA)—both charged and polar uncharged AAs—showed the ability to induce the biomimetic hydroxyapatite formation. The presence of a hydroxyapatite peak in the X-ray powder diffraction (XRD) pattern indicated hydroxyapatite formation after all samples’ immersion in SBF. Moreover, longer immersion time in SBF contributed to the nucleation and growth of hydroxyapatite shown by the changing of the crystal structure including lattice parameters, crystallinity index, and crystallite size. The XRD results confirmed that surface modification using AA-AuNPs significantly affected the orientation of the hydroxyapatite crystal, where AAs served as a binding site for Ca2+ and PO43− ions. Furthermore, grayscale analysis based on scanning electron microscope images showed that charged AAs exhibited a role in hydroxyapatite nucleation and growth while polar uncharged AAs only contributed to hydroxyapatite growth. The calculated Ca/P ratio also confirmed the formation of hydroxyapatite from CDHA. XRD and scanning electron microscopy/energy-dispersive X-ray spectroscopy results signify the bioactivity of CDHA-modulated AA-AuNPs in hydroxyapatite formation for new bone tissue regeneration.

Coating the magnesium implants with reinforced nanocomposite nanoparticles for use in orthopedic applications

The use of calcium silicate coatings has extensively increased due to properties such as biocompatibility and proper bioactivity response. The present study was aimed to investigate the bioactivity of wollastonite-hydroxyapatite (WS-HA) bio-nanocomposite for the treatment of orthopedic implant coatings by adding magnetic nanoparticles (MNPs) and single-walled carbon nanotubes (SWCNTs) to the matrix. The bio-nanocomposite was coated on Mg substrate for 40 min at 40 V using electrophoretic deposition (EPD), following which the heat treatment was performed at 550–650 °C for 1 h. The coatings were incubated in simulated body fluid (SBF) and phosphate buffer saline (PBS) for 28 days to detect and confirm apatite-like layer formation Inductively coupled plasma-optical emission spectroscopy (ICP-OES) was used to evaluate the concentration of calcium and silicon ions.

Improvement in mechanical and biological performance of porous baghdadite scaffold by applying chitosan coating

This research aimed at fabrication of baghdadite scaffolds with chitosan coating via combining of polymeric sponge replication and dip-coating methods with improved mechanical and biological properties. The composite was characterized using x-ray diffraction, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Porosity, compressive strength, in vitro bioactivity and biological responses of human bone marrow mesenchymal stem cells were evaluated. The porosity percentage and compressive strength values were 79 ± 0.87 and 2.88 ± 0.34, respectively. The results showed chitosan coating could largely enhance the mechanical strength of baghdadite scaffolds. Also apatite-like layer formation was observed. Based on the MTT assay and SEM micrographs, human bone marrow mesenchymal stem cells were spread and attached well on the surface of the scaffold, which indicated a high biocompatibility. The results showed that this composite scaffold has the potential to be used as a temporary substrate for bone tissue engineering applications.

A comparative study of apatite-like layer formation and protein adsorption on four bioceramic scaffolds

The aim of this study was to systematically investigate the apatite layer formation and protein adsorption on the bioceramics, trying to reveal their relationship and the mechanisms of the process. Four different materials, hydroxyapatite (HA), apatite/wollastonite bioactive glass ceramics (BGC), biphasic calcium phosphate (BCP), and nano-hydroxyapatite (nHA), were prepared to meet the specific tissue engineering scaffold requirements. The porous samples in four groups were immersed into simulated body fluid (SBF) solution, and the structural and morphological changes for different times (maximum of 14 days) were analyzed. Then, the effect of their structure and chemical composition on protein adsorption capacity was systematically compared.

Electrophoretic co-deposition of PEEK-hydroxyapatite composite coatings for biomedical applications.

This study focuses on the optimization of electrophoretic deposition (EPD) and suspension parameters for producing PEEK-hydroxyapatite (HA) coatings with feasible microstructure, adhesion strength, and in-vitro bioactivity. Nanostructured hydroxyapatite (HA) micro-granules were incorporated with PEEK to form PEEK-hydroxyapatite composite coatings via EPD. After EPD, a heat-treatment at 375 °C was applied for densification of the coatings and for enhancing the adhesion between the coatings and the substrates. It was found that both adhesion strength and in-vitro bioactivity of the coatings were dependent on the PEEK and HA relative contents. Thus, increasing the amount of HA improved the bioactivity while decreased the adhesion strength of the coatings. Apatite-like layer formation was observed on coatings with high HA content after incubation for three days in simulated body fluid (SBF). Finally, a deposition mechanism was proposed for the EPD of the PEEK-hydroxyapatite composite system.

Research of formation of apatite-like layer on the surface of glass-ceramic coatings for dental implants

Research of formation of apatite-like layer on the surface of glass-ceramic coatings for dental implants

New Insight into Mixing Fluoride and Chloride in Bioactive Silicate Glasses

Adding fluoride into bioactive glasses leads to fluorapatite formation and a decrease in glass transition temperature. Recently, chloride has been introduced into glasses as an alternative to fluoride. The presence of the large chloride ion lowers glass crystallisation tendency and increases glass molar volume, which effectively facilitates glass degradation and bone-bonding apatite-like layer formation. However, there is no information regarding the effect of mixing fluoride and chloride on the glass structure and properties. This study aims to synthesize mixed fluoride and chloride containing bioactive glasses; investigate the structural role of fluoride and chloride and their effects on glass properties. The chloride content measurements reveal that 77–90% of chloride was retained in these Q2 type glasses. Glass transition temperature reduced markedly with an increase in CaX2 (X = F + Cl) content, while the glass molar volume increased. 29Si MAS-NMR results show that the incorporation of mixed fluoride and chloride did not cause significant change in the polymerization of the silicate network and no detectable concentration of Si-F/Cl bands were present. This agrees with 19F NMR spectra showing that F existed as F-Ca(n) species.

Formation of Apatite-Like Layer on the Surface of Nanostructured Calcium–Phosphate–Silicate Coatings on Titanium Alloys

Formation of Apatite-Like Layer on the Surface of Nanostructured Calcium–Phosphate–Silicate Coatings on Titanium Alloys

Zn and Sr incorporated 64S bioglasses: Material characterization, in-vitro bioactivity and mesenchymal stem cell responses.

Essential element like Zn or Sr is known to play an important role in bone remodeling process. In this study, we have used the sol-gel process to synthesize the Zn (2%) and Sr (5%) doped 64S bioglasses (BGs, 64SiO2-5P2O5-31CaO, mol.%), alone and co-doped. The synthesized glasses were characterized by XRD, FTIR and STEM. For biological evaluation, the effects of Zn and Sr incorporation on the in vitro bioactivity of the synthesized BGs were studied using the simulated body fluid (SBF) soaking. The proliferation and differentiation (ALP, OCN) of rat mesenchymal stem cells (MSCs) on these BGs were studied using CCK-8 and ELISA analyses. The results indicated that Zn had been uniformly incorporated into the bioglass, and demonstrated a stimulating effect on apatite-like layer formation, MSC proliferation and differentiation. On the other hand, most of Sr appeared to form a secondary crystal phase with extremely high solubility in SBF, showing an enhancing effect only in MSC differentiation but not in proliferation, as well as an inhibitory effect on apatite-like layer formation. The different dissolution behaviors of Sr and Zn ions seemed to have a strong correlation with the different apatite-like layer formation capabilities and the cellular responses of Zn and Sr containing BGs.

Improved bioactivity of PAN-based carbon nanofibers decorated with bioglass nanoparticles

Composite nanofibers composed of polyacrylonitrile (PAN)-based carbon nanofibers and bioactive glass (BG) nanoparticles have been prepared by electrospinning and in situ sintering. Morphology observation showed that the BG nanoparticles of size 20–50 nm were uniformly distributed on the surface of composite nanofibers with 350 nm average diameter after carbonization. Biological mineralization indicated the formation of apatite-like layer on the surface of composite nanofibers, in which the composition of carbonate hydroxyapatite was proved by FTIR and XRD analysis. Cell growth dynamics according to cellular morphology, CCK-8 assay, and alkaline phosphatase activity assay exhibited better cell adhesion, proliferation, and osteogenic induction of bone marrow-derived mesenchymal stem cells cultured on the composite nanofibers, which suggested the higher bioactivity of composite nanofibers compared to pure PAN-based carbon nanofibers.

Stimulated osteoblastic proliferation by mesoporous silica xerogel with high specific surface area

Specific surface area is a critical parameter of mesoporous silica-based biomaterials, however, little is known about its effects on osteoblast responses in vitro. In the present study, mesoporous silica xerogels (MSXs) with different surface area (401, 647 and 810 m(2)/g, respectively) were synthesized by a sol-gel process. Surface silanol contents decreased with the increase of surface area with which protein adsorption capability positively correlated. And the apatite-like surface seemed to form faster on MSXs with higher surface area determined by XRD analysis. Using MG63 osteoblast-like cells as models, it was found that cell proliferations were promoted on MSXs with higher surface area, based on the premise that the effects of Si released from materials on osteoblast viability were excluded by real-time Transwell(®) assay. RT-PCR results indicated cell adhesion-related integrin subunits α5 were up-regulated by higher surface area at day 1, which was further confirmed by flow cytometry analysis. The data suggest that increasing SSA of MSXs could promote surface cellular affinity by adsorbing serum proteins and accelerating apatite-like layer formation, which results in promoted osteoblastic proliferation via integrin subunit α5 at initial adhesion stage. Regulating SSA, an effective approach in designing mesoporous silica-based materials, provides an alternative method to obtain desirable tissue-response in bone regeneration and drug-delivery system.

In vitro degradability and bioactivity of mesoporous CaO-MgO-P2O5-SiO2 glasses synthesized by sol–gel method

Two glasses of the CaO-MgO-P2O5-SiO2 system with different MgO contents (0 and 10 mol%, respectively) have been synthesized by sol–gel method. The degradation of glass samples was evaluated through the weight loss in the tris-(hydroxymethyl)-aminomethane and hydrochloric acid (Tris–HCl) buffer solution, and the in vitro bioactivity was assessed by determining the changes in surface morphology and composition after soaking in a simulated body fluid. Formation of the apatite-like layer on glasses surface was studied by means of X-ray diffraction, Fourier-transform infrared, scanning electron microscopy. Results indicate that, with the partial substitution of MgO for CaO in glass composition, the glass degradation decrease and the formation of apatite-like layer is delayed. Furthermore, it is observed that the glass bioactivity is relative to its dissolution, and the effects of MgO on glass degradability and bioactivity may be attributed to the influence of ionic field strength and distinct bonding configuration of glass.

Comparative Study of the Degradation Behavior of Mechanically Mixed and Chemically Precipitated Biphasic Calcium Phosphates

Surface morphology and degradation behavior of mechanically mixed and chemically precipitated biphasic calcium phosphate (M-BCP and P-BCP) were compared. For the M-BCP powder, commercial HA and TCP powders were used. In order to prepare P-BCP powder, precipitation method was used. The particle size of P-BCP was smaller than that of M-BCP. The disk-type specimens of each powder were prepared for the morphology comparison and degradation test. The surface morphology of sintered samples was porous in M-BCP and dense in P-BCP. The degradation test was conducted in the revised simulated body fluid (R-SBF) for 1, 7, and 21 days. Surface morphology and degradation rate of two samples were different. The weight gain in both samples increased linearly with immersion period due to apatite-like layer formation. However, the weight gain in M-BCP was much higher than that in P-BCP. The weight gain was related to the surface morphology and degradation with immersion period.