Ability In Simulated Body Fluid Research Articles

Characteristics of plasma electrolytic oxide coating on magnesium-hydroxyapatite composites

Plasma electrolytic oxidation (PEO) is a surface modification of metals to grow a ceramic-like oxide coating with remarkably enhanced corrosion resistance. This work studies the characteristics of the PEO coating formed on magnesium-hydroxyapatite (Mg-HA) composites with HA concentrations of 0, 10, 20, and 30 wt% prepared by spark plasma sintering (SPS). Thin PEO coatings of 1–3 μm were successfully formed on all specimens in 0.5 M Na3PO4 electrolyte for 5 min. The plasma became finer, reducing the pore size and thickness, with increasing HA concentration. Agglomeration of HA particles in Mg-20HA and Mg-30HA inhibited coating coverage. EDS and XRD analyses confirmed the similar composition of Mg3(PO4)2 in all the coatings. The coating improved surface wettability and showed high apatite-forming ability in simulated body fluid. The optimum coating performance was obtained for Mg-10HA.

Fabrication and in vitro evaluation of Ca11B2Si4O22 ceramic for bone tissue engineering

• For the first time, a novel Ca 11 B 2 Si 4 O 22 powder was prepared by a sol-gel method. • In vitro experimental results indicated that the Ca 11 B 2 Si 4 O 22 ceramic enhanced osteogenic differentiation of mBMSCs. • Ca 11 B 2 Si 4 O 22 ceramics had good mechanical property. Calcium borosilicates are bioactive materials. This work synthesized a novel Ca 11 B 2 Si 4 O 22 powder by a sol-gel method. Besides, Ca 11 B 2 Si 4 O 22 ceramic was prepared via the dry-pressure molding and high temperature sintering. XRD analysis results revealed that the high-purity Ca 11 B 2 Si 4 O 22 crystalline powder was successfully prepared. Meanwhile, the compressive strength of the Ca 11 B 2 Si 4 O 22 ceramic reached to 290 MPa. More interestingly, the Ca 11 B 2 Si 4 O 22 ceramic exhibited excellent apatite-forming ability in simulated body fluid and osteogenic activity in vitro . These results indicated that the novel Ca 11 B 2 Si 4 O 22 ceramic holds great potential for load-bearing bone repair.

In-vitro cell interaction and apatite forming ability in simulated body fluid of ICIE16 and 13-93 bioactive glass coatings deposited by an emerging suspension high velocity oxy fuel (SHVOF) thermal spray

ICIE16 and 13-93 bioactive glasses have been proposed as alternative chemically stable compositions in physiological fluid keeping bioactivity comparable to Bioglass®. ICIE16 and 13-93 bioactive glasses coatings were produced via an emerging suspension high-velocity oxy-fuel (SHVOF) thermal spraying technique. Suspensions of ICIE16 and 13-93 with 10 wt% solid loading in isopropanol (IPA) and water were used to produce coatings on AISI304 stainless steel using a flame power of 50 kW and 75 kW. For both glass formulations, the coatings deposited at a lower flame power were more porous, less hard, and less rough (~6% porous and 242 HV) than the coatings obtained at a higher flame power (~4% porosity and 300 HV). ICIE16 coatings showed more dissolution in SBF (simulated body fluid) than the 13-93 coatings. Moreover, the 13-93 glass coating sprayed at 75 kW showed the highest stability in SBF since only 2% of the coating was resorbed in SBF after 7 days of immersion and revealed apatite precipitation after 7 days. In-vitro cell tests, using MG63 cells, showed good cell attachment and proliferation on the surfaces of the coatings, revealing good cytocompatibility. The 13-93 coating sprayed at 75 kW revealed the highest cell proliferation after 7 days of incubation. This can be attributed to the higher surface roughness of the coating (Ra = 6.5 ± 0.6 μm).

Injectable bioactive glass-based pastes for potential use in bone tissue repair

AbstractIn this study, injectable pastes based on a clinically-tested bioactive glass and glycerol (used as organic carrier) were produced and characterized for further application in regenerative medicine. The paste preparation route, apatite-forming ability in simulated body fluid (SBF) solution, viscoelastic behavior and structural features revealed by means of scanning electron microscopy (SEM), FTIR and Raman spectroscopy were presented and discussed, also on the basis of the major experimental data obtained in previous studies. A mechanism illustrating the chemical interaction between bioactive glass and glycerol was proposed to support the bioactivity mechanism of injectable pastes. Then, the results of In vivo tests, conducted through injecting moldable paste into osseous defects made in rabbit’s femur, were reported. Animal studies revealed good osteoconductivity and bone bonding that occurred initially at the interface between the glass and the host bone, and further supported the suitability of these bioactive glass pastes in bone regenerative medicine.

Impartation of apatite-forming ability to chitosan nanofibres by using apatite nuclei.

Chitosan nanofibre-apatite nuclei composites obtained by mixing apatite nuclei which possess high apatite-forming ability with chitosan nanofibre have been expected to be novel bone restorative materials with suitable properties such as light weight, low coefficient of thermal expansion, high mechanical strength, biocompatibility and bioactivity. In this study, the authors prepared three types of apatite nuclei by changing the reaction time aimed to optimise their crystallinity and fabricated their composites with chitosan nanofibre. In order to evaluate the bioactivity in vitro, the authors tested apatite-forming ability in simulated body fluid. As a result, the materials showed enough apatite-forming ability in a short time by mixing chitosan nanofibre and apatite nuclei with extremely low crystallinity and their high reactivity in simulated body fluid.

Comparative Study of Surface Modification Treatment for Porous Titanium.

ABSTRACTObjectivesThis study was to investigate suitable surface treatment methods for porous titanium by ex vivo study of material properties and calcium phosphate deposition in simulated body fluid.Material and MethodsPorous titanium with acid (H2SO4 and HCl mixed acid) or alkali (NaOH) treatment was prepared. The surfaces were observed, and the weight change ratio (after and before surface treatment) and compression strength were measured. To investigate the apatite formation ability, each sample was immersed in simulated body fluid (SBF). Surface observations were performed, and the weight change ratio (before/after immersing SBF) and calcification (by alizarin red staining) were measured.ResultsThe acid group showed a martensitic micro-scale rough structure and the weight and mechanical strength greatly decreased compared to the other groups. The alkali group exhibited a nano-scale roughness structure with similar weight and mechanical strength. Following immersion in SBF, an apatite-like crystal layer in the alkali group was observed. The weight of all samples increased. The change in weight of the samples in the alkali, acid, and control groups were significantly different, showing the following trend: alkali group (1.6%) > acid group (1.2%) > control group (0.8%). Calcium precipitation values were higher in the samples from alkali group than in those from the acid and control groups.ConclusionsAlkali treatment was found to be a suitable surface modification method for porous titanium, resulting in good mechanical strength and apatite formation ability in simulated body fluid.

Copper-doped Ordered Mesoporous Bioactive Glass: A Promising Multifunctional Platform for Bone Tissue Engineering †.

The design and development of biomaterials with multifunctional properties is highly attractive in the context of bone tissue engineering due to the potential of providing multiple therapies and, thus, better treatment of diseases. In order to tackle this challenge, copper-doped silicate mesoporous bioactive glasses (MBGs) were synthesized via a sol-gel route coupled with an evaporation-induced self-assembly process by using a non-ionic block co-polymer as a structure directing agent. The structure and textural properties of calcined materials were investigated by X-ray powder diffraction, scanning-transmission electron microscopy and nitrogen adsorption-desorption measurements. In vitro bioactivity was assessed by immersion tests in simulated body fluid (SBF). Preliminary antibacterial tests using Staphylococcus aureus were also carried out. Copper-doped glasses revealed an ordered arrangement of mesopores (diameter around 5 nm) and exhibited apatite-forming ability in SBF along with promising antibacterial properties. These results suggest the potential suitability of copper-doped MBG powder for use as a multifunctional biomaterial to promote bone regeneration (bioactivity) and prevent/combat microbial infection at the implantation site, thereby promoting tissue healing.

Synthesis and characterization of rubidium-containing bioactive glass nanoparticles

Developing bioactive glass nanoparticles (BGNs) comprising biologically active ions is a promising strategy to enhance therapeutic performance. Given the pro-osteogenic activity of rubidium (Rb), a new type of Rb-containing BGNs was developed in this work. Here, a modified Stӧber method was employed to synthesize monodispersed spherical BGNs (particle size ~ 100 nm) with different contents of Rb incorporation (nominal 1, 3 and 5 at.%). The results showed that Rb incorporation did not significantly affect the size, shape and amorphous characteristic of BGNs. The real Rb contents (maximum 0.62 at.%) in BGNs were much lower than the designed ones. Compared with Rb-free BGNs, Rb-BGNs exhibited enhanced hydroxyapatite-forming ability in simulated body fluid. The results suggest that Rb-BGNs are promising to be used as bioactive fillers for bone regeneration applications.

Mechanistic studies of biomineralisation on silver incorporated anatase TiO2.

Here we report silver incorporated anatase TiO2 developed on Ti metal by H2O2-AgNO3 and heat treatment to have faster biomineralisation or apatite-forming ability in simulated body fluid (SBF). Apatite-forming ability has been investigated concerning heat treatment temperatures ranges, 400-800°C and duration of soaking period in SBF. The apatite formation showed an increasing trend with increase in the heat treatment temperatures up to 600°C and beyond that the Ti metal lost this ability. XRD as wells as Raman results of such chemical and heat-treated Ti metal at different temperatures further correlates the apatite nucleation directly in relation with that of anatase to rutile TiO2 formation. Further, a time dependent apatite mineralisation study by XPS revealed simultaneous calcium and phosphate deposition at the early stage of soaking in SBF. Therefore, the apatite nucleation in the present chemically treated Ti metal depends on the crystalline phase of TiO2 formed by H2O2 and heat treatment along with Ag+ ion release.

Resorbable PCEC/gelatin-bismuth doped bioglass-graphene oxide bilayer membranes for guided bone regeneration

Guided bone regeneration (GBR) is a therapeutic modality applied prior to dental implant placement to increase bone density at the defect site or during placement for directing bone growth around implant. In this study, an asymmetric, bilayer structure was prepared by covalently bonding a dense polycaprolactone-polyethylene glycol-polycaprolactone (PCEC) membrane layer with a hydrogel layer composed of bismuth doped bioactive glass (BG, 45S5) and graphene oxide (GO) particles incorporated in gelatin. Structural and mechanical properties (surface morphology and chemistry, thickness, degradation rate and tensile strength of GBR membranes) were studied. Membranes had a 3D structure having almost 1 mm thickness which is suitable for space filling. Highest tensile strength (TS) (1.71 ± 0.10 MPa, p < 0.001) was observed for membranes having the highest BG containing group (BG20) while lowest TS was observed (1.23 ± 0.11 MPa, p < 0.001) for BG8/GO2 samples. Similarly, hydrolytic degradation of BG20 involving bilayer structures was slower in phosphate buffered saline (PBS) (23% ± 5% in 4 weeks) than other GBR membranes while biodegraded at an equal rate in lipase (BG20 as 72% ± 3%, BG10 as 69% ± 1%, BG8/GO2 as 71% ± 7% and BG2/GO8 as 74% ± 8%). BG8/GO2, displayed lowest gelatin (GEL) release in PBS over 28 d period (175% ± 9% and 164% ± 10% mgGEL/gsample, p < 0.001). However, all bilayer membranes displayed a similar rate of degradation in lipase solution and also had similar mineral deposition ability in simulated body fluid. Significantly higher cell proliferation (p < 0.001) and osteogenic differentiation (p < 0.001) of human dental pulp stem cells were observed in BG20 and BG10 membrane groups than all other groups. On the other hand, GO presence decreased both mechanical and osteoinductive properties compared to pure BG counterparts. Collectively, amine introduced (aminolysis) synthetic dense PCEC layer was covalently bonded to composite hydrogel layer to obtain coherent bilayer membranes for GBR. They were successfully produced to have two layers designed to prevent fibrous tissue movement towards bone defect while enabling bone regeneration. BG20 membrane groups demonstrated higher calcium phosphate deposition TS, cellular growth and osteogenic differentiation.

In vitro apatite mineralization and heat generation of magnetite-reduced graphene oxide nanocomposites for hyperthermia treatment

Nanocomposites of magnetite (Fe3O4) and reduced graphene oxide (rGO) generate heat under an alternating magnetic field and therefore have potential applications as thermoseeds for cancer hyperthermia treatment. However, the properties of such nanocomposites as biomaterials have not been sufficiently well characterized. In this study, the osteoconductivity of Fe3O4-rGO nanocomposites of various compositions was evaluated in vitro in terms of their apatite-forming ability in simulated body fluid (SBF). Furthermore, the heat generation of the nanocomposites was measured under an alternating magnetic field. The apatite-forming ability in SBF improved as the Fe3O4 content in the nanocomposite was increased. As the Fe3O4 content was increased, the nanocomposite not only rapidly raised the surrounding temperature to approximately 100 °C, but the specific absorption rate also increased. We assumed that the ionic interaction between the Fe3O4 and rGO was enhanced and that Brown relaxation was suppressed as the proportion of rGO in the nanocomposite was increased. Consequently, a high content of Fe3O4 in the nanocomposite was effective for improving both the osteoconductivity and heat generation characteristics for hyperthermia applications.

Role of calcium ions in defining the bioactivity of surface modified Ti metal

Nano-structured hydrogen titanate and sodium hydrogen titanate layers were formed when Ti metal was treated with H2O2 and NaOH solutions, respectively. The chemically treated Ti metals upon subsequent treatment with Ca(NO3)2 and CaCl2 solutions, resulted in incorporation of Ca2+ ions into the nano-structured titanate layer. Thus formed nano-structured titanate layers containing Ca2+ ions when subjected to heat treatment, forms anatase and calcium titanate-rutile phases, respectively. In vitro apatite-forming ability in simulated body fluid (SBF) was positive for H2O2-Ca and heat-treated Ti metal in contrast to NaOH-Ca and heat treatment. Formation of anatase phase together with Ca2+ ion release into SBF was found to be the key driving force for such a high bioactivity of Ca2+ containing H2O2 treated Ti metal on contrary to NaOH and heat treatment. This study provides a new insight into the factors accelerating the bioactivity of Ti metals during various chemical and thermal treatments, which further aid and abet to design dental and orthopaedic implants with high bone-bonding ability.

Effect of Doubled Sandblasting Process and Basic Simulated Body Fluid Treatment on Fabrication of Bioactive Stainless Steels.

In our recent study, we aimed to impart hydroxyapatite (HA)-forming to bioinert stainless steels (SUS316L). The surfaces of SUS316L specimen were treated by a sandblasting process using alumina grinding particles with 14.0 or 3.0 μm for average particle size, respectively. In addition, a doubled sandblasting process (DSP) using the 14.0 μm particles and subsequently 3.0 μm ones were also conducted. Compared with the case of the 14.0 μm particles, the 3.0 μm particles were available to increase the surface roughness and the surface area of the specimen. Moreover, these values were further increased in the case of the DSP. These specimens were soaked in simulated body fluid (SBF) at pH = 8.4, 25 °C and were directly heated in the solution by electromagnetic induction. By this treatment, formation of CaP was induced on each specimen. These materials performed high HA-forming ability in SBF. Average bonding strength of the HA film formed on them in SBF was increased depending on the increase of surface roughness and surface area. These results indicated that sandblasting condition was an important factor to improve interlocking effect related to the increase of the surface roughness and the surface area.

Calcium phosphate coating on dental composite resins by a laser-assisted biomimetic process

ObjectivesDental composite resins with better biocompatibility and osteoconductivity have been sought in endodontic treatments. This study aimed to develop a technique to produce the osteoconductive resin surfaces through calcium phosphate (CaP) coating using a laser-assisted biomimetic (LAB) process. MethodsLight-cured, acrylic-based composite resins were used as substrates. The resin substrate was subjected to a LAB process comprising Nd:YAG pulsed laser irradiation in a supersaturated CaP solution. The LAB-processed substrate was immersed for 3 days in a simulated body fluid (SBF) for the preliminary osteoconductivity assessment. ResultsAfter irradiation for 30 min, the resin surfaces were partly coated with a newly formed CaP layer. The coating layer contained hydroxyapatite as the main crystalline phase and the coating coverage depended on the laser wavelength and the type of resin. The LAB-processed CaP-coated surface exhibited apatite-forming ability in SBF. ConclusionsLAB process is effective for CaP coating on light-cured dental composite resins and improving their osteoconductivity. Clinical significanceThe LAB process is a potential new tool to create a cementum-like osteoconductive surface on dental composite resins.

Surface structure and in vitro apatite-forming ability of titanium doped with various metals

Surface modification by sodium hydroxide (NaOH) and subsequent heat treatment can provide titanium and its alloys an apatite-forming ability in simulated body fluid (SBF), and is used clinically to treat titanium alloy hip joints in Japan. However, there is no systematic study on the relationship between the amount and chemical state of metals incorporated into titanium and the apatite-forming ability in SBF. We have studied this relationship herein by treating NaOH–modified titanium with aqueous solutions containing different types (aluminum, calcium, chromium, copper, zinc, and silver) and concentrations (0.01, 0.1, and 1 M) of metal ions. As a result, we found that formation of anatase and the chemical states of the metals incorporated into titanium control the apatite-forming ability. Further, the chemical states of the metals can be interpreted in terms of the ionization tendency. These findings would aid future design of metal-doped bioactive titanium for orthopedic or dental implants.

Ultra-fast, highly efficient and green synthesis of bioactive forsterite nanopowder via microwave irradiation

Forsterite (Mg2SiO4) has recently attracted considerable attention in different fields because of its wide range of applications. In this paper, pure forsterite nanopowders were synthesized by an ultra-fast, highly efficient and green method for the first time. Microwave irradiation was used to synthesize forsterite nanopowder. The formation of highly crystalline forsterite nanopowder was confirmed by X-ray diffraction (XRD) and energy dispersive X-ray spectrometer (EDS) analyses. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses showed that the agglomerated powder composed of nanocrystalline particles with the mean particle size of ~100 nm. Microwave irradiation significantly accelerated the rate of the reactions and dramatically decreased reaction times from hours to minutes and seconds. In vitro bioactivity evaluation was performed by soaking the forsterite samples in simulated body fluid (SBF). Results indicated that synthesized forsterite nanopowder via microwave irradiation method possessed excellent apatite-forming ability in SBF. Cell viability results showed that synthesized forsterite nanopowder not only showed no cytotoxicity but also improved cell proliferation. Alkaline phosphatase (ALP) activity assay indicated that the fabricated forsterite nanopowder could facilitate the MG63 osteoblast-like cells to proliferate and differentiate. Therefore, microwave-assisted synthesis technique could be considered as a novel, safe and high efficient method in saving time and energy for bioactive forsterite nanopowder production.

In vitro investigation of the growth of hydroxyapatite and proliferation of human cell lines on the sol gel derived diopside co-substituted tricalcium phosphate bioceramics

Sol-gel derived bioceramic samples with the composition formula x(CaO.MgO.2SiO2).(100-x)3CaO.P2O5 where x = 0, 10, 20, 30 and 40 mass% have been prepared in the laboratory. Diopside (CaO.MgO.2SiO2) co-substituted tricalcium phosphate (3CaO.P2O5) bioceramics are speculated to be successful bone repair materials for clinical applications due to improved bone bonding ability and bioresorbability properties. Authors have employed x-ray diffraction, Raman spectroscopy, field emission scanning electron microscopy along with energy dispersive spectroscopy, hardness testing and cell culture studies during the investigations. X-ray diffraction spectra demonstrated the formation of crystalline phases of diopside, merwinite and whitlockite in the samples and Raman spectra shows the presence of phosphate species in the orthophosphate environment. In vitro hydroxyapatite forming ability in simulated body fluid has been investigated by x-ray diffraction, Raman and field emission scanning electron microscopy techniques for time durations varying between day 1 to day 12 and results demonstrated that hydroxyapatite layer has developed from day 1 in sample with composition 40 mass% tricalcium phosphate and 60 mass% diopside. Pure diopside has shown the best hardness value. Although, 10 mass% tricalcium phosphate and 90 mass% diopside composition has shown the slower rate for growth of hydroxyapatite but it has shown the best cell viability values for human cell line. Results indicate that growth rate of hydroxyapatite is composition as well as sample synthesis technique dependent.

Chemical-physical Properties and Apatite-forming Ability of Mineral Trioxide Aggregate Flow

IntroductionThis study aimed to analyze the chemical-physical properties, including pH, volumetric change, radiopacity, and apatite-forming ability in simulated body fluid, of a new tricalcium silicate material (MTA Flow; Ultradent Products Inc, South Jordan, UT). MethodsMTA Flow was tested in comparison with MTA Angelus (Angelus, Londrina, PR, Brazil). The pH of soaking water was tested up to 168 hours in deionized water. In the solubility test, the root-end fillings of 20 acrylic teeth were scanned twice by micro–computed tomographic imaging before and after immersion in ultrapure water for 168 hours. In addition, using an aluminum step wedge, the radiopacity of each material was evaluated as recommended by international standards. The mean gray values of the test materials were measured using ImageJ software (National Institutes of Health, Bethesda, MD). The morphologic and chemical analyses of the material surface were performed using scanning electron microscopic energy-dispersive X-ray spectroscopic analysis after 28 days in Hank’s balanced salt solution (HBSS). The data were analyzed using 2-way analysis of variance with the Student-Newman-Keuls test (P < .05). ResultsMTA Flow showed similar alkalizing activity to that of MTA Angelus. In the solubility test, both materials presented lower values without statistical differences. Both materials showed a marked alkalinizing activity within 3 hours, which continued for 168 hours. MTA Angelus showed statistically higher radiopacity values (P < .05). All materials showed the ability to nucleate calcium phosphate on their surface after 28 days in HBSS. ConclusionsMTA Flow showed remarkable alkalinizing capability, low solubility, good radiopacity, and the ability to form calcium phosphate deposits after being soaked in simulated body fluid, showing values similar to those of MTA Angelus.

Effects of Ca/P molar ratios on regulating biological functions of hybridized carbon nanofibers containing bioactive glass nanoparticles

Biological functions of hybridized carbon nanofibers (CNFs) depend closely on the incorporated bioactive components. For hybridized CNFs containing bioactive glass (BG) nanoparticles (CNF/BG), chemical compositions of BG nanoparticles might have decisive effects on their cell affinity and osteocompatibility. Herein, three hybridized CNF/BGs were produced by incorporating 68S-type BG nanoparticles with different Ca/P molar ratios (1.0, 1.67 or 2.5) into CNFs via a sol–gel/electrospinning and carbonization method. Structural evolution of these hybridized CNF/BGs was studied in relation to their Ca/P molar ratios. Crystalline wollastonite was found to be the dominant phase at a high feeding Ca/P molar ratio (i.e. 2.5), but weak crystallized hydroxyapatite was the main phase at the low feeding Ca/P molar ratio (i.e. 1.0). These findings were correlated to the biological functions of the resulted CNF/BG hybrids including apatite formation ability in simulated body fluid and osteoblast behaviors in in vitro culture. All the CNF/BG hybrids displayed a strong affinity for inducing apatite deposition, showing insignificant difference after the initial nucleation stage, while they behaved differently in promoting the proliferation and osteogenic differentiation of osteoblasts. The fastest proliferation rate and the highest expression of alkaline phosphatase activity was found on the CNF/BG (Ca/P = 1.0). The results suggested a feasible way to upregulate osteoblast behaviors is by changing the feeding Ca/P molar ratios in the preparation of CNF/BG hybrids for potential bone repairing applications.

Effect of surface charge of TiO2 particles on hydroxyapatite formation in simulated body fluid

TiO2 particles formed by heat treatment in a nitrogen atmosphere with an extremely low oxygen partial pressure exhibited high hydroxyapatite (HAp)-forming ability in simulated body fluid (SBF). X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning transmission electron microscopy (STEM) combined with electron energy loss spectroscopy (EELS) indicated that the particles were rutile-type TiO2, which contains hardly any nitrogen. Electron spin resonance (ESR) spectra revealed the reduction of Ti4+ in TiO2 to Ti3+ and the simultaneous introduction of oxygen vacancies to maintain charge neutrality. The enhanced HAp-forming ability of the TiO2 particles was likely related to their negatively charged surface, induced by water adsorption on oxygen vacancies, which resulted in acidic point formation. In contrast, TiO2 particles formed by heat treatment in air showed low HAp-forming ability because their surfaces had almost zero charge.