Formation Of Carbonated Hydroxyapatite Research Articles

Komposit Bioactive Glass Berbasis Silika Abu Ampas Tebu dan Gum Mimba Menstimulasi Proses Remineralisasi Permukaan Gigi

Dentin hypersensitivity results from exposed dentinal tubules. One of the treatments used is remineralization of dentin and cementum. Bioactive glass (BAG) is a material that can stimulate the remineralization process due to its silica content. Sugarcane bagasse contains high levels of silica and is used as a BAG material. Adding binders and emulsifiers to paste forms increases bonding and stability and makes application easier. Neem gum is a polysaccharide, has emulsifying properties, and can unite two or more ingredients with different properties, increasing the strength of the ingredients. The study aims to analyse the effect of neem gum and bioactive glass composites based on silica bagasse ash on tooth remineralisation. There were three research groups, namely control (BAG paste), treatment A (hyaluronic acid BAG paste) and treatment B (BAG paste, hyaluronic acid and neem gum). The injection paste was applied to the teeth [using cow teeth] on the mesial surface, then soaked in artificial saliva for six days and stored in an incubator at 370C. The remineralization process was observed by forming hydroxycarbonate apatite (HCA) on the tooth root surface using a scoring method based on the Scanning Electron Microscope (SEM) results. CA formation in the BAG, hyaluronic acid and neem gum composite group had a significantly (p<0.05) higher HCA formation score than the group without gum. The control group experienced a washout, so no HCA was formed. BAG composite paste with silica based on bagasse ash and neem gum stimulates the remineralization process marked by the formation of HCA on the tooth root surface.

Hydroxycarbonate apatite formation, cytotoxicity, and antibacterial properties of rubidium-doped mesoporous bioactive glass nanoparticles

Rubidium (Rb) has been shown to impact biological activity. This work synthesized Rb-doped mesoporous bioactive glass nanoparticles (MBGNs) based on the composition 70SiO2–30CaO mol% with a sol-gel method. Rb2O was substituted for CaO in concentrations of 5 and 10 mol%. The influence of Rb incorporation on the hydroxycarbonate apatite (HCA) formation, cytotoxicity, and antibacterial capacity of particles was evaluated. XRD analysis confirmed the amorphous structure of the particles. In vitro, biomineralization studies showed HCA on the surface of MBGN and Rb-doped MBGN pellets after 7 days of soaking in simulated body fluid (SBF). An inhibition zone of Escherichia coli (E.coli) and Staphylococcus aureus (S. aureus) around Rb-doped MBGN pellets was detected, while MBGN pellets did not show any inhibition zone. Additionally, MC3T3-E1 pre-osteoblastic cells demonstrated cytocompatibility when exposed to Rb-MBG suspensions at different concentrations of up to 250 µg/ml. Based on their overall properties, Rb-containing MBGNs are proposed for biomedical applications, such as filler nanoparticles in composite bone scaffolds.

Pembentukan Hidroksikarbonat Apatit Oleh Pasta Injeksi Bioactive Glass Berbasis Silika Abu Ampas Tebu Dan Penambahan Karageenan Rumput Laut

Root caries is common in the elderly, usually detected late, involving enamel, cementum, and dentin below the cementoenamel junction (CEJ). Remineralisation is used to treat it when cavitation has not occurred. Bioactive glass triggers remineralisation by forming hydroxycarbonate apatite (HCA) at an early stage. Injectable paste preparations are needed to overcome these problems. The use of hyaluronic acid and carrageenan polymers supports the physical and mechanical properties of the paste preparation. The purpose this research to analyse the formation of HCA on the tooth root surface by administering bioactive glass (BAG) injection paste with the addition of seaweed carrageenan. This study was a laboratory experimental study with three research groups, namely treatment group 1 (BAG paste and hyaluronic acid), treatment 2 (BAG paste, hyaluronic acid and carrageenan), and control group (BAG without polymer). All groups were immersed in artificial saliva, incubated at 37oC for six days and then tested by Scanning Electron Microscope (SEM) to see the formation of HCA and FTIR. HCA was quantified by a scoring method according to predetermined score criteria. SEM showed HCA formation in both treatment groups, not the control group. There is HCA formation on the tooth surface by administering BAG injection paste with seaweed carrageenan.

Hydroxycarbonate apatite formation and 5-fluorouracil delivery by strontium containing mesoporous bioactive glass nanoparticles

Sol-gel method was employed for the preparation of strontium-doped mesoporous bioactive glass nanoparticles (Sr-MBG NPs). These NPs have the size of 50 ± 5 nm, a pore size of 8.2 nm, and a surface area of 379 m2/g. Biocompatibility was confirmed by MTT and tissue histopathology in Balb/c mice. 5-Fluorouracil (5-Fu) was loaded to obtain Fu-Sr-MBG NPs which posed substantial inhibitory effects on the viability of the cancer cells (AGS). The amount of released drug was controlled by changing the pH of release medium. Formation of hydroxycarbonate apatite (HCA) was evaluated in simulated body fluid (SBF) and confirmed by XRD and FTIR. Thus a multipurpose nano-biomaterial was prepared and screened.

Features of biodegradation of sol-gel bioactive glass 60S doped with Ga, Ge

Samples of BG 60S (4% P2O5, 36% CaO, 60% SiO2) and doped with Ga2О3 (1%), GeО2 (1%) were synthesized by the sol-gel method. In the environment of model physiological fluid (Kokubo's SBF) in vitro biodegradation processes of synthesized BG samples were studied and in vivo studies of bone formation were performed. The methods of atomic absorption (for Ca2+, Mg2+) and photometric (for HPO4 2–) analysis were used to study the change in the ionic composition of the model physiological fluid, the pH changes of which were recorded potentiometrically. BG samples before and after in vitro bioresorption studies were tested by IR spectroscopy. The studied dependences of the activity of ion exchange processes and the rate of formation of hydroxy-carbonate apatite on the surface from doping additives confirm the bioactivity of the synthesized samples. The highest bioactivity according to the results of in vitro and in vivo studies shows BG 60S without alloying additives.

Luminescence Sensing Method for Degradation Analysis of Bioactive Glass Fibers.

The effects of Sm3+ content on the optical properties and bioactivity of 13-93 bioactive glass were presented. Sm3+ doped glass fibers drawn from bioactive glass were analyzed in simulated body fluid (SBF) for the determination of ion release. Optical analysis of the Sm3+ ions in bioactive glass fibers was used for degradation monitoring. While the fibers were immersed in SBF solution, changes in their luminescence spectra under 405 nm laser excitation were measured continuously for 48 h. The morphology of the fibers after the immersion process was determined by SEM/EDS. It was shown that the proposed approach to the analysis of changes in Sm3+ ion luminescence is a sensitive method for the monitoring of degradation processes and the formation of hydroxycarbonate-apatite (HCA) layers on glass fiber surfaces. SEM/EDS measurements showed a significant deterioration on the surface of the fibers and the formation of HCA on 13-93_02Sm bioactive glass. The optical analysis of the time constant indicated that bioactive glass fibers doped with 2 %mol Sm3+ degrade at a rate almost five times slower than 13-93_02Sm.

Magnesium doped mesoporous bioactive glass nanoparticles: A promising material for apatite formation and mitomycin c delivery to the MG-63 cancer cells

Dual functional, magnesium-doped mesoporous bioactive glass nanoparticles (Mg-MBG NPs) were prepared for bone regeneration and drug delivery. Template-assisted (F127) economical sol-gel method was used to prepare spherical Mg-MBG NPS of 65 ± 5 nm as determined by TEM. Different initial concentrations (0.1–0.5 mg/mL) of Mitomycin C (Mc) were used for loading to the Mg-MBG, and as a result, the variable amount of drug was loaded. Drug release was studied at different pH values (6.4, 7.4 & 8.4) of the release media which showed a maximum cumulative release of 89%, at a pH of 6.4. MTT assay indicated no significant cytotoxicity in normal human fibroblast (NHFB) cells and in vivo tissue histopathology revealed no damage to the cells. Mc loaded Mg-MBG NPs inhibited the MG-63 cancer cell viability at all concentrations and showed the IC50 value of 20.8 µg/mL. XRD and FTIR spectra confirmed the formation of hydroxycarbonate apatite (HCA) upon immersion in simulated body fluid (SBF). Thus biocompatible Mg-MBG with low cytotoxicity and sustained drug release was entitled as a safe biomaterial.

In vitro study of bioactive glass coatings obtained by atmospheric plasma spraying

This research has addressed a complete study of the bioactivity of bioactive glass coatings obtained by atmospheric plasma spraying. The coatings have been characterized in terms of microstructure, adhesion, crystalline phases and bioactivity. Hydroxycarbonate apatite formation was also monitored following a standard protocol and the in vitro cell response was evaluated by human osteoblast-like cells (MG-63 cells) incubation.The obtained coatings shown a microstructure typical of glass coatings. A simulated body fluid test proved that coatings are capable of developing a surface layer of hydroxycarbonate apatite whereas the appearance of this phase takes place at a longer time than that observed for the powder feedstock. Cell-culture test showed multidirectional growth of MG-63 cells which promoted good contact between cells and the surface of the coating. This study has confirmed a positive effect of the coatings in terms of surface bioactivity and, more interestingly, it has proven an adequate cell-material interaction on the coating surface.

Bone ‘spackling’ paste: Mechanical properties and in vitro response of a porous ceramic composite bone tissue scaffold

Bone defects are treated with bone grafts, replacing damaged or diseased bone tissue with either natural bone or bone substitutes. This study investigates the structure, mechanical properties, and in vitro response of an all-ceramic composite designed for use as a bone ‘spackling’ paste: a formable synthetic bone graft paste used to repair bone defects in place, reacting with CO2 gas in ambient conditions to become a void-filling, rigid scaffold. The composite is comprised of bioactive glass frit and a soluble liquid silicate precursor combined to form an air-setting, open porous scaffold with compressive strength within the low range for trabecular bone (1.3-4.4 MPa). Characterization of scaffolds, with varying amounts of binder, was executed in accordance with established design criteria of porosity, load-bearing capacity, and bioactivity. Bioactivity was assessed via morphological, structural, and chemical changes in surface mineralization that occurred during in vitro immersion in simulated body fluid. All phases of composite specimens were observed to form calcium phosphate minerals, indicating that a chemical change occurred between the bioactive glass and sodium silicate binder phase. Ion exchange between the two phases was likely, as sodium silicate (control) was not found to produce calcium phosphate in the absence of bioactive glass. Of the selected compositions, composites with 7.4 vol% sodium silicate binder were observed to possess the highest open porosity (44 vol%), highest rate of calcium phosphate mineralization, most uniform surface mineral distribution, and largest amount of hydroxycarbonate apatite formation. The structure, mechanical properties, and in vitro response of the composite scaffolds analyzed in this research signify their potential success as bone tissue scaffolds.

Multifunctional zinc ion doped sol – gel derived mesoporous bioactive glass nanoparticles for biomedical applications

Mesoporous bioactive glasses have been widely investigated for applications in bone tissue regeneration and, more recently, in soft tissue repair and wound healing. In this study we produced mesoporous bioactive glass nanoparticles (MBGNs) based on the SiO2–CaO system. With the intention of adding subsidiary biological function, MBGNs were doped with Zn2+ ions. Zn-MBGNs with 8 mol% ZnO content were synthesized via microemulsion assisted sol-gel method. The synthesized particles were homogeneous in shape and size. They exhibited spherical shape, good dispersity, and a size of 130 ± 10 nm. The addition of zinc precursors did not affect the morphology of particles, while their specific surface area increased in comparison to MBGNs. The presence of Zn2+ ions inhibited the formation of hydroxycarbonate apatite (HCAp) on the particles after immersion in simulated body fluid (SBF). No formation of HCAp crystals on the surface of Zn-MBGNs could be observed after 14 days of immersion. Interestingly, powders containing relatively high amount of zinc released Zn2+ ions in low concentration (0.6–1.2 mg L−1) but in a sustained manner. This releasing feature enables Zn-MBGNs to avoid potentially toxic levels of Zn2+ ions, indeed Zn-MBGNs were seen to improve the differentiation of osteoblast-like cells (MG-63). Additionally, Zn-MBGNs showed higher ability to adsorb proteins in comparison to MBGNs, which could indicate a favourable later attachment of cells. Due to their advantageous morphological and physiochemical properties, Zn-MBGNs show great potential as bioactive fillers or drug delivery systems in a variety of applications including bone regeneration and wound healing.

Easy manufacturing of 3D ceramic scaffolds by the foam replica technique combined with sol-gel or ceramic slurry

A material, whose composition was based on the SiO 2 –CaO–P 2 O 5 system, was used to prepare 3D porous ceramic scaffolds made by the foam replication technique linking the sol-gel route or ceramic slurry in barbotine suspension processes. With an appropriate heat treatment, it was possible to obtain a 3D-scaffold containing two crystalline phases or more, and a controlled nano-to microscale microstructure. The obtained scaffolds presented an interconnected and well-defined porous structure. Its pore size was 0.060–600 μm. It had a rough pore wall that could potentially benefit ingrowth and cell adhesion. In terms of hydroxycarbonate apatite formation in simulated body fluid (SBF), the 3D scaffolds’ bioactivity was confirmed after 3 and 14 days of immersion in SBF. This clearly confirms that these new scaffolds are suitable for bone regeneration applications. Processing technology allows 3D scaffolds to be adapted with particular microstructures to increase/decrease their in vitro behavior.

Electro-crystallization of hydroxyapatite coatings on Nitinol rotating disk electrode

In this study, the rotating disk electrode technique was used to produce hydroxyapatite coatings on NiTi shape-memory alloy. The morphology and composition of the coatings were characterized using SEM, EDS, XRD. Also, the effect of the rotation speed on the corrosion resistance of the coatings was investigated using Electrochemical Impedance Spectroscopy (EIS). Based on the results, the coatings produced at the rotation rates below 2000 rpm was porous and revealed a reticular morphology. However, pore sizes were decreased by increasing the rotational speed and relatively dense and uniform coatings were produced on the substrate at rotation rates of 2500 and 3000 rpm. The results revealed that the Ca/P ratio of the coatings is increased by increasing the rotation rate. According to XRD and EDS data, the coating obtained at the rotation rate of 2500 rpm was composed of pure hydroxyapatite (HAp) phase. Although, the thickness of the coatings was decreased by increasing the rotation rate, the higher rotation rate than 2500 rpm resulted in carbonated HAp formation. According to EIS data, the corrosion resistance of the coatings is depend on the rotation rate and the coating electrodeposited at the highest rotation rate revealed the best corrosion resistance. Probably, increasing the rotation rate result in enough ions supplementation at the cathode surface and more dense and uniform coatings are produced which prevents from substrates corrosion in the human body environment.

Electrospun Filaments Embedding Bioactive Glass Particles with Ion Release and Enhanced Mineralization.

Efforts in tissue engineering aim at creating scaffolds that mimic the physiological environment with its structural, topographical and mechanical properties for restoring the function of damaged tissue. In this study we introduce composite fibres made by a biodegradable poly(lactic acid) (PLLA) matrix embedding bioactive silica-based glass particles (SBA2). Electrospinning is performed to achieve porous PLLA filaments with uniform dispersion of bioactive glass powder. The obtained composite fibres show in aligned arrays significantly increased elastic modulus compared with that of neat polymer fibres during uniaxial tensile stress. Additionally, the SBA2 bioactivity is preserved upon encapsulation as highlighted by the promoted deposition of hydroxycarbonate apatite (HCA) upon immersion in simulated body fluid solutions. HCA formation is sequential to earlier processes of polymer erosion and ion release leading to acidification of the surrounding solution environment. These findings suggest PLLA-SBA2 fibres as a composite, multifunctional system which might be appealing for both bone and soft tissue engineering applications.

Contrasting In Vitro Apatite Growth from Bioactive Glass Surfaces with that of Spontaneous Precipitation.

Body-fluid-exposed bioactive glasses (BGs) integrate with living tissues due to the formation of a biomimetic surface layer of calcium hydroxy-carbonate apatite (HCA) with a close composition to bone mineral. Vast efforts have been spent to understand the mechanisms underlying in vitro apatite mineralization, as either formed by direct precipitation from supersaturated solutions, or from BG substrates in a simulated body fluid (SBF). Formally, these two scenarios are distinct and have hitherto been discussed as such. Herein, we contrast them and identify several shared features. We monitored the formation of amorphous calcium phosphate (ACP) and its crystallization into HCA from a NaO–CaO–SiO–PO glass exposed to SBF for variable periods out to 28 days. The HCA growth was assessed semi-quantitatively by Fourier transform infrared spectroscopy and powder X-ray diffraction, with the evolution of the relative apatite content for increasing SBF-exposure periods evaluated against trends in Ca and P concentrations in the accompanying solutions. This revealed a sigmoidal apatite growth behavior, well-known to apply to spontaneously precipitated apatite. The results are discussed in relation to the prevailing mechanism proposed for in vitro HCA formation from silicate-based BGs, where we highlight largely simultaneous growth processes of ACP and HCA.

New sintered wollastonite glass-ceramic for biomedical applications

We developed a new bioactive glass-ceramic (GC) based on the CaO-SiO2-MgO-Na2O-Li2O system. Four glass compositions were formulated by a proprietary software (Reformix) and tested by changing mainly the calcium content (from 20 mol% to 40 mol%) and the minor components - alumina, zirconia and zinc oxide. We produced our GCs using the sinter-crystallization process at different temperatures (800–1000 °C) and evaluated the effects of compositional changes on the sintering kinetics, microstructure (residual porosity and crystalline phases), hardness, bending strength and bioactivity. We then followed the hydroxycarbonate apatite (HCA) formation in simulated body fluid by Fourier-transform infrared spectroscopy (FTIR), which revealed the onset of HCA formation after approximately 3 days. These GCs are phosphorus and fluorine free, elements that are present in most bioactive glasses, glass-ceramics and ceramics. Our most bioactive GC has a residual porosity of 9 ± 1%, hardness of 5.5 ± 0.3 GPa, 4p-bending strength of 98 ± 7 MPa and is non-cytotoxic. This combination of good bioactivity and mechanical properties (despite its high porosity) suggests that this new GC could be tested for bone graft implants.

Bioactive glass/hydroxyapatite- containing electrospun poly (ε-Caprolactone) composite nanofibers for bone tissue engineering

In this study, bioactive glass and hydroxyapatite (HA)-containing poly(e-caprolactone) (PCL) nanocomposite fiber mats were fabricated through electrospinning. For this purpose, microscale bioactive glass (silicate-based 45S5 and borate-based 13-93B3 compositions) or HA particles (at 10 wt%) were incorporated into the PCL matrix. The fabricated biocomposite fibers were investigated in terms of morphological and chemical properties. An in vitro mineralization assay in simulated body fluid was performed to understand the capability of the composite electrospun fibers to induce the formation of hydroxycarbonate apatite. Results showed that the diameter of the electrospun PCL-based fibrous scaffolds increased by the inclusion of bioactive glass or HA particles. All of the fibrous mats prepared in the study showed hydrophobic character. Relatively high contact angles (> 90°) obtained for fibrous scaffolds was attributed to the high porosity and surface roughness. Bioactive glass or HA addition to the PCL matrix enhanced the bioactivity of the fibrous scaffolds. The deposition rate of calcium phosphate-based material precipitates was higher on the surface of HA-containing samples compared to bioactive glass-containing PCL scaffolds. Additionally, mineralization ability of borate-based 13-93B3 glass-containing samples was higher compared to 45S5 glass-containing PCL fibers. The biocomposite fibrous scaffolds prepared in the study may find applications in wound healing as wound dressing and in bone tissue engineering.

Tensile Properties, Biodegradability and Bioactivity of Thermoplastic Starch (TPS)/ Bioglass Composites for Bone Tissue Engineering

Composite fabricated from the combination of biodegradable polymer and bioactive filler is beneficial for bone tissue engineering if the biomaterial can perform similar characteristics of the natural inorganic-organic structures of bone. In this study, we have investigated the thermoplastic starch (TPS)/sol-gel derived bioglass composite as new biomaterial for bone tissue engineering. The composites were produced using selected TPS/bioglass mass ratio of 100/0, 95/5, 90/10, 85/15 and 80/20 by a combination of solvent casting and salt leaching techniques. Tensile test results showed the addition of bioglass increased the tensile strength and Young’s modulus, but reduced the elongation at break of the samples. The modulus of all samples were higher than the requirement for cancellous bone (10-20 MPa). The SEM imaging showed the presence of porous structure on the surface of all samples. XRD results confirmed the formation of hydroxycarbonate apatite (HCA) layer on the surface of bioglass containing samples; indicating the occurrence of surface reactions when the samples were immersed in Simulated Body Fluid (SBF). Furthermore, the presence of P-O stretch band in FTIR spectrum between 1000 and 1150 cm-1 and Si-O-Si stretch band at 1000 cm-1 also proved the bioactivity of TPS/bioglass composite. The in vitro biodegradability analysis shows the biodegradability of TPS/bioglass composite decreases with increasing mass ratio of the bioglass.

Preparation and in vitro investigation on bioactivity of magnesia-contained bioactive glasses

Mg plays an important role in the human skeletal system as it stimulates the bone formation and reduces bone resorption. Magnesium has been substituted into SiO2–Na2O–CaO–P2O5 bioactive glass. In the present work, the bioactive glasses were designed to enhance bioactivity. Bioactivity of these glasses was assessed by the immersion of the samples in simulated body fluid (SBF) for different time periods. The formation of hydroxy carbonate apatite (HCA) layer was confirmed by scanning electron microscopy, X-ray diffractometry, and FTIR spectrometry which had shown the HCA layer formation and growth. The formation of HCA layer was found to increase on the surface of the SBF immersed bioactive glasses with increasing magnesia contents in the glass. In vitro cell culture investigations such as viability, proliferation, and cell attachment were studied using human osteosarcoma U2-OS cell lines. The in vitro results of new magnesium containing bioactive glasses had shown improved bioactivity as well as better biocompatibility.

Preparation and characterization of bioactive glass tablets and evaluation of bioactivity and cytotoxicity in vitro

In this study, the SiO2CaOP2O5 ternary component of bioactive glass particles were successfully synthesized by sol-gel method, then the bioactive glass particles were pressed into tablets with dry pressing molding technology. The physicochemical structure, in-vitro bioactivity and biocompatibility of BG tablets were characterized by various methods, such as XRD、SEM、FTIR, etc. The results showed that the sol-gel bioactive glass particle was distinguished with its amorphous structure and micron-size. After being soaked in Tris-Hcl solution for 15 d, the bioactive glass tablets didn't collapse. Also, the mineralization assay in vitro showed that the bioactive glass tablets had good capability of inducing the formation of hydroxycarbonate apatite (HCA) after being immersed in simulated body fluid (SBF). In addition, the cytotoxicity assay indicated that the osteoblast (MC3T3) grew well on the surface of bioactive glass tablets. According to the above results, the bioactive glass tablets presented good mechanical strength, excellent apatite-forming activity and high biocompatibility, which demonstrated their potential applications in the field of bone defect repairing.

Synthesis and in vitro studies of sol-gel derived lithium substituted 58S bioactive glass

Abstract A lithium substituted 58S bioactive glass (BG) containing from 0 to 10 mol% Li 2 O was synthesized through the sol-gel technique and the effect of Lithium substitutions on in vitro hydroxycarbonate apatite formation, osteoblast-like cell responses and antibacterial efficiency was studied. Structural and morphological evaluation using X-ray diffraction analysis, Fourier transform infrared spectroscopy, scanning electron microscopy revealed that 58S BG with 5 mol% Li 2 O (BG-5) had no significant effect on the formation rate of crystalline hydroxycarbonate apatite however 58S BG with 10 mol% Li 2 O lowered the bioactivity of the BG. The lower bioactivity of BG-10 was associated with a lower rate of Si and Ca ion release into the simulated body fluid. The 3-(4,5dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and alkaline phosphatase (ALP) assessment methods revealed that the presence of Li had a stimulating influence on increasing of both proliferation and differentiation of MC3T3-E1 cells. A qualitative assessment of cell viability with Live/Dead technique and visualization of the morphology of actin fibers and nuclei of MC3T3 cells treated with Li-BGs with DAPI/Actin staining techniques showed that addition of Li resulted in an increase in the mean number of DAPI-labeled nuclei which was in reasonable agreement with MTT test. The Li substituted BGs exhibited a potential antibacterial effect against methicillin-resistant Staphylococcus aureus bacteria (MRSA). Results suggest that sample BG-5 is a good candidate for bone tissue engineering with optimal cell proliferation and ALP activity, good bioactivity and significant high antibacterial potential against MRSA.