Carbonated Hydroxyapatite Research Articles

Clinical and Technological Evaluation of the Remineralising Effect of Biomimetic Hydroxyapatite in a Population Aged 6 to 18 Years: A Randomized Clinical Trial

The aim of this randomized clinical trial was to evaluate the efficacy of two different remineralising toothpastes in preventing dental caries and promoting oral health. Patients aged 6–18 years old with healthy and fully erupted first permanent molars (C1 and C2 DIAGNOdent scores) were enrolled and randomized into two groups according to the home-hydroxyapatite-based remineralising treatment used: the Trial group used zinc carbonate hydroxyapatite-based treatment (Biorepair Total Protective Repair), while the Control group used magnesium strontium carbonate hydroxyapatite conjugated with chitosan toothpaste (Curasept Biosmalto Caries Abrasion & Erosion). Dental and periodontal parameters were measured over a six-month period, including the DIAGNOdent Pen Index (primary outcome), BEWE Index, Plaque Index, Bleeding Score, Schiff Air Index, and ICDAS assessed with DIAGNOcam. A total of 40 patients were equally allocated in the two groups and finally analyzed. A significant reduction in the DIAGNOdent Pen score was reported in the Trial group after 1 month of treatment, while in the Control group, no significant change was found. The Trial group also showed a significant reduction in plaque levels after 3 months of treatment, while in the Control group, it occurred after 1 month. However, the Bleeding Score and Schiff Air Index showed no significant differences between the groups, suggesting that additional measures may be required to address gingival inflammation and hypersensitivity. The ICDAS index also showed no statistically significant changes, due to the limited duration of this study. Overall, zinc-hydroxyapatite-based toothpaste was more effective than magnesium strontium carbonate hydroxyapatite toothpaste in enhancing enamel remineralisation in the short-term period. The assigned treatments did not result in significant improvements in the oral indexes assessed in this study.

Microstructure and Bioactivity of Ca- and Mg-Modified Silicon Oxycarbide-Based Amorphous Ceramics.

Silicon oxycarbide (SiOC), Ca- and Mg-modified silicon oxycarbide (SiCaOC and SiMgOC) were synthesized via sol-gel processing with subsequent pyrolysis in an inert gas atmosphere. The physicochemical structures of the materials were characterized by XRD, SEM, FTIR, and 29Si MAS NMR. Biocompatibility and in vitro bioactivity were detected by MTT, cell adhesion assay, and simulated body fluid (SBF) immersion test. Mg and Ca were successfully doped into the network structure of SiOC, and the non-bridging oxygens (NBO) were formed. The hydroxycarbonate apatite (HCA) was formed on the modified SiOC surface after soaking in simulated body fluid (SBF) for 14 days, and the HCA generation rate of SiCaOC was higher than that of SiMgOC. Accompanying the increase of bioactivity, the network connectivity (NC) of the modified SiOC decreased from 6.05 of SiOC to 5.80 of SiCaOC and 5.60 of SiMgOC. However, structural characterization and biological experiments revealed the nonlinear relationship between the biological activity and NC of the modified SiOC materials.

Characteristics of Chitosan Gelatine Limestone-Based Carbonate Hydroxyapatite Composite Scaffold After Crosslinking

Bone damage is one of the most common cases in dentistry. Tissue engineering is advancing in biotechnology to aid bone regeneration using scaffolds. Scaffolds need to be biocompatible, bioactive, and bioresorbable. Purpose: Analyzing the characteristics of scaffold C-G:CHA after crosslinking with 0.25% glutaraldehyde. Methods: The scaffold is synthesized from C–G:CHA in ratios of 40:60, 30:70, and 20:80 (w/w) using a freeze-drying technique and crosslinked with 0.25% glutaraldehyde. Compressive strengths are tested with a Universal Testing Machine Mini Autograph. FTIR, XRD, and SEM EDX were used to identify the most optimal base of each ratio. Data are analyzed with a one-way ANOVA parametric test. Results: The FTIR test showed that adding 0.25% glutaraldehyde formed a new chemical group. The XRD test indicated the use of 0.25% glutaraldehyde as a crosslinking agent contributed to the scaffold having an amorphous form. The SEM test results of the porosity of the C-G:CHA were 88.41% to 91.14%. After crosslinking the porosities slightly decreased. The EDX analysis showed that the Ca/P ratio in the C-G:CHA scaffold is 1.79 to 2.07. The average compressive strength of the C-G:CHA scaffold increases after being crosslinked with glutaraldehyde. Conclusion: Scaffold C-G:CHA crosslinked with 0.25% glutaraldehyde effective to increase compressive strength. The 30:70 ratio is ideal because it has a Ca/P ratio and average pore size closest to bone.

ESR measurement of carbonated hydroxyapatite for dosemeter.

We have examined a dosimetry characteristic of carbonate hydroxyapatite (CO3HAp), which is a dental bone graft material. The purpose of this work is to investigate the reproducibility and stability of radiation-induced radicals on CO3HAp samples and assess the feasibility of using these materials as dosemeters. CO3HAp samples were exposed to gamma rays with dose range from 10 to 10000Gy. The electron spin resonance (ESR) spectra for irradiated samples were measured. Variation of peak-to-peak amplitude of the ESR signal intensity as a function of absorbed dose for CO3HAp was compared with that for alanine dosemeters, suggesting that the CO3HAp sample has a good linear dose response in the range from 10to 10000Gy as well as does the alanine dosemeters.

Influence of Additives on Crystallization of Calcium Phosphates from Prototypes of Blood Plasma

The paper presents the results of studies on the effect of additives on crystallization in solutions simulating the composition of human blood plasma. Synthesis from prototypes of human blood plasma in the presence of organic and inorganic additives was carried out, and it was found that the obtained solid phases consisted of octacalcium phosphate, B-type carbonate hydroxyapatite, and vitlocite. The effect of additives (magnesium ions, alanine, and glycine) on the crystallization of calcium phosphates was studied. It was found that the presence of additives in the model solution reduces the crystallite size and the fraction of carbonate hydroxyapatite in the solid phase. The bioactivity of synthetic samples was studied, and kinetic characteristics were established. A study of thermal transformations.

Comprehensive investigation into thermal stability of AB-type bio- carbonate hydroxyapatite synthesized via heat-treated bovine bone

This study investigates the thermal stability and structural changes of AB-type carbonate-hydroxyapatite (AB-type CHA) prepared from heat-treated bovine bone occurring during calcination at 1000, 1100, 1200, and 1300 °C. The structural phase changes and morphological properties of the calcined AB-type CHA samples were assessed by SEM/EDX, XRD, FTIR, and Raman spectroscopy. The findings highlighted that the decomposition of AB-type CHA undergoes three stages: Dehydroxylation, formation of A-type carbonate-hydroxyapatite (A-type CHA), and decomposition. Pure AB-type CHA was stable in a vacuum atmosphere, and no decomposition occurred at temperatures up to 1000 °C. Dehydroxylation and formation of A-type CHA occurred at 1100 °C. The AB-type CHA partially decomposed at a temperature of 1200 °C. A-type CHA, tricalcium phosphate (α-TCP), and tetracalcium phosphate (TTCP) were the main products of the decomposition reactions, and tricalcium phosphate (β-TCP) was also detected in the system. After sintering at 1300 °C, the AB-type CHA was completely decomposed and converted into α-TCP, β-TCP, and TTCP.

Burnt Cervidae bones and sedimentary environments at Luotuodun, Jiangsu Province, China: New insights for Neolithic human behavior

The Luotuodun archaeological site is located in Yixing City, Jiangsu Province, in the transition zone from the Yili Mountains to the coastal plain. It is of Neolithic Age and dates from approximately 7000 to 5000 years ago. A large number of animal skeleton fossils have been unearthed at the site, many of which, especially those belonging to species of Cervidae (possibly Sika, Cervis nippon), are characterized by the presence of black residue on the surface. There are three types of residue, one is black film-like coating, which is suggestive of exposure to fire, one is also black, but crystalline in nature, while the other is grey-white, particulate deposit. With the aim of exploring the nature of these residues and their possible origins, we applied a number of analytical techniques, including Raman Spectroscopy (RS), Fourier Transform Infrared Spectroscopy (FTIR), Energy dispersive spectroscopy (EDS) and Electron Microscopy (EM) on six bone fossils belonging to different parts of Cervidae skeleton unearthed from Luotuodun to evaluate the possible influence of fire and/or depositional processes in their formation. The black film-like coating, widespread on the surface of these bones, is highly reflective and appears white under the Raman microscope. The RS peak indicates that the film-like substance is rich in carbonaceous (graphitic carbon) components, suggesting that the bones have been exposed to combustion. FTIR measurements on these bones show that the structure of hydroxyapatite carbonate (Ca10(PO4)6−x(CO3)x(OH)2) has changed, consistent with their exposure to very high temperatures (500–600 °C), and implying that they were burnt, either for cooking or ritual behavior by ancient humans. In the case of the crystallized black particles, these are primarily confined to localities on the surface of bone fractures. EDS results, as confirmed by the RS analysis, show that the black crystals are comprised of an iron-rich, phosphatic mineral, compatible with vivianite (Fe3(PO4)2·(H2O)8). The substantial vivianite content is consistent with the fossil bones being submerged and deposited in waterlogged soils. The results of EDS show that the composition of the grey-white particle is hydroxyapatite carbonate (Ca10(PO4)6−x(CO3)x(OH)2). Non-destructive geochemical analysis of the surface residues of these Luotuodan bones provides valuable evidence for reconstructing the taphonomy of the Cervidae bones, and reveals that they were utilized by ancient humans during the Luotuodun culture period in SE China.

Mathematical modeling of bioactive glass degradation

Bioactive glasses (BGs) are promising for bone tissue engineering (BTE). Mathematical modeling is a powerful tool for understanding BTE scaffold degradation. We developed mathematical functions based on chemical reaction equations governing dissolution and diffusion processes to model the degradation of 45S5 BGs. An empirical mathematical model was employed to characterize the formation process of hydroxycarbonate apatite (HCA). Two sets of numerical simulations with BG powder and bulk samples immersed in simulated body fluid were compared with in vitro experiments to validate and parameterize the model. The model could accurately predict BG degradation and HCA formation. Our findings indicate that the proposed parameters K1=2600 mm/(μmol·h), K2=2.0 mm/h and K3=0.001 mm/h are suitable for simulating the degradation of silicate-based BGs, specifically 45S5 BG. The proposed model successfully predicted the degradation behavior and subsequent HCA formation over 21 days. The proposed mathematical model serves as a valuable tool for designing degradable BG-containing scaffolds.

Physico-mechanical properties, hydroxyapatite conversion, biodegradability and antibacterial activity studies of melt-derived BGs based on SiO2-CaO-Na2O-P2O5 quaternary system

The slow biodegradation and low hydroxyapatite (HA) conversion of silicate-based bioactive glasses (BGs) have severely limited their compatibility with biological tissues. To address these challenges, four samples in the form of (52-x)SiO2-24Na2O-24CaO-xP2O5, where x is 2, 4, 6, and 8 mol%, were prepared by a unified melt-quenching method, and the feasibility of P2O5 content fine-tuning in improving glass structure, biodegradability, bioactivity, and antibacterial efficiency was evaluated. The results indicated that as the degree of P2O5 substitution increased, the network structure of the glass became looser, which provided favourable conditions for its degradation. The variation in activation energy for Si4+ ion release from 0.39 eV to 0.25 eV also supported this observation. After 7 days of immersion in simulated body fluid (SBF), analyses by energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) confirmed that the Ca-P compounds deposited on the glass surfaces were essentially hydroxycarbonated apatite (HCA), and scanning electron microscopy (SEM) images revealed that the generation rate of the HCA were positively correlated with the P2O5 content in the glass system. Meanwhile, antibacterial studies showed that after 24 h of incubation, the antibacterial activity of the four glass samples against Escherichia coli (E. coli) successively increased, with the highest percentage reaching 87.13 ± 2.51 %. In conclusion, this study demonstrates that controllable degradation and high-level bioactivity can be achieved by modulating the P2O5 content in silicate-based BGs, which proves to be an effective and practicable strategy.

Structural connectivity and bioactivity in sol–gel silicate glass design

Bioactive glasses (BGs) bond with bone by forming hydroxy carbonate apatite (HCA) upon reaction in physiological fluid, a phenomenon known as bioactivity. BGs structural network connectivity determines their bioactivity. Sol–gel BGs are synthesized through the hydrolysis and condensation of metal alkoxide precursors in the presence of a catalyst, in aqueous environments. Several sol–gel synthesis parameters directly impact BG network connectivity: pH (i.e. acid or basic catalysis), water to alkoxide ratio (Rw), alkoxide type and presence of dopant ions. However, the relationship between bioactivity and these parameters remains surprisingly unexplored.This study highlights the relationship between synthesis pH, Rw, network connectivity and bioactivity in silica-based sol-gel BGs and BGs doped with titanium (Ti) ions (TiBGs), the latter selected for their known ability to enhance network connectivity. BGs and TiBGs are synthesized with various Rw values under acidic and basic conditions, and their bioactivity is assessed in simulated body fluid for 7 days.Increasing Rw decreases network connectivity and increases bioactivity of BGs with high network connectivity, as observed for base-catalyzed BGs and for both acid and base catalyzed TiBGs, but not in BGs with lower connectivity as evidenced in acid-catalyzed BGs. Basic catalysis of TiBGs prevents crystalline TiO2 domain formation, which was instead consistently observed in TiBGs synthesized under acidic catalysis.These findings help the design of BGs for applications where ion release needs to be enhanced even in the presence of dopants that slow down HCA formation, and of BGs with specific properties, e.g. TiO2-containing BGs with potential bactericidal activity. Statement of significanceBioactive glasses (BGs) bond with bone by dissolving and forming hydroxycarbonate apatite (HCA) on their surface, offering applications in medicine and dentistry. BG's network connectivity influences its dissolution rate, and hence HCA formation. While solution-gelation (sol-gel) is commonly used for BG production, the effect of sol gel synthesis parameters on HCA formation remains unexplored. We studied the relationship between synthesis parameters (water-to-alkoxide ratio (Rw), catalyst, and dopant ions, particularly titanium), BG network connectivity, and HCA formation. We find that increasing Rw with any catalyst enhances HCA formation, particularly in glasses with high network connectivity. This understanding allows tailoring BG synthesis for different applications, e.g. those requiring doping with ions that increase network connectivity and fills a crucial gap in BG literature.

Microwave-assisted hydrothermal synthesis of carbonated apatite with calcium and phosphate resources derived from green mussel shell and bovine bone wastes

Resources recovery of calcium and phosphates from respective green mussel shells and bovine bones by calcination and chemically extracting are viable precursors for carbonate-rich apatite biomedical material applications. Because of their high osteoconductivity, carbonate-rich apatite bioceramics are being studied intensively for synthetic bone transplants. In the study, powder processing routes of calcination and following chemical dissolution in MgCl2 and H2SO4 were each for recovering calcium of mussel shells and phosphate of bovine bones yielding a crystal-forming solution feedstock for use in microwave-irradiated synthesis. FTIR spectra and XRD patterns validated the crystallinity and phase identification for as-synthesized powders. As a result, the presence of CO3, PO43-, and OH- bands in carbonate-calcium phosphate complexes were present in FTIR spectra. According to the XRD Rietveld method, the as-synthesized powder product contained brushite, carbonated hydroxyapatite (CHA), calcite, and gypsum. The recoverable CHA crystallites' size was 40 nm. This present study demonstrated that microwave irradiation synthesis of CHA powder with calcium and phosphates derived from mussel shells and bovine bones is the potential to yield a large amount of CHA for bioceramics and would aid in the design of a powder processing step for preparing the CHA powder precursor in biomedical applications.

Infrared spectral library of tooth enamel from African ungulates for accurate electron spin resonance dating

Electron spin resonance coupled with uranium-series dating (ESR/U-series) of carbonate hydroxyapatite in tooth enamel is the main technique used to obtain age determinations from Pleistocene fossils beyond the range of radiocarbon dating. This chronological information allows to better understand diachronic change in the palaeontological record, especially with regard to the evolution of the genus Homo. Given the relative paucity of human teeth at palaeontological and archaeological localities, ESR/U-series is widely applied to the teeth of ungulate species. However, the accuracy of ESR/U-series ages is greatly affected by the incorporation of uranium in the enamel during burial in sediments. It has been shown that uranium content is positively correlated with an increased degree of atomic order in carbonate hydroxyapatite crystals, the latter determined using infrared spectroscopy. Here we present a reference infrared spectral library of tooth enamel from African ungulates, based on the grinding curve method, which serves as baseline to track the diagenetic history of carbonate hydroxyapatite in different species and thus select the best-preserved specimens for dating.

Effect of Cu incorporation in silicate and modified borate bioglass materials for health applications: insights from synchrotron-based x-ray absorption spectroscopy

This contribution investigates the effect of variable copper incorporation (x = 0.2, 1.0, 2.0, and 4.0) in silicate (45 SiO2, 24.5 CaO, 24.5 Na2O, 6P2O5wt%) and modified borate (45 B2O3, 24.5 CaO, 24.5 Na2O, 6P2O5wt%) bioglass materials to be used for bone bonding applications. X-ray absorption fine structure spectroscopy (XAFS) has been used to determine the oxidation states and local coordination structure of Cu atoms in silicate-based and borate-based glasses at the Cu K-edge (~ 8979 eV). The oxidation states of Cu atoms have been determined by near-edge XAFS (XANES) fingerprinting employing reference standard compounds of Cu. Cu (I) and Cu (II) XANES spectra of the standard reference compounds were linearly combined to fit the normalized μ(E) data of the collected XANES spectra using linear combination fitting (LCF approach). The obtained results prove that most of the silicate glass samples contain Cu2O almost exclusively, while modified borate glass samples contain a significant mixture of Cu2O and CuO phases. According to the literature, the remarkable coexistence of Cu2O and CuO phases within the borate sample, particularly when x = 4, promotes the conversion process to allow the more facile formation of hydroxy carbonate apatite (HCA). The best fit structural parameters derived from extended-XAFS (EXAFS) fitting show that the ratio between Cu (I) and Cu (II) in borate glass agreed well with that extracted from XANES analysis. XANES and EXAFS conclude that borate glass with x = 4 is the most suitable composition for bone bonding applications.

3D printed β-tricalcium phosphate versus synthetic bone mineral scaffolds: A comparative in vitro study of biocompatibility.

β-tricalcium phosphate (β-TCP) has been successfully utilized as a 3D printed ceramic scaffold in the repair of non-healing bone defects; however, it requires the addition of growth factors to augment its regenerative capacity. Synthetic bone mineral (SBM) is a novel and extrudable carbonate hydroxyapatite with ionic substitutions known to facilitate bone healing. However, its efficacy as a 3D printed scaffold for hard tissue defect repair has not been explored. To evaluate the biocompatibility and cell viability of human osteoprecursor (hOP) cells seeded on 3D printed SBM scaffolds via in vitro analysis. SBM and β-TCP scaffolds were fabricated via 3D printing and sintered at various temperatures. Scaffolds were then subject to qualitative cytotoxicity testing and cell proliferation experiments utilizing (hOP) cells. SBM scaffolds sintered at lower temperatures (600 °C and 700 °C) induced greater levels of acute cellular stress. At higher sintering temperatures (1100 °C), SBM scaffolds showed inferior cellular viability relative to β-TCP scaffolds sintered to the same temperature (1100 °C). However, qualitative analysis suggested that β-TCP presented no evidence of morphological change, while SBM 1100 °C showed few instances of acute cellular stress. Results demonstrate SBM may be a promising alternative to β-TCP for potential applications in bone tissue engineering.

Multiscale investigation on the formation path of the apatite phase in bioactive glasses

Mesoporous bioactive glasses (MBGs) have been reported as promising biomaterials to stimulate and promote the growth of bones. When exposed to Simulated Body Fluid (SBF), MBGs develop an apatite phase called carbonate hydroxyapatite (H(C)A) on their surfaces that closely mimics the mineral phase of bones. In order to gain deeper insights into the key stages of the surface reactions of two different types of MBGs (58S and 70S30C) soaked in SBF, we have used high energy total X-ray scattering coupled to Pair Distribution Function (PDF) analysis, along with Raman spectroscopy and scanning electron microscopy. This type of coupled analytical approach can ultimately help to unravel the details of the reaction kinetics in the complex calcium phosphate environment around the BGs surfaces. The data obtained in our in-vitro study point to the formation of other intermediate phases like amorphous calcium phosphate (ACP) and calcite (CC), that transform after a specific time into H(C)A depending on the composition of the MBGs, their surface properties and their interaction times with SBF.

Antimicrobial Efficacy of Carbonated Hydroxyapatite Against Streptococcus mutans, Enterococcus faecalis, and Candida albicans: An In Vitro Study

Background: Dental caries commonly lead to pulp infection, necessitating vital pulp therapy (VPT) to protect the health of the pulp tissue. Effective pulp-capping materials, including those with antimicrobial properties, are crucial for successful VPT. This study aimed to evaluate the antimicrobial efficacy of carbonated hydroxyapatite (CHA), a novel pulp-capping material, compared to frequently used materials, against Streptococcus mutans, Enterococcus faecalis, and Candida albicans. Methods: CHA was synthesized at three concentrations (0.05 M, 0.1 M, and 0.5 M) and compared with mineral trioxide aggregate (MTA). Antimicrobial efficacy was evaluated using the agar diffusion method. Zones of inhibition were evaluated after 24 hours of incubation. A one-way analysis of variance (ANOVA) and post hoc tests were used for the statistical analysis. Results: All materials exhibited antimicrobial activity against the tested microorganisms, with CHA at 0.1 M concentration demonstrating the highest efficacy against E. faecalis and C. albicans. MTA and CHA at 0.5 M concentrations showed strong activity against S. mutans. According to statistical analysis, significant differences were found in antibacterial activity among the tested materials (P<0.0001). Conclusion: CHA, particularly at 0.1 M concentration, demonstrated significant antimicrobial efficacy against S. mutans, E. faecalis, and C. albicans, suggesting its potential as a pulp-capping agent. Further research is warranted to explore its clinical applicability in VPT.

Carbonate Hydroxyapatite - A Multifunctional Bioceramics with Non-Medical Applications

Carbonate hydroxyapatite is the common derivative of hydroxyapatite found in living systems. It is the building block of most hard tissues, including the teeth and bones. A vast majority of the applications of this versatile material focus on its biomedical applications, which is attributable to its closeness to biological apatites. Hydroxyapatite is a strong precursor to carbonate apatite in nature, and many experiments show that both are similar in a few respects. A significant divergence point is carbonate's obvious impact on its physicochemical properties and concomitant applications. The inclusion of carbonate ions into the lattice of hydroxyapatite results in morphological and physicochemical changes that vary with the method of synthesis and extent of substitution. The unique crystal structure, improved surface area, and porous morphology of carbonate hydroxyapatites also make it useful for catalysis and environmental remediation as adsorbents for heavy metals. This review briefly examines carbonate hydroxyapatite, its synthesis, its modification, and its characterization. It also highlights its biomedical applications while drawing attention to its non-medical potential.

Morphological Properties of Poly (vinyl alcohol)/Gelatin contained Indonesian Carbonated Hydroxyapatite Abalone Nanofibrous Scaffold by Electrospinning

One strategy for dealing with bone defects is replicating and reconstructing artificial bone for bone tissue engineering (BTE) application, known as the scaffold. Bone consists of an extracellular matrix (ECM) which, at the nanoscale, has a fibrous structure that can be replicated in synthetic scaffolds using an electrospinning method. This work describes the analysis of the morphological properties of Poly (vinyl alcohol) (PVA)/Gelatin contained Indonesian carbonated hydroxyapatite (CHA) abalone nanoparticle scaffold by electrospun nanofiber. CHA nanoparticles were produced using a co-precipitation method, and nanofibrous PVA/Gelatin/CHA 5 wt% scaffold was fabricated by electrospinning. The synthesized CHA produced the same condition as B-type CHA, ensured by Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffractometer (XRD), and differential scanning calorimetry (DSC), and energy-dispersive X-ray spectroscopy (EDS) tests. The morphological properties of PVA/Gelatin/CHA are analyzed using Scanning Electron Microscopy (SEM). The SEM image indicated that PVA/Gelatin nanofiber tended to have a fine morphology without beads. The agglomeration of the PVA/Gelatin/CHA 5 wt% nanofiber scaffold can be neglected because it is still on the sub-micron scale (1 μm–100 nm). Moreover, adding CHA 5 wt% in the PVA/Gelatin matrix decreased the average fiber diameter. The diameter fiber results are within the fiber diameter range (100–450 nm) in native bone ECM. Therefore, PVA/Gelatin/CHA 5 wt% has the potential to serve as an alternative scaffold material for BTE application.

Bioactive coatings on biopolymer materials: evaluation of mechanical, physical, thermal, and in vitro properties

The aim of this study was to develop and characterize coatings of bioglass nanoparticles (BGNs) on biopolymer (poly [glycolide-co-L-lactide], (PGLA)) surgical sutures, and to investigate the effects of these coatings on the performance of the sutures as they slid through a skin substitute. Melt-derived BGNs were used to coat resorbable PGLA biopolymers, providing them with bioactivity, biocompatibility, and improved physical and mechanical properties. The structural, thermal, and physical properties of the coated and uncoated biopolymers were analyzed using Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FE-SEM) and Energy-Dispersive X-ray Spectroscopy (EDXS). The dissolution profiles and bioactivity of the BGNs-coated PGLA biopolymers were assessed through Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). Tensile strength tests were conducted on the biopolymers before and after immersion in simulated body fluid to evaluate the impact of the BGNs coating on the degradation of PGLA biopolymers. Incorporating BGNs into PGLA resulted in improved tensile strength properties. The study also found that increasing the BGNs ions content facilitated the formation of a hydroxycarbonate apatite (HCA) layer in Dulbecco’s Modified Eagle Medium and medium with L-glutamine and sodium bicarbonate solutions. In vitro bioactivity tests demonstrated that the coated suture biopolymers exhibited enhanced attachment, migration, and proliferation of fibroblasts, indicating favorable biocompatibility of the biomaterial for clinical applications.

In vitro immersion study and characterization of biomimetic bovine hydroxyapatite scaffolds: Influence of calcination temperature (600 and 1000 °C) on apatite formation

This work reports on the properties of natural bovine hydroxyapatite (HAp) scaffolds calcined at temperatures of 600 and 1000 °C and on the effects of apatite formation on these calcined scaffolds during immersion experiments in Hank's Balanced Salt Solution (HBSS) from 0 to 28 days. The study systematically identifies different mechanisms that determine the formation of the apatite layer. First, compositional analysis of the scaffolds by inductively couple plasma (ICP) reveals significant differences in macromineral content, which includes calcium, phosphorus, magnesium, and sodium. Subsequent X-ray diffraction (XRD) analysis reveals the presence of hydroxyapatite in both scaffolds, while the 1000 °C sample has additional β-whitlockite due to the higher calcination temperature. Further investigation by Fourier Transform Infrared Spectroscopy (FTIR) and Raman analyzes revealed carbonated HAp in the 600 °C scaffolds and characteristic bands of HAp in the 1000 °C scaffolds. Morphological changes during immersion, documented by Scanning Electron Microscopy (SEM) images, display leaf-like and cauliflower-like structures in the 600 °C sample and rash-like features leading to leaf-type apatite formation in the 1000 °C sample. High-Resolution Transmission Electron Microscopy (HR-TEM) showed elongated crystals in both samples, confirming exclusive HAp presence in the 600 °C sample and the coexistence of HAp and β-whitlockite phases in the 1000 °C sample. After 28 days of immersion, TEM images at 600 °C reveal ordered apatite particles, while the 1000 °C images exhibit random apatite formation, confirmed by Energy Dispersive X-ray Spectroscopy in TEM (EDS-TEM). In addition, both scaffolds calcined at 600 and 1000 °C showed biocompatibility, as cytotoxicity tests confirmed a remarkable 100 % cell viability, underlining their non-toxicity. The scaffolds calcined at 600 and 1000 °C therefore exhibit high bioactivity and viability, supporting their suitability for bone tissue engineering applications.