Nanocrystalline Hydroxyapatite Research Articles

Comparing the effects of humic acid and oxalic acid on Pb(II) immobilization by a green synthesized nanocrystalline hydroxyapatite

Dissolved organic matter (DOM) is one of the most significant parameters to affect the remediation efficiency of Pb(II) by apatites. Numerous studies chose humic substances as a surrogate of DOM to investigate its influence on Pb(II) immobilization. However, the effect of low-molecular-weight organic acids such as oxalic acid (OA), which is ubiquitous in the environment and a primary component of DOM, in immobilizing Pb(II) was still not fully understood. Herein, humic acid (HA) and OA were examined to distinguish their influence on Pb(II) immobilization by a green synthesized nanocrystalline hydroxyapatite (nHAP). Various parameters were considered to evaluate the removal performance of nHAP towards Pb(II) as affected by HA/OA. Results indicated that Pb(II) immobilization was significantly promoted in the coexistence of OA owing to the precipitation of hydroxypyromorphite (HPY) as well as PbC2O4, but was independent on the addition sequence and slightly hindered by HA, disclosing that Pb(II) preferred to bind directly with nHAP instead of via HA. Characterization of the Pb(II) loaded solids by multiple technologies revealed that HPY was the predominant precipitate both in the absence and presence of HA, while the formation of PbC2O4 was preferred over that of HPY in the existence of OA. X-ray photoelectron spectroscopy indicated that PbC2O4 was the prevalent solid phase with the ratio of 62.97% after Pb(II) immobilization by nHAP in the presence of OA. These findings implied that the transformation efficiency of Pb(II) to HPY by apatites can be overestimated in the presence of OA due to the precipitation of PbC2O4.

EFFECTIVENESS OF PLATELET RICH FIBRIN (PRF) AS A SOLE GRAFT MATERIAL VERSUS NANO-CRYSTALLINE HYDROXYAPATITE IN MAXILLARY SINUS AUGEMENTATION WITH IMPLANT PLACEMENT SIMULTANEOUSLY.: A RANDOMIZED CONTROLLED CLINICAL TRIAL

Aim: The aim of this study was to evaluate the effectiveness of platelet rich fibrin (PRF) as sole graft material versus Nano crystalline hydroxyapatite in maxillary sinus augmentation with implant placement simultaneously. Patients and Methods: This was a randomized controlled clinical trial conducted on 18 patients suffering from atrophied maxillary ridge (less than 5 mm in bone height) for implantation indicating the need for maxillary sinus floor augmentation before implant placement. Group (A) received sinus augmentation with nano crystalline hydroxyapatite with immediate implantation (Nano bone ARTOSS GmbH hydroxyapatite particles) and Group B received sinus augmentation with PRF as sole graft material with immediate implantation. All patients were followed up for 6 months recording the progress of the healing both clinically and radiographically via CBCT and to evaluate the new bone formation. Results: Surgeries went uneventful in patients of both groups. No notable complications occurred during the surgical procedures and the healing period of the two groups. Radiographic results after 6 months showed that there was no statistically significant difference between the two groups. The highest mean value was found in (Group B) while the least mean value was found in (Group A). All implants were clinically stable at the time of abutment insertion, 6 months after sinus augmentation. Conclusions: The use of the PRF as a sole graft material in maxillary sinus augmentation proved to be a successful material that offers sufficient amount of natural bone in the sinus that cover all the surface of the inserted implant.

Effects of nanocrystalline hydroxyapatite concentration and skeletal site on bone and cartilage formation in rats

Most fractures heal by a combination of endochondral and intramembranous ossification dependent upon strain and vascularity at the fracture site. Many biomaterials-based bone regeneration strategies rely on the use of calcium phosphates such as nano-crystalline hydroxyapatite (nHA) to create bone-like scaffolds. In this study, nHA was dispersed in reactive polymers to form composite scaffolds that were evaluated both in vitro and in vivo. Matrix assays, immunofluorescent staining, and Western blots demonstrated that nHA influenced mineralization and subsequent osteogenesis in a dose-dependent manner in vitro. Furthermore, nHA dispersed in polymeric composites promoted osteogenesis by a similar mechanism as particulated nHA. Scaffolds were implanted into a 2-mm defect in the femoral diaphysis or metaphysis of Sprague-Dawley rats to evaluate new bone formation at 4 and 8 weeks. Two formulations were tested: a poly(thioketal urethane) scaffold without nHA (PTKUR) and a PTKUR scaffold augmented with 22 wt% nHA (22nHA). The scaffolds supported new bone formation in both anatomic sites. In the metaphysis, augmentation of scaffolds with nHA promoted an intramembranous healing response. Within the diaphysis, nHA inhibited endochondral ossification. Immunohistochemistry was performed on cryo-sections of the bone/scaffold interface in which CD146, CD31, Endomucin, CD68, and Myeloperoxidase were evaluated. No significant differences in the infiltrating cell populations were observed. These findings suggest that nHA dispersed in polymeric composites induces osteogenic differentiation of adherent endogenous cells, which has skeletal site-specific effects on fracture healing. Statement of significanceUnderstanding the mechanism by which synthetic scaffolds promote new bone formation in preclinical models is crucial for bone regeneration applications in the clinic where complex fracture cases are seen. In this study, we found that dispersion of nHA in polymeric scaffolds promoted in vitro osteogenesis in a dose-dependent manner through activation of the PiT1 receptor and subsequent downstream Erk1/2 signaling. While augmentation of polymeric scaffolds with nHA enhanced intramembranous ossification in metaphyseal defects, it inhibited endochondral ossification in diaphyseal defects. Thus, our findings provide new insights into designing synthetic bone grafts that complement the skeletal site-specific fracture healing response.

Preparation and characterization of Fe doped n-hydroxyapatite for biomedical application

Natural and synthetic biomaterials are often used in clinical utilization to assist, strengthen and to restore impaired tissue or biological functions. Iron doped bioactive nano-crystalline hydroxyapatite (Fe doped n-HAp) powder with different concentrations of Fe was successfully synthesized by the reflux method. The crystallinity of the samples was confirmed by powder XRD analysis and in 0.2 M Fe doping, the smallest crystalline size of 3.2 nm was obtained. SEM results indicate that higher concentration of Fe content has a considerable impact on the morphology of n-HAp material. The functional group assignments and the iron dopant incorporation has been analyzed and confirmed through FTIR and Raman results. The antibacterial activity test of Fe doped n-HAp mixed with amoxicillin antibiotic displays good inhibition to the bacterial strains.

Hydroxyapatite nanophases augmented with selenium and manganese ions for bone regeneration: Physiochemical, microstructural and biological characterization

Hydroxyapatite (HAP) nanopowders with different manganese (Mn) and selenium (Se) contents with Mn/Ca and Se/P molar ratio of 1 mol%, 2.5 mol% and 5 mol% were synthesized by wet-co-chemical precipitation method. The results revealed that with either Mn or Se doping, ion-substituted apatite phase was achieved with good crystallographic features. The combined evidence obtained from spectrometric techniques revealed that nanocrystalline HAP was effectively doped with Mn and Se ions, where Se in form of SeO32− replaced PO43− and Mn2+ replaced Ca2+. Mn and Se doped HAP samples exhibited rod-like and needle-like morphology with strong tendency to form agglomerates. HAP enriched with Mn and Se represented a strong antibacterial effect and also showed prominent blood compatibility. From the biocompatibility testing, it was evident that Mn and Se doped HAP augmented the osteoblasts adhesion, migration and proliferation in a dose-dependent manner. To conclude from this study, it is clearly evident that the doping amount of both Mn and Se ions can determine the size and morphology of the final HAP product. Therefore, Mn and Se HAP nanopowders with molar ratio less than 5 mol% without any heat treatment can provide good crystallographic features to HAP with satisfying micro-structural, thermal and biological properties.

Tetracalcium Phosphate/Monetite/Calcium Sulfate Hemihdrate Biocement Powder Mixtures Prepared by the One-Step Synthesis for Preparation of Nanocrystalline Hydroxyapatite Biocement-Properties and In Vitro Evaluation.

A modified one-step process was used to prepare tetracalcium phosphate/monetite/calcium sulfate hemihydrate powder cement mixtures (CAS). The procedure allowed the formation of monetite and calcium sulfate hemihydrate (CSH) in the form of nanoparticles. It was hypothesized that the presence of nanoCSH in small amounts enhances the in vitro bioactivity of CAS cement in relation to osteogenic gene markers in mesenchymal stem cells (MSCs). The CAS powder mixtures with 15 and 5 wt.% CSH were prepared by milling powder tetracalcium phosphate in an ethanolic solution of both orthophosphoric and sulfuric acids. The CAS cements had short setting times (around 5 min). The fast setting of the cement samples after the addition of the liquid component (water solution of NaH2PO4) was due to the partial formation of calcium sulfate dihydrate and hydroxyapatite before soaking in SBF with a small change in the original phase composition in cement powder samples after milling. Nanocrystalline hydroxyapatite biocement was produced by soaking of cement samples after setting in simulated body fluid (SBF). The fast release of calcium ions from CAS5 cement, as well as a small rise in the pH of SBF during soaking, were demonstrated. After soaking in SBF for 7 days, the final product of the cement transformation was nanocrystalline hydroxyapatite. The compressive strength of the cement samples (up to 30 MPa) after soaking in simulated body fluid (SBF) was comparable to that of bone. Real time polymerase chain reaction (RT-PCR) analysis revealed statistically significant higher gene expressions of alkaline phosphatase (ALP), osteonectin (ON) and osteopontin (OP) in cells cultured for 14 days in CAS5 extract compared to CSH-free cement. The addition of a small amount of nanoCSH (5 wt.%) to the tetracalcium phosphate (TTCP)/monetite cement mixture significantly promoted the over expression of osteogenic markers in MSCs. The prepared CAS powder mixture with its enhanced bioactivity can be used for bone defect treatment and has good potential for bone healing.

Spongostan™ Leads to Increased Regeneration of a Rat Calvarial Critical Size Defect Compared to NanoBone® and Actifuse.

Bone substitute materials are becoming increasingly important in oral and maxillofacial surgery. Reconstruction of critical size bone defects is still challenging for surgeons. Here, we compared the clinically applied organic bone substitute materials NanoBone® (nanocrystalline hydroxyapatite and nanostructured silica gel; n = 5) and Actifuse (calcium phosphate with silicate substitution; n = 5) with natural collagen-based Spongostan™ (hardened pork gelatin containing formalin and lauryl alcohol; n = 5) in bilateral rat critical-size defects (5 mm diameter). On topological level, NanoBone is known to harbour nanopores of about 20 nm diameter, while Actifuse comprises micropores of 200–500 µm. Spongostan™, which is clinically applied as a haemostatic agent, combines in its wet form both nano- and microporous topological features by comprising 60.66 ± 24.48 μm micropores accompanied by nanopores of 32.97 ± 1.41 nm diameter. Micro-computed tomography (µCT) used for evaluation 30 days after surgery revealed a significant increase in bone volume by all three bone substitute materials in comparison to the untreated controls. Clearly visual was the closure of trepanation in all treated groups, but granular appearance of NanoBone® and Actifuse with less closure at the margins of the burr holes. In contrast, transplantion of Spongostan™ lead to complete filling of the burr hole with the highest bone volume of 7.98 ccm and the highest bone mineral density compared to all other groups. In summary, transplantation of Spongostan™ resulted in increased regeneration of a rat calvarial critical size defect compared to NanoBone and Actifuse, suggesting the distinct nano- and microtopography of wet Spongostan™ to account for this superior regenerative capacity. Since Spongostan™ is a clinically approved product used primarily for haemostasis, it may represent an interesting alternative in the reconstruction of defects in the maxillary region.

Hydrothermal synthesis of nanocrystalline hydroxyapatite\u2013graphene nanosheet on Ti-6Al-7Nb: mechanical and in vitro corrosion performance

The hybrid coatings containing the graphene nano-sheet (GNS) and nano-hydroxyapatite (nHA) phases have been successfully synthesized on Ti6Al7Nb alloys by a one-step hydrothermal method. The hydrothermal reaction was carried out for 24 h at 200 °C. The GNS ratio has been altered as 1, 3, 5 and 7 wt.% in the coatings and, the results have compared with non- GNS containing coatings. The effect of the GNS ratio on the microstructure, hardness, and in vitro corrosion responses has been investigated in detail. The characterizations of the coatings were carried out by SEM, EDS, AFM, XRD and, FTIR. The corrosion behavior of the hybrid coatings was compared in Kokubo’s solution at 37 °C by using potentiodynamic polarization tests. The results showed that the hydroxyapatite phases were deposed on the graphene layers with nano-size nucleation with its Ca/P stoichiometric ratio. The best hydrophilicity (~52°) property has been obtained in nHA/3GNS coatings. In addition, the corrosion rates of coatings increased in the following order: nHA/3GNS < nHA/1GNS < nHA/7GNS < nHA/5GNS < only nHA.

Effect of hexagonal structure nanoparticles on the morphological performance of the ceramic scaffold using analytical oscillation response

Porous bony scaffolds are utilized to manage the growth and migration of cells from adjacent tissues to a defective position. In the current investigation, the effect of titanium oxide (TiO2) nanoparticles on mechanical and physical properties of porous bony implants made of polymeric polycaprolactone (PCL) is studied. The bio-nanocomposite scaffolds are prepared with composition of nanocrystalline hydroxyapatite (HA) and TiO2 powder using the freeze-drying technique for different weight fractions of TiO2 (0 wt%, 5 wt%, 10 wt%, and 15 wt%). In order to identify the microstructure and morphology of the fabricated porous bio-nanocomposites, the X-ray diffraction (XRD), atomic force microscope (AFM) and scanning electron microscopy (SEM) are employed. Also, the biocompatibility and biodegradability of the manufactured scaffolds are examined by placing them in a simulated body fluid (SBF) for 21 days, their weight and pH changes are measured. The rate of degradation of the PCL-HA scaffold can be controlled by varying the percentage of its constituent components. Due to an increasing growth and activity of bone cells and the apatite formation on the free surface of the fabricated bio-nanocomposite implants as well as their reasonable mechanical properties, they have the potential to be used as a bone substitute. Additionally, with the aid of the experimentally extracted mechanical properties of the scaffolds, the vibrational characteristics of a beam-type implant made of the proposed porous bio-nanocomposites are explored. The results obtained from SEM image indicate that the scaffolds produced by the employed method have high total porosity (70%–85%) and effective porosity. The pore size is obtained between 60 and 200 μm, which is desirable for the growth and propagation of bone cells. Also, it is revealed that the addition of TiO2 nanoparticles leads to reduce the rate of dissolution of the fabricated bio-nanocomposite scaffolds.

Microstructural properties of novel nanocomposite material based on hydroxyapatite and carbon nanotubes: fabrication and nonlinear instability simulation

In this work, a novel porous bio-nanocomposite material containing the commercial nanocrystalline hydroxyapatite (n-HA) composed using single-walled carbon nanotubes (SWCNTs) with different weight fractions (0, 2.5, 5, and 7.5 wt%) is fabricated via a space holder technique for bone tissue engineering applications. The hydroxyapatite (HA) presents a weak mechanical performance which the addition of the SWCNT can enhance the mechanical strength of the matrix. The manufactured n-HA-SWCNT bio-nanocomposite samples are then coated by gelatin-ibuprofen (GN-IBO) bio-polymer with a dip-coating method. The X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) are employed for the phase characterization and surface morphology analysis of the fabricated bio-nanocomposite specimens. The mechanical properties, the rate of drug release, and biological characteristics of the specimens with and without SWCNTs are investigated. After that, the nonlinear instability and vibration responses of an axially loaded plate-form bone implant made of the manufactured n-HA-SWCNT bio-nanocomposite samples coated with GN-IBO thin layers are simulated through a sandwich-plate model and based upon the experimentally extracted mechanical properties. The obtained results indicate the presence of SWCNT and n-HA in the composition due to the fuzzy metamorphism or degradation. It is found that by increasing the amount of SWCNTs, the mass density of the fabricated bio-nanocomposite samples reduces, but the porosity and strength of them are higher than those of the pure n-HA. Therefore, it is expected that these newly manufactured bio-nanocomposites have an excellent capability for bone formation with better bonds with surrounding tissues.

Biodegradable ceramic matrix composites made from nanocrystalline hydroxyapatite and silk fibers via crymilling and uniaxial pressing

The treatment of severe bone loss and resultant large bone gaps is a challenge due to the need to stimulate bone growth using a biomaterial that biodegrades slowly and has mechanical properties similar to the surrounding bone. This work proposes a novel biodegradable nanocomposite to address these needs. The first step of the technology is to prepare composite powders consisting of 5 wt% or 15 wt% silk fibers and nanocrystalline hydroxyapatite. Both are biodegradable materials. The composite powders are prepared using cryomilling. The second step is uniaxial pressing of the powders at a pressure up to 1 GPa and a temperature of 80 °C. This leads to a homogenous and dense ceramic matrix composite with good adhesion between the nano-hydroxyapatite and silk fibers. The nano-hydroxyapatite retains its nanocrystalline form.The compressive strength is 276 MPa and the bending strength is 82 MPa, which are comparable to the strength of cortical bone.

The Role of the Surface Acid-Base Nature of Nanocrystalline Hydroxyapatite Catalysts in the 1,6-Hexanediol Conversion.

Hydroxyapatite is known to have excellent catalytic properties for ethanol conversion and lactic acid conversion, and their properties are influenced by the elemental composition, such as Ca/P ratio and sodium content. However, few reports have been examined for the surface acid–base nature of hydroxyapatites containing sodium ions. We prepared nanocrystalline hydroxyapatite (Ca-HAP) catalysts with various Ca/P ratios and sodium contents by the hydrothermal method. The adsorption and desorption experiments using NH3 and CO2 molecules and the catalytic reactions for 2-propenol conversion revealed that the surface acid–base natures changed continuously with the bulk Ca/P ratios. Furthermore, the new catalytic properties of hydroxyapatite were exhibited for 1,6-hexanediol conversion. The non-stoichiometric Ca-HAP(1.54) catalyst with sodium ions of 2.3 wt% and a Ca/P molar ratio of 1.54 gave a high 5-hexen-1-ol yield of 68%. In contrast, the Ca-HAP(1.72) catalyst, with a Ca/P molar ratio of 1.72, gave a high cyclopentanemethanol yield of 42%. Both yields were the highest ever reported in the relevant literature. It was shown that hydroxyapatite also has excellent catalytic properties for alkanediol conversion because the surface acid–base properties can be continuously controlled by the elemental compositions, such as bulk Ca/P ratios and sodium contents.

Cold sintering of as-dried nanostructured calcium hydroxyapatite without using additives

A novel low-temperature densification method of nanocrystalline calcium hydroxyapatite (HAp) at a temperature as low as 200 °C with no liquid additives is investigated. To understand the underlying mechanism of the low-temperature sintering of hydroxyapatite, two types of lab-synthesized nanocrystalline HAp, dried (110 °C, 12 h) and calcined (1000 °C, 2 h), were subjected to cold sintering conditions (200 °C, 500 MPa) and compared thoroughly. The dried samples were found to be nanocrystalline, enveloped by an amorphous shell, whereas the calcined samples were fully crystalline, as confirmed by X-ray diffraction, transmission electron microscopy, and solid-state nuclear magnetic resonance techniques. A relative density of 98.8% was achieved for the dried samples; however, the calcined samples could not be sintered. This indicates a clear dependence of densification on the surface chemistry of the nanocrystals involving rearrangement and dehydration of the amorphous layer present on the surface of the nanocrystals under the influence of applied pressure and temperature. Moreover, the calcined sample, which had a fully developed crystalline structure, did not undergo sintering, even with the use of added water. Therefore, it is demonstrated that wet-precipitated and dried nanocrystalline HAp can be cold-sintered to full densification for applications in biomedical materials or radioactive waste immobilization of volatile radionuclides at a considerably low temperature, without the addition of sintering aids.

Relative performance of various biomaterials used for maxillary sinus augmentation: A Bayesian network meta-analysis.

ObjectivesTo assess the histomorphometric outcomes obtained in randomized clinical trials (RCTs) with different biomaterials used for maxillary sinus augmentation (MSA).Materials and MethodsA search of the existing medical literature until October 1, 2019, was performed. Inclusion criteria were (a) RCTs assessing a two‐stage MSA from the lateral approach using autologous bone or biomaterials for grafting and (b) reported histomorphometric outcomes based on crestal bone core biopsy samples. The Bayesian method was used to perform pairwise meta‐analyses and network meta‐analysis (NMA). The primary outcome, the new bone percentage (NB %), was calculated as mean differences with 95% credible intervals. The interventions were ranked by their posterior probability by calculating the surface under the cumulative ranking curve values.ResultsThirty‐four RCTs (842 MSAs) were included in the analysis with a normal healing period (5–8 months). All comparisons were presented in a league table. On the basis of the ranking probability, the most effective bone grafting material for NB% was bovine xenograft + bone marrow concentrate (BMC) (81%), followed by bovine xenograft + platelet‐rich plasma (PRP) (77%), bioactive glass ceramic + autologous bone 1:1 (70%), nanocrystalline hydroxyapatite in silica gel (70%), and bioactive glass ceramic (70%). Autologous bone graft alone took the twelfth position with 57%.ConclusionWithin the limitations of the present NMA, the analysis did not confirm autologous bone alone as the gold standard for MSA and showed superiority of composite grafts such as bovine xenograft + BMC after 5–8 months of healing.

The synthesis of hydroxyapatite from artificially grown Red Sea hydrozoan coral for antimicrobacterial drug delivery system applications

The hydrozoan Millepora dichotoma (MD) is a typical Red Sea species containing a porous skeleton in the form of aragonite crystalline calcium carbonate. Due to environmental considerations, the artificial production of coralline species under controlled conditions is pertinent and underway. Artificially grown MD was used as a raw material for the production of calcium phosphate, mainly hydroxyapatite bioceramics, to be used in the drug delivery systems as a drug carrier or in the tissue engineering such as bone graft. DTA-TGA, XRD, FT-IR, Raman, and SEM analysis were carried out to analyze both unconverted and converted artificial corals. Hydrothermally converted coral fine powders were loaded with gentamicin (Gm) antibiotic, and the drug-loaded particles were analyzed by SEM. Unconverted coral was mainly aragonite, while hydrothermally treated coral was completely converted to hydroxyapatite. Hydrothermally treated coral was showing agglomerated nodules up to 1-μm size consisting of nanocrystalline hydroxyapatite platelets in the size range of less than 100 nm. The general macropore size of the coral was found to be appropriate for osteoid growth, which is 100 to 600 μm range. These artificially grown corals can be easily produced and used for bone growth and repair and other biomedical applications.

Clinical and radiographic evaluation of open flap debridement with or without Nanocrystalline Hydroxyapatite bone graft in management of periodontal intrabony defects

Abstract: Background: Nanocrystalline hydroxyapatite (n-HA) bone graft could improve proliferation and differentiation of periodontal ligament fibroblasts. The osteoconductive and biomimetic properties incorporated into the early stage of human physiological bone turnover assumed that deposition of these molecules promoted early osteogenesis in and around Nano Bone. Methods: 20 periodontitis patients with intra-bony defects participated in this clinical trial and treated with either open flap debridement (OFD) alone as control group or OFD and n-HA bone graft as intervention group. Clinical outcomes included plaque index (PI), gingival index (GI), probing depth (PD), clinical attachment level (CAL) and gingival recession (GR). Bone defect area (BDA) was measured by digital periapical radiographs and linear measurements were used to calculate the radiographic bone fill. Measurements at baseline and 6-months postoperatively were subjected to statistical analysis. Results: Both OFD and OFD with n-HA bone substitute resulted in statistically significant improvement in all clinical and radiographic parameters from baseline to 6 months. But no significant difference was observed between both groups. After 6 months, OFD showed 2.4(±0.5)mm PD reduction and 1.2(±0.8)mm CAL gain, while n-HA group showed 3.2(±1.1)mm PD reduction and 2.7(±1.3)mm CAL gain. The BDA was reduced by 1.7(±1)mm2 with OFD and by 3.4(±2.2)mm2 in n-HA group. Conclusion: Both OFD and OFD with n-HA showed significant reduction in clinical and radiographic outcomes after 6 months with no statistically significant difference between them. Clinical relevance: Both treatment modalities are successful procedures for treating intrabony defects

Extracellular matrix containing nanocomposite bone graft in periodontal regeneration - A randomized controlled clinical and radiographic evaluation.

Background:The study aims to evaluate the effect of adding extracellular matrix (ECM) component – natural collagen to nanocrystalline hydroxyapatite (nHA) bone graft in the treatment of intrabony defect in chronic periodontitis patients.Materials and Methods:Forty chronic periodontitis patients having at least one intrabony defect were treated surgically by open flap debridement and the defect grafted (Group A: 20 sites grafted with nHA with natural collagen and Group B: 20 sites grafted with nHA). Plaque index, gingival index, probing pocket depth (PPD), clinical attachment level (CAL), and radiographic defect depth (RDD) were evaluated.Results:The mean PPD reduced from 7.6 ± 0.88 at baseline to 4.45 ± 0.69 and 2.60 ± 0.6 at 3 and 6 months, respectively, in Group A. In Group B, the mean PPD reduced from 7.5 ± 0.89 at baseline to 4.95 ± 0.60 and 2.65 ± 0.59 at 3 and 6 months, respectively. The mean CAL reduced from 7.75 ± 0.85 at baseline to 5.05 ± 0.76 and 3.6 ± 0.68 at 3 and 6 months, respectively, in Group A. In Group B, the mean CAL reduced from 7.70 ± 0.86 at baseline to 5.8 ± 0.7 and 3.75 ± 0.64 at 3 and 6 months, respectively. The mean RDD reduced from 8.13 ± 0.78 and 8.12 ± 0.83 at baseline to 4.27 ± 0.66 and 3.94 ± 0.5 after 6 months in Groups A and B, respectively. After 3 months, a statistically significant reduction in mean PPD and CAL values was noted in Group A while the results were comparable after 6 months.Conclusion:The effectiveness of nHA composite during initial healing phase (3 months) can be attributed to the presence of ECM-collagen in bone graft matrix.

Synthesis and Characterization of a Biocompatible Bioactive Borate Glass

A typical bioactive borate glass of composition 5Na2O-30Ca-65B2O3(NCBO) was prepared by melt quenching method. The NCBO glass powder and solid glass fibers were found to slowly converted to nanocrystalline hydroxyapatite (or Ca10(PO4)6(OH)2) by soaking in (0.25M)K2HPO4(KDP) solution (with pH = 9.5 and Ca/P ratio ˜1.6 at 37°C) for about one month. We studied biocompatibility (cells adhesion and proliferation) of the NCBO glass by allowing adhesion and proliferation of human cord blood derived mesenchymal stem cells (CB-hMSCs) directly on the thin glass plate. The cells viability on glass surface was determined by MTT [3-(4,5-di-methylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide] assay analysis. The NCBO glass exhibiting excellent biocompatibility might be suitable forinvivo tissue engineering applications.

The influence of periostin on osteoblastic adhesion and proliferation on collagen matrices - An in vitro study.

Purpose:The purpose of the study was to evaluate the ability of periostin when impregnated onto varied collagen matrices to influence osteoblast cell adhesion, proliferation, and activity.Materials and Methods:Saos-2 osteoblast cells were cultured and seeded onto two different collagen matrices as follows: Group A: absorbable collagen sponge (ACS), Group B: ACS impregnated with recombinant human periostin, Group C: nanocrystalline hydroxyapatite collagen (NcHC), and Group D: NcHC impregnated with recombinanant human periostin. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to evaluate cell viability as well as adhesion and proliferation on 2nd, 5th, and 7th day. Osteoblast activity was studied using alkaline phosphatase (ALP) assay for the study groups.Results:The periostin-treated absorbable collagen matrices showed a statistically significant increase in the osteoblast adhesion compared to periostin-treated NcHC on days 2, 5, and 7 (P < 0.001). The osteoblast activity as evaluated by ALP assay showed that there is increased activity in the periostin-treated ACS compared to the periostin-treated NcHC.Conclusion:From the observations of this study, it is evident that Periostin has a significant role in the modulating cellular response of the osteoblast cells. Further, incorporation of periostin into the ACS has been shown to increase the cell viability, proliferation, and adhesion of osteoblast-like Saos-2 cells.

Study of the impact of amino acids hydrochloride forms on the formation of biomimetic composites in the presence of nanocrystalline hydroxyapatite

The study of molecular composition of the biomimetic composites on the basis of nanocrystalline carbonate-substituted (C-HAP) and polar amino acids of L-lysine hydrochloride and L-arginine hydrochloride was performed in the work. Results of the study show that the change in acidity of the medium (pH≥11.2, ≥7.55 и ≤5) occurs under transformation of the conformational environment of L-lysine hydrochloride molecules with the formation of L-lysine structure as while increase of pH level as in the presence of C-HAP nanocrystals. At the same time composites basing on L-arginine keep their amorphous structure in the presence of synthesized C-HAP in the different media. The detected differences in the molecular environment of hydrochloride forms of amino acids during the interaction with nanocrystalline C-HAP prove to be significant for the development of technology of the integration between biocomposites and hard dental tissues.