Addition Of Nano-hydroxyapatite Research Articles

Phenolated alginate hydrogel induced osteogenic properties of mesenchymal stem cells via Wnt signaling pathway

Osteogenic properties of phenolated alginate (1.2 %) hydrogel containing collagen (0.5 %)/nano-hydroxyapatite (1 %) were studied on human mesenchymal stem cells in vitro. The phenolation rate and physical properties of the hydrogel were assessed using nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM), swelling ratio, gelation time, mechanical assay, and degradation rate. The viability of encapsulated cells was monitored on days 7, 14, and 21 using an MTT assay. Osteoblast differentiation was studied using western blotting, and real-time PCR. Using PCR array analysis, the role of the Wnt signaling pathway was also investigated. Data showed that the combination of alginate/collagen/nanohydroxyapatite yielded proper mechanical features. The addition of nanohydroxyapatite, and collagen reduced degradation, swelling rate coincided with increased stiffness. Elasticity and pore size were also diminished. NMR and FTIR revealed suitable incorporation of collagen and nanohydroxyapatite in the structure of alginate. Real-time PCR analysis and western blotting indicated the expression of osteoblast-related genes such as Runx2 and osteocalcin. PCR array revealed the induction of numerous genes related to Wnt signaling pathways during the maturation of human stem cells toward osteoblast-like cells. In vivo data indicated that transplantation of phenolated alginate/collagen/nanohydroxyapatite hydrogel led to enhanced de novo bone formation in rats with critical-sized calvarial defects. Phenolated alginate hydrogel can promote the osteogenic capacity of human amniotic membrane mesenchymal stem cells in the presence of nanohydroxyapatite and collagen via engaging the Wnt signaling pathway.

Effects of Nanohydroxyapatite Incorporation into Glass Ionomer Cement (GIC)

Glass ionomer cement (GIC) or polyalkenoate cement is a water-based cement that is commonly used in clinical dentistry procedures as a restorative material. It exhibits great properties such as fluoride-ion release, good biocompatibility, ease of use and great osteoconductive properties. However, GIC’s low mechanical properties have become a major drawback, limiting the cement’s usage, especially in high stress-bearing areas. Nanohydroxyapatite, which is a biologically active phosphate ceramic, is added as a specific filler into glass ionomer cement to improve its properties. In this review, it is shown that incorporating hydroxyapatite nanoparticles (nHA) into GIC has been proven to exhibit better physical properties, such as increasing the compressive strength and fracture toughness. It has also been shown that the addition of nanohydroxyapatite into GIC reduces cytotoxicity and microleakage, whilst heightening its fluoride ion release and antibacterial properties. This review aims to provide a brief overview of the recent studies elucidating their recommendations which are linked to the benefits of incorporating hydroxyapatite nanoparticles into glass ionomer cement.

Histological and Nanomechanical Properties of a New Nanometric Hydroxiapatite Implant Surface. An In Vivo Study in Diabetic Rats.

Implant therapy is a predictable treatment to replace missing teeth. However, the osseointegration process may be negatively influenced by systemic conditions, such as diabetes mellitus (DM). Microtopography and implant surface developments are strategies associated to better bone repair. This study aimed to evaluate, in healthy and diabetic rats, histomorphometric (bone to implant contact = %BIC; and bone area fraction occupancy = %BAFO) and nanomechanical (elastic modulus = EM; and hardness = H) bone parameters, in response to a nanometric hydroxyapatite implant surface. Mini implants (machined = MAC; double acid etched = DAE, and with addition of nano-hydroxyapatite = NANO) were installed in tibias of healthy and diabetic rats. The animals were euthanized at 7 and 30 days. NANO surface presented higher %BIC and %BAFO when compared to MAC and DAE (data evaluated as a function of implant surface). NANO surface presented higher %BIC and %BAFO, with statistically significant differences (data as a function of time and implant surface). NANO surface depicted higher EM and H values, when compared to machined and DAE surfaces (data as a function of time and implant surface). Nano-hydroxyapatite coated implants presented promising biomechanical results and could be an important tool to compensate impaired bone healing reported in diabetics.

Glass Ionomer Cement Modified by Resin with Incorporation of Nanohydroxyapatite: In Vitro Evaluation of Physical-Biological Properties.

Resin-modified glass ionomer cement (RMGIC) has important properties. However, like other restorative materials, it has limitations such as decreased biocompatibility. The incorporation of nanoparticles (NP) in the RMGIC resulted in improvements in some of its properties. The aim of this study was to evaluate the physical-biological properties of RMGIC with the addition of nanohydroxyapatite (HANP). Material and Methods: Vitremer RMGIC was used, incorporating HANP by amalgamator, vortex and manual techniques, totaling ten experimental groups. The distribution and dispersion of the HANP were evaluated qualitatively by field emission scanning electron microscope (SEM-FEG). The evaluation of image porosity (SEM-FEG) with the help of imageJ. Cell viability 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazoline bromide (MTT) and cell morphology analyses were performed on MDPC-23 odontoblastoid cells at 24 and 72 h. Results: It was possible to observe good dispersion and distribution of HANP in the samples in all experimental groups. The incorporation of 5% HANP into the vortex stirred RMGIC resulted in fewer pores. The increase in the concentration of HANP was directly proportional to the decrease in cytotoxicity. Conclusions: It is concluded that the use of a vortex with the incorporation of 5% HANP is the most appropriate mixing technique when considering the smallest number of pores inside the material. A higher concentration of HANP resulted in better cell viability, suggesting that this association is promising for future studies of new restorative materials.

Microtomographic evaluation of a nanometric implant surface associated to L‐PRF: Study in osteoporotic rats

Background Osteoporosis is associated to decrease of bone mineral density, leading to an increase of skeletal frailty and fracture risk. Surface characteristics of dental implants may influence bone response, modulating cell proliferation and differentiation. Nanostructures applied to biomaterials may contribute to a higher bone to implant contact. Previous studies have shown that Leukocyte platelet rich fibrin (L-PRF) can increase the amount and formation rate of new bone around implants. Aim/Hypothesis To micro-tomographically evaluate, in osteoporotic rats, the bone repair around two implant surfaces, associated of not to L-PRF, analyzing Bone to Implant Contact (IS TS,%), Bone Volume Fraction (BV TV,%), Bone Surface Volume (BS BV,%) Trabecular Thickness (Tb.Th,mm), and Total Porosity (To.Po,%). Materials and Methods Mini implants with 2 types of surface (double acid etched=DAE, or with the addition of nano-hydroxyapatite = NHA + 24 implants of each type) were installed in the tibias of osteoporotic rats. In 24 rats, L-PRF was obtained with blood collection by means of cardiac puncture and posterior centrifugation, and inserted in the prepared bone site before implant insertion. The 48 rats were randomly divided into 4 experimental groups of 12 rats each- G1- DAE implants installed+ G2- NHA implants installed+ G3- DAE implants installed in association to L-PRF+ G4- NHA implants installed in association to L-PRF. All the mini implants were prepared for the study, measured 2.7 mm in length x 1.4 mm in diameter, and had the same macrostructure. The animals were euthanized 7 and 30 days (7d and 30d) after implants placement (6 from each group period). The tibias were removed for microtomographic evaluation of the bone between the threads of the implants, analyzing the previously described parameters. Results Inter-groups differences were assessed using One-way Analysis of Variance (P < 0.05 was considered). For IS TS, statistically significant differences were found in L-PRF treated rats between DAE (45.31 ± 5.06) versus NHA (52.81 ± 4.43) implants. For BV TV, there were statistically significant differences between G3 7d (44.08 ± 6.98) versus G4 7d (58.95 ± 5.53) and between G3 30d (54.33 ± 4.18) versus G4 30d (68.09 ± 6.56) + for the NHA surface, there were also statistical differences between rats without (49.57 ± 4.94) or with (63.52 ± 5.09) L-PRF treatment association. The results of BS BV showed statistically significant differences between DAE (36.71 ± 3.31) and NHA (32.13 ± 2.95) implant surfaces in L-PRF treated animals. For Tb.Th, there were statistically significant differences between G3 30d (0.093 ± 0.010) versus G4 30d (0.115 ± 0.012). For To.Po, statistically significant differences were found in L-PRF treated rats between DAE (53.69 ± 5.80) versus NHA (45.25 ± 4.98) implants. Conclusion and Clinical Implications Microtomographic analysis showed that the nano-hydroxyapatite implant surface presented more tridimensional bone to implant contact, bone volume fraction and trabecular thickness, and also less bone surface volume and porosity, when compared to DAE surface. Furthermore, the NHA surface was the most benefited by the association to L-PRF treatment. These results suggest that this treatment protocol (NHA + L-PRF) should be tested in humans, in trials evaluating challenging clinical situations.

Alginate-nanohydroxyapatite hydrogel system: Optimizing the formulation for enhanced bone regeneration.

Ceramic/polymer-based biocomposites have emerged as potential biomaterials to fill, replace, repair or regenerate injured or diseased bone, due to their outstanding features in terms of biocompatibility, bioactivity, injectability, and biodegradability. However, these properties can be dependent on the amount of ceramic component present in the polymer-based composite. Therefore, in the present study, the influence of nanohydroxyapatite content (30 to 70 wt%) on alginate-based hydrogels was studied in order to evaluate the best formulation for maximizing bone tissue regeneration. The composite system was characterized in terms of physic-chemical properties and biological response, with in vitro cytocompatibility assessment with human osteoblastic cells and ex vivo functional evaluation in embryonic chick segmental bone defects. The main morphological characteristics of the alginate network were not affected by the addition of nanohydroxyapatite. However, physic-chemical features, like water-swelling rate, stability at extreme pH values, apatite formation, and Ca2+ release were nanoHA dose-dependent. Within in vitro cytocompatibility assays it was observed that hydrogels with nanoHA 30% content enhanced osteoblastic cells proliferation and expression of osteogenic transcription factors, while those with higher concentrations (50 and 70%) decreased the osteogenic cell response. Ex vivo data underlined the in vitro findings, revealing an enhanced collagenous deposition, trabecular bone formation and matrix mineralization with Alg-nanoHA30 composition, while compositions with higher nanoHA content induced a diminished bone tissue response. The outcomes of this study indicate that nanohydroxyapatite concentration plays a major role in physic-chemical properties and biological response of the composite system and the optimization of the components ratio must be met to maximize bone tissue regeneration.

Improvement of physico-chemical properties of dextran-chitosan composite scaffolds by addition of nano-hydroxyapatite

Nano-hydroxyapatite was incorporated into polymer matrix of Dextran/Chitosan to achieve a novel composite scaffold by freeze drying technique. The synthesized composite scaffolds were recognized by different performances such as: X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and Scanning electron microscope (SEM). The results revealed the complex formation between dextran and chitosan with an excellent dispersion of nHA inside the polymer matrix. The SEM images showed the presence of interconnected pore structure inside the scaffolds. The porosity of the composites was found to decrease from 82% to 67% by adding nanohydroxyapatite to the polymer matrix of Dextran/Chitosan. The mechanical properties of the scaffolds were measured by compression test. The obtained results verified that the presence of nHA can noticeably enhance young’s modulus and compressive strength of the composite scaffolds. All the obtained results essentially recommend that these composites can be a good candidate for bone tissue engineering applications.

Modification of Silk Fibroin and Gelatin-Chondroitin Sulfate Matrix with the Addition of Nanohydroxyapatite by FreezeDrying Method for Tissue Engineering Application

Modification of Silk Fibroin and Gelatin-Chondroitin Sulfate Matrix with the Addition of Nanohydroxyapatite by FreezeDrying Method for Tissue Engineering Application

Effect of addition of Nano hydroxyapatite particles on wear of resin modified glass ionomer by tooth brushing simulation

BackgroundRecently, incorporation of nanohydroxyapatite (NHA) has been suggested to improve the mechanical properties of glass ionomers (GIs). This study aimed to assess the effect of addition of NHA on wear of resin modified glass ionomer (RMGI) by tooth brushing simulation.Material and MethodsIn this in vitro, experimental study, NHA in 1, 2, 5, 7 and 10wt% concentrations was added to Fuji II LC RMGI powder, and 48 samples (5×5mm) in five experimental and one control group (n=8) were fabricated. After polishing, cleaning and incubation at 37°C for three weeks, the samples were weighed and subjected to tooth brushing simulation in a toothpaste slurry according to ISO14569-1. Then, they were weighed again and the weight loss was calculated. The data were analyzed using one-way ANOVA and Tukey’s test.ResultsThe highest and the lowest weight loss was found in the 0% NHA (-1.052±0.176) and 5% NHA (-0.370±0.143) groups, respectively. Wear was significantly higher in 0% NHA group (P<0.05). No difference was detected in wear between 2 and 5wt% NHA or among 1, 7 and 10wt% NHA groups. Significant differences were noted in wear between 2 and 5wt% NHA and 1, 7 and 10wt% NHA groups (P<0.001).ConclusionsIncorporation of up to 10wt% of NHA increases the wear resistance of Fuji II LC RMGI. This increase was the highest when 2 and 5wt% NHA were added. Key words:Glass ionomer, hydroxyapatites, nanoparticles, dental restoration wear.

Addition of a Fluoride-containing Radiopacifier Improves Micromechanical and Biological Characteristics of Modified Calcium Silicate Cements

IntroductionCalcium silicate cements (CSCs) with the addition of nanohydroxyapatite and calcium carbonate play a critical role in dental applications. To further improve their properties, particularly radiopacity and biointeractivity, the fluoride-containing radiopacifier ytterbium trifluoride (YbF3) was added to their composition, and biological and mechanical characteristics were evaluated. MethodsYbF3 was added to 3 different CSCs: cement I (CSC + calcium carbonate), cement II (CSC + nanohydroxyapatite), and Portland cement. Material characterization encompassed measurements of pH, calcium, ytterbium, and fluoride ion release; radiopacity; setting time; porosity; microindentation properties; wettability; and Fourier transform infrared spectroscopic, x-ray diffraction, and scanning electron microscopic analyses. Osteoblast- and osteoclast-like cells were grown on the materials' surface to evaluate their adherence. ResultsThe addition of calcium carbonate, nanohydroxyapatite, and 30 wt% of YbF3 improved radiopacity and the setting time of experimental cements. The pH values did not differ among the groups. The greatest ytterbium and fluoride releases occurred in the Portland cement + YbF3 group. Combined x-ray diffraction and Fourier transform infrared spectroscopic analysis showed the presence of calcium hydroxide and calcium silicate hydrates. In addition, the presence of calcium ytterbium fluoride and ytterbium oxide proved that YbF3 reacted with cement compounds. Wettability of cement I + YbF3 was superior to other formulations, but its porosity and microindentation properties were weaker than in the Portland cement + YbF3 mixture. Cement II + YbF3 presented micromechanical indentation and porosity characteristics similar to the Portland-based cement formulation. Osteoclast- and osteoblast-like cells adhered to the cements' surfaces without alteration of the cell structural integrity. ConclusionsYbF3-containing CSCs with nanostructured hydroxyapatite and calcium carbonate are well suited for dental application.

글래스아이오노머에 대한 나노 하이드록시아파타이트의 최적 첨가 비율(나노 하이드록시아파타이트의 첨가 비율에 따른광중합형 글래스아이오노머의 결합강도와 탈회저항성의 변화 비교)

이 연구의 목적은 광중합형 글래스아이오노머인 Fuji II <TEX>$LC^{TM}$</TEX>를 대조군으로 삼고 다양한 비율의 나노 하이드록시아파타이트(HA ; hydroxyapatite)를 첨가하여 최적의 물성을 나타내는 HA의 첨가비율을 알아보는 것이다. 각각 무게비로 5~30%의 나노 HA를 첨가하여 HA-5, HA-10, HA-15, HA-20, HA-25, HA-30의 여섯 개의 실험군을 설정하였으며 ISO 9917-2:2004 기본 규정에 따른 물리적 성질과 탈회저항성, 결합강도 실험을 시행하고 주사전자 현미경을 통해 탈회양상과 파절 양상을 관찰하였다. 결합강도 실험 결과 HA의 함량이 증가하면서 결합강도는 증가하여 HA-15 군에서 최대치를 기록하였다(p < 0.05). 탈회 저항성 실험으로 4일간의 탈회 후 CLSM을 이용하여 탈회면을 관찰한 결과, HA 첨가군에서 탈회 구간의 감소가 나타났으나 HA의 첨가량에 따른 유의한 차이는 없었다. 주사전자현미경 상에서 탈회면을 관찰한 결과에서는HA 입자가 탈회된 법랑질의 미세공극을 채우고 있는 양상이 나타났다. The aim of this study was to evaluate changes in demineralization resistance and bonding strength of light cured glass ionomer after the addition of nano hydroxyapatite in various ratios. Fuji II LC GIC (GC Co., Japan) was used as the control group and also as a base material for experimental group. HA was mixed into the RMGIC at various ratio to create a HA-LC GIC mixture, preparing six experimental groups, i.e. 5%, 10%, 15%, 20%, 25%, 30% HA-LC GIC. According to the results, the bonding strength increased due to the addition of HA, showing the maximum value at the 15% nano HA group (p < 0.05). Under CLSM observation after 4 days of demineralization, the HA groups were more resistant to demineralization compared to the control group. No significant difference was observed between HA groups. In analysis through SEM, the HA groups showed attachment of granular materials and decreased demineralized tooth surfaces under influence of HA particles.

Electrical and Dielectric Behavior of Nano-bio Ceramic Filler Incorporated Polymer Electrolytes for Rechargeable Lithium Batteries

A series of nanocomposite solid polymer electrolytes (NCSPE) consisting of PMMA as host polymer, lithium bisoxalatoborate (LiBOB) as doping salt and nano-hydroxy apatite as filler have prepared by membrane hot-press method. To enhance the electrochemical properties and stiffness of polymer electrolyte film, a bioactive ceramic filler nano-hydroxy apatite is incorporated in the polymer matrix. The prepared different weight contents of NCSPE films are subjected to various electrochemical characterizations such as ionic conductivity, electric modulus and dielectric spectroscopy studies. The complexation behavior and structural reorganization in polymer electrolytes are confirmed by means of FT-IR (Fourier-Transform Infra Red Spectroscopy) analysis. The electrical response and relaxation of dipole in polymer electrolytes are investigated by means of electric modulus and dielectric studies. The addition of nano-hydroxy apatite significantly enhances the ionic conductivity and blocking the reorganizing tendency of polymer matrix. The maximum ionic conductivity is found to be in the range of 10-4.8 S/cm for sample containing 10 wt. % nanoceramic filler.

Hydroxyapatite-Reinforced Polyamide 6,6 Nanocomposites through Melt Compounding

Hydroxyapatite-reinforced polyamide 6,6 nanocomposites were prepared for load-bearing bone implant applications. Nanoparticles of hydroxyapatite (nHAp) were synthesized through a wet chemical reaction and were incorporated into the polymer melt at different loading fractions by melt compounding so as to sensitively modulate the mechanical properties of the latter. Tensile properties of the nanocomposites were found to be substantially improved at filler loading fractions as low as 3 wt%. Theoretical calculations also confirm the improved extent of reinforcement for nanocomposites over the predicted data for conventional micro counterparts. Differential scanning calorimetry studies revealed that the melting and crystallization characteristics of the polyamide matrix were unaltered with the incorporation of nHAp. However, the addition of nanohydroxyapatite considerably influenced the thermal stability of the nanocomposites.

Proliferation and Differentiation of MC 3T3-E1 Cells Cultured on Nanohydroxyapatite/chitosan Composite Scaffolds

Nanohydroxyapatite/chitosan composite scaffolds were fabricated and the proliferation and differentiation of preosteoblast MC 3T3-E1 on them were examined for the assessment of their biocompatibility. Nanohydroxyapatite was combined with chitosan in situ using a chemical method and a porous structure was then obtained through lyophilization. Preosteoblast MC 3T3-E1 cells were inoculated into the porous composite scaffolds and chitosan scaffolds, respectively. The morphology of cells cultured on the scaffolds was examined after staining it with Wright's stain. Their proliferation was assessed using MTT assay. After being cultured in conditioned medium for 30 days, the cells' alkaline phosphatase (ALP) activities on the scaffolds were studied in situ to compare their differentiation level. Moreover, the alkaline phosphatase activities were assessed with a quantitative ALP examination kit. The expression level of characteristic osteogenic gene was evaluated using Reverse Transcription–Polymerase Chain Reaction (RT-PCR). The results indicated that MC 3T3-E1 cells grown on the composite scaffolds showed a higher proliferation rate and spread better than that on chitosan scaffolds. The alkaline phosphatase stain results showed that the alkaline phosphatase activity of cells on composite scaffolds was significantly higher than that on the chitosan scaffolds. In addition, the quantitative examination of alkaline phosphatase activity indicated that the cells cultured on the composite scaffolds expressed an activity level 8 times higher than that on chitosan scaffolds. Simultaneously, the osteogenic gene osteopontin ( OPN) of cells cultured on composite scaffolds showed a higher expression level than that on chitosan scaffolds. Another osteogenic gene osteocalcin ( OC) was expressed in cells cultured on composite scaffolds, whereas it was not detected in cells on chitosan scaffolds. The addition of nanohydroxyapatite in the scaffolds improved not only the proliferation but also the differentiation of preosteoblast cultured on them. The composite scaffolds showed good biocompatibility and bioactivity. These scaffolds would be promising in bone tissue engineering.