Addition Of Hydroxyapatite Research Articles

Effect of process parameters on the synthesis and lead ions removal performance of novel porous hydroxyapatite sheets prepared via non-aqueous precipitation method

Herein, porous hydroxyapatite sheets with high lead ions removal performance are synthesized via self-assembly non-aqueous precipitation method, and the effects of process parameters on the synthesis and lead ions removal performance are systematically investigated. The optimized precursors concentration, the molar ratio of calcium to phosphorus and the calcination temperature are 0.25 mol/L, 1.67 and 650 °C, respectively. The refinement XRD, FE-SEM and EDS tests of the optimized samples show that the samples have a porous sheet structure with uniform pore size and wall thickness. The lead ions removal rate of hydroxyapatite sheets has the maximum value of 99.6% when the hydroxyapatite addition amount is 1 g/L. The lead ions removal content is the maximum of 1303.6 mg/g when the initial lead ions concentration is 9 mmol/L. The removal mechanism of lead ions by porous hydroxyapatite sheets prepared in this work is the composite mechanisms of surface adsorption, surface complexation and ions exchange. The hydroxyapatite porous sheet material prepared by optimizing the process parameters in this study has the advantages of high removal capacity and wide adaptability, so it is expected to become a novel adsorbent to solve lead-containing wastewater.

NOVEL PIEZOELECTRIC AND OSTEOCONDUCTIVE NANOFIBRES FOR BONE TISSUE ENGINEERING

The current procedures being applied in the clinical setting to address osteoporosis-related delayed union and nonunion bone fractures have been found to present mostly suboptimal outcomes. As a result, bone tissue engineering (BTE) solutions involving the development of implantable biomimetic scaffolds to replace damaged bone and support its regeneration are gaining interest. The piezoelectric properties of the bone tissue, which stem primarily from the significant presence of piezoelectric type I collagen fibrils in the tissue's extracellular matrix (ECM), play a key role in preserving the bone's homeostasis and provide integral assistance to the regeneration process. However, despite their significant potential, these properties of bone tend to be overlooked in most BTE-related studies. In order to bridge this gap in the literature, novel hydroxyapatite (HAp)-filled osteoinductive and piezoelectric poly(vinylidene fluoride-co-tetrafluoroethylene) (PVDF-TrFE) electrospun nanofibers were developed to replicate the bone's fibrous ECM composition and electrical features. Different HAp nanoparticle concentrations (1–10%, wt%) were tested to assess their effect on the physicochemical and biological properties of the resulting fibers. The fabricated scaffolds displayed biomimetic collagen fibril-like diameters, while also presenting mechanical features akin to type I collagen. The increase in HAp presence was found to enhance both surface and piezoelectric properties of the fibers, with an improvement in scaffold wettability and increase in β-phase nucleation (translating to increased piezoelectricity) being observed. The HAp-containing scaffolds also exhibited an augmented bioactivity, with a more comprehensive surface mineralization of the fibers being obtained for the scaffolds with the highest HAp concentrations. Improved osteogenic differentiation of seeded human mesenchymal stem/stromal cells was achieved with the addition of HAp, as confirmed by an increased ALP activity, calcium deposition and upregulated expression of key osteogenic markers. Overall, our findings highlight, for the first time, the potential of combining PVDF-TrFE and HAp to develop electroactive and osteoinductive nanofibers for BTE.Acknowledgements: The authors thank FCT for funding through the projects InSilico4OCReg (PTDC/EME-SIS/0838/2021), OptiBioScaffold (PTDC/EME-SIS/4446/2020) and BioMaterARISES (EXPL/CTM-CTM/0995/2021), the PhD scholarship (2022.10572.BD) and to the research institutions iBB (UIDB/04565/2020 and UIDP/04565/2020) and Associate Laboratory i4HB (LA/P/0140/2020).

Nanofibrous electrospun scaffold doped with hydroxyapatite derived from sand lobster shell (Panulirus homarus) for bone tissue engineering.

Healing of significant segmental bone defects remains a challenge, and various studies attempt to make materials that mimic bone structures and have biocompatibility, bioactivity, biodegradability, and osteoconductivity to native bone tissues. In this work, a nanofiber scaffold membrane of polyvinyl alcohol (PVA)/polyvinylpyrrolidone (PVP)/chitosan (CS) combined with hydroxyapatite (HAp) from sand lobster (SL; Panulirus homarus) shells, as a calcium source, was successfully synthesized to mimic the nanoscale extracellular matrix (ECM) in the native bone. The HAp from SL shells was synthesized by co-precipitation method with Ca/P of 1.67 and incorporated into the nanofiber membrane PVA/PVP/CS synthesized by the electrospinning method with varying concentrations, i.e. 0, 1, 3, and 5% (w/v). Based on the morphological and physicochemical analysis, the addition of HAp into the nanofiber successfully showed incorporation into the nanofiber with small agglomeration at HAp concentrations of 1, 3, and 5% (w/v). This led to a smaller fiber diameter with higher concentration of Hap, and incorporating HAp into the nanofiber could improve the mechanical properties of the nanofiber closer to the trabecula bone. Moreover, in general, swelling due to water absorption increases due to higher hydrophilicity at higher HAp concentrations and leads to the improvement of the degradation process and protein adsorption of the nanofiber. Biomineralization in a simulated body fluid (SBF) solution confirms that the HAp in the nanofiber increases bioactivity, and it can be seen that more apatite is formed during longer immersion in the SBF solution. The nanofiber PVA/PVP/CS HAp 5% has the most potential for osteoblast (MC3T3E1) cell viability after being incubated for 24 h, and it allowed the cell to attach and proliferate. Additionally, the higher HAp concentration in the nanofiber scaffold membrane can significantly promote the osteogenic differentiation of MC3T3E1 cells. Overall, the PVA/PVP/CS/HAp 5% nanofiber scaffold membrane has the most potential for bone tissue engineering.

Polyvinyl alcohol/Polyvinylpyrrolidone/Chitosan Nanofiber Scaffold with Hydroxyapatite from Sand Lobster Shells (Panulirus homarus) for Bone Tissue Engineering

In this work, nanofiber scaffold membrane polyvinyl alcohol (PVA)/polyvinylpyrrolidone (PVP)/Chitosan (CS)/hydroxyapatite (HAp) from sand lobster (SL; Panulirus homarus) shells have successfully synthesized to mimic the extracellular matrix (ECM) nanoscale in the native bone. HAp was synthesized by co-precipitation method with Ca/P was 1.67, then nanofiber membrane PVA/PVP/CS/HAp was synthesized by electrospinning method. Nanofiber solution was prepared from PVA 10% (w/v) polymer solution that dissolved in the distilled water, then the PVP/CS 15% (w/v) polymer solution was dissolved in acetic acid 1% (v/v) separately. The PVA polymer solution and PVP/CS solution were mixed with a ratio of 8.5: 1.5 (v/v). HAp dispersed into mixture solution with variation concentration 0, 1, 3, and 5 wt%. The composite solution was put into a 10 ml syringe with a hole diameter = 0.5 mm. Electrospinning was carried out at a 10 kV voltage, the flow rate at 0.1 ml/h, and the distance between the collector to the tip was 12 cm. Nanofiber scaffold membrane was characterized using SEM, FTIR, and XRD. The addition of HAp into the fiber showed incorporation into nanofiber with small agglomeration in the concentration of HAp at 1, 3, and 5 wt%. Based on the physicochemical analysis, the nanofiber scaffold PVA/PVP/CS/HAp 5 wt% with a fiber diameter of 0.328 ± 0.049 μm has the most potential to be used for bone tissue engineering.

The effect of incorporating hydroxyapatite into Type II glass ionomer cement on flexural strength and the examination of fractured surfaces using scanning electron microscopy

Background: Glass ionomer cement (GIC) is widely recognized as the prevailing direct esthetic restorative material. In order for a restoration material to be considered effective, possess favorable physical and mechanical properties. Incorporating with hydroxyapatite (HA) can provide these properties. This research is to investigate the impact of integrating HA into GIC on the flexural strength and scanning electron microscopy (SEM) of the fractured surfaces. Methods: The study consisted of 28 samples of GIC, which are fabricated in the shape of rectangular prisms (25x2x2mm). The samples were divided into four groups n=7. Group 1 is a control group (GIC), Group 2 GIC+2%HA, group 3 GIC+2%HA, and GIC+4%HA. The flexural strength of the sample was evaluated by a Universal testing machine, followed by an examination of the fracture surface using SEM. Result: The Brown-Forsythe was used as data analysis to examine the flexural strength values across all groups, resulting in a statistically significant p-value of less than 0.05. The addition of HA does not result in a significant increase in the flexural strength value of the glass ionomer cement (GIC). The integration of microstructure based on scanning electron microscopy (SEM) pictures demonstrates improved visual quality following the incorporation of HA. Conclusion: The addition of HA to GIC did not result in a significant change in flexural strength compared to the control group. However, GIC group with 2% HA exhibited the highest average flexural strength value among all the groups

KARAKTERISASI BIODEGRADASI PADA KOMPOSIT POLYMER POLYLACTID ACID (PLA) DENGAN PENAMBAHAN CHITOSAN DAN HYDROXYAPATITE

Polylactid Acid (PLA) is a biodegradable polymer made from natural ingredients so it is safe to use for biomaterials. The purpose of this study was to determine the biodegradation characteristics of the addition of chitosan powder and Hydroxyapatite to PLA. There were 4 variations in this study, namely PLA 100 (pure PLA), PLA-chitosan-Hydroxyapatite 94-3-3 (Composite 1), PLA-chitosan-Hydroxyapatite 94-0-6 (Composite 2), PLA-chitosan-Hydroxyapatite 94-6-0 (Composite 3). Samples were prepared using the extrusion method to form filaments, then the filaments were injected with a temperature of 170-190°C and an injection pressure of 5-6 bar. Characterization was carried out using the Immerse Test, FTIR Test, and SEM-EDS Test. The results of the Immerse Test showed an increase in sample mass of 1.04%, 1.1%, 1.05% and 1.14% respectively. FTIR test results did not show any new functional groups in the composite. The results of the SEM test indicated the presence of Na and Cl deposits on the sample surface as evidenced by the results of the EDS test that all samples contained Na and Cl elements. So that the weight gain occurs because the three materials are not chemically mixed which easily separate and cause cavities, these cavities are filled with HBSS liquid.

Gelling characteristics of fish surimi gel added with calcium hydroxyapatite (HAp)

Surimi is widely used as the main ingredient for various innovative seafood products (ISP), e.g., imitation crab meat, fish balls, fish sausage, kamaboko, fish sticks, and paupiette. Sodium chloride (NaCl), a primary ingredient of surimi, plays an important role in gelling and flavor. A reduced-NaCl product is preferred by consumers due to health-related reasons. This study focuses on evaluating the gelling characteristics of fish surimi gel formulated with different levels (0.5, 1, and 1.5%) of calcium hydroxyapatite (HAp). Surimi gel added with HAp showed a good gel-forming ability (p<0.05). The texture profile analysis indicated an acceptable value. As for the water-holding capacity (76.88%), the highest value (p<0.05) was recorded for 1% of HAp addition. On the contrary, the cooking loss (21.09%), expressible moisture content (23.48%), and whiteness index (70.20) for samples with 1% HAp were the lowest compared to other samples. This preliminary finding suggests that the addition of calcium HAp at 0.5 to 1% could be an alternative ingredient to NaCl for maintaining gelling characteristics of surimi. It also adds nutritional value to the product. This finding could be a reference to the industry in improving the processing of surimi-based products.

Multifunctional electrospun nanofibrous scaffold enriched with alendronate and hydroxyapatite for balancing osteogenic and osteoclast activity to promote bone regeneration.

Electrospun composite nanofiber scaffolds are well known for their bone and tissue regeneration applications. This research is focused on the development of PVP and PVA nanofiber composite scaffolds enriched with hydroxyapatite (HA) nanoparticles and alendronate (ALN) using the electrospinning technique. The developed nanofiber scaffolds were investigated for their physicochemical as well as bone regeneration potential. The results obtained from particle size, zeta potential, SEM and EDX analysis of HA nanoparticles confirmed their successful fabrication. Further, SEM analysis verified nanofiber's diameters within 200-250nm, while EDX analysis confirmed the successful incorporation of HA and ALN into the scaffolds. XRD and TGA analysis revealed the amorphous and thermally stable nature of the nanofiber composite scaffolds. Contact angle, FTIR analysis, Swelling and biodegradability studies revealed the hydrophilicity, chemical compatibility, suitable water uptake capacity and increased in-vitro degradation making it appropriate for tissue regeneration. The addition of HA into nanofiber scaffolds enhanced the physiochemical properties. Additionally, hemolysis cell viability, cell adhesion and proliferation by SEM as well as confocal microscopy and live/dead assay results demonstrated the non-toxic and biocompatibility behavior of nanofiber scaffolds. Alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRAP) assays demonstrated osteoblast promotion and osteoclast inhibition, respectively. These findings suggest that developed HA and ALN-loaded PVP/PVA-ALN-HA nanofiber composite scaffolds hold significant promise for bone regeneration applications.

An HA/PEEK scaffold with modified crystallinity via 3D-bioprinting for multiple applications in hard tissue engineering

Hard tissues, especially teeth and bones, are highly mineralized and the large-scale defect or total loss of them is irreversible. There is still no ideal strategy for the reconstruction of various hard tissue defects that can achieve the balance between biological and mechanical properties. Polyether ether ketone (PEEK) has the potential to substitute for natural hard tissue in defect areas but is limited by its biological inertness. The addition of hydroxyapatite (HA) can significantly improve the osteogenic properties and osteointegration of PEEK materials. But the mechanical properties of HA/PEEK scaffolds are far from satisfaction making scaffolds easy to fracture. We put forward a strategy to balance the mechanical and biological properties of HA/PEEK scaffolds via the regulation of the inner crystallinity and HA mixing ratio and we systematically evaluated the modified HA/PEEK scaffolds through material characterization, in vitro and in vivo experiments. And we found that the 20%HA/PEEK scaffolds with low crystallinity achieved the required strength and elasticity, and exhibited the characteristics of promoting the proliferation, migration and osteogenic differentiation of bone marrow mesenchymal stem cells. The results of the implantation of beagles’ teeth, mandible and rib showed that the 20%HA/PEEK scaffold with low crystallinity could well withstand the local complex force in the defect area and combine well with natural bone tissue, which made it a candidate for a practical versatile hard tissue engineering scaffold.

Shape memory thermoplastic polyurethane/polycaprolactone blend and composite with hydroxyapatite for biomedical application

Depending on its composition, thermoplastic polyurethane (TPU)/polycaprolactone (PCL) blend may present interesting properties for biomedical applications. Here, we have extensively developed and characterized blends of TPU/PCL and composites with 5, 10, and 20 wt% of hydroxyapatite (HA). The thermal, rheological, and mechanical characterizations showed that the blends present an intermediate behavior between pure TPU and PCL. The 75TPU/25PCL blend exhibited the best shape memory performance at temperatures below 50 °C. Filaments of this blend presented a fixation rate of 86.6% and a recovery rate of 73.3% at 50 ℃. The addition of HA had little influence on the shape memory properties; on the other hand, it strengthened the material, reaching elastic modulus values close to 100 MPa. In vitro tests revealed a biocompatible behavior for all blends, and the composite with 10 wt% HA from the 75TPU/25PCL blend demonstrated greater cell proliferation compared to the other composites.Graphical abstract

The Effect of Nano Hydroxyapatite on the Bond Strength of Acrylic Teeth Repaired to an Acrylic Resin Denture Base Using Two Types of Auto Polymerized Acrylic Resins

The insufficiently binder between acrylic teeth and dentures is considered to be the primary cause of teeth fractures from the dentures and is one of the disadvantages of acrylic denture base material. This research has been conducted to assess various concentrations of Nano hydroxyapatite addition on the shear bond between repaired acrylic teeth and polymer. One-hundred specimens of resin were split into two main subdivisions. 50 specimens were repaired with cold cured Duracryl Plus and the other 50 were repaired with a special type of acrylic O-cry1. Each one was sectioned into tested groups depending on (1%., 2%., 3%, and 5% by wt. of nano hydroxyapatite) incorporation and control group (0% of nano hydroxyapatite) with (n=10). The Universal testing machine was utilized for shear bond strength measurement. The obtained values were diffracted by t-test, ANOVA, and LSD-test. There was an increase in bond strength that repairing with O-cry1 than Duracryl Plus with a heightening in the bond strength, which was seen with incorporating nano hydroxyapatite into the acrylic resin with a significant difference between them. The 2% wt. Nano hydroxyapatite group demonstrated the maximum mean values, while those for the 5% wt. Nano hydroxyapatite group were recording minimum value with a significant difference between them. Repairing with O-cry1 recording better bond strength than Duracryl Plus acrylic. Furthermore, the addition of hydroxyapatite in Nano-form has successfully improved the “shear bond strength” of teeth to the PMMA at 2% wt. nano hydroxyapatite.

A toxicokinetics approach using Enchytraeus crypticus to evaluate the efficiency of hydroxyapatite to remediate soils contaminated with rare earth elements

Extensive rare earth element (REE) mining activities pose threats to agricultural soils surrounding the mining areas. Here, low and high REE-contaminated soils from farmlands around mine tailings were remediated with hydroxyapatite. A toxicokinetic approach was applied to assess whether the use of hydroxyapatite reduced the bioavailability of REEs and thus inhibited their accumulation in the terrestrial organism Enchytraeus crypticus. Our results showed that addition of hydroxyapatite increased soil pH, DOC and anion contents. CaCl2-extractable REE concentrations significantly decreased, indicating the stabilization by hydroxyapatite. The influence of hydroxyapatite on the REE accumulation in enchytraeids was quantified by fitting a toxicokinetic model to dynamic REE body concentrations. The estimated uptake (Ku) and elimination rate constants (Ke), and bioaccumulation factor (BAF) for REEs were in the range of 0.000821 – 0.122 kgsoil/kgworm day−1, 0.0224 – 0.136 day−1, and 0.00135 – 1.96, respectively. Both Ku and BAF were significantly reduced by over 80% by hydroxyapatite addition, confirming the decreased REE bioavailability. Low atomic number REEs had higher BAFs in slightly contaminated soil, suggesting a higher bioaccumulation potential of light REEs in soil organisms. Overall, chemical stabilization with amendments can attenuate the bioavailability of REEs and reduce the potential ecological risk of contaminated agricultural soils near REE mining areas.

CNT incorporation improves the resolution and stability of porous 3D printed PLGA/HA/CNT scaffolds for bone regeneration

In this study, 3D printed porous poly(lactide-co-glycolide) (PLGA) and its nanocomposites with 5 wt. % hydroxyapatite (HA) and 0.5, 1 and 2 wt. % carboxyl-functionalized multi-walled carbon nanotube (CNT) scaffolds were fabricated by using extrusion-based printing. The printing parameters were optimized by rheological studies. The rheological studies demonstrated shear thinning properties for all compositions and an increase in storage modulus was observed after the addition of CNT. Porous PLGA/HA/CNT scaffolds were printed by applying a pressure of 4.76 bar at 125 °C. The addition of 0.5 wt. % of CNT reduced the strut size and increased the porosity from 42% to 60%. The increase in storage modulus and decrease in strut size were related to hydrogen bonding between CNT, HA and PLGA which ultimately improved shape fidelity. The scaffolds were characterized by analysis of their chemical structure, water contact angle measurement, in vitro bioactivity test, biodegradation test, mechanical analysis, and in vitro cell studies. The scaffolds were found to be more hydrophilic by the incorporation of CNTs. Also, degradation studies showed that the microstructure of the scaffold became more stable with the addition of HA and CNT. The compressive modulus of PLGA/HA/CNT2 scaffold was found to be 548.5 MPa, which is found suitable to replace cancellous bone. The scaffolds were found to be highly biocompatible which is possibly due to alignment of CNT and PLGA during 3D printing process. Alizarin red staining indicated improvement of mineralization of MC3T3-E1 cells on the CNT incorporated porous 3D scaffolds. The results suggest that the produced porous 3D printed PLGA/HA/CNT scaffolds are promising for bone regeneration applications.

Polymer and composite materials used in medicine

The article is a review of the literature on the use of polymers in medicine as biomaterials.Examples of the preparation of the most commonly used synthetic polymers in medicine, such as: polylactide(PLA), polyglycolide (PGA), polyhydrobutyrate (PHB), polycaprolactone (PCL) are described.The characteristics of ceramic materials: hydroxyapatite (HAp) and tricalcium phosphate (TCP) are alsopresented in terms of the use of synthetic biodegradable polymers as biofillers. The last part of articleis devoted to the functional properties of composites based on PLA with the addition of HAp and TCP.

Polymer and composite materials used in medicine

The article is a review of the literature on the use of polymers in medicine as biomaterials.Examples of the preparation of the most commonly used synthetic polymers in medicine, such as: polylactide(PLA), polyglycolide (PGA), polyhydrobutyrate (PHB), polycaprolactone (PCL) are described.The characteristics of ceramic materials: hydroxyapatite (HAp) and tricalcium phosphate (TCP) are alsopresented in terms of the use of synthetic biodegradable polymers as biofillers. The last part of articleis devoted to the functional properties of composites based on PLA with the addition of HAp and TCP.

Porcelain Ceramic Tile Manufactured with the Addition of Hydroxyapatite in Ceramic Formulations

In this study, we developed formulations of a clay, kaolin, quartz, talc, and feldspar ceramic coating as a standard formulation, with the addition of Hap to improve the mechanical characteristics of the final product. The addition of Hap will help to fill the gaps in the formulation. Furthermore, it could lower the sintering temperature due to the high presence of calcium oxide in its composition. The main mineralogical phases (mullite, quartz, and anorthite) were identified in the sintered samples by X-ray diffraction. After evaluating the physical–mechanical properties (water absorption, linear shrinkage, apparent porosity, and resistance to flexion), the incorporation of Hap (5% in weight, 10% in weight, and 20% in weight) significantly altered the physical and mechanical properties of the final product, where we obtained, in relation to the standard formulation, an increase of more than 15% in mechanical resistance.

Research on Cartilage 3D Printing Technology Based on SA-GA-HA.

Cartilage damage is difficult to heal and poses a serious problem to human health as it can lead to osteoarthritis. In this work, we explore the application of biological 3D printing to manufacture new cartilage scaffolds to promote cartilage regeneration. The hydrogel made by mixing sodium alginate (SA) and gelatin (GA) has high biocompatibility, but its mechanical properties are poor. The addition of hydroxyapatite (HA) can enhance its mechanical properties. In this paper, the preparation scheme of the SA-GA-HA composite hydrogel cartilage scaffold was explored, the scaffolds prepared with different concentrations were compared, and better formulations were obtained for printing and testing. Mathematical modeling of the printing process of the bracket, simulation analysis of the printing process based on the mathematical model, and adjustment of actual printing parameters based on the results of the simulation were performed. The cartilage scaffold, which was printed using Bioplotter 3D printer, exhibited useful mechanical properties suitable for practical needs. In addition, ATDC-5 cells were seeded on the cartilage scaffolds and the cell survival rate was found to be higher after one week. The findings demonstrated that the fabricated chondrocyte scaffolds had better mechanical properties and biocompatibility, providing a new scaffold strategy for cartilage tissue regeneration.

Description of Biofilm Density on Glass Ionomer Cement Modified by 5% Hydroxyapatite from the Synthesis of Chicken Eggshells

Background: Oral microbiome biofilms can appear on all surfaces of the oral cavity as well as restorative materials such as Glass Ionomer Cement (GIC). GIC is considered superior because it has the ability to produce fluoride, which has a cariostatic effect, but the fluoride produced is inadequate to inhibit the growth of biofilms, so modifications were made by adding hydroxyapatite from eggshell. Purpose: To evaluate the levels of hydroxyapatite contained in chicken eggshells and to assess the description of oral microbiome biofilm density on the surface of hydroxyapatite-modified GIC from chicken eggshell synthesis. Methods: The research group was divided into a control group, namely GIC without the addition of hydroxyapatite, and a treatment group, namely GIC with the addition of 5% hydroxyapatite. The oral microbiome biofilm obtained from the voluntary dental plaque swab was cultured on the specimen surface at a time span of 24 hours, 48 hours, and 72 hours. Biofilm density was examined using Scanning Electron Microscopy and analyzed using ImageJ software. Results: The average density of biofilm on GIC without the addition of hydroxyapatite at 24 hours, 48 hours, and 72 hours, respectively, was 2,640.02 p/μm, 1,130.08 p/μm, 16,797.33 p/μm. Meanwhile, the GIC with the addition of hydroxyapatite was 1,921.52 p/μm, 1.029 p/μm, and 5,764.50 p/m. Conclusion: Statistical analysis performed showed that time affected the density value of the oral microbiome formed, and the two groups of materials had different effects in reducing biofilm density descriptively but statistically did not have a significant difference.

Construction and performance study of double-layer periosteal material for repairing bone tissue damage

Microscopic observation is necessary for the treatment of bone tissue microloss. To observe the process of bone tissue maturation is an essential research content in the field of orthopaedics. In many cases, people have to distinguish between new bone and mature bone, sometimes involving software calculation, and conventional HE staining obviously cannot fully meet the requirements. The quality of imaging directly affects the therapeutic effect of medical staff. In order to prove the effect of laser scanning confocal microscope (LSCM) on the observation of bone tissue micro damage, a piece of pig iliac bone and a piece of human femoral head were selected. The two kinds of bone tissue were divided into three small pieces respectively, and then stained with calcein green and alizarin red, or added with 5 ml of 1000 ml/L ethanol, and then placed under the LSCM and fluorescein Scanning under light microscope. This article uses silk fibroin as the raw material to prepare high-strength bilayer membranes using rotary evaporation method. Through relevant performance experiments, the results show that the mechanical properties of the double-layer silk fibroin film are about 12.48 MPa, and the tensile strength at break is about 13.66%. With the addition of hydroxyapatite, the mechanical properties of the silk fibroin film are improved. The addition of VEGF has little effect on the mechanical properties, and the addition of growth factor has little effect on the tensile strength of the material. The double-layer silk fibroin membrane was degraded in protease for 2 weeks, with a mass loss of about 19.3%. There was almost no degradation phenomenon in PBS solution; The release of VEGF from the double-layer silk fibroin membrane was about 17.3% after 2 weeks, with a relatively fast release rate in the early stage, and then the rate slowed down. The total release of VEGF decreased compared to the pure SF/VEGF membrane. Through the analysis of the scanning image, it is found that the image signal-to-noise ratio of alizarin red stained human femoral head is 6.956 higher than that of fluorescence microscope. In terms of image error rate, fluorescence microscope is 4.228 higher than laser scanning confocal microscope. The edge definition of laser scanning confocal microscope was 22.17 higher than that of fluorescence microscope, and the image clarity of stained bone tissue was higher than that of bone tissue only added ethanol. Therefore, the imaging effect of bone tissue staining is better, and the image generated by LSCM is higher than that generated by fluorescence microscope.

Fabrication of osteogenesis induced WE43 Mg-Hydroxyapatite composites with low biodegradability and increased biocompatibility for orthopedic implant applications

Good biocompatibility, low biodegradation rate and excellent mechanical properties are essential for desirable performance of metallic biomaterials during osseointegration process. In the present study, bioabsorbable WE43 Mg alloy was used for fabrication of bio-composites with addition of nanosized hydroxyapatite (HA) particles by means of multi pass friction stir processing (FSP) for orthopedic implant applications. Microstructure, in vitro biodegradation and biocompatibility, wettability, and microhardness of resultant bio-composites were characterized. Results showed that applying severe plastic deformation through FSP caused significant grain refinement of Mg matrix and homogenous dispersion of fragmented secondary phase particles. Moreover, applying higher number of FSP passes increased uniformity of distribution of HA nanoparticles throughout Mg matrix. Compared to coarse grain samples, grain refined samples showed lower Mg2+ concentration and H2 evolution in simulated body fluid (SBF). Moreover, addition of HA into Mg matrix, reduced Mg2+ release and H2 evolution. The bio-composites illustrated uniformly and flatly corroded surface compared to samples without HA nanoparticles. During immersion of the bio-composites in SBF solution, a cauliflower structure of Ca–P compounds deposited on the surface of bio-composites which confirmed acceptable biomineralization. Contact angle measurement demonstrated that wettability of fabricated bio-composites increased by increasing number of FSP passes. Mouse osteoblast MC3T3 cell culture indicated that the fabricated bio-composites with uniform distribution of HA nanoparticles showed excellent in vitro biocompatibility, cell viability, and cell proliferation. Eventually, it was found that applying further FSP and presence of HA nanoparticles resulted in increased microhardness which is an indication of higher load-bearing capability of the fabricated bone implants.