Bone Composition Research Articles

Osseointegrative and immunomodulative 3D-Printing Ti6Al4V-based implants embedded with biogenic hydroxyapatite

Although titanium-based metal implants have become a game changer in dental and orthopedic therapies, they still have several problems such as late osseointegration and immune response. In this study, we present a novel strategy to develop Ti6Al4V-based implants embedded with biogenic hydroxyapatite derived from equine bone to overcome these problems. A selective laser melting technique was employed for facile fabrication with flexible fusing feedstock and regular uniform distribution of equine bone. The physicochemical characteristics, cell attachment and proliferation, osteogenic differentiation, osseointegration, inflammatory response, and metabolomics of the developed Ti6Al4V/equine bone composite were then investigated. The Ti6Al4V-based composite integrated with equine bone at a certain concentration has improved the crystalline structure (β-Ti) suitable for implantation and exhibited higher hydrophilicity and protein adsorption. They significantly promoted cell attachment, osteogenic differentiation, and anti-inflammatory effects in vitro. In vivo study confirmed the osseointegration and alleviated inflammatory responses. Furthermore, the Ti6Al4V-based implants integrated with equine bone significantly reduced metabolites associated with inflammatory responses both in vitro and in vivo. The observed reduction in inflammatory responses suggests a subsequent promotion of osteogenesis. These promising results position the Ti6Al4V-based implant integrated with equine bone as a potential candidate for replacing conventional dental and orthopedic implants.

Immature porcine cortical bone mechanical properties and composition change with maturation and displacement rate

Computational models of mature bone have been used to predict fracture; however, analogous study of immature diaphyseal fracture has not been conducted due to sparse experimental mechanical data. A model of immature bone fracture may be used to aid in the differentiation of accidental and non-accidental trauma fractures in young, newly ambulatory children (0–3 years). The objective of this study was to characterize the evolution of tissue-level mechanical behavior, composition, and microstructure of maturing cortical porcine bone with uniaxial tension, Raman spectroscopy, and light microscopy as a function of maturation. We asked: 1) How do the monotonic uniaxial tensile properties change with maturation and displacement rate; 2) How does the composition and microstructure change with maturation; and 3) Is there a correlation between composition and tensile properties with maturation? Elastic modulus (p < 0.001), fracture stress (p < 0.001), and energy absorption (p < 0.014) increased as a function of maturation at the quasistatic rate by 110%, 86%, and 96%, respectively. Fracture stress also increased by 90% with maturation at the faster rate (p = 0.001). Fracture stress increased as a function of increasing displacement rate by 28% (newborn p = 0.048; 1-month p = 0.004; 3-month p= < 0.001), and fracture strain decreased by 68% with increasing displacement rate (newborn p = 0.002; 1-month p = 0.036; 3-month p < 0.001). Carbonate-to-phosphate ratio was positively linearly related to elastic modulus, and fracture stress was positively related to carbonate-to-phosphate ratio and matrix maturation ratio. The results of this study support that immature bone is strain-rate dependent and becomes more brittle at faster rates, contributing to the foundation upon which a computational model can be built to evaluate immature bone fracture.

Investigating the in vitro antibacterial efficacy of composite bone cement incorporating natural product-based monomers and gentamicin

ObjectiveThe objective of this study is to investigate the impact of four natural product extracts, namely, aloe-emodin, quercetin, curcumin, and tannic acid, on the in vitro bacteriostatic properties and biocompatibility of gentamicin-loaded bone cement and to establish an experimental groundwork supporting the clinical utility of antibiotic-loaded bone cements (ALBC).MethodsBased on the components, the bone cement samples were categorized as follows: the gentamicin combined with aloe-emodin group, the gentamicin combined with quercetin group, the gentamicin combined with curcumin group, the gentamicin combined with tannic acid group, the gentamicin group, the aloe-emodin group, the quercetin group, the curcumin group, and the tannic acid group. Using the disk diffusion test, we investigated the antibacterial properties of the bone cement material against Staphylococcus aureus (n = 4). We tested cell toxicity and proliferation using the cell counting kit-8 (CCK-8) and examined the biocompatibility of bone cement materials.ResultsThe combination of gentamicin with the four natural product extracts resulted in significantly larger diameters of inhibition zones compared to gentamicin alone, and the difference was statistically significant (P < 0.05). Except for the groups containing tannic acid, cells in all other groups showed good proliferation across varying time intervals without displaying significant cytotoxicity (P < 0.05).ConclusionIn this study, aloe-emodin, quercetin, curcumin, and tannic acid were capable of enhancing the in vitro antibacterial performance of gentamicin-loaded bone cement against S. aureus. While the groups containing tannic acid displayed moderate cytotoxicity in in vitro cell culture, all other groups showed no discernible cytotoxic effects.

Degradable Nanohydroxyapatite-Reinforced Superglue for Rapid Bone Fixation and Promoted Osteogenesis.

Bone glue with robust adhesion is crucial for treating complicated bone fractures, but it remains a formidable challenge to develop a "true" bone glue with high adhesion strength, degradability, bioactivity, and satisfactory operation time in clinical scenarios. Herein, inspired by the hydroxyapatite and collagen matrix composition of natural bone, we constructed a nanohydroxyapatite (nHAP) reinforced osteogenic backbone-degradable superglue (O-BDSG) by in situ radical ring-opening polymerization. nHAP significantly enhances adhesive cohesion by synergistically acting as noncovalent connectors between polymer chains and increasing the molecular weight of the polymer matrix. Moreover, nHAP endows the glue with bioactivity to promote osteogenesis. The as-prepared glue presented a 9.79 MPa flexural adhesion strength for bone, 4.7 times that without nHAP, and significantly surpassed commercial cyanoacrylate (0.64 MPa). O-BDSG exhibited degradability with 51% mass loss after 6 months of implantation. In vivo critical defect and tibia fracture models demonstrated the promoted osteogenesis of the O-BDSG, with a regenerated bone volume of 75% and mechanical function restoration to 94% of the native tibia after 8 weeks. The glue can be flexibly adapted to clinical scenarios with a curing time window of about 3 min. This work shows promising prospects for clinical application in orthopedic surgery and may inspire the design and development of bone adhesives.

In vitro development and optimization of cell-laden injectable bioprinted gelatin methacryloyl (GelMA) microgels mineralized on the nanoscale

Bone defects may occur in different sizes and shapes due to trauma, infections, and cancer resection. Autografts are still considered the primary treatment choice for bone regeneration. However, they are hard to source and often create donor-site morbidity. Injectable microgels have attracted much attention in tissue engineering and regenerative medicine due to their ability to replace inert implants with a minimally invasive delivery. Here, we developed novel cell-laden bioprinted gelatin methacrylate (GelMA) injectable microgels, with controllable shapes and sizes that can be controllably mineralized on the nanoscale, while stimulating the response of cells embedded within the matrix. The injectable microgels were mineralized using a calcium and phosphate-rich medium that resulted in nanoscale crystalline hydroxyapatite deposition and increased stiffness within the crosslinked matrix of bioprinted GelMA microparticles. Next, we studied the effect of mineralization in osteocytes, a key bone homeostasis regulator. Viability stains showed that osteocytes were maintained at 98 % viability after mineralization with elevated expression of sclerostin in mineralized compared to non-mineralized microgels, showing that mineralization can effectively enhances osteocyte maturation. Based on our findings, bioprinted mineralized GelMA microgels appear to be an efficient material to approximate the bone microarchitecture and composition with desirable control of sample injectability and polymerization. These bone-like bioprinted mineralized biomaterials are exciting platforms for potential minimally invasive translational methods in bone regenerative therapies.

Resistance training effects on pubertal children with a risk of developing pediatric dynapenia

PurposeMany modern-day children are at risk of pediatric dynapenia (muscle weakness). We examined the effects of a 12-week resistance training (RT) program on neuromuscular function and body composition parameters in pubertal children with a risk of dynapenia.MethodsTwelve children (13.4 ± 0.9 y) with dynapenia performed a progressive RT program consisting of knee extension and flexion, bench press, abdominal crunch, back extension, lateral pull-down, elbow flexion, and upright row (1–2 sets of 10–15 repetitions/exercise) twice/week for 12 weeks. Outcome measures included one-repetition maximum (1-RM) strength, maximal voluntary isometric contraction (MVIC) torque, rate of torque development (RTD), electromyographic (EMG) activity, muscle thickness (MT), muscle quality (MQ) assessed by echo intensity (MQEI) of the knee extensors and specific tension of MVIC torque to thigh fat-free mass (MQST), and total and regional body and bone composition assessed by dual-energy X-ray absorptiometry. Changes in the measures before and after the 12-week RT and associations among the measures were analyzed by linear mixed models.ResultsSignificant (p < 0.05) increases in 1-RM (63.9 ± 4.5%), MVIC torque (16.3 ± 17.8%), MT (18.8 ± 5.5%) and MQ (MQEI: -25.9 ± 15.2%; MQST: 15.1 ± 18.8%;) were evident from pre- to post-training. Total fat-free mass (FFM) increased by 2.3 ± 3.2% from baseline (p = 0.01), but no changes (p > 0.05) in the other measures were observed. Significant (p < 0.05) associations between the changes in 1-RM and/or MVIC torque and the changes in quadriceps MT, MQEI, MQST and total body FFM were evident.ConclusionsThe 12-week RT was effective for improving neuromuscular and body composition parameters, and thereby reversed the risk of pediatric dynapenia.

Biomechanical comparison of composite and cadaveric humeri models in experiments on operated humeral shaft fractures

A study was undertaken to determine how well contacting fracture fragments of composite bone replicated the behavior of fracture fragments in real bone. Ten composite and ten real humeral diaphyses were transected and reconstructed with limited-contact dynamic-compression plates. Two screws were placed on each side of the transection site and a calibrated electronic sensor sheet was placed between the imitated fracture fragments. After insertion of the distal screws, pressure measurements were made during insertion of the first proximal screw in compression mode, during insertion of the second screw in compression mode after loosening the first screw, and finally after retightening the first screw. The process was repeated after bending the plate. The contact area, the net compression force and the average compressive stress were computed and statistically compared. The composite bone and cadaveric bone differed in contact area and compressive stress but not in net compressive force. Plate bending did not produce a significant difference between composite and cadaveric bone. The results indicate that composite bone does not reproduce all the local fracture fragment conditions so that hardware testing in composite bone should proceed carefully. A gap between fracture fragments as is often used in comminuted fracture tests may remain as the most appropriate situation for fracture hardware testing.

Chitosan-Based Hierarchical Scaffolds Crosslinked with Genipin

Osteochondral defects present significant challenges for effective tissue regeneration due to the complex composition of bone and cartilage. To address this challenge, this study presents the fabrication of hierarchical scaffolds combining chitosan/β-tricalcium phosphate (β-TCP) to simulate a bone-like layer, interconnected with a silk fibroin layer to mimic cartilage, thus replicating the cartilage-like layer to mimic the native osteochondral tissue architecture. The scaffolds were produced by freeze-drying and then crosslinking with genipin. They have a crosslinking degree of up to 24%, which promotes a structural rearrangement and improved connection between the different layers. Micro-CT analysis demonstrated that the structures have distinct porosity values on their top layer (up to 84%), interface (up to 65%), and bottom layer (up to 77%) and are dependent on the concentration of β-tricalcium phosphate used. Both layers were confirmed to be clearly defined by the distribution of the components throughout the constructs, showing adequate mechanical properties for biomedical use. The scaffolds exhibited lower weight loss (up to 7%, 15 days) after enzymatic degradation due to the combined effects of genipin crosslinking and β-TCP incorporation. In vitro studies showed that the constructs supported ATDC5 chondrocyte-like cells and MC3T3 osteoblast-like cells in duo culture conditions, providing a suitable environment for cell adhesion and proliferation for up to 14 days. Overall, the physicochemical properties and biological results of the developed chitosan/β-tricalcium phosphate/silk fibroin bilayered scaffolds suggest that they may be potential candidates for osteochondral tissue strategies.

Multi-scale cortical bone traits vary in females and males from two mouse models of genetic diversity.

Understanding the genetic basis of cortical bone traits can allow for the discovery of novel genes or biological pathways regulating bone health. Mice are the most widely used mammalian model for skeletal biology and allow for the quantification of traits that cannot easily be evaluated in humans, such as osteocyte lacunar morphology. The goal of our study was to investigate the effect of genetic diversity on multi-scale cortical bone traits of 3 long bones in skeletally-mature mice. We measured bone morphology, mechanical properties, material properties, lacunar morphology, and mineral composition of mouse bones from 2 populations of genetic diversity. Additionally, we compared how intrabone relationships varied in the 2 populations. Our first population of genetic diversity included 72 females and 72 males from the 8 inbred founder strains used to create the Diversity Outbred (DO) population. These 8 strains together span almost 90% of the genetic diversity found in mice (Mus musculus). Our second population of genetic diversity included 25 genetically unique, outbred females and 25 males from the DO population. We show that multi-scale cortical bone traits vary significantly with genetic background; heritability values range from 21% to 99% indicating genetic control of bone traits across length scales. We show for the first time that lacunar shape and number are highly heritable. Comparing the 2 populations of genetic diversity, we show that each DO mouse does not resemble a single inbred founder, but instead the outbred mice display hybrid phenotypes with the elimination of extreme values. Additionally, intrabone relationships (eg, ultimate force vs. cortical area) were mainly conserved in our 2 populations. Overall, this work supports future use of these genetically diverse populations to discover novel genes contributing to cortical bone traits, especially at the lacunar length scale.

3D printing of personalized magnesium composite bone tissue engineering scaffold for bone and angiogenesis regeneration

Critical-size trabecular bone defects remain challenging to treat in orthopedic clinical practice. This study utilized a polyethylene glycol dispersion method to uniformly disperse magnesium (Mg) and nano-hydroxyapatite (n-HA) in a polylactic acid (PLA) solution, resulting in the fabrication of an Mg/n-HA/PLA composite material. We next generated personalized bone repair scaffolds through Fused Deposition Modeling (FDM) 3D printing. The composite scaffolds were characterized, and their biocompatibility, osteogenic properties, and angiogenic capabilities were assessed through in vitro experiments. In vivo experiments were conducted to explore the pathways underlying osteogenesis and angiogenesis. The results confirmed that the properties and biological efficacy of the Mg composite material could be regulated by controlling the quantitative ratio of Mg. The results showed that the 10 % Mg composite group exhibited optimal osteogenic properties, whereas the 20 % Mg composite group showed the best angiogenic effects and the most promising induction properties. The beneficial effect of the composite scaffold was associated with the interconnected REK and FAK/HIF-1/VEGF signaling pathways. In conclusion, the Mg composite biomaterial exhibited desirable processability, mechanical properties, and degradability, and induced osteogenesis and angiogenesis. These features of composite scaffold meet the complex requirements for treating critical-size trabecular bone defects in load-bearing animals and having potential for clinical development and application.

Impact of heavy alcohol consumption on cortical bone mechanical properties in male rhesus macaques

Chronic heavy alcohol consumption may influence the skeleton by suppressing intracortical bone remodeling which may impact the quality of bone and its mechanical properties. However, this aspect has not been thoroughly assessed in either humans or animal models whose cortical bone microstructure resembles the microstructure of human cortical bone. The current study is the first to investigate the effects of chronic heavy alcohol consumption on various mechanical properties of bone in a non-human primate model with intracortical remodeling. Male rhesus macaques (5.3 years old at the initiation of treatment) were induced to drink alcohol and then given the choice to voluntarily self-administer water or ethanol (4 % w/v) for approximately 14 months, followed by three abstinence phases (lasting 34, 41, and 39–46 days) with approximately 3 months of ethanol access in between. During the initial 14 months of open-access, monkeys in the alcohol group consumed an average of 2.9 ± 0.8 g/kg/d ethanol (mean ± SD) resulting in a blood ethanol concentration of 89 ± 47 mg/dl in longitudinal samples taken at 7 h after the daily sessions began. To understand the impact of alcohol consumption on material properties, various mechanical tests were conducted on the distal tibia diaphysis of 2–5 monkeys per test group, including dynamic mechanical analysis (DMA) testing, nano-indentation, microhardness testing, compression testing, and fracture resistance curve (R-curve) testing. Additionally, compositional analyses were performed using Fourier-transform infrared (FTIR) spectroscopy. Significant differences in microhardness, compressive stress-strain response, and composition were not observed with alcohol consumption, and only minor differences were detected in hardness and elastic modulus of the matrix and osteons from nanoindentation. Furthermore, the R-curves of both groups overlapped, with similar crack initiation toughness, despite a significant decrease in crack growth toughness (p = 0.032) with alcohol consumption. However, storage modulus (p = 0.029) and loss factor (p = 0.015) from DMA testing were significantly increased in the alcohol group compared to the control group, while loss modulus remained unchanged. These results indicate that heavy alcohol consumption may have only a minor influence on the material properties and the composition of cortical bone in young adult male rhesus macaques.

Effect of using nano-particles of magnesium oxide and titanium dioxide to enhance physical and mechanical properties of hip joint bone cement

In this work, the effect of adding Magnesium Oxide (MgO) and Titanium Dioxide (TiO2) nanoparticles to enhance the properties of the bone cement used for hip prosthesis fixation. Related to previous work on enhanced bone cement properties utilizing MgO and TiO2, samples of composite bone cement were made using three different ratios (0.5%:1%, 1.5%:1.5%, and 1%:0.5%) w/w of MgO and TiO2 to determine the optimal enhancement ratio. Hardness, compression, and bending tests were calculated to check the mechanical properties of pure and composite bone cement. The surface structure was studied using Fourier transform infrared spectroscopy (FTIR) and Field emission scanning electron microscopy (FE-SEM). Setting temperature, porosity, and degradation were calculated for each specimen ratio to check values matched with the standard range of bone cement. The results demonstrate a slight decrease in porosity up to 2.2% and degradation up to 0.17% with NP-containing composites, as well as acceptable variations in FTIR and setting temperature. The compression strength increased by 2.8% and hardness strength increased by 1.89% on adding 0.5%w/w of MgO and 1.5%w/w TiO2 NPs. Bending strength increases by 0.35% on adding 1.5% w/w of MgO and 0.5% w/w TiO2 NPs, however, SEM scan shows remarkable improvement for surface structure.

Zinc isotope composition of enameloid, bone and muscle of gilt-head seabreams (Sparus aurata) raised in pisciculture and their relation to diet

The isotope ratios of zinc (66Zn/64Zn expressed as δ66Zn), a vital nutrient, increasingly demonstrate trophic discrimination among vertebrates, making δ66Zn a valuable dietary proxy for ecological, archaeological, and palaeontological studies. Given the novelty of the methodology, tissue-diet and tissue-tissue zinc isotope fractionation factors remain poorly understood and have so far only been studied in a few terrestrial mammals. Here, we investigate δ66Zn compositions of enameloid, bone, and white muscle of seven artificially-fed pisciculture gilt-head seabreams (Sparus aurata) from offshore Israel, in comparison to the Zn isotope composition of their diet. In addition, we also analysed δ66Zn values in the same tissues of wild-caught S. aurata, bluespotted seabream (Pagrus caeruleostictus) and grey triggerfish (Balistes capriscus) caught off the coast of Israel. We determine a tissue-diet δ66Zn offset for Sparus aurata of − 0.04 ± 0.09 ‰ (2SD) for bone, − 0.29 ± 0.06 ‰ (2SD) for enameloid, and − 0.45 ± 0.07 ‰ (2SD) for white muscle. Wild-caught fish have much higher among-individual δ66Zn variability with values distinct from the pisciculture S. aurata, documenting a much more isotopically heterogeneous diet consumed by the wild individuals. Still, tissue–tissue δ66Zn differences in wild-caught individuals are close to those observed in the pisciculture ones with progressively lower δ66Zn values in the order bone > enameloid > white muscle. Our results demonstrate predictable tissue-diet and tissue-tissue δ66Zn differences among fish hard and soft tissues and can be applied to identify the δ66Zn values of dietary input, thereby informing trophic (palaeo)ecological reconstructions.

Clinical and Radiographic Evaluation of Calcium Phosphate-Poly(lactide-co-glycolide) Graft in Regeneration of Intrabony Defects: Randomized Control Trial.

This study aims to evaluate the efficacy of calcium phosphate-poly(lactide-co-glycolide) composite graft in the regeneration of intrabony defects in chronic periodontitis patients over a period of 12 months. A total of 11 systemically healthy chronic periodontitis patients with 22 graftable sites were treated with calcium phosphate cement (CPC) bone graft (control group) and CPC-poly(lactic-co-glycolic acid)(PLGA) composite (test group) after flap reflection and debridement. Clinical parameters such as probing pocket depth (PPD) and clinical attachment level (CAL) were recorded at baseline and 3, 6, 9, and 12 months. Bone probing depth (BPD) and radiographic parameters such as defect depth (DD), changes in alveolar crest level (ALR), defect depth reduction (DDR), and percentage in defect depth reduction (PDDR) were calculated at baseline, and 6 and 12 months. The data were recorded and statistically analyzed. On intragroup comparison, there was a significant improvement in all the parameters over a period of 1 year (clinically and radiographically). However, there was no statistically significant difference between the two groups in any of the parameters though there was a slightly higher bone fill noted in the test group. Even though the CPC-PLGA composite bone graft showed a slight improvement in clinical and radiographic parameters as compared to the CPC graft, it was not statistically significant. A major drawback of Calcium Phosphate cements as bone grafts is their poor degradability. The PLGA microspheres degrade to expose macropores and interconnected pores in the graft substrate which in turn would promote the ingrowth of osteoblasts. Also, this composite graft is mouldable, and resorbable and has been shown to snugly fit into the defects making them a suitable scaffold material. How to cite this article: Ojha M, Pawar Chandrashekara Rao D, Gowda V. Clinical and Radiographic Evaluation of Calcium Phosphate-Poly(lactide-co-glycolide) Graft in Regeneration of Intrabony Defects: Randomized Control Trial. J Contemp Dent Pract 2023;24(12):921-927.

Comprehensive study through imaging techniques of the degradation of a resorbable calcium sulphate-based composite bone cement

The stabilization and treatment of vertebral compression fractures via vertebroplasty procedure foresees the injection of bone cements and recent research is focused on the use of degradable cements featuring an appropriate degradation kinetics. This study presents an investigation into the degradation behaviour of a resorbable ceramic composite cement based on calcium sulphate hemihydrate (CSH), supplemented with strontium-containing mesoporous bioactive glasses (Sr-MBG) and zirconia nanoparticles (ZrO2). The alterations in the material's microstructure resulting from the degradation process were thoroughly analysed using two image analysis techniques. Micro-computed tomography (Micro-CT) was employed for scanning, while CT-An software associated with the instrument and a Python-coded image analysis tool were utilised to assess porosity and pore size distribution over time. Comparative analysis of the obtained results demonstrated the efficacy of both techniques in comprehensively understanding the internal microstructural changes and volume variations during the degradation of the ceramic composite cement.

The Effect of Sex on the Chemical and Mineral Composition of the Meat, Bone and Liver of Giraffe (Giraffa giraffa angolensis)

Consumers tend to buy meat based on visual physical characteristics, which are affected by the chemical composition of the meat, and there is very little known about the chemical composition of the meat of giraffe. This study therefore aims to broaden the knowledge base on the chemical composition of giraffe meat, rib bone and liver. Eight different muscles from 15 giraffes were analyzed to determine the chemical composition, yielding an average moisture of 77.2 ± 0.09 g/100 g meat, an average protein of 20.8 ± 0.09 g/100 g meat, an average intramuscular fat (IMF) of 1.4 ± 0.03 g/100 g meat and an average ash of 1.1 ± 0.01 g/100 g meat. There was a significant interaction between sex and muscle for the moisture, protein and ash contents, while only muscle had an effect on the fat content. The mineral content of the bone, liver and Longissimus thoracis et lumborum muscle was also analyzed, and bone was found to be a rich source of calcium (highest concentration), whilst the liver had the highest concentration of iron. The chemical composition of the giraffe meat was such that it could be classified as lean meat.

Risk factors for periprosthetic femoral fracture risk around a cemented polished taper-slip stem using an osteoporotic composite bone model.

This biomechanical study aimed to determine if variations in stem material, stem geometry, stem offset and cement viscosity affect mechanical resistance to postoperative periprosthetic fracture (PFF) after hip arthroplasty with a commonly used cemented polished taper-slip (PTS) stem (CPT, Zimmer Biomet) in a novel osteoporotic composite femoral bone model. Thirty-six osteoporotic composite femoral models were tested using a standardised in-vitro loading technique to simulate a typical PFF. Outcome measures were torque to failure (N), fracture energy (N/m2) and rotation to failure (°). Comparisons were made by stem material (cobalt chrome vs stainless steel), stem geometry (CPT stem vs Exeter stem), stem offset (standard offset vs extra extended offset) and cement viscosity (high viscosity vs low viscosity). Statistical comparisons were carried out with significance set at p < 0.05. All tested samples produced clinically representative fracture patterns with varying degrees of bone and cement comminution. There was no statistically significant difference in torque to failure, fracture energy or rotation to failure between any of the compared variables (all p > 0.05). This is the first biomechanical study on mechanical resistance to PFF using osteoporotic composite bone models. For the CPT stem, it confirms that stem material, stem offset, stem geometry and cement viscosity do not affect mechanical resistance to PFF in an osteoporotic bone model.

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

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

Phytate utilization using feed grade acidifiers to improve tibia composition, gut microbiology and intestinal pH of broiler chickens

Phytate is an anti-nutrient in feedstuffs that inhibits nutrient utilization by chelating multivalent cations and other nutrients. Hence, the need to buffer feeds to improve digestibility. Two hundred and eighty eight (288) broiler finisher chickens were used for the study. They were allotted to four treatments each replicated thrice with twenty four (24) broiler chickens per replicate in a completely randomized design. The control diet had adequate available phosphorus at 0.5% while others were sub-optimal at 0.4%. Three acidifiers; Fysal®, Acidomix® and Orgacid® were supplemented in the diets of broiler chickens in treatments two to four at 0.1%. Investigations carried out were determination of intestinal pH, tibia bone compositions and gut microbiology. Broiler chickens fed with acidified diets showed significantly (P&lt;0.05) lower pH levels compared to those on the control diet. Tibia weight, calcium and robusticity index were significantly (P&lt;0.05) better in broiler chickens fed with diets containing acidifier supplementation. Those broiler chickens fed diets supplemented with Fysal® showed the best results in all tibia compositions. Organic acids significantly (P&lt;0.05) reduced Escherichia coli, Salmonella sp. and Staphylococcus sp. in the intestinal segments of broiler chickens fed with acidified diets. It was concluded that supplementation of organic acid in broiler chickens’ diets at 0.1% can reduce phytate’s chelation on fed minerals, improving bone mineralization and enhancing gut health for better performance.

Preparation and Properties of GO/ZnO/nHAp Composite Microsphere Bone Regeneration Material.

The purpose of this study is to explore the possibility of using graphene-zinc oxide-hydroxyapatite (GO/ZnO/nHAp) composite microspheres as bone regeneration materials by making use of the complementary advantages of nanocomposites, so as to provide reference for the clinical application of preventing and solving bacterial infection after implantation of synthetic materials. Firstly, GO/ZnO composites and hydroxyapatite nanoparticles were synthesized using the hydrothermal method, and then GO/ZnO/nHAp composite microspheres were prepared via high-temperature sintering. The graphene-zinc oxide-calcium phosphate composite microspheres were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), energy dispersion spectroscopy (EDS), water contact angle measurement, degradation and pH determination, and differential thermal analysis (DiamondTG/DTA). The biocompatibility, osteogenic activity, and antibacterial activity of GO/ZnO/nHAp composite microspheres were further studied. The results of the cell experiment and antibacterial experiment showed that 0.5% and 1% GO-ZnO-nHAp composite microspheres not only had good biocompatibility and osteogenic ability but also inhibited Escherichia coli and Staphylococcus aureus by more than 45% and 70%. Therefore, GO/ZnO/nHAp composite microspheres have good physical and chemical properties and show good osteogenic induction and antibacterial activity, and this material has the possibility of being used as a bone regeneration material.