Search

Osteomyelitis with a high recurrence rate. Timely-prevention can avoid severe consequence and death. However, conventional drug response-release has the disadvantages of unnecessary release and waste, causing ineffective prevention. Inspired by "Lattice-defense technology", gridding lesion areas and constructing a "Triggered-precise response-release system" may be an effective multiple-prevention method. Here, a new strict pH-triggered response drug controlled-release mechanism was proposed innovatively to construct a "Triggered-precise response-release system" and achieve multiple-effective prevention. PO 4 3- -Ce 3+ strict pH responsive release system is prepared through simultaneous hydration reaction of solution-polymerization and compounded in bone-implant. The dispersed system only targets micro-interface contact areas, achieving gridded management of the lesion site. In a normal environment, Ce 3+ is captured by PO 4 3- and kept electrostatic-attraction balance, ensuring the zero-concentration Ce 3+ release continuously. Once osteomyelitis recurs and pH decrease, H+ at the interface will combine with PO 4 3- under electrostatic drive and disrupt potential balance, achieving the release of Ce 3+ only when the infection recurs. In vivo experiments was confirmed effective prevention and excellent promote bone regeneration. The adoption of "Lattice defense technology" has achieved accuracy spatiotemporal of drug delivery. Even if other lesion sites unfortunately recur again, effective-prevention can be guaranteed. Bone-implant show great potential in preventing osteomyelitis., (© 2024 Wiley‐VCH GmbH.)

Near-infrared (NIR) persistent luminescence (PersL) materials have unique optical properties with promising applications in bioimaging and anticounterfeiting. However, their development is currently hindered by poor red-light-exciting ability. In this study, CaTiO 3 :Cr 0.001 ,Y 0.02 (CTCY) was synthesized with 650 nm-excited 772 nm NIR PersL. The Y 3+ doping in the Ca 2+ lattice plays a key role in the PersL property. A charge compensation mechanism was proposed, in which Cr 3+ in the Ti 4+ lattice was stabilized by Y 3+ -doping while oxygen vacancies were generated to store the excitation energy at the same time. A thermal ionization mechanism might elucidate the red-light-excited NIR PersL of CTCY, which benefits from the perovskite structure of CaTiO 3 . CTCY has 120 times more intense red-light-excited PersL than Zn 3 Ga 2 Ge 2 O 10 :Cr. Its potential applications in luminescence anticounterfeiting and bioimaging were demonstrated using a visible/NIR dual-channel PersL flower painting and a CTCY-labeled bone screw for in situ reactivable PersL imaging using red light illumination instead of X-ray, respectively. This study not only provides a new NIR PersL material but also will add to our understanding in developing other potential red-light- or even NIR-activable PersL materials with perovskite-like structures.

An opaque, white chitosan/ Hydroxyapatite nanocomposite was prepared by a simple blend method. Morphology, pore size and dispersion of nano-hydroxyapatite in chitosan matrix were visualized using SEM images. The FTIR and SEM with EDX analysis confirmed the bony apatite layer was formed on the outside of the composite. Porosity measurements and water uptake studies of the nanocomposite were evaluated which revealed the maximum porosity of 80% to 92% in the chitosan: hydroxyapatite nanocomposite at the ratio of 20:80. The results also showed that water absorption ability was inversely proportional to the hydroxyapatite present in the nanocomposite. The porosity of prepared nanocomposite was corresponding to the cancellous bone porosity of 50% to 90% suggesting possible applications in bone transplantation. The nanocomposite exhibited antibacterial activity towards the tested Gram-negative and Gram-positive species of bacteria and reduced the bacterial adhesion in biofilm formation.

Porous scaffolds can be used for treating bone defects. To manufacture porous scaffolds similar to bone, two types of ceramic scaffolds with different porosity, namely, octagon and rhombus scaffolds were designed and fabricated by Digital Lighting Process technology. Compression test, finite element analysis, computational fluid dynamics (CFD), and in vitro cell experiment were conducted for systematic investigation of the properties of the scaffolds. The results showed that the elastic modulus of alumina octagon and rhombus lattice structure was within 0.5–4 GPa. Through the CFD simulation, the permeability of the scaffold was found to be in the range of 4.10 × 10−9 to 2.32 × 10−8 m2 and the wall shear stress of different structures ranged from 4.9 × 10−4 to 84.4 mPa. Live/dead staining and Cell Counting Kit-8 assay showed that all groups were biocompatible and beneficial to cell proliferation except for octagon structure with 1.049 mm pore and rhombus structure with 0.6 mm pore. Analysis of the results of the mechanical properties, CFD simulations, and in vitro cell studies indicated that the porous scaffolds suitable for bone engineering were 0.566 mm-pore-size octagon unit and 1.0 mm-pore-size rhombus unit with elastic modulus of 3834.9 and 599.8 MPa, respectively.

Periodic cellular materials such as body-centered cubic, face-centered cubic, and triply periodic minimal surfaces, have been used to construct scaffolds for bone tissue engineering. Their use is suboptimal for reasons like stress concentration at nodes, and/or poor anisotropy. Stochastic structures can mimic the bone microarchitecture with anisotropic mechanical properties. While several methods exist for generating stochastic structures, they face limitations like being computationally expensive, complex, or only applicable in specific cases. In this work, scaffolds are created using level set equations which permit spatially controllable porosity. A 3D volume is populated with random nodes, which segment the 3D volume into subdomains. Each subdomain is occupied with a basic architecture generated through level-set equations. All the architectures in the subdomains are then smoothly integrated at sub-domain boundaries to form the stochastic scaffold. Stainless steel stochastic scaffolds with porosities from 58% to 70% were fabricated and their mechanical characteristics, as well as cell viability, was assessed. Young’s modulus of the scaffolds ranges from 0.02 to 2 GPa, in the same range as that of trabecular bone, thus, mitigating stress shielding. In-vitro assay displayed a statistically significant osteoblast growth from Day 1 to Day 3 in 58%, 61%, and 64% porosity scaffolds.

[Display omitted] • Nano/sub-micron pores, along with topography changes from LSPwC, cues for controlling gene expression and cell adhesion. • Surface oxide is mostly composed of mainly Ti4+ and a small amount of Ti3+ is crucial for tribo-corrosion resistance. • Synergistic porous topography and surface oxide crucial for tribo-corrosion, gene expression, and stem cell conformation. Laser shock peening without coating (LSPwC), a prospective surface modification technique for improving the mechanical aspects of Ti-6Al-4V alloy for automotive/aerospace sector, is also expected to dictate the efficiency of this material class for implant application. Here we unravel the impact of LSPwC on Ti-6Al-4V material surface characteristics, in-vitro tribocorrosion and biocompatibility. Micrography shows the presence of nano and sub-micron sized pores after LSPwC process. The role of nano and sub-micron sized pores along with topography modification induced by LSPwC to serve as cues for controlling gene expressions, cell adhesion and activities offer novel insights in this research direction. A detailed X-ray photoelectron spectroscopy analysis detected local chemical non-stoichiometry with reduced number of oxygen diffusion channels. A crucial outcome of this oxide layer modification is the negative skewness (−0.55 ± 0.11) and reduced kurtosis (3.49 ± 0.14) of the surface, along with localized plastic deformation. These factors are correlated with the shift in potential during fretting tribo-corrosion from −800 to −250 mV after LSPwC, accompanied by a lower coefficient of friction of 0.4. Furthermore, the presence of well-spread cells and the up-regulation of beneficial genetic markers (Ki67) on LSPwC surfaces have the potential to form a better bone-material interface. The findings open new frontiers of the LSPwC-treated Ti-6Al-4V surface to synergistically modulate the tribocorrosion and biocompatibility aspects, with exciting possibilities for biomedical implants. [ABSTRACT FROM AUTHOR]

Ion-substituted calcium phosphate (CP) coatings have been extensively studied as promising materials for biomedical implants due to their ability to enhance biocompatibility, osteoconductivity, and bone formation. This systematic review aims to provide a comprehensive analysis of the current state of the art in ion-doped CP-based coatings for orthopaedic and dental implant applications. Specifically, this review evaluates the effects of ion addition on the physicochemical, mechanical, and biological properties of CP coatings. The review also identifies the contribution and additional effects (in a separate or a synergistic way) of different components used together with ion-doped CP for advanced composite coatings. In the final part, the effects of antibacterial coatings on specific bacteria strains are reported. The present review could be of interest to researchers, clinicians, and industry professionals involved in the development and application of CP coatings for orthopaedic and dental implants.

3D printing, that is, additive manufacturing, has solved many major problems in general manufacturing, such as three-dimensional tissue structure, microenvironment control difficulty, product production efficiency and repeatability, etc., improved the manufacturing speed and precision of personalized bone implants, and provided a lot of support for curing patients with bone injuries. The application of 3D printing technology in the medical field is gradually extensive, especially in orthopedics. The purpose of this review is to provide a report on the related achievements of bone implants based on 3D printing technology in recent years, including materials, molding methods, optimization of implant structure and performance, etc., in order to point out the existing shortcomings of 3D printing bone implants, promote the development of all aspects of bone implants, and make a prospect of 4D printing, hoping to provide some reference for the subsequent research of 3D printing bone implants. [ABSTRACT FROM AUTHOR]

This review summaries more than three decades of scientific knowledge on electrodeposition of calcium phosphate coatings. This low-temperature process aims to make the surface of metallic bone implants bioactive within a physiological environment. The first part of the review describes the reaction mechanisms that lead to the synthesis of a bioactive coating. Electrodeposition occurs in three consecutive steps that involve electrochemical reactions, pH modification, and precipitation of the calcium phosphate coating. However, the process also produces undesired dihydrogen bubbles during the deposition because of the reduction of water, the solvent of the electrolyte solution. To prevent the production of large amounts of dihydrogen bubbles, the current density value is limited during deposition. To circumvent this issue, the use of pulsed current has been proposed in recent years to replace the traditional direct current. Thanks to breaking times, dihydrogen bubbles can regularly escape from the surface of the implant, and the deposition of the calcium phosphate coating is less disturbed by the accumulation of bubbles. In addition, the pulsed current has a positive impact on the chemical composition, morphology, roughness, and mechanical properties of the electrodeposited calcium phosphate coating. Finally, the review describes one of the most interesting properties of electrodeposition, i.e., the possibility of adding ionic substituents to the calcium phosphate crystal lattice to improve the biological performance of the bone implant. Several cations and anions are reviewed from the scientific literature with a description of their biological impact on the physiological environment. [ABSTRACT FROM AUTHOR]

The issues of designing bone implants capable of creating an electrical stimulus for bone tissue regeneration under the influence of an external magnetic field are considered. A promising method for generating local electric fields is the use of magnetoelectric (multiferroid) micro- and nanoparticles that are polarized under the action of an external magnetic field and create electric fields comparable in amplitude to endogenous ones. Of practical interest are composite magnetoelectric particles consisting of a ferrimagnetic core and a piezoelectric shell brought into close mechanical contact. Modeling the magnetoelectric effect in a composite particle is carried out; composite particles with cobalt ferrite as a magnetostrictor are fabricated, and the issues of the chemical interaction of phases are discussed. [ABSTRACT FROM AUTHOR]

Background and Aim: Calcium phosphate bioceramics have been used for at least a decade, and many investigations have focused on the use of hydroxyapatite (HA) derivative in the regeneration of bone defects. Biphasic calcium phosphate (BCP) is a biomaterial composed of HA and beta-tricalcium phosphate (BCP), with a structure similar to bone. The aim of the study was to determine the influence of the BCP/alginate scaffold on tissue growth, blood, the lungs, and the electrical activity of the heart during bone healing in the tibia of pig. Materials and Methods: Three pigs were implanted with BCP/alginate scaffolds in the tibias. Pigs were acclimatized and treated with antibiotics and anthelminthic drugs 14 days before implantation. Each pig was implanted with a BCP/ alginate scaffold in the right tibia and a defect without the implant was made in the left tibia as the control. Radiographic images of the tibia were captured 0, 7, 30, and 60 days after the operation. Erythrograms, radiography of the lungs, and electrocardiogram (ECG) recordings were done 0, 30, and 60 days after the operation. Results: Radiographic evaluations showed that the implant and peri-implant density of BCP decreased throughout the process of bone healing. The erythrogram profile indicated that a substantial amount of time (60 days) was required to adapt and return to pre-operative conditions. No significant differences in ECG recordings or pulmonary radiography were detected. Conclusion: The BCP/alginate scaffold did not induce a faster recovery rate from the bone defect compared to the control with no implant. However, the BCP/alginate scaffold was biodegradable, bioresorbable, and non-toxic.

This study aimed to obtain as much and as accurate information as possible about the process of osseointegration of titanium implants, through histological processing. For this purpose, the combination of a mercury chloride fixator (Stieve mixture) and a complex staining method (Goldner’s trichrome) was used, which can highlight the microscopic structures in several colors and shades. The Stieve mixture proved to have distinguished qualities both in the preservation of basophilic and acidophilic structures and especially in the chemical preparation of the substrate for the binding of each structural component with a specific acidophilic dye. On the substrate thus prepared, the acidophilic dyes used in the Goldner’s trichrome staining highlighted the structural components in different colors and shades, offering the possibility of high precision assessment of the newly proliferated bone, in different stages of proliferation, consolidation and reshaping. Complex information was obtained, which allows the appreciation of osseointegration for endosseous implants and the amount of proliferated bone at the bone-implant interface, the stage of proliferation, consolidation and reshaping of the mature bone, the degree of fixation to deep bone structures. The possibility of complex assessment of the osseointegration process for endosseous implants at a given time is of great practical importance for correct assessment of the waiting time required for safe installation of prosthesis. The combination of Stieve fixator mixture with Goldner’s trichrome staining method has proven to be very effective in histology, highlighting on excellent level the existing structural components of each stage, in which the osseointegration process goes through. A very important role in this combination was achieved by mercury chloride mixture, which prepared the substrate for specific reaction with dyes. Regarding the results obtained, we recommend this combination for histological investigations aimed on bone proliferation and repair.

Magnesium (Mg) alloy shows great potential as bone implant owing to its favourable biocompatibility and degradability. In the present work, bioglass-reinforced Mg-based composite was manufactured via laser additive manufacturing. The results showed that too low a volumetric energy density (Ev) resulted in the appearance of open pores on the surface, which significantly deteriorated the densification behaviour. In contrast, too high an Ev caused the occurrence of the‘balling phenomenon’ with discontinuous surface, because of the excessive liquid formation and extended pool lifetime. Under a proper Ev of 185.19 J/mm3, favourable part with high densification rate was obtained. Meanwhile, the refined grains together with orderly dispersed reinforcing particles contributed to the enhanced mechanical properties. Significantly, the incorporated bioglass promoted the apatite deposition on Mg matrix, which served as an effective protection layer and reduced the degradation rate. Furthermore, it also improved the cell growth and differentiation, showing great potential in clinical bone repair.

Abstract Si3N4 ceramics show excellent characteristics of mechanical and chemical resistance in combination with good biocompatibility, antibacterial property and radiolucency. Therefore, they are intensively studied as structural materials in skeletal implant applications. Despite their attractive properties, there are limited data in the field about in vitro studies of cellular growth on ceramic implant materials. In this study, the growth of bone cells was investigated on porous silicon nitride (Si3N4) ceramic implant by using electrochemical impedance spectroscopy (EIS). Partial sintering was performed at 1700 °C with limited amount of sintering additive for the production of porous Si3N4 scaffolds. All samples were then sterilized by using ethylene oxide followed by culturing MG-63 osteosarcoma cells on the substrates for in vitro assays. At 20 and 36 h, EIS was performed and results demonstrated that magnitude of the impedance as a result of the changes in the culture medium increased after incubation with osteosarcoma cells. The changes are attributed to the cellular uptake of charged molecules from the medium. Si3N4 samples appear to show large impedance magnitude changes, especially between 100 and 1 Hz. Impedance changes were also correlated with WST-1 measurements (36 h) and DAPI results.

Cuttlefish bones are an inexpensive source of calcium carbonate, which are produced in large amounts by the marine food industry, leading to environmental contamination and waste. The nontoxicity, worldwide availability and low production cost of cuttlefish bone products makes them an excellent calcium carbonate precursor for the fabrication of hydroxyapatite. In the present study, a novel oil-bath-mediated precipitation method was introduced for the synthesis of hydroxyapatite (Hap) nanorods using cuttlefish bone powder as a precursor (CB-Hap NRs). The obtained CB-Hap NRs were investigated using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA) techniques to evaluate their physicochemical properties. The crystallite size (20.86 nm) obtained from XRD data and the elemental analysis (Ca/P molar ratio was estimated to be 1.6) showed that the Hap NRs are similar to that of natural human bone (≈1.67). Moreover, the FTIR data confirmed the presence of phosphate as a functional group and the TGA data revealed the thermal stability of Hap NRs. In addition, the antibacterial study showed a significant inhibitory effect of CB-Hap NRs against S. aureus (zone of inhibition – 14.5 ± 0.5 mm) and E. coli (13 ± 0.5 mm), whereas the blood compatibility test showed that the CB-Hap NRs exhibited a concentration-mediated hemolytic effect. These biogenic CB-Hap NRs with improved physicochemical properties, blood compatibility and antibacterial efficacy could be highly beneficial for orthopedic applications in the future.

This review is focused on potential or already implemented applications of hydroxyapatite (HA) - zeolite composites as a human bones implant. The methodology is to synthesize and broaden the collection of literature published in the last ten years. The reviews are divided into two main sections, namely the synthesis and the characterization of HA-zeolite composites as candidates for human bone implants. Each article that has the same topic, whether it is about synthesis or characterization, is grouped, reviewed, and synthesized. The review generally covers important aspects of material testing and the results of the study. All reviewed literature shows that HA-zeolite composites can be produced by various methods. The chemical and morphological properties are suitable with the nature of human bones. The composites are also suitable as coatings on metal bone implants from Ti6Al4V and SS316L. In conclusion, HA-zeolite composites are potentially used as human bone implant material.

Polyetheretherketone (PEEK) is a thermoplastic polymer that has been recently employed for bone tissue engineering as a result of its biocompatibility and mechanical properties being comparable to human bone. PEEK, however, is a bio-inert material and, when implanted, does not interact with the host tissues, resulting in poor integration. In this work, the surfaces of 3D-printed PEEK disks were functionalized with: (i) an adhesive peptide reproducing [351–359] h-Vitronectin sequence (HVP) and (ii) HVP retro-inverted dimer (D2HVP), that combines the bioactivity of the native sequence (HVP) with the stability toward proteolytic degradation. Both sequences were designed to be anchored to the polymer surface through specific covalent bonds via oxime chemistry. All functionalized PEEK samples were characterized by Water Contact Angle (WCA) measurements, Atomic Force Microscopy (AFM), and X-ray Photoelectron Spectroscopy (XPS) to confirm the peptide enrichment. The biological results showed that both peptides were able to increase cell proliferation at 3 and 21 days. D2HVP functionalized PEEK resulted in an enhanced proliferation across all time points investigated with higher calcium deposition and more elongated cell morphology.

Ceramic additive manufacturing currently relies on binders or high-energy lasers, each with limitations affecting final product quality and suitability for medical applications. To address these challenges, our laboratory has devised a surface activation technique for ceramic particles that eliminates the necessity for polymer binders or high-energy lasers in ceramic additive manufacturing. We utilized this method to 3D print bioactive SiC orthopedic screws and evaluated their properties. The study's findings reveal that chemical oxidation of SiC activated its surface, enabling 3D printing of orthopedic screws in a binder jet printer. Post-processing impregnation with NaOH and/or NH 4 OH strengthened the scaffold by promoting silica crystallization or partial conversion of silicon oxide into silicon nitride. The silica surface of the SiC 3D printed orthopedic screws facilitated osteoblast and neuron adhesion and extensive axon synthesis. The silicate ions released from the 3D printed SiC screws favorably modulated macrophage immune responses toward an M1 phenotype as indicated by the inhibition of TNFα secretions and of reactive oxygen species (ROS) expression along with the promotion of IL6R shedding. In contrast, under the same experimental conditions, Ti ions released from Ti6Al4V discs promoted macrophage TNFα secretion and ROS expression. In vivo tests demonstrated direct bone deposition on the SiC scaffold and a strong interfacial bond between the implanted SiC and bone. Immunostaining showed innervation, mineralization, and vascularization of the newly formed bone at the interface with SiC. Taken altogether, the 3D printed SiC orthopedic screws foster a favorable environment for wound healing and bone regeneration. The novel 3D printing method, based on ceramic surface activation represents a significant advancement in ceramic additive manufacturing and is applicable to a wide variety of materials., (© 2024 The Author(s). Journal of Biomedical Materials Research Part A published by Wiley Periodicals LLC.)

The biosafety of thermally calcined poultry manure as a hydroxyapatite source for potential use as bone-making material was investigated in this study. In vitro assays were used to determine the sensitivity of the antioxidant properties to the thermal calcination temperature used to process the poultry manure (750, 800, and 850 °C ). The effect of the extract of both calcined poultry manure (local) and analytical grade hydroxyapatite (foreign) at various concentrations of 100%-25 % inclusion at (100 mg/kg) body weight intubation for 21 days on kidney, liver, and serum of animal model used was assessed. The results show that the thermally calcined poultry manure-derived hydroxyapatite generally possessed good antioxidant properties with the poultry manure treated at 750 °C having the most promising antioxidant properties compared to those treated at 800 and 850 °C , and hence a more likely improved anti-toxicity potential. The various blends of the analytical high-grade hydroxyapatite and thermally calcined poultry manure hydroxyapatite samples are safe compared to the normal control rats with regards hepatic function and renal function parameters with the equal blend of analytical high grade and thermally calcined poultry manure-derived hydroxyapatite (1:1) possessing the lowest activity concentrations. In addition, the enzymatic (glutathione peroxidase) and non-enzymatic (reduced glutathione) antioxidant concentrations of the experimental animals administered the varied compositions of the analytical high grade and thermally calcined poultry manure-derived hydroxyapatite, were lower when compared to normal control rats. The microbiological evaluation suggests that the calcined poultry manure inclusion at various concentrations could not pose a negative effect on various pathology in the liver, kidney, and blood., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Kenneth Alaneme reports financial support was provided by Tertiary Education Trust Fund. Kenneth Alaneme reports article publishing charges was provided by National Research Fund. None If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

This study investigates the feasibility of coating Ni-Ti alloy with sea buckthorn extract via a hydrothermal method for targeted delivery of beneficial phenolic compounds to bone tissue. The qualitative analysis confirmed the presence of flavonoids and tannins in sea buckthorn extract, supporting its osteogenic potential. The microhardness of the NiTi alloy substrate was suitable for biomedical applications, and successful coating was achieved without compromising its properties. NiTi alloy samples were coated with 18.1, 20.1, and 12.4 mg of extract, respectively. Comprehensive evaluations confirmed the successful integration of the extract onto the alloy's surface. The coated system exhibited sustained release properties over five days, with the highest release occurring on the first day (on average 32.1 % for the first peak and 72.1 % for the second peak), as determined by HPLC analysis. The findings demonstrate the potential of this novel approach in developing dual-functionality implants for bone health promotion. Overall, this study underscores the promising potential of Ni-Ti alloy coated with sea buckthorn extract as a targeted drug delivery system for bone tissue., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Featured Application: Collaboration between material science and mechanical engineering can be used to drive improvements in medical implants and applications. Using a magnesium-based alloy, we developed a new suture anchor design with four distinctive parameters, and we optimized its structural performance. Our findings indicated that the Young's modulus of the newly developed magnesium-based alloy must be lower than that of industrial magnesium alloy for enhanced clinical results. A suture anchor is a medical device commonly used in rotator cuff repair surgery to attach tendons to the greater tuberosity of the humerus. Patient- and device-related factors, such as structural designs and poor bone density, can cause unsatisfactory clinical results. In this study, a new suture anchor design with four distinctive parameters was proposed, and the structural performance was optimized in a full factorial experimental design using finite element analysis. Two types of bone blocks—normal and osteoporotic bone—which received screw implants, were simulated to investigate the parametrical effects on various bone qualities. The prescribed motion at a constant removal velocity was used to evaluate the pullout strength. The von Mises criterion was employed in a force control simulation for topology optimization. Moreover, mechanical tests guided by ASTM-F543-17 were conducted for validation. This paper demonstrates the comprehensive process for developing a suture anchor with sufficient mechanical integrity for clinical use and clarifies the contributions of each distinctive design parameter in this application. [ABSTRACT FROM AUTHOR]

Autologous bone grafting remains the gold standard for almost all bone void‐filling orthopedic surgery. However, autologous bone grafting has several limitations, thus scientists are trying to identify an ideal synthetic material as an alternative bone graft substitute. Magnesium‐doped biphasic calcium phosphate (Mg‐BCP) has recently been in the spotlight and is considered to be a potential bone substitute. The Mg‐BCP is a mixture of two bioceramics, that is, hydroxyapatite (HA) and β‐tricalcium phosphate (β‐TCP), doped with Mg2+, and can be synthesized through chemical wet‐precipitation, sol–gel, single diffusion gel, and solid state reactions. Regardless of the synthesis routes, it is found that the Mg2+ preferentially accommodates in β‐TCP lattice instead of the HA lattice. The addition of Mg2+ to BCP leads to desirable physicochemical properties and is found to enhance the apatite‐forming ability as compared to pristine BCP. In vitro results suggest that the Mg‐BCP is bioactive and not toxic to cells. Implantation of Mg‐BCP in in vivo models further affirmed its biocompatibility and efficacy as a bone substitute. However, like the other bioceramics, the optimum physicochemical properties of the Mg‐BCP scaffold have yet to be determined. Further investigations are required regarding Mg‐BCP applications in bone tissue engineering. [ABSTRACT FROM AUTHOR]

Currently, metals such as titanium and various new high-performance engineering plastics such as polyether-ether-ketone (PEEK) are widely used in clinics. Compared with human cortical bone, traditional metals may cause stress shielding. In contrast, the elastic modulus of PEEK is slightly lower than that of human bones. In this study, PEEK and polymethyl methacrylate (PMMA) were electrospun into fibers and mixed with carbon fiber (CF). The mixture was then hot-pressed to prepare PEEK/PMMA/CF ternary composites. Mechanical tests showed that the Young's moduli of the PEEK/PMMA/CF ternary composites were between 4.67 ± 0.38 and 6.37 ± 0.81 GPa, similar to human bones. In vitro cytotoxicity tests, after 7 days of cell culture, showed that the relative growth rates were 86–97%, and the corresponding cytotoxicity levels were 0 or 1. In addition, in vivo experiments demonstrated that the ternary composites exhibited good histocompatibilities and displayed no rejection or inflammatory reactions. No artifacts were observed when the material was examined using X-ray, CT (computerized tomography computed tomography), and MRI (magnetic resonance imaging) scanning. Thus, the PEEK/PMMA/CF ternary composites fabricated in this study may be used as promising bone implant materials in orthopedic applications.

An opaque, white chitosan/ Hydroxyapatite nanocomposite was prepared by a simple blend method. Morphology, pore size and dispersion of nano-hydroxyapatite in chitosan matrix were visualized using SEM images. The FTIR and SEM with EDX analysis confirmed the bony apatite layer was formed on the outside of the composite. Porosity measurements and water uptake studies of the nanocomposite were evaluated which revealed the maximum porosity of 80% to 92% in the chitosan: hydroxyapatite nanocomposite at the ratio of 20:80. The results also showed that water absorption ability was inversely proportional to the hydroxyapatite present in the nanocomposite. The porosity of prepared nanocomposite was corresponding to the cancellous bone porosity of 50% to 90% suggesting possible applications in bone transplantation. The nanocomposite exhibited antibacterial activity towards the tested Gram-negative and Gram-positive species of bacteria and reduced the bacterial adhesion in biofilm formation. [ABSTRACT FROM AUTHOR]

For bone implants, osseointegration resulting in a good and fast bone–implant contact is of primary importance to secure a proper implant function and to avoid implant loosening or inflammation resulting in necessary revision surgeries causing pain to the patients and immense costs. In particular, polyetheretherketone (PEEK) is a promising implant material due to the close mechanical properties to bone, but it is entirely bio‐inert, hindering osseointegration and making surface functionalization necessary. Many different surface functionalization technologies have been reported of both physical and chemical nature. The same is true for the other prominent implant materials titanium and ceramics. Although they already have inherently better osseointegration than PEEK, they are much harder and stiffer than bone and brittle in the case of ceramics. Surface functionalization, which can be subdivided into surface coating and material modification, needs to be judged from a quality and safety viewpoint. However, a literature research resulted in the realization that no quality standard yet exists for implant surface functionalizations. This makes it difficult to near impossible to compare the safety and performance of different surface‐functionalized bone implants, clearly showing the need to establish a transparent quality evaluation system for bone implants. This perspective article gives the state of the art and then develops a quality evaluation system based on six main categories as important benchmarks for the quality of surface‐functionalized bone implant materials. A simple catalog of questions can be answered, and from the resulting scores the Safety and Performance Evidence Level (SPEL) representing the safety and quality of a given implant can be calculated as a percentage. This simple SPEL system allows an easy and transparent judgment and comparison of bone implants, ensuring the easy identification of safe and well‐performing high‐quality bone implants in the future. © 2020 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In this work, the stacking of different layers of silk fabric reinforced polycaprolactone biocomposites were prepared by compression moulding technique. The mechanical and biodegradation behaviour were investigated. The mechanical properties of the different layers of silk/polycaprolactone composite were observed. The 14 layers of silk/polycaprolactone composites showed higher mechanical properties when compared to other composites. This was due to its sufficient mechanical interlocking between the fabric and the matrix. Further, scanning electron microscopy analysis confirmed the good interfacial bonding between silk and polycaprolactone. The in-vitro degradation study revealed that silk/polycaprolactone composite uptakes more water due to hydrophilic nature of silk while polycaprolactone showed higher amount of weight loss. Though there was a decrease in trend in the tensile properties of composite, still they can be used as a biodegradable plate due to its adequate mechanical strength. The changes in pH of the composite were also noticed and found negligible. Thus, the biodegradable silk/polycaprolactone composites are a promising alternative implant for patients, as they provide temporary mechanical support and controlled rate of biodegradation for the bone plate application. [ABSTRACT FROM AUTHOR]

[Display omitted] • Complex polymer structures were grafted on PEEK to increase its biocompatibility. • SI-ATRP was used to synthesize hydrophilic polymer brushes over 300 nm. • High density of functional groups enhanced the formation of 3D HAp layers. • Extensive analysis of product hints its high potential of use in implantology. In the search of the ideal bone implant material, surface initiated atom transfer radical polymerization (SI-ATRP) techniques were successfully employed to modify the polyetheretherketone (PEEK) surface with complex architecture nanolayers featuring hydrophilic poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) or poly(2-hydroxyethyl methacrylate) (PHEMA) branches. As a result, polymer layers with height up to over 300 nm were synthesized to decrease the water contact angle from 92.8° to 23.0°. In-depth analysis of layer topography, structure and elemental composition realized with atomic force microscopy (AFM), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), time-of-flight secondary ions mass spectroscopy (TOF-SIMS) and X-ray photon spectroscopy (XPS) confirmed successful surface modification. Additionally, to demonstrate the applicability of proposed PEEK functionalization, the biomineralization assay in simulated body fluid (SBF) solution was conducted. The high density of hydroxyl and amine groups in branched polymer brushes structure enhanced the rate of hydroxyapatites (HAp) formation substantially. Compared to untreated PEEK, modification with polymer brushes resulted in the creation of cauliflower-like structures with high specific surface area and Ca/P ratio equal to 1.83–1.87 for PEEK grafted with brushes composed of PHEMA backbone segment and PDMAEMA or PHEMA as block polymer branches (PEEK- g -PHEMA- g -PDMAEMA or PEEK- g -PHEMA- g -PHEMA) after 2 weeks. Finally, the process of the hydroxyapatite formation and increase of the layer thickness in a range of 14 days to 6 weeks of immersion in SBF was thoroughly visualized by scanning electron microscopy (SEM). [ABSTRACT FROM AUTHOR]

Jin-Woo Park,1 Takao Hanawa,2 Jong-Hyuk Chung31Department of Periodontology, School of Dentistry, Kyungpook National University, Daegu 41940, Republic of Korea; 2Department of Metallic Biomaterials, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo 101-0062, Japan; 3Department of Periodontology, School of Dentistry, Kyung Hee University, Seoul, Republic of KoreaPurpose: Calcium (Ca) and magnesium (Mg) ions have been used as promising bioactive ions in the surface chemistry modification of titanium (Ti) bone implants to increase bone regeneration capacity. However, it is not clear which (Ca or Mg) plays the more important role in the early osteogenic differentiation of mesenchymal stem cells (MSCs) when applied to the surface of commercially available microstructured Ti implants. This study investigated the relative effect of these two ions on the early osteogenic functionality of primary mouse bone marrow MSCs in order to obtain insights into the surface design of Ti implants with enhanced early osteogenic capacity.Methods and results: Wet chemical treatment was performed to modify a microrough Ti implant surface using Ca or Mg ions. Both the Ca and Mg-incorporated surfaces accelerated early cellular events and the subsequent osteogenic differentiation of MSCs compared with an unmodified microrough Ti surface. Surface Mg modification exhibited a more potent osteoblast differentiation-promoting effect than the Ca modification. Surface Mg incorporation markedly inhibited the phosphorylation of β-catenin.Conclusion: These results indicate that alteration of the surface chemistry of microstructured Ti implants by wet chemical treatment with Mg ions exerts a more effect on promoting the early osteogenic differentiation of MSCs than Ca ions by enhancing early cellular functions, including focal adhesion development and stabilization of intracellular β-catenin.Keywords: divalent cations, surface chemistry, nanotopography, bone implant

This report aims to summarize key concerns regarding customized devices and conditional approval during the premarket evaluation of bone implants, and to explore the correlation between them. Based on the experience of approval of the first domestic custom‐designed bone implant, we consider the process of gaining conditional approval for urgently‐needed medical devices and medical devices for rare diseases, as well as the guidance available for clinical investigation. We also streamlined the scientifically administrative concept of this unique device, from the design and development of premarket technical evaluation to continuous post‐market study. The present study found that those two aspects have certain connections, but they are not directly correlated to each other. In contrast to the USA, Canada, Australia and the EU, where regulations and guidelines have been established for the use of customized devices, in this regard, China is still it its infancy. Thus, there is considerable potential for China to develop and perfect the policies relating to customized devices and to develop relevant strategies to ensure their efficacy with the aid of conditional approval. Appropriate scientific conditional approval for mass production of individualized anatomy‐matching bone implants could become a valuable approach for precision medicine.

Fixing bone fractures with controlled axial interfragmentary micromotion improves bone healing; however, the optimal type of implant construct for this purpose is still lacking. The present study describes a novel axial micromotion locking plate (AMLP) construct that allows axial interfragmentary micromotion of 0.3 or 0.6 mm. We investigated whether the AMLP constructs enhance bone healing compared to an ordinary locking plate (LP) using an ovine osteotomy model. The stiffness of the constructs was tested under axial loading. We created a 3-mm osteotomy in the left hind leg tibia of sheep that was then stabilized with a 0.3- or 0.6-mm AMLP or LP construct (n = 6/group). Bone healing was monitored weekly by X-ray radiography starting from week 3 after surgery. At week 9, the specimens were collected and evaluated by computed tomography and torsional testing. We found that the AMLPs had a lower stiffness than the LP; in particular, the stiffness of the 0.6-mm AMLP construct was 86 and 41% lower than that of the LP construct for axial loads 200 N, respectively. In the in vivo experiments, tibial osteotomies treated with the 0.6-mm AMLP construct showed the earliest maximum callus formation (week 5) and the highest volume of bone callus (9.395 ± 1.561 cm3 at week 9). Specimens from this group also withstood a 27% greater torque until failure than those from the LP group (P = 0.0386), with 53% more energy required to induce failure (P = 0.0474). These results demonstrate that AMLP constructs promote faster and stronger bone healing than an overly rigid LP construct. Moreover, better bone healing was achieved with an axial micromotion of 0.6 mm as compared to 0.3 mm.

Bone defects caused by surgery or trauma pose great essential challenges to modern clinical medicine. The donor limits traditional bone graft therapies. Thus, it is essential to find alternative therapies. Thanks to fatigue resistance and penetrating of X-rays, polyether ether ketone (PEEK) and its composites which have an elastic modulus similar to natural human bone and good biocompatibility and chemical stability, can be used as implantable material for spinal, trauma and orthopedic applications. Excellent wear resistance shows great superiority in artificial joint replacement. The stable chemical resistance and potential antimierobial activity make it play an important role in dental restorations as well. It is a potential material for the treatment of bone defects, but its surface hydrophobicity and biological inertia limit its application in biomedical science. Thus, improving the poor surface performances of PEEK and functioning PEEK become the focus of PEEK study at home and abroad. Inspired by bone tissue composition, structure and function, many strategies have been proposed to change PEEK structure and make PEEK surface functional. In order to make it better used in surgical clinical application, researchers adopted two different strategies of mixed modification and surface modification, so that the obtained PEEK-based material had better biocompatibility, osteointegration, antibacterial, angiogenesis, anti-tumor, immune regulation and multiple regulation properties. In this paper, various modification strategies for improving the biological activity of PEEK and the application status and prospect of PEEK-based materials in the biomedical field are reviewed. The modification strategies are going through single modification to multi-modification. Multi-modification will become the key of clinic applications of PEEK. [ABSTRACT FROM AUTHOR]

The high demand for bone grafts has motivated the development of implants with excellent osteogenic activity, whereas the risk of implant-associated infection, particularly given the rise of antimicrobial resistance, has compelled the development of implants with innovative antimicrobial strategies in which a small amount of bactericidal agent can effectively kill a wide range of bacteria. To induce antibacterial property, the surface of Grade-5 bone plate titanium implants used in clinical applications was modified using direct current (DC) sputter coating followed by thermal annealing. The 15 nm silver film-coated implants were thermally annealed in the furnace for 15 min at 750 °C. The modified implant surface's antibacterial efficacy against Escherichia coli ( E. coli ), Staphylococcus aureus ( S. aureus ), Salmonella typhi , and Methicillin-resistant staphylococcus aureus bacteria has been assessed using a colony-forming assay. On the modified implant surface, the growth of E. coli and S. aureus bacteria is reduced by 99.72%, while highly drug-resistant bacteria are inhibited by 96.59%. The MTT assay was used to assess the cytotoxicity of the modified bone-implant surface against NIH3T3 mouse fibroblast cells. The modified bone-implant surface promoted fibroblast growth and demonstrated good cytocompatibility. Furthermore, the mechanical properties of the implant were not harmed by this novel surface modification method. This method is simple and provides new insight into surface modification of commercial metallic implants to have effective antibacterial properties against various classes of bacteria., (© 2024 IOP Publishing Ltd.)

3D printing, that is, additive manufacturing, has solved many major problems in general manufacturing, such as three-dimensional tissue structure, microenvironment control difficulty, product production efficiency and repeatability, etc., improved the manufacturing speed and precision of personalized bone implants, and provided a lot of support for curing patients with bone injuries. The application of 3D printing technology in the medical field is gradually extensive, especially in orthopedics. The purpose of this review is to provide a report on the related achievements of bone implants based on 3D printing technology in recent years, including materials, molding methods, optimization of implant structure and performance, etc., in order to point out the existing shortcomings of 3D printing bone implants, promote the development of all aspects of bone implants, and make a prospect of 4D printing, hoping to provide some reference for the subsequent research of 3D printing bone implants.

The addition of biomaterials such as Calcium Hydroxyapatite (cHAp) and incorporation of porosity into poly-ether-ether-ketone (PEEK) are effective ways to improve bone-implant interfaces and osseointegration of PEEK composite. Hence, the morphological effects of nanocomposite on surfaces biocompatibility of a newly fabricated composite of PEEK polymer and cHAp for a bone implant, using additive manufacturing (AM) were investigated. Fused deposition modeling (FDM) method and a surface treatment strategy were employed to create a microporous scaffold. PEEK osteointegration was slow and, therefore, it was accelerated by surface coatings with the incorporation of bioactive cHAp, with enhanced mechanical and biological behaviors for bone implants. Characterization of the new PEEK/cHAp composite was done by X-ray diffraction (XRD), differential scanning calorimetry (DSC), mechanical tests of traction and flexion, thermal dynamic mechanical analysis (DMA). Also, the PEEK/cHAp induced the formation of apatite after immersion in the simulated body fluid of DMEM for different days to check its biological bioactivity for an implant. In-vivo results depicted that the osseointegration and the biological activity around the PEEK/cHAp composite were higher than that of PEEK. The increase in the mechanical performance of cHAp-coated PEEK can be attributed to the increase in the degree of crystallinity and accumulation of residual polymer. [ABSTRACT FROM AUTHOR]

Background and Aim: Calcium phosphate bioceramics have been used for at least a decade, and many investigations have focused on the use of hydroxyapatite (HA) derivative in the regeneration of bone defects. Biphasic calcium phosphate (BCP) is a biomaterial composed of HA and beta-tricalcium phosphate (BCP), with a structure similar to bone. The aim of the study was to determine the influence of the BCP/alginate scaffold on tissue growth, blood, the lungs, and the electrical activity of the heart during bone healing in the tibia of pig. Materials and Methods: Three pigs were implanted with BCP/alginate scaffolds in the tibias. Pigs were acclimatized and treated with antibiotics and anthelminthic drugs 14 days before implantation. Each pig was implanted with a BCP/alginate scaffold in the right tibia and a defect without the implant was made in the left tibia as the control. Radiographic images of the tibia were captured 0, 7, 30, and 60 days after the operation. Erythrograms, radiography of the lungs, and electrocardiogram (ECG) recordings were done 0, 30, and 60 days after the operation. Results: Radiographic evaluations showed that the implant and peri-implant density of BCP decreased throughout the process of bone healing. The erythrogram profile indicated that a substantial amount of time (60 days) was required to adapt and return to pre-operative conditions. No significant differences in ECG recordings or pulmonary radiography were detected. Conclusion: The BCP/alginate scaffold did not induce a faster recovery rate from the bone defect compared to the control with no implant. However, the BCP/alginate scaffold was biodegradable, bioresorbable, and non-toxic. [ABSTRACT FROM AUTHOR]

Multi-level porous material based on additive manufacturing, is a potentially disruptive material across multiple industries, including medical implants, thermal insulation and filtration. In this study, we propose a novel approach to fabricate materials with controllable pores via digital light processing (DLP) and decomposition of Al(OH) 3. DLP can be used to fabricate macro pores bigger than 300 μm. And the decomposition of Al(OH) 3 can result in micro pores of about 1 μm inside the scaffolds. The process parameters of curing, debinding and sintering temperature (1100−1500 ℃) of ceramic scaffolds with containing proportion of Al(OH) 3 (0−60 wt.%) were examined. The results indicated multi-level porous ceramic scaffold has controllable porosity and pore size distribution and meets the requirement of implant strength. Biological test show that ceramic scaffolds with multi-level pores promoted osteoblast proliferation and adhesion. The multi-level porous ceramic scaffolds prepared by DLP and decomposition of Al(OH) 3 have great prospects for the application in bone implants. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) is an inert material with excellent biocompatibility properties. A major issue that limits its use as a medical device is the difficult processing technique that requires hot pressing at a temperature (>2,000oC) and pressure (1,000–2,000 atm). In the present study, we developed a protocol to synthesize a porous SiC scaffold by pressing the powder at 50 MPa and heating at 900oC/2 hr. The surface of SiC was chemically modified by NaOH to facilitate sintering and induce bioactivity. Porous discs with 51.51 ± 3.17% porosity and interconnected pores in the size range from 1 to 1,000 μm were prepared using 40% PEG. The average compressive strength and Young's modulus of the scaffolds were 1.94 ± 0.70 and 169.2 ± 0.08 MPa, respectively. FTIR analysis confirmed the formation of biomimetic hydroxyapatite layer after 2 hr of immersion in simulated body fluid. The Ca/P ratio was dependent on the concentration of the silanol groups created on the material surface. Increasing the atomic % of silicon on the SiC surface from 33.27 ± 9.53% to 45.13 ± 4.74% resulted in a 76% increase in the osteocalcin expression by MC3T3‐E1 cells seeded on the material after 7 days. The cells colonized the entire thickness of the template and filled the pores with mineralized extracellular matrix after 14 days. Taken all together, the porous SiC scaffolds can serve as a bone graft for tissue reconstruction and cell delivery in trauma surgery. [ABSTRACT FROM AUTHOR]

Magnesium (Mg) alloy shows great potential as bone implant owing to its favourable biocompatibility and degradability. In the present work, bioglass-reinforced Mg-based composite was manufactured via laser additive manufacturing. The results showed that too low a volumetric energy density (Ev) resulted in the appearance of open pores on the surface, which significantly deteriorated the densification behaviour. In contrast, too high an Ev caused the occurrence of the'balling phenomenon' with discontinuous surface, because of the excessive liquid formation and extended pool lifetime. Under a proper Ev of 185.19 J/mm3, favourable part with high densification rate was obtained. Meanwhile, the refined grains together with orderly dispersed reinforcing particles contributed to the enhanced mechanical properties. Significantly, the incorporated bioglass promoted the apatite deposition on Mg matrix, which served as an effective protection layer and reduced the degradation rate. Furthermore, it also improved the cell growth and differentiation, showing great potential in clinical bone repair. [ABSTRACT FROM AUTHOR]

During craniotomies, a portion of the calvarium or skull is removed to gain access to the intracranial space. When it is not possible to re-implant the flap, surgeons may repair the defect intraoperatively or at a later date. With larger defects being more difficult to repair intraoperatively, we investigated a method for the creation of patient-specific moulds for ad hoc bone flap reconstruction using rapid prototyping. Patient-specific moulds were created based on light scanned models of the defect, using custom software and rapid prototyping. Polymethylmethacrylate bone implants were created for three retrospective craniotomy cases and evaluated based on original flap and skull reconstruction accuracy. Bone implants created using our moulding method reconstruct the original flap and skull with an average reconstruction accuracy of 0.82 and 1.3 mm, respectively. Average skull reconstruction accuracy obtained by surgeons performing freehand implant reconstruction was 1.49 mm. Time needed to generate moulds was between 2 h and 45 min and 6 h and 20 min. Improvements to current printing technology will make this procedure technically feasible for future cranial procedures. [ABSTRACT FROM AUTHOR]

BACKGROUND: Biomedical implants have been widely used in various orthopedic treatments. However, the existing bone implants often have the disadvantages of poor mechanical properties, immune response, microbial infection, poor healing and so on. Different surface modification techniques can effectively make up for these shortcomings. OBJECTIVE: To summarize the surface modification techniques of the current bone tissue engineering implants. METHODS: The first author searched the PubMed, CNKI, and VIP datadase to retrieve the article regarding repair of tuberculous bone defect published during 2000-2009 with the search terms "'bone tissue engineering; bone implant; surface modification; coating" in Chinese and English, respectively. The articles published recently or in high-impact journals were included in this study. RESULTS AND CONCLUSION: The surface of bone tissue engineering implants was modified by inorganic and organic components or by changing the surface topography of the implants. This improves the osteogenesis, bone conductivity, bacteriostasis，and biocompatibilily of bone implant to different degrees. However, we, need to solve some problems before this new implant is applied to the clinic: how to determine the optimal concentration of different surface modification componets, maximize bone healing, inhibit bacterial activity, and avoid other adverse reactions; how to avoid foreign body reaction and immune response caused by particles generatedby surface abrasion of these bone tissue engineering implants over time; how to incorporate various growth factors, proteins and other biological molecules into the coating without damaging their respective chemical structures and functions; how to guide the release of growth factors and molecules in a coordinated and controllable way. [ABSTRACT FROM AUTHOR]

Similar to metallic implant, using the compact bio-nanocomposite can provide a suitable strength due to its high stiffness and providing sufficient adhesion between bone and orthopedic implant. Therefore, using zirconia-reinforced calcium phosphate composites with new generation of calcium silicate composites was considered in this study. Additionally, investigation of microstructure, apatite formation, and mechanical characteristic of synthetic compact bio-nanocomposite bones was performed. Desired biodegradation, optimal bioactivity, and dissolution of tricalcium phosphate (TCP) were controlled to optimize its mechanical properties. The purpose of this study was to prepare the nanostructured TCP-wollastonite-zirconia (TCP-WS-Zr) using the space holder (SH) technique. The X-ray diffraction technique (XRD) was used to confirm the existence of favorable phases in the composite's structure. Additionally, the effects of calcination temperature on the fuzzy composition, grain size, powder crystallinity, and final coatings were investigated. Furthermore, the Fourier-transform infrared spectroscopy (FTIR) was used for fundamental analysis of the resulting powder. In order to examine the shape and size of powder's particles, particle size analysis was performed. The morphology and microstructure of the sample's surface was studied by scanning electron microscopy (SEM), and to evaluate the dissolution rate, adaptive properties, and the comparison with the properties of single-phase TCP, the samples were immersed in physiological saline solution (0.9% sodium chloride) for 21 days. The results of in vivo evaluation illustrated an increase in the concentration of calcium ion release and proper osseointegration ratio, and the amount of calcium ion release in composite coatings was lower than that in TCP single phase. Nanostructured TCP-WS-Zr coatings reduced the duration of implant fixation next to the hardened tissue, and increased the bone regeneration due to its structure and dimensions of the nanometric phases of the forming phases. Finally, the animal evaluation shows that the novel bio-nanocomposite has increasing trend in healing of defected bone after 1 month. [ABSTRACT FROM AUTHOR]

This study aimed to obtain as much and as accurate information as possible about the process of osseointegration of titanium implants, through histological processing. For this purpose, the combination of a mercury chloride fixator (Stieve mixture) and a complex staining method (Goldner's trichrome) was used, which can highlight the microscopic structures in several colors and shades. The Stieve mixture proved to have distinguished qualities both in the preservation of basophilic and acidophilic structures and especially in the chemical preparation of the substrate for the binding of each structural component with a specific acidophilic dye. On the substrate thus prepared, the acidophilic dyes used in the Goldner's trichrome staining highlighted the structural components in different colors and shades, offering the possibility of high precision assessment of the newly proliferated bone, in different stages of proliferation, consolidation and reshaping. Complex information was obtained, which allows the appreciation of osseointegration for endosseous implants and the amount of proliferated bone at the boneimplant interface, the stage of proliferation, consolidation and reshaping of the mature bone, the degree of fixation to deep bone structures. The possibility of complex assessment of the osseointegration process for endosseous implants at a given time is of great practical importance for correct assessment of the waiting time required for safe installation of prosthesis. The combination of Stieve fixator mixture with Goldner's trichrome staining method has proven to be very effective in histology, highlighting on excellent level the existing structural components of each stage, in which the osseointegration process goes through. A very important role in this combination was achieved by mercury chloride mixture, which prepared the substrate for specific reaction with dyes. Regarding the results obtained, we recommend this combination for histological investigations aimed on bone proliferation and repair. [ABSTRACT FROM AUTHOR]

The growing interest in multi-functional metallic biomaterials for bone substitutes challenges the current additive manufacturing (AM, =3D printing) technologies. It is foreseeable that advances in multi-material AM for metallic biomaterials will not only allow for complex geometrical designs, but also improve their multi-functionalities by tuning the types or compositions of the underlying base materials, thereby presenting unprecedented opportunities for advanced orthopedic treatments. AM technologies are yet to be extensively explored for the fabrication of multi-functional metallic biomaterials, especially for bone substitutes. The aim of this review is to present the viable options of the state-of-the-art multi-material AM for Ti-, Mg-, and Fe-based biomaterials to be used as bone substitutes. The review starts with a brief review of bone tissue engineering, the design requirements, and fabrication technologies for metallic biomaterials to highlight the advantages of using AM over conventional fabrication methods. Five AM technologies suitable for metal 3D printing are compared against the requirements for multi-material AM. Of these AM technologies, extrusion-based multi-material AM is shown to have the greatest potential to meet the requirements for the fabrication of multi-functional metallic biomaterials. Finally, recent progress in the fabrication of Ti-, Mg-, and Fe-based biomaterials including the utilization of multi-material AM technologies is reviewed so as to identify the knowledge gaps and propose the directions of further research for the development of multi-material AM technologies that are applicable for the fabrication of multi-functional metallic biomaterials. Addressing a critical bone defect requires the assistance of multi-functional porous metallic bone substitutes. As one of the most advanced fabrication technology in bone tissue engineering, additive manufacturing is challenged for its viability in multi-material fabrication of metallic biomaterials. This article reviews how the current metal additive manufacturing technologies have been and can be used for multi-material fabrication of Ti-, Mg-, and Fe-based bone substitutes. Progress on the Ti-, Mg-, and Fe-based biomaterials, including the utilization of multi-material additive manufacturing, are discussed to direct future research for advancing the multi-functional additively manufactured metallic bone biomaterials. Image, graphical abstract [ABSTRACT FROM AUTHOR]

A well-distributed nano-silver hydroxyapatite composite has been successfully prepared by a one-pot synthesis method. Hydroxyapatite was separately synthesized by a sol-gel method, then impregnated with silver nanoparticles with the mediation of Uncaria gambir Roxb. leaf extract in the presence of three kinds of alkanolamine compound; monoethanolamine (MEA), diethanolamine (DEA), and triethanolamine (TEA) as capping agents. The effect of different capping agents on the properties of the silver nanoparticles and the nano-silver hydroxyapatite composite were studied. UV–visible spectrophotometer analysis exhibited absorbance peaks at 402–439 nm which specifically corresponds to spherical silver nanoparticles. Higher optical absorbance was observed in TEA-capped silver nanoparticles, than in DEA and MEA-capped ones. X-ray diffraction (XRD) analysis showed a highly crystalline hexagonal structure for hydroxyapatite and no detected metallic silver. However, the presence of 1.65% silver was confirmed by energy dispersive x-ray (EDX) spectroscopy analysis. Transmission electron microscopy (TEM) analysis revealed spherical silver nanoparticles with a size range of 2–62 nm (smallest mean diameter of 2 nm) adhered to the hydroxyapatite surface. The TEA capped impregnated silver nanoparticles were the smallest, corresponding to the best capping performance, followed by those capped by DEA and MEA. Small-sized nanoparticles on hydroxyapatite are beneficial for highly antibacterial bone implants. [ABSTRACT FROM AUTHOR]

A biologically - validated biodegradable material must comfortably stay in the physiological environment it is placed in, before finally disappearing over the intended period of time with adequate rates of degradation. The primary objective and utility of such a material is to eliminate the requirement of secondary surgery in applications involving bone implants. In recent decades, biodegradable alloys have exhibited enhanced biocompatibility, and improved mechanical and biodegradation properties. This has generated renewed interest in the design of bone implants made up of such materials that can successfully support fractured bone till the culmination of the healing process. However, striking a balance between two seemingly conflicting requirements, namely - sustaining the strength of the implant till the bone acquires the desired strength of its own, and allowing the implant to keep losing strength with its gradual degradation – may be rather complex. To manage this, different healing phases and the associated bone - biodegradable implant interface mechanobiology needs to be focused upon. An adequate and/or optimal design of the implant is based on mechanical properties, degradation rates of implant and bone-biodegradable implant interface interactivity. This review mainly focuses on bone - biodegradable implant interface with due consideration accorded to the mechanical properties, degradation rates and healing process in a standard duration. [ABSTRACT FROM AUTHOR]