Search Results (74)

The rapid advancement of materials science has revolutionized total hip arthroplasty (THA), a critical orthopedic procedure aimed at restoring mobility and improving patient quality of life. This review investigates the evolution of biomaterials used in THA, analyzing their mechanical, biological, and chemical properties. The study outlines the transition from early natural materials to modern metals, polymers, and ceramics, highlighting their benefits and limitations in clinical applications. Particular emphasis is placed on the development of advanced materials such as highly cross-linked polyethylene (HXLPE), zirconia-toughened alumina (ZTA), and tantalum alloys (Ta), which demonstrate enhanced biocompatibility, wear resistance, and longevity. By examining emerging trends, including bioactive coatings and nanotechnology, this paper aims to provide a comprehensive understanding of current challenges and future directions in material selection for hip prostheses, ultimately aiming to minimize annual revision rates and improve long-term outcomes. Full article

To increase the wear and corrosion resistance of (α + β) titanium-aluminium-vanadium (Ti6Al4V) alloy, ceramic tantalum oxide coatings were deposited by direct current (DC) magnetron sputtering at three different substrate temperatures—400, 450, and 500 °C. The crystallographic structure, surface morphology, chemical compositions, film adhesion, and hardness of the coatings were described using XRD, SEM, EDS, scratch tests, and microhardness measurements. The samples’ ability to withstand corrosion was assessed using electrochemical studies. Results revealed that thin films have an amorphous or crystalline structure dependent on temperature. The film’s thicknesses varied between 560 and 600 nm. With the increase in deposition temperature, the hardness of the film rose. All oxide coatings were tightly adherent to the titanium alloy substrate, and critical force increased from about 8.6 up to 20 N when the temperature rose from 400 to 500 °C. During the polarisation investigations, after 1 h of immersion, a drop in current density (j_corr) verified an improvement in the corrosion resistance of the amorphous and well-crystalline coatings. A two-layer model of the surface film accurately describes the coated systems’ electrochemical behaviour. However, according to the EIS analysis, the well-crystalline film deteriorates greatly, whereas the amorphous film prevents penetration during the 7-day immersion test in SBF. The wettability tests demonstrated the hydrophilic nature of the coatings, and after seven days, the mineralisation of calcium phosphate proves the coatings become bioactive in simulated bodily fluid (SBF). Thus, we produced films of tantalum oxide, which, with the proper deposition parameters, may prove to be appropriate surfaces for titanium-based implant bio-applications. Full article

The process of osteointegration depends significantly on the surface roughness, structure, chemical composition, and mechanical characteristics of the coating. In this regard, an important direction in the development of medical materials is the development of new techniques of surface modification and the creation of bioactive ceramic coatings. Calcium-phosphate materials based on hydroxyapatite have been proposed as bioactive ceramic coatings on titanium implants for the effective acceleration of bone tissue healing. To obtain bioactive ceramic coatings, pulse power sources are best suited, namely detonation spraying, in which the energy of the explosion of gas mixtures is used as a source of pulse action. The pulse mode of operation in the detonation spraying method is preferable for the formation of bioactive ceramic coatings. It provides a high velocity of hydroxyapatite particles, which promotes their effective fixation on the titanium substrate, while minimizing the heating of the material. This approach preserves the substrate structure and improves the coating adhesion. Four different types of coatings with varying O₂/C₂H₂ molar ratios, ranging from 2.6 to 3.7, were obtained using detonation spraying. Powders and obtained coatings of hydroxyapatite were studied by Raman spectroscopy and XRD structural analysis. The results of XRD phase analysis showed the partial conversion of the hydroxyapatite phase to the α-tricalcium phosphate (α-TCP) phase during the detonation spraying process. The results obtained by Raman spectroscopy indicate that hydroxyapatite is the main phase in coatings. All hydroxyapatite-based coatings exhibited hydrophobic properties, which was confirmed by contact-angle values above 90° in wettability tests, characteristic of hydrophobic surfaces. The adhesive strength of the coatings was measured by the scratch test method. Tribological tests were conducted using the ball-on-disk method under both dry conditions and in Ringer’s solution. This approach enabled the evaluation of wear resistance and friction coefficient of the coatings in different environments, simulating both lubrication-free conditions and those resembling physiological environments. Full article

The deposition of agglomerated hydroxyapatite (HAp) powders by low-pressure cold spray has been a topic of interest in recent years. Key parameters influencing the deposition of HAp powders include particle morphology and impact kinetic energy. This work examines the deposition of HAp powders on various metal surfaces to assess the impact of substrate properties on the formation of HAp deposits via cold spray. The substrates studied here encompass metals with varying hardness and thermal conductivities, including Al6061, Inconel alloy 625, AISI 316 stainless steel, H13 tool steel, Ti6Al4V, and AZ31 alloy. Single-track experiments offer insights into the initial interactions between HAp particles and different substrate surfaces. In this study, the results indicate that the ductility of the substrate may enhance HAp particle deposition only at the first deposition stages where substrate/particle interaction is the most critical factor for deposition. Features on the substrate associated with the first deposition sprayed layer include localized substrate deformation and the formation of clusters of HAp agglomerates, which aid in HAp deposition. Furthermore, after multiple spraying passes on the various metallic surfaces, deposition efficiency was significantly reduced when the build-up process of HAp coatings shifted from ceramic/metal to ceramic/ceramic interactions. Overall, this study achieved agglomerated HAp deposits with high deposition efficiencies (30–60%) through single-track experiments and resulted in the preparation of HAp coatings on various substrates with thickness values ranging from 24 to 53 µm. These coatings exhibited bioactive behavior in simulated body fluid. Full article

Titanium (Ti), as a hard tissue implant, is facing a big challenge for rapid and stable osseointegration owing to its intrinsic bio-inertness. Meanwile, surface-related infection is also a serious threat. In this study, large-scale quasi-vertically aligned sodium titanate nanowire (SNW) arrayed coatings incorporated with bioactive Cu²⁺ ions were fabricated through a compound process involving acid etching, hydrothermal treatment (HT), and ion exchange (IE). A novel coating based on sustained ion release and a shape-preserving design is successfully obtained. Cu²⁺ substituted Na⁺ in sodium titanate lattice to generate Cu-doped SNW (CNW), which maintains the micro-structure and phase components of the original SNW, and can be efficiently released from the structure by immersing them in physiological saline (PS) solutions, ensuring superior long-term structural stability. The synergistic effects of the acid etching, bidirectional cogrowth, and solution-strengthening mechanisms endow the coating with higher bonding strengths. In vitro antibacterial tests demonstrated that the CNW coatings exhibited effective good antibacterial properties against both Gram-positive and Gram-negative bacteria based on the continuous slow release of copper ions. This is an exciting attempt to achieve topographic, hydrophilic, and antibacterial activation of metal implants, demonstrating a paradigm for the activation of coatings without dissolution and providing new insights into insoluble ceramic-coated implants with high bonding strengths. Full article

Coating materials offers an intriguing solution for imparting inert implants with additional bioactive characteristics without changing underlying parameters such as mechanical strength. Metallic implants like endoprostheses or polymeric implants can be coated with a thin layer of bioactive film capable of stimulating bone-forming cells to proliferate or release a drug. However, irrespective of the final implantation site of such a coating biomaterial, it is necessary to conduct detailed mechanical and physicochemical in vitro analyses to determine its likely behavior under biological conditions. In this study, polymeric and composite coatings with hydroxyapatite obtained under UV light underwent incubation tests in four different artificial biological fluids: simulated body fluid (SBF), artificial saliva, Ringer’s fluid, and water (as the reference fluid). The potentiometric and conductometric properties, sorption capacity, and degradation rate of the coatings were examined. Furthermore, their hardness, modulus of elasticity, and deformation were determined. It was demonstrated that the coatings remained stable in SBF liquid at a pH value of around 7.4. In artificial saliva, the greatest degradation of the polymer matrix (ranging between 36.19% and 39.79%) and chipping of hydroxyapatite in the composite coatings were observed. Additionally, the effect of ceramics on sorption capacity was determined, with lower capacity noted with higher HA additions. Moreover, the evaluation of surface morphology supported by elemental microanalysis confirmed the appearance of new apatite layers on the surface as a result of incubation in SBF. Ceramics also influenced mechanical aspects, increasing hardness and modulus of elasticity. For the polymer coatings, the value was 11.48 ± 0.61, while for the composite coating with 15% ceramics, it increased more than eightfold to a value of 93.31 ± 11.18 N/mm². Based on the conducted studies, the effect of ceramics on the physicochemical as well as mechanical properties of the materials was determined, and their behavior in various biological fluids was evaluated. However, further studies, especially cytotoxicity analyses, are required to determine the potential use of the coatings as biomaterials. Full article

A hierarchical hybrid coating (HHC) comprising a ceramic oxide layer and two biodegradable polymeric (polycaprolactone, PCL) layers has been developed on Mg3Zn0.4Ca cast alloy in order to provide a controlled degradation rate and functionality by creating a favorable porous surface topography for cell adhesion. The inner, ceramic layer formed by plasma electrolytic oxidation (PEO) has been enriched in bioactive elements (Ca, P, Si). The intermediate PCL layer sealed the defect in the PEO layer and the outer microporous PCL layer loaded with the appropriate active molecule, thus providing drug-eluting capacity. Morphological, chemical, and biological characterizations of the manufactured coatings loaded with ciprofloxacin (CIP) and paracetamol (PAR) have been carried out. In vitro assays with cell lines relevant for cardiovascular implants and bone prosthesis (endothelial cells and premyoblasts) showed that the drug-loaded coating allows for cell proliferation and viability. The study of CIP and PAR cytotoxicity and release rate indicated that the porous PCL layer does not release concentrations detrimental to the cells. However, complete system assays revealed that corrosion behavior and increase of the pH negatively affects cell viability. H₂ evolution during corrosion of Mg alloy substrate generates blisters in PCL layer that accelerate the corrosion locally in crevice microenvironment. A detailed mechanism of the system degradation is disclosed. The accelerated degradation of the developed system may present interest for its further adaptation to new cancer therapy strategies. Full article

This paper reviews different approaches to obtain biomaterials with tailored functionalities and explains their significant characteristics that influence their bioactivity. The main goal of this discussion underscores the significance of surface properties in materials, with a particular emphasis on their role in facilitating cell adhesion in order to obtain good biocompatibility and biointegration, while preventing adverse effects, such as bacterial contamination and inflammation processes. Consequently, it is essential to design strategies and interventions that avoid bacterial infections, reducing inflammation and enhancing compatibility systems. Within this review, we elucidate the most prevalent techniques employed for surface modification, notably emphasizing surface chemical composition and coatings. In the case of surface chemical composition, we delve into four commonly applied approaches: hydrolysis, aminolysis, oxidation, and plasma treatment. On the other hand, coatings can be categorized based on their material composition, encompassing ceramic-based and polymer-based coatings. Both types of coatings have demonstrated efficacy in preventing bacterial contamination, promoting cell adhesion and improving biological properties of the surface. Furthermore, the addition of biological agents such as drugs, proteins, peptides, metallic ions plays a pivotal role in manifesting the prevention of bacterial infection, inflammatory responses, and coagulation mechanism. Full article

Bone tissue degeneration, caused by disease as well as trauma, is a problem affecting many social groups in the 21st century. It involves pain and reduced patient comfort. Developments in materials engineering allow for the design of novel, innovative materials that can be used in therapies to promote bone regeneration. This work presents the preparation of a ceramic–polymer coating modified with carbon nanotubes on a titanium alloy for biomedical applications. The ceramic part is hydroxyapatite synthesized by the wet precipitation method using orthophosphate and calcium hydroxide. The polymer of choice was polyethylene glycol. A UV light synthesis method was successfully applied to obtain coatings characterized by continuity and full crosslinking. Extensive physicochemical analysis and incubation studies were carried out. Interactions between coatings and fluids mimicking artificial biological environments were analyzed for 9 days, i.e., in fluids such as SBF solution, artificial saliva, and distilled water. During the in vitro incubation, changes in pH values were measured by potentiometric tests, and ionic conductivity was measured by analyzing conductometry. After incubation, the surface morphology was studied by scanning electron microscopy (SEM) together with energy-dispersive (EDS) microanalysis, which made it possible to determine the presence of individual elements on the surface, as well as to observe the appearance of new apatite layers. Fourier-transform infrared (FT-IR) spectrometry was also performed before and at the end of the incubation period. On the basis of the presented studies, it was concluded that coatings that contain nanotubes are bioactive and do not negatively affect the properties of the coatings. Bioactivity was confirmed microscopically by observing new apatite layers after incubation in SBF, which were identified as phosphorus and calcium deposits. Degradation of the polymer phase was observed in the artificial saliva. These materials require further study, including safety analysis, but they demonstrate potential for further work. Full article

In this work, we have developed and characterized a ceramic composite based on a core of directionally solidified calcium zirconate-calcium stabilized zirconia (CZO-CSZ) eutectic composite coated with a bioactive glass-ceramic. The aim is to research new orthopedic implants as an alternative to conventional 3Y-TZP bioinert ceramics. The CZO-CSZ eutectic rods were grown from the melt of rods of CaO-ZrO₂ in the eutectic composition using the laser floating zone technique (LFZ). The mechanical results indicated that directional eutectics prepared with this technique exhibited good mechanical strength and significant hardness and toughness. The LFZ technique was also used to melt the bioactive coating previously placed by dip coating on the CZO-CSZ rod surface. Depending on the thickness of the coating and the applied laser power, an alloying or coating process was achieved. In the first case, the coating was diluted with the surface of the eutectic cylinder, leading to the segregation of the calcium zirconate and zirconia phases and the formation of a bioactive phase embedding zirconia particles. In the second case, a layer of ceramic glass was formed, well attached to the eutectic cylinder. These layers were both studied from the microstructural and bioactivity points of view. Full article

Titanium-coated ceramic materials with varying roughness and surface topography have been developed and utilized in clinical trials within the realms of medical and dental implantology. The objective of this study was to assess how cellular attachment is affected by the surface porosity and roughness of the titanium alloy (Ti-6Al-4V) coated with titania (TiO₂)-reinforced yttria-stabilized zirconia (YZP). Additionally, the wettability of different types of TiO₂-coated YZP was also evaluated for its effect on cellular migration and attachment. The results showed excellent adhesion between fibroblast cells and the surface of the YZP/TiO₂ coating, with TiO₂ reinforcement exhibiting bioactive properties that promote rapid cell growth and reproduction. Despite its average micro surface roughness measuring 5.86 ± 0.36 µm, the YZP/TiO2 surface coating demonstrated superior suitability for both fibroblast cell adhesion and the promotion of osseointegration. The YZP coating with 30% TiO₂ demonstrated the most desirable properties, significantly enhancing biocompatibility. This study can serve as a basis for determining the biocompatibility and bioactivity of the YZP/TiO₂ coating, which holds promise as a new coating material. Full article

Autologous bone transplantation is still considered as the gold standard therapeutic option for bone defect repair. The alternative tissue engineering approaches have to combine good hardiness of biomaterials whilst allowing good stem cell functionality. To become more useful for load-bearing applications, mechanical properties of calcium phosphate materials have to be improved. In the present study, we aimed to reduce the brittleness of β-tricalcium phosphate (β-TCP). For this purpose, we used three polymers (PDL-02, -02a, -04) for coatings and compared resulting mechanical and degradation properties as well as their impact on seeded periosteal stem cells. Mechanical properties of coated and uncoated β-TCP scaffolds were analyzed. In addition, degradation kinetics analyses of the polymers employed and of the polymer-coated scaffolds were performed. For bioactivity assessment, the scaffolds were seeded with jaw periosteal cells (JPCs) and cultured under untreated and osteogenic conditions. JPC adhesion/proliferation, gene and protein expression by immunofluorescent staining of embedded scaffolds were analyzed. Raman spectroscopy measurements gave an insight into material properties and cell mineralization. PDL-coated β-TCP scaffolds showed a significantly higher flexural strength in comparison to that of uncoated scaffolds. Degradation kinetics showed considerable differences in pH and electrical conductivity of the three different polymer types, while the core material β-TCP was able to stabilize pH and conductivity. Material differences seemed to have an impact on JPC proliferation and differentiation potential, as reflected by the expression of osteogenic marker genes. A homogenous cell colonialization of coated and uncoated scaffolds was detected. Most interesting from a bone engineer’s point of view, the PDL-04 coating enabled detection of cell matrix mineralization by Raman spectroscopy. This was not feasible with uncoated scaffolds, due to intercalating effects of the β-TCP material and the JPC-formed calcium phosphate. In conclusion, the use of PDL-04 coating improved the mechanical properties of the β-TCP scaffold and promoted cell adhesion and osteogenic differentiation, whilst allowing detection of cell mineralization within the ceramic core material. Full article

A novel approach to surface modification was developed to improve the corrosion performance of biodegradable magnesium alloys. Additively manufactured magnesium samples and Mg-Mn-based magnesium alloys were used in this study. This method involves the combination of plasma electrolytic oxidation to create a porous ceramic-like matrix, followed by treatment with protective biocompatible agents. The most efficient method for the PEO-layer impregnation using sodium oleate and polycaprolactone was selected and optimized. The correlation between the structure, composition, and protective properties of the hybrid coatings was established. The composition of the formed polymer-containing layers was established using XPS and Raman microspectroscopy. The presence of sodium oleate and its distribution across the coating surface was confirmed at the microscale. The corrosion-protection level of the hybrid layers was assessed using potentiodynamic polarization measurements, electrochemical impedance spectroscopy, hydrogen evolution testing, and gravimetry (mass-loss tests) in vitro. The oleate-containing polycaprolactone layers (HC-SO 0.1–2) demonstrated stable corrosion behavior even after 7 days of immersion in Hank’s balanced salt solution. The corrosion-current density and impedance modulus measured at a frequency of 0.1 Hz for the samples with hybrid coating after 7 days of exposure were equal to 5.68 × 10⁻⁸ A∙cm⁻² and 2.03 × 10⁶ Ω∙cm², respectively. The developed method of surface modification demonstrates the coating’s self-healing properties. The effectiveness of employing hybrid anticorrosive bioactive PEO coatings for biomedical products made from magnesium and its alloys was demonstrated. Full article

Implantology is crucial for restoring aesthetics and masticatory function in oral rehabilitation. Despite its advantages, certain issues, such as bacterial infection, may still arise that hinder osseointegration and result in implant rejection. This work aims to address these challenges by developing a biomaterial for dental implant coating based on 45S5 Bioglass^® modified by zirconium insertion. The structural characterization of the glasses, by XRD, showed that the introduction of zirconium in the Bioglass network at a concentration higher than 2 mol% promotes phase separation, with crystal phase formation. Impedance spectroscopy was used, in the frequency range of 10²–10⁶ Hz and the temperature range of 200–400 K, to investigate the electrical properties of these Bioglasses, due to their ability to store electrical charges and therefore enhance the osseointegration capacity. The electrical study showed that the presence of crystal phases, in the glass ceramic with 8 mol% of zirconium, led to a significant increase in conductivity. In terms of biological properties, the Bioglasses exhibited an antibacterial effect against Gram-positive and Gram-negative bacteria and did not show cytotoxicity for the Saos-2 cell line at extract concentrations up to 25 mg/mL. Furthermore, the results of the bioactivity test revealed that within 24 h, a CaP-rich layer began to form on the surface of all the samples. According to our results, the incorporation of 2 mol% of ZrO₂ into the Bioglass significantly improves its potential as a coating material for dental implants, enhancing both its antibacterial and osteointegration properties. Full article

A rapidly developing area of ceramic science and technology involves research on the interaction between implanted biomaterials and the human body. Over the past half century, the use of bioceramics has revolutionized the surgical treatment of various diseases that primarily affect bone, thus contributing to significantly improving the quality of life of rehabilitated patients. Calcium phosphates, bioactive glasses and glass-ceramics are mostly used in tissue engineering applications where bone regeneration is the major goal, while stronger but almost inert biocompatible ceramics such as alumina and alumina/zirconia composites are preferable in joint prostheses. Over the last few years, non-oxide ceramics—primarily silicon nitride, silicon carbide and diamond-like coatings—have been proposed as new options in orthopaedics in order to overcome some tribological and biomechanical limitations of existing commercial products, yielding very promising results. This review is specifically addressed to these relatively less popular, non-oxide biomaterials for bone applications, highlighting their potential advantages and critical aspects deserving further research in the future. Special focus is also given to the use of non-oxide ceramics in the manufacturing of the acetabular cup, which is the most critical component of hip joint prostheses. Full article