Review on titanium and titanium based alloys as biomaterials for orthopaedic applications

All-in-one design of titanium-based dental implant systems for enhanced soft and hard tissue integration

Enhancing the sealing between titanium abutment and surrounding soft tissue is crucial for preventing peri-implantitis. Meanwhile, exploring non-invasive antibacterial strategies as alternatives for traditional antibiotic therapy is central to improving the effect of peri-implantitis treatment. Furthermore, facilitating effective integration between titanium implant and osteoporotic bone is the cornerstone for ensuring long-term implant stability in patients with osteoporosis. In light of this, this work innovatively constructed multifunctional vertical graphene-based coatings on titanium implants and abutments using plasma-enhanced chemical vapor deposition technology. The results demonstrated that the vertical graphene coatings promoted soft tissue sealing and exhibited inherent antibacterial activities with the bacteriostasis rates of 65.60 % against Staphylococcus aureus (S. aureus) and 43.89 % against Escherichia coli (E. coli) in vitro which could prevent early infections. Moreover, vertical graphene coatings presented photothermal antibacterial effects with the antibacterial rates of 99.99 % and 95.83 % for S. aureus in vitro and in vivo, respectively, and 92.23 % for E. coli in vitro under near-infrared irradiation, which provided a non-invasive and highly effective treatment option for peri-implantitis. Furthermore, teriparatide acetate was loaded on vertical graphene coatings which enhanced osseointegration between titanium implants and osteoporotic bone. By comprehensively considering the critical functional requirements of dental implants and abutments, this work meticulously designed vertical graphene-based coatings on titanium dental implant systems for soft and hard tissue integration. This innovative design demonstrates immense application potential, especially for dental implant restoration in patients with osteoporosis.

Bioactive Zn ingredients endow Ti-Zn composites with exceptional mechanical and osteogenic properties as biomedical implants

Titanium-based (Ti-) alloys are promising materials as bioimplants with superior mechanical properties and excellent biocompatibility. However, their bioinertia and high elastic moduli are not comparable to natural bone tissue; thus, novel Ti alloys with good biomechanical adaptation and high bioactivity are desired. Zinc (Zn) is recognized for ideal biodegradability and its biological effects can be considered to endow pure Ti with rewarding bio functions. Herein, this study has employed a designed spark plasma sintering (SPS) procedure to effectively diffuse varying amounts of Zn into pure Ti as bioactive ingredients and generate novel TiZn composites as bone defect implants. The as-sintered TiZn samples feature a gradient core-shell structure, achieving a match of high strength and low elastic moduli to satisfy the load-bearing requirements while avoiding the stress-shielding effect. A moderate degradation of the Zn component allows TiZn materials to maintain stable mechanical support and exhibit satisfactory cytocompatibility. Ti20Zn, Ti30Zn, and Ti90Zn are confirmed to exert antibacterial and osteogenic abilities by in vitro experiments. Further analyses of in vivo implantation in the rat femur show they exhibit qualified biosafety and are superior to pure Ti in treating bone defects through bio-friendly Zn ions release. This study achieves a reasonable combination of the mechanical properties of pure Ti and the biological functions of pure Zn, providing a better choice for bone injury and fracture treatment.

Insulin for oral bone tissue engineering: a review on innovations in targeted insulin-loaded nanocarrier scaffold

The occurrence of oral bone tissue degeneration and bone defects by osteoporosis, tooth extraction, obesity, trauma, and periodontitis are major challenges for clinicians. Traditional bone regeneration methods often come with limitations such as donor site morbidity, limitation of special shape, inflammation, and resorption of the implanted bone. The treatment oriented with biomimetic bone materials has achieved significant attention recently. In the oral bone tissue engineering arena, insulin has gained considerable attention among all the known biomaterials for osteogenesis and angiogenesis. It also exhibits osteogenic and angiogenic properties by interacting with insulin receptors on osteoblasts. Insulin influences bone remodelling both directly and indirectly. It acts directly through the PI3K/Akt and MAPK signalling pathways and indirectly by modulating the RANK/RANKL/OPG pathway, which helps reduce bone resorption. The current review reports the role of insulin in bone remodelling and bone tissue regeneration in the oral cavity in the form of scaffolds and nanomaterials. Different insulin delivery systems, utilising nanomaterials and scaffolds functionalised with polymeric biomaterials have been explored for oral bone tissue regeneration. The review put forward a theoretical basis for future research in insulin delivery in the form of scaffolds and composite materials for oral bone tissue regeneration.

Effect of Stable and Metastable Phase Microstructures on Mechanical Properties of Ti-33Nb Alloys

In this paper, the crystal structure, microstructure, and deformation behavior in the Ti-33Nb alloy under furnace-cooling (FC) and water-quenching (WQ) conditions after holding at 950 °C for 0.5 h are reviewed. The stable and metastable phases obtained under FC and WQ heat treatments have significantly different influences on the mechanical properties of this alloy. The furnace-cooling specimens possess a β and α phase at room temperature, while water-quenched specimens are composed of a metastable β phase and martensite α″ phase. According to the results of the nanoindentation test, the hardness value of the FC specimens is 2.66 GPa, which is lower than that of the WQ specimens. It can be attributed to the presence of a large number of α phases. The indentation depth recovery ratio (ηh) and work recovery ratio (ηw) of the WQ specimens are 19.02% and 19.54%, respectively, indicating a better superelastic response than the FC specimens. In addition, the wear resistance (H/Er) and yield pressure (H3/Er2) of the WQ specimens are 0.0282 and 0.0030 GPa, respectively, suggesting a better wear resistance and resistance of plastic deformation.

Corrosion Behavior of Shot Peened Ti6Al4V Alloy Fabricated by Conventional and Additive Manufacturing

Ti6Al4V titanium alloy is one of the most studied for its properties after additive manufacturing. Due to its widely use in medical applications, its properties are investigated in various aspects of surface layer property improvement and later compared to conventionally manufactured Ti-6Al-4V. In this study, the corrosion behavior in a 0.9% NaCl solution of shot peened Ti-6Al-4V prepared using direct metal laser sintering (DMLS) was examined using corrosion electrochemical testing and compared with conventionally forged titanium alloy. Shot peening was performed on previously polished samples and subsequently treated with the CrNi steel shots. Two sets of peening pressure were selected: 0.3 and 0.4 MPa. X-ray diffraction analysis (XRD), X-ray micro-computed tomography (Micro-CT), scanning electron microscope (SEM) tests with roughness and hardness measurements were used to characterize the samples. The conventional samples were characterized by an α + β structure, while the additive samples had an α' + β martensitic structure. The obtained results indicate that the corrosion resistance of the conventionally forged Ti-6Al-4V alloy was higher than DMLSed Ti-6Al-4V alloy. The lowest corrosion rates were noted for untreated surfaces of CM/ref and DMLS/ref samples and reached 0.041 and 0.070 µA/cm2, respectively. Moreover, the development of the surface has an influence on corrosion behavior. Therefore, increasing pressure results in inferior corrosion resistance. However, better performance for shot peened samples was reported in the low frequency range. This is due to the refinement of the grain acquired after the peening process. All the results obtained, related to the corrosion behavior, were satisfactory enough that the all samples can be characterized as materials suitable for implant applications.

Effect of Ti6Al4V Alloy Surface and Porosity on Bone Osseointegration: In Vivo Pilot Study in Rabbits

Unmodified Ti6Al4V can osseointegrate, but sometimes this capacity needs to be improved. This study aimed to see how much porosity improves osseointegration in a Ti6Al4V implant. Three types of Ti6Al4V cylindrical-shaped implants (13.00 mm length × 5.00 mm diameter) were evaluated: solid sandblasted acid-etched, sintered, and porous 3D-printed (681.00 µm average pore size). Fifteen 20-week-old nullipara female parasite-free New Zealand California white rabbits were used, employing the femoral condyle defect model and undertaking µ-CT analysis and pull-out testing eight weeks later. On µ-CT densitometric analysis, the solid sandblasted rod showed the highest new bone growth around the implant. Bone growth was higher inside the implants for the porous 3D-printed (54.00 ± 5.00 mm3) than for the sintered (1.00 ± 0.05 mm3) and zero for the sandblasted implants. In the pull-out test, there were no statistically significant differences in the ANOVA analysis between the sintered (900.00 N ± 310.00 N) and porous 3D-printed (700.00 N ± 220.00 N) implants. Such differences did exist between the sandblasted material (220.00 N ± 50.00 N) and the two other materials (sintered p 0.002, porous p 0.034). The porous 3D-printed and sintered implant pull-out strength were significantly better than that of the solid rod sandblasted implant. Still, there were no statistically significant differences between the first two.

Improved physicochemical properties of structurally modified titanium coated with zein-mesoporous bioactive glass nanoparticles-Commiphora wightii for orthopaedic applications

Titanium (Ti) is an ideal implant material due to its strength, biocompatibility, and corrosion resistance. Ti is often structurally modified to overcome its inert nature. Nanostructures (pores, rods, tubes, etc.) formed on the surface of Ti followed by bioactive and antibacterial coatings can be exploited for many biomedical applications. A combination of zein (a biopolymer with low elastic modulus), mesoporous bioactive glass nanoparticles (MBGNs, a bioactive material) and Commiphora wightii (CW, an antibacterial herb) could result in a multi-functional coating for osteogenic purposes. Zein, not only reduces the stress shielding effect at the bone-implant interface but also acts as a binder for MBGNs and CW particles in the matrix and facilitates their uniform dispersion in the coating. In this work, zein nanoparticles (ZNPs), MBGNs, and CW were deposited on electrochemically synthesized titania nanotubes (TNTs) via electrophoretic deposition (EPD). A uniform and adherent composite coating named ZNPs/MBGNs/CW was obtained. The in-vitro bioactivity test in the simulated body fluid (SBF) revealed the formation of a biologically active calcium-deficient apatitic layer (cd-HA) on the coating surface. The electrophoretically deposited composite coating was also resistant to corrosion in SBF. Furthermore, the viability of MG-63 cells was tested in which coating displayed 100 % viability after 14 days of incubation. The presence of natural herb CW inhibited the growth of gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria. Hence, the results demonstrate that the ZNPs/MBGNs/CW composite coating system may be a strong candidate for orthopaedic applications.

Selective laser melting fabrication of functionally graded macro-porous Ti-6Al-4V scaffold for cavity bone defect reconstruction

Reconstruction of cavitary bone defects poses significant challenges in orthopedic surgery due to the irregular shapes and compromised mechanical properties of surrounding bone. This study developed a functionally graded macro-porous scaffold (FGMPS) using selective laser melting (SLM) for cavitary bone defect reconstruction. The FGMPS featured a porosity gradient (74%-86%) and macropores ≥1,600 µm, mimicking the natural density gradient of cancellous bone. Micro-CT analysis confirmed high structural fidelity and interconnected porosity. Compression tests in two orientations revealed distinct stress-strain responses: vertically aligned gradients (FGMPS-V) exhibited sequential layer engagement, while horizontally aligned gradients (FGMPS-H) demonstrated higher stiffness and strength due to uniform load distribution. The elastic modulus ranged from 383 MPa (FGMPS-V) to 577 MPa (FGMPS-H), with yield strength of 22-40 MPa, aligning well with cancellous bone properties. These findings highlight the FGMPS's potential to offer a promising solution for cavitary bone defect repair.

A Review of Past Research and Some Future Perspectives Regarding Titanium Alloys in Biomedical Applications

This review paper provides a comprehensive synthesis of the current advancements in investigations of different titanium-based alloys, including pure titanium, commercially available Ti6Al4V, and modified alloys, such as Ti-Nb-Zr-Fe alloys, for biomedical applications. Several researchers have explored the effects of alloying elements and processing techniques on enhancing the mechanical, chemical, and biological properties of these materials. Ti-Nb-Zr-Fe alloys are of particular interest due to their potential to address critical requirements in medical applications, including reduced Young's modulus, superior corrosion resistance, biocompatibility, and mechanical strength. Despite substantial progress, the detailed mechanisms for optimizing these properties remain underexplored in the current literature. The main objective of the present review paper is to emphasize the importance of ongoing investigations aimed at overcoming challenges such as biocompatibility concerns, fatigue resistance, and wear under biological conditions. By critically analyzing existing data, this study highlights gaps in knowledge and identifies opportunities for advancing research on these alloys. Specifically, this review paper highlights the need for targeted studies to reduce the Young's modulus and improve other critical characteristics of Ti-Nb-Zr-Fe alloys to better meet the demands of orthopedic implants, dental prosthetics, and cardiovascular devices. Even if the current scientific literature is ample on this topic, we consider that through this review we can positively contribute to the collective effort in this field trying to fill some gaps, including some updates on the topic, time frames, advantages, and limitations, and pave the way for further advancements that could revolutionize biomedical implant technology. The review encompasses studies performed over the last 5 decades, specifically from 1975 to 2025, to ensure the inclusion of the most relevant and up-to-date research. This approach aims to highlight the significant progress made while situating the findings within the broader context of ongoing investigations.

Transcriptomic Profile of Human Osteoblast-like Cells Grown on Trabecular Titanium

Trabecular titanium implants are widely used in orthopedic surgery and are known to promote osseointegration. In this study, we investigated whether primary human osteoblast-like cells grown inside a 3D trabecular titanium scaffold undergo changes in migration capacity, transcriptomic profile, and cellular phenotype as compared to the same osteoblasts not grown inside the scaffold. Scratch tests have shown that primary human osteoblast-like cells grown inside the 3D trabecular titanium scaffold promote the migration of cells from the external environment into the scaffold. Next generation sequencing analysis demonstrated that primary human osteoblast-like cells grown inside the 3D trabecular titanium scaffold modified the expression of genes involved in cell cycle and extracellular matrix remodeling, while maintaining a normal expression of the specific osteoblast markers, such as osteocalcin and osterix, as well as a comparable mineralization capacity. These data demonstrate that primary human osteoblast-like cells grown inside the titanium scaffold in a 3D environment acquire specific features favoring osseointegration.

Immunology in Osseointegration After Implantation

Bone tissue is renowned for its regenerative capabilities, yet handling extensive defects and complex fractures presents considerable medical challenges. Osteoimmunology, studying the complex mechanism of the mutual influence within the range of immunity and skeletal systems, has highlighted the indispensable function of immune reactions in the process of bone integration. This procedure, primarily immune-driven, fosters new bone formation around implants instead of relying solely on osteogenic mechanisms. Traditionally, implant research has emphasized bone bonding and osteoinduction, often overlooking the significant influence of immune interactions. Implants pose risks including donor site morbidity, decreased bioactivity, and pathogen transmission risks. To mitigate these, implant surfaces are modified through altering local factors such as electrical fields and applying physical treatments to change roughness, hydrophilicity, and nanotopography. These modifications aim to regulate immune reactions at the surface of the bone implant, improving osseointegration and the repair of bone. This review examines the types of immune cells in osseointegration, especially the pivotal function that macrophages serve in the regeneration of bone tissue, and investigates key implant features-morphology, wettability, cytokine interaction, and metal ion and bioactive molecule adsorption-that impact immune responses. These insights underscore the immune system's importance in bone repair and advance osteoimmunology as essential for developing strategies to control bone immune responses, enhancing implant integration and bone regeneration.

Optogenetic activation of mechanical nociceptions to enhance implant osseointegration

Orthopedic implants with high elastic modulus often suffer from poor osseointegration due to stress shielding, a phenomenon that suppresses the expression of intracellular mechanotransduction molecules (IMM) such as focal adhesion kinase (FAK). We find that reduced FAK expression under stress shielding is also mediated by decreased calcitonin gene-related peptide (CGRP) released from Piezo2+ mechanosensitive nerves surrounding the implant. To activate these nerves minimally invasively, we develop a fully implantable, wirelessly rechargeable optogenetic device. In mice engineered to express light-sensitive channels in Piezo2+ neurons, targeted stimulation of the L2-3 dorsal root ganglia (DRG) enhances localized CGRP release near the implant. This CGRP elevation activates the Protein Kinase A (PKA)/FAK signaling pathway in bone marrow mesenchymal stem cells (BMSCs), thereby enhancing osteogenesis and improving osseointegration. Here we show that bioelectronic modulation of mechanosensitive nerves offers a strategy to address implant failure, bridging neuroregulation and bone bioengineering.

A multimodal defect-rich nanoreactor triggers sono-piezoelectric tandem catalysis and iron metabolism disruption for implant infections

Tracking and eradicating drug-resistant bacteria are critical for combating implant-associated infections, yet effective antibacterial therapies remain elusive. Herein, we propose an oxygen vacancy-rich (BiFe)0.9(BaTi)0.1O3-x nanoreactor as a piezoelectric sonosensitizer by spatiotemporal ultrasound-driven sono- and chemodynamic tandem catalysis to amplify antibacterial efficacy. The piezoelectric charge carriers under a built-in electric field synchronize the reaction of O2 and H2O, efficiently generating H2O2. The electron-rich oxygen vacancies modulate the local electronic structure of an Fe site. It facilitates reactive oxygen species generation by piezoelectric electrons and accelerates valence state cycles of Fe(III)/Fe(II) to achieve the sustained maintenance of hydroxyl radicals via H2O2/Fe(II)-catalyzed chemodynamic reactions, which lead to bacterial membrane damage. Transcriptomics analysis revealed that intracellular Fe overload induced by excessive Fe(II)-mediated dysregulation of the two-component system disrupts bacterial metabolism, triggering bacterial ferroptosis-like death. Thus, the porous titanium scaffold, engineered with a piezoelectric nanoreactor, demonstrates superior antibacterial efficacy under ultrasound and facilitates osteogenesis via piezoelectric immunomodulation-activated therapy.

Antibacterial and Osteogenesis Promotion of Bionic Extracellular Matrix Implant Coating Based on Gallic Acid Self-Assembly

Oral health problems, particularly tooth defects, can significantly affect people's quality of life and overall well-being. The development of titanium (Ti) dental implants has largely replaced natural tooth roots to prevent periodontal and gastrointestinal diseases. However, challenges such as postoperative bacterial infections and poor osseointegration continue to hinder progress in dental implant technology. To tackle these issues, we used hydroxypropyl trimethylammonium chloride chitosan (HACC) and gallic acid-modified gelatin (GAG) to create extracellular matrix (ECM) coatings on titanium using layer-by-layer self-assembly. GAG showed better water solubility at room temperature, being over 99.0 times more soluble than regular gelatin. In vivo and in vitro analyses of the ECM coatings revealed their antibacterial properties and their ability to promote osteogenic differentiation, resulting in over 31.5 times more calcareous deposits than Ti. This strategy shows potential for improving oral health and reducing the complications associated with dental implants in clinical settings.

Metal Hypersensitivity in Patients With Failure of Joint Prosthesis Treatment

The objective of this study is to measure lymphocyte responses to metal antigens using MELISA (memory lymphocyte immunostimulation assay) test-modified lymphocyte transformation test (mLTT) and to evaluate metal sensitization in patients with and without the need of prosthetic surgery. This study is a case-control retrospective survey. We retrospectively analyzed all patients from 2013 to 2018 who were referred to the Institute of Dental Medicine, General University Hospital in Prague, and First Faculty of Medicine, Charles University, Prague, either following joint prosthesis-related complications or as a preoperative evaluation concerning metal hypersensitivity. For the control group, we selected healthy adults from our database. A group of 127 patients aged 25-81 years was chosen, 92 of which were female and 35 were male. The patients completed a special questionnaire aimed at information regarding their health status and history of metal exposure. After clinical examination, their peripheral blood samples were taken to perform mLTT. mLTT provided quantitative lymphocyte proliferation measurement, where a stimulation index of >2 indicated metal sensitivity. For statistical analysis, the Fisher's exact test, χ2 test, McNemar's exact test Student's paired t-test were used. By comparison of the study group and control group mLTT results, it can be stated that patients of the study group showed a higher level of lymphocyte reactivity to most of the tested metal antigens (Ag [silver], Cu [copper], Fe [iron], Mo [molybdenum], Pd [palladium], Pt [platinum], Ti [titanium], and Zn [zinc]) and an elevated incidence of metal hypersensitivity to Hg (mercury), Al (aluminum), Au (gold), Co (cobalt), Cr (chromium), Ni (nickel), and Sn (tin). The evaluation of the data obtained from patients in this study confirmed a significant clinical benefit of mLTT in diagnostics of metal hypersensitivity. Our study has revealed that the patients with the need of prosthetic surgery exhibited an elevated lymphocyte response to metal antigens. This result supports a metal-specific adaptive immune response and suggests involvement of metal exposure as a trigger for their health problems. This knowledge could be helpful in effectively enhancing the treatment of patients with need of orthopedic joint prosthesis.

Evaluation of Titanium Particles, TNF-α, and Caspase-3 Concentrations in Patients with Bones Fixations of the Maxilla and Mandibule

The aim of the study was to evaluate the effect of titanium implants (Ti6Al4V) on the surrounding tissues by analyzing the concentration of titanium particles, TNF-α, and caspase-3 in patients treated for jaw fractures and dentofacial deformities. The research material consisted of peri-implant tissues: fragments of periosteum adhering to a titanium miniplate and blood serum collected from 42 patients treated for mandibular fractures (Group I), and dentofacial deformities (Group II) who underwent bimaxillary osteotomy. The control group consisted of 24 generally healthy patients before bimaxillary osteotomy. The concentrations of selected cytokines, caspase-3, TNF-α in blood serum, and homogenized tissues, were determined using the immunoenzymatic method (ELISA). The concentration of titanium particles was assessed using a scanning electron microscope equipped with an X-ray microanalyzer. A significant increase in the concentration of titanium, caspase-3, and TNF-α was observed in serum and periosteum in all patients who underwent bone fixation. Increased TNF-α levels indicate an intense immune response, which may lead to the degradation of peri-implant tissues and bone resorption around the miniplates and screws, while an increase in caspase-3 levels suggests that cells surrounding the implants are destroyed in response to inflammatory stress or damage induced by the presence of titanium particles.

Enhancement of Osseointegration via Endogenous Electric Field by Regulating the Charge Microenvironments around Implants

The regulation of the charged microenvironment around implants is an effective way to promote osseointegration. Although homeostasis of the charged microenvironment plays an integral role in tissues, current research is externally invasive and unsuitable for clinical applications. In this study, functional materials with different surface potential differences are prepared by changing the spatial layout of Ta and Ag on the surface of a Ti-6Al-4V alloy (TC4). This naturally formed an endogenous electric field (EEF) with a negatively charged cell membrane after in vivo implantation and promoted osseointegration at the interface between the bone and implant through the upregulation of Ca2+ concentration and activation of subsequent pathways. Interestingly, the promotion of stem cell differentiation, regulation of the direction of immune cell polarization, and antibacterial efficacy are determined by the free charge contained in the implant, rather than by the magnitude of the surface potential difference. This functional implant represents a unique strategy for regulating the charged microenvironment around the implant and enhancing osseointegration, thereby providing ideas and technical approaches for the clinical development of novel implant materials.

Electrophoretic Deposition of Gentamicin Into Titania Nanotubes Prevents Evidence of Infection in a Mouse Model of Periprosthetic Joint Infection

Periprosthetic joint infection (PJI) is a leading cause and major complication of joint replacement failure. As opposed to standard-of-care systemic antibiotic prophylaxis for PJI, we developed and tested titanium femoral intramedullary implants with titania nanotubes (TNTs) coated with the antibiotic gentamicin and slow-release agent chitosan through electrophoretic deposition (EPD) in a mouse model of PJI. We hypothesized that these implants would enable local gentamicin delivery to the implant surface and surgical site, effectively preventing bacterial colonization. In the mouse PJI model, C57BL/6 mice received implants with TNTs coated with chitosan (chitosan group; control group) or with TNTs coated with chitosan and gentamicin (chitosan + gentamicin group; experimental group). Following implant placement, the surgical site was inoculated with 1 × 103 CFUs of Xen36 bioluminescent Staphylococcus aureus. All the mice in the chitosan group and none in the chitosan + gentamicin group had evidence of infection based on CFU analysis and bioluminescence imaging through the 14-day assessment postsurgery. Correspondingly, scanning electron microscopy analysis at the implant surface demonstrated bacterial biofilm only in the chitosan group. Furthermore, periosteal reaction and peri-implant bone loss at the femur were significantly reduced in the chitosan + gentamicin group. The chitosan + gentamicin group had reduced pain behavior, improved weight-bearing, and increased weight compared to the chitosan-control group. This study provides preclinical evidence supporting the efficacy of implants with TNTs coated with chitosan and gentamicin through EPD for preventing bacterial colonization and biofilm formation in a mouse model of PJI.

Enhancing Implantable Medical Devices: Surface Functionalization of Titanium with Quaternary Ammonium Salts for Antibacterial Adhesion Properties

Bacterial colonization of titanium-based materials used in implantable medical devices represents a significant challenge in the dental and orthopedic fields, often leading to infections and implant failure. This study reports the surface modification of titanium discs with ammonium salts containing carbon atom chains of different lengths (from 6 to 12) to provide antibacterial properties to the modified metal surfaces while maintaining their biocompatibility. The chemically modified samples have been characterized by ATR-FTIR and SEM-EDX analyses and evaluated for roughness and hydrophilic behavior. This surface modification not only provides hydrophobic properties to titanium surfaces but also introduces a hindering environment for bacterial adhesion. Antibacterial tests performed against methicillin-sensitive and methicillin-resistant Staphylococcus aureus strains demonstrated a proportional increase in antibacterial activity with increasing carbon chain length. The best antibacterial performance is reported for the sample containing 12 carbon atoms (Ti-ADTEAB), which showed inhibition values of 87.5 and 86.6% for the sensitive and resistant strains, respectively. The results suggest that this surface modification could lead to a new generation of implantable medical devices with improved patient outcomes by reducing the risk of postoperative infections.

Composition design and performance analysis of binary and ternary Mg-Zn-Ti alloys for biomedical implants

Magnesium-based implants are highly valued in the biomedical field for biocompatibility and biodegradability, though their inherent low strength in body fluids is a limitation. This study addresses this by alloying magnesium with zinc and titanium to enhance its properties. Mechanical alloying was used to synthesize binary (Mg-Zn, Mg-Ti) and ternary (Mg-Zn-Ti) alloys, which were then compacted and sintered. The alloy powders, composed of 10 wt% Zn and 5 wt% Ti, were milled at 360 rpm for 10 h. Microstructural analysis revealed uniformly dispersed particles, with SEM confirming spherical and fine particles alongside laminates. XRD identified intermetallic compound formation. The ternary alloy demonstrated superior micro-hardness and Young's modulus similar to human bone, making it particularly promising for biomedical applications. Incorporating zinc and titanium into the magnesium matrix resulted in a ternary alloy that outperformed its binary counterparts.

Microscale bone interlocking enhances osseointegration strength on the rough surface of 3D-printed titanium implants: experimental and finite element analysis

BACKGROUND

The advent of 3D-printing technology, which is capable of on-demand fabrication, has ushered in a new era for fixed implant prosthodontics. Over the past decade, immediately loaded 3D-printed titanium implants have demonstrated predictable clinical outcomes in human jaws, highlighting their superior osseointegration strength, which is attributed to their increased surface roughness. However, the biomechanical mechanisms underlying this enhanced osseointegration strength remain elusive, thereby impeding the standardization and broader clinical application of 3D-printed titanium implants.

METHODS

Experimental 3D-printed titanium implants were fabricated via selective laser melting (SLM), and conventional sandblasted and acid-etched titanium implants (CNC-SLA) served as the control group. Implant surfaces were characterized with scanning electron microscopy, surface profilometry, energy-dispersive X-ray spectroscopy, and a contact angle meter. Implants (n = 10) were surgically inserted into the femoral condyle of New Zealand rabbits. At weeks 1, 2, and 8, micro-CT and undecalcified histological sections were used to assess histological osseointegration (n = 6), whereas removal torque analysis was performed to evaluate osseointegration strength (n = 4). At week 8, microscale finite element analysis of different bone-implant interfaces was conducted to predict the peri-implant bone strain under multidirectional implant loading.

RESULTS

The surface roughness of the SLM implants was significantly greater than that of the CNC-SLA implants. Histological osseointegration assessments revealed equal levels of SLM and CNC-SLA implants at weeks 1, 2, and 8. Notably, after week 2, bone interlocking phenomenon appeared on the SLM implants. The removal torque for the SLM implants at week 2 were significantly greater (P < 0.05) than that for the CNC-SLA implants at the same time point and was comparable to the CNC-SLA implants at week 8 (P = 0.775). The removal torque for the SLM implants at week 8 was further increased. Microscale finite element analysis revealed that the rough surface of the SLM implants dispersed harmful strains at the bone-implant interface into the surrounding bone, thereby mitigating the risk of damage to the bone-implant interface.

CONCLUSIONS

The rough surface of 3D-printed titanium implants fosters microscale bone interlocking and alleviates peri-implant bone strain concentration, which is a promising biomechanical basis for osseointegration strength.

Retrograde Femoral Lengthening Below a Total Hip Arthroplasty

BACKGROUND

Limb length discrepancy (LLD) after total hip arthroplasty (THA) is a common occurrence and can lead to back pain, disordered gait, and decreased functional outcomes. Femoral lengthening ipsilateral to a THA using a retrograde motorized intramedullary lengthening nail (MILN) is a hip-sparing option for limb equalization. There has been little published on the technique and results of this method.

METHODS

We retrospectively reviewed all patients at our institution who underwent unilateral femoral lengthening using a retrograde MILN ipsilateral and distal to a THA between April 2016 and June 2022. We describe the technique and considerations for this procedure in detail and report the patient demographic variables, etiology and magnitude of LLD, concomitant deformity, knee range of motion, time to union, and all adverse events and complications.

RESULTS

Eleven lengthening procedures were included in this cohort. Etiology for LLD included osteonecrosis (4); postinfection (3); and one each of post-trauma, congenital deficiency, hip dysplasia, and iatrogenic discrepancy secondary to the index THA procedure. The mean lengthening was 35.7 ± 14.7 mm (range 20 to 70 mm) with a lengthening index of 1.5 ± 1.2 months until union per cm of lengthening. Complications included two patients who required reamed exchange nailing to achieve union and one interprosthetic fracture treated with removal of the MILN and plate fixation. No adverse effects on THA function were documented.

CONCLUSION

Femur lengthening using a retrograde MILN ipsilateral to a THA is a safe and reliable hip-sparing option for post-THA limb length equalization.

Predicting the biomechanical behavior of lumbar intervertebral Discs: A comparative finite element analysis of a novel artificial disc design

Osseointegration along with better mimicry of natural bone behaviour addresses the long-term performance of artificial intervertebral disc prosthesis. Here the effect of a novel artificial intervertebral disc geometry on stress, deformation and strain on lumbar segments to restore movement of the spine was investigated. The process involved, using CT image data, and solid modelling, simulation-driven design and finite element (FE) analysis, hexahedral mesh sensitivity analysis, implant placements. The range of motion (ROM) was calculated using an ANSYS deformation probe. The intact lumbar spine model established was compared with two implants, replacement at segment L4-L5 level, and biomechanical results were compared using axial loads of 500 N, 800 N, 1000 N and 10Nm moment. The two lumbosacral FE models, a novel implant Titanium Conix (TIC) and another FDA approved SB Charite™ (SBC) implant were considered. Novel TIC implant geometry exhibited comparable ROM values in four physiological motions, which were comparable to as required for restoring natural motion. The result shows that the proposed TIC observed the deformation during flexion, extension, bending and twist as 3.43 mm, 3.19 mm, 3.33 mm and 3.48 mm respectively. Similarly strain of 0.01 during flexion, 0.02 during extension, 0.01 during bending and 0.02 during twist. The implants designed in this study demonstrate the suitability of titanium alloy in endplates and annulus. The FE models in the study with their biomechanical parameters can be considered before clinical implementation of any implants, pre-surgery evaluations, implant placement simulations, postsurgical response, follow-up revisions, implant customization and manufacturing.

Deferoxamine functionalized alginate-based collagen composite material enhances the integration of metal implant and bone interface

Poor osseointegration markedly compromises the longevity of prostheses. To enhance the stability of titanium implants, surface functionalization is a proven strategy to promote prosthesis-bone integration. This study developed a hydrogel coating capable of simultaneous osteoangiogenesis and vascularization by incorporating deferoxamine (DFO) into a sodium alginate mineralized collagen composite hydrogel. The physicochemical properties of this hydrogel were thoroughly analyzed. In vivo and in vitro experiments confirmed the hydrogel scaffold's osteogenic and angiogenic capabilities. Results indicated that sodium alginate notably enhanced the mechanical characteristics of the mineralized collagen, allowing it to fully infiltrate the interstices of the 3D-printed titanium scaffold. Furthermore, as the hydrogel degraded, collagen, calcium ion, phosphate ion, and DFO were gradually released around the scaffolds, altering the local osteogenic microenvironment and strongly inducing new bone tissue growth. These findings offer novel perspectives for the creation and utilization of functionalized bone implant materials.

Influence of different polymeric materials of implant and attachment on stress distribution in implant-supported overdentures: a three-dimensional finite element study

PURPOSE

Investigating high performance thermoplastic polymers as substitutes to titanium alloy, in fabrication of implants and attachments to support mandibular overdenture, aiming to overcome stress shielding effect of titanium alloy implants. AIM OF STUDY: Assessment of stress distribution in polymeric prosthetic components and bone around polymeric implants, in case of implant-supported mandibular overdenture.

MATERIALS AND METHODS

3D finite element model was established for mandibular overdenture, supported bilaterally by two implants at canine region, and retained by two ball attachments. Linear static stress analysis was carried out by ANSYS 2020 R1. Three identical models were created with different materials for modeling of prosthetic components (implant body, gingival former, ball attachment and matrix). The Monolithic principle was applied as the same material was used in modelling all the prosthetic components in each model (Titanium alloy grade V, poly-ether-ether-ketone (PEEK) and poly-ether-ketone-ketone (PEKK)). Simultaneous Force application of 60 N was carried out bilaterally at the first molar occlusal surface area using 3 runs (vertical, lateral and oblique).

RESULTS

PEEK and PEKK prosthetic components exhibited the highest total deformation and critical Maximum von Mises stresses values in implant body and gingival former under lateral and oblique loads. The stress values approached the fatigue limit of both polymeric materials presenting low factor of safety (< 1.5). The Peri-implant cortical bone in case of PEEK and PEKK showed nearly double maximum principal stresses compared with the titanium model. Conversely, Maximum von Mises stresses in spongy bone were lower in polymeric models than those of titanium ones. Additionally maximum equivalent strain values in spongy peri-implant bone of polymeric models were also lower than those of titanium model.

CONCLUSION

Critical high stresses were induced in implant body and gingival former under oblique or lateral loadings, accordingly, fatigue failure of both PEEK and PEKK polymer prosthetic elements was estimated due to low factor of safety. Both PEEK and PEKK Polymer models offered no advantage over titanium one regarding stress shielding effect, due to low stress and strain values generated at spongy peri-implant bone in polymer models.

The Effect of Low-Temperature Short-Term Annealing on the Microstructure and Properties of Ultrafine-Grained Pure Titanium

Industrial pure titanium was processed through 1-4 passes by equal-channel angular pressing (ECAP), and the processed samples were subsequently short-term annealed for 15 min at 300 °C, to achieve better mechanical properties for industrial applications. The microstructure was analyzed using TEM, EBSD, and XRD observations. The mechanical properties were studied through tensile testing. The TEM and EBSD results showed that the grain size of industrial pure titanium was refined to approximately 420 nm after four passes of ECAP processing, with very little grain growth after annealing. The XRD analysis proved the enhanced basal texture in the subsequent annealed samples. Tensile tests indicated that the strength of the processed sample increased with more ECAP passes and was improved by 39% after four passes compared with the as-received state; in addition, the low-temperature short-term annealing resulted in a further strengthening phenomenon. It was concluded that the strengthening after annealing in industrial pure titanium was likely due to the improved basal texture, resulting in texture strengthening.

Nanostructured TiO2 Surface Enriched with CeO2 over Ti Metal for Enhanced Cytocompatibility and Osseointegration for Biomedical Applications

The present study aims to analyze the thermal regulation of the Ce3+/Ce4+ ratio on the nanonetwork titania layer over the titanium (Ti) surface developed by the alkali-mediated surface modification approach. The effect of sequential heat treatment from 200 to 800 °C was evaluated for its surface characteristics such as morphology, phase formation, roughness, hardness, hydrophilicity, etc. Surface oxidation by temperatures up to 600 °C demonstrated a progressive increase in the Ce4+ (CeO2) content with a rutile TiO2 network layer over the Ti surface. In contrast, a bulk reduction with increased Ce3+ (Ce2O3) content was observed at 800 °C. Heat treatment at 800 °C was also characterized by an improved nanohardness and roughness with a distorted surface network layer. The coexistence of Ce4+/Ce3+ (CeO2/Ce2O3) on a porous titania layer displayed a noticeable enhancement in antibacterial activity, which was evaluated against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The surface-modified sample heat-treated at 600 °C and enriched with a high Ce4+/Ce3+ ratio revealed enhanced cell compatibility toward MG-63 in terms of cell adhesion, noncytotoxicity, and mitochondrial membrane potential with higher extracellular matrix mineralization. Further, in vivo bone defect investigations in a rat model using additively manufactured cancellous Ti scaffolds functionalized with surface incorporation of Ce ions heat-treated at 600 °C demonstrated significant enhancement in the osseointegration potential observed from histological and micro-computed tomography analyses. The upregulation of osteogenic marker genes (ALP, OCN, OPN, OSX, and RUNX2) at the implantation site evaluated by reverse transcription polymerase chain reaction confirmed the osteogenic potential of ceria surface functionalization. Hence, the Ce-incorporated nanostructured titania layer predominantly possessing a high Ce4+/Ce3+ ratio or CeO2 content on Ti metal is expected to reduce the risk of implant-related infections and improve cellular responses in orthopedic applications.

3D-printed surfaces of titanium implant: the fibroblasts response

Ti-6Al-4V (wt%) is the most widely used titanium alloy and its additive manufactured (or 3D printed) parts with near net-shape have provided great advantages for biomedical applications. While the impact of surface roughness on the biocompatibility of 3D-printed Ti-6Al-4V part is recognized, further exploration is needed to fully understand this complex relationship. Hence, this study presents a comprehensive evaluation of as-printed Ti-6Al-4V structures, both with and without surface texturing, with particular focus on the fibroblast response. Alongside a flat surface, or as-printed surface, two different types of surface textures: diamond texture and diamond crystal texture, were meticulously designed and printed through laser powder bed fusion (LPBF). The viability, cell adhesion, and morphology of human and murine fibroblasts seeded on the surface patterns was investigated, as well as the distribution of extracellular matrix (ECM) proteins (collagen I, fibronectin). The results demonstrated that the as-fabricated surface morphologies did not impact fibroblast viability, however, a reduced density of human fibroblasts was observed on the diamond texture surface, likely owing to the upright strut structure preventing cell adhesion. Interestingly, spreading of the human, but not murine, fibroblasts was limited by the remaining partially-sintered powders. The relative intensity of ECM protein signals was unaffected, however, ECM protein distribution across the surfaces was also altered. Thus, the as-printed substrates, particularly with diamond crystal struts, present a promising avenue for the cost-effective and efficient fabrication of Ti-6Al-4V components for medical applications in the future.

Prospects of osteosynthesis with fixators based on magnesium alloys, mechanical and physiological properties. The state of the problem at the current stage

OBJECTIVE

Aim: The aim of this work is to analyze the available scientific information regarding to the prospects of metal-osteosynthesis with biodegradable fixators based on magnesium alloys.

PATIENTS AND METHODS

Materials and Methods: A set of general and special methods of scientific knowledge are used in the article. Search and analysis of full-text articles and scientific publications - carried out in databases of systematic reviews of MEDLINE, PubMed, Web of Science, Google Scholar, Scopus.

CONCLUSION

Conclusions: Magnesium-based implants contribute to a tissue regeneration and healing during degradation and do not require removal. This allows you to avoid the second surgical intervention and reduces treatment costs. That is why the development and implementation of biodegradable fixators for osteosynthesis is of great importance.

Enhanced osseointegration and antimicrobial properties of 3D-Printed porous titanium alloys with copper-strontium doped calcium silicate coatings

The 3D printing of porous titanium scaffolds reduces the elastic modulus of titanium alloys and promotes osteogenic integration. However, due to the biological inertness of titanium alloy materials, the implant-bone tissue interface is weakly bonded. A calcium silicate (CS) coating doped with polymetallic ions can impart various biological properties to titanium alloy materials. In this study, CuO and SrO binary-doped CS coatings were prepared on the surface of 3D-printed porous titanium alloy scaffolds using atmospheric plasma spraying and characterized by SEM, EDS, and XRD. Both CuO and SrO were successfully incorporated into the CS coating. The in vivo osseointegration evaluation of the composite coating-modified 3D-printed porous titanium alloy scaffolds was conducted using a rabbit bone defect model, showing that the in vivo osseointegration of 2% CuO-10% SrO-CS-modified 3D-printed porous titanium alloy was improved. The in vitro antimicrobial properties of the 2% CuO-10% SrO-CS-modified 3D-printed porous titanium alloy were evaluated through bacterial platform coating, co-culture liquid absorbance detection, and crystal violet staining experiments, demonstrating that the composite coating exhibited good antimicrobial properties. In conclusion, the composite scaffold possesses both osteointegration-promoting and antimicrobial properties, indicating a broad potential for clinical applications.

The potential carcinogenicity of orthopaedic implants - a scoping review

BACKGROUND

Every year, hundreds of thousands of patients receive an orthopaedic or dental implant containing metals such as cobalt, chromium and titanium. Since the European Chemicals Agency (2020) classified pure cobalt metal as a Category 1B carcinogen, manufacturers of products containing ≥ 0.1% of this metal must perform a risk assessment and justify that there are no viable alternatives. The up-classification of cobalt metal to a carcinogen without good evidence that its use in implants is carcinogenic may cause unnecessary concern to the many patients who have, or may require such implants. Although in vitro and animal studies have shown such metals to be carcinogenic, human epidemiological studies have not been definitive. In addition, although many advances have been made in the past few decades with regard to the materials used in implant metals, no recent review of their carcinogenic effects have been published.

METHODS

This scoping review aims to summarise epidemiological studies conducted in recent years (from 2010 to present) to outline the carcinogenic effects of orthopaedic metal implants that have been published. This encompasses implants of different materials and surfaces, including metal, polyethylene and ceramic orthopaedic implants, cemented and cementless joint replacement surgeries, and surgical techniques such as resurfacing and total joint replacements that are currently in use and the potential carcinogenicity related to their use. Research papers with various study designs published in the English language were included. Studies were excluded if participants had a prior history of cancer before receiving orthopaedic implants and if they focused solely on the carcinogenicity of metals or materials not related to orthopaedic implants.

RESULTS

A total of 16 studies, encompassing over 700,000 implant patients, were identified through PubMed and have been included in this review. In long term follow-up of up to 17.9 years, no increased risk of all-site cancer was seen in these patients. However, an increase in site-specific cancers, namely prostate, melanoma and haematological cancers have been identified. Specifically, an increase in prostate cancer was identified in three studies.

CONCLUSION

Based on the summarised evidence, there is no consistent evidence to show that patients with any type of orthopaedic implant has an increased risk of cancer, although slight (non-statistically significant) increases in prostate cancer was observed and this, in particular, deserves longer-term surveillance.

Amorphous Magnesium Coating for Achieving Functional Changes from Antibacterial to Osteogenic Activities

Medical devices composed of titanium (Ti) should exhibit antibacterial and osteogenic activities to achieve both infection prevention and rapid bone reconstruction. Here, a Ti surface was modified by performing magnetron sputtering (MS) using pure Mg or Mg-30Ca alloy targets for surface functionalization. MC0, prepared with a pure Mg target, had a crystalline metallic-Mg coating layer, whereas MC30, prepared with an Mg-30Ca alloy target, had an amorphous coating composed of Mg and Ca. Both samples rapidly dissolved when immersed in a cell culture medium and exhibited antibacterial activities against methicillin-resistant Staphylococcus aureus and cytotoxicity against MC3T3-E1 cells. Furthermore, MC30 promoted the proliferation and calcification of MC3T3-E1 cells because of the subsequent deposition of calcite on the surface after rapid dissolution. Our findings are the first to reveal that MS performed by using an Mg-30Ca alloy target endowed Ti surfaces with functional changes from antibacterial to osteogenic activities over time. Our results provide fundamental insights into the surface design of Ti-based medical devices for enhanced bone reconstruction and infection prevention and offer possibilities for biomedical applications of Mg-based coatings.

Corrosion behavior of Zr-14Nb-5Ta-1Mo alloy in simulated body fluid

Metals that are used to reconstruct skeletal structures often interfere with magnetic resonance imaging (MRI) owing to differences in magnetic susceptibility; consequently, metals with lower magnetic susceptibilities need to be developed for use in implant devices. Herein, we investigated the corrosion properties of the Zr-14Nb-5Ta-1Mo alloy, which exhibits low magnetic susceptibility and excellent mechanical properties. The pitting potential of Zr-14Nb-5Ta-1Mo was higher than that of pure Zr. The passive current density of Zr-14Nb-5Ta-1Mo also higher than that of pure Zr, which is ascribable to slow reconstruction of the initial passive film associated with the presence of Nb and Ta. XPS revealed that the passive film is enriched with Nb and Ta. Therefore, while the Zr-14Nb-5Ta-1Mo alloy exhibited a high initial passive current density in simulated body fluid, it formed a stable passive film that suppressed localized corrosion. Zr-14Nb-5Ta-1Mo is therefore a prospective implant-material alloy candidate.

Biomaterials for bone tissue engineering: achievements to date and future directions

Advancement in medicine and technology has resulted into prevention of countless deaths and increased life span. However, it is important to note that, the modern lifestyle has altered the food habits, witnessed increased life-style stresses and road accidents leading to several health complications and one of the primary victims is the bone health. More often than ever, healthcare professionals encounter cases of massive bone fracture, bone loss and generation of critical sized bone defects. Surgical interventions, through the use of bone grafting techniques are necessary in such cases. Natural bone grafts (allografts, autografts and xenografts) however, have major drawbacks in terms of delayed rehabilitation, lack of appropriate donors, infection and morbidity that shifted the focus of several investigators to the direction of synthetic bone grafts. By employing biomaterials that are based on bone tissue engineering (BTE), synthetic bone grafts provide a more biologically acceptable approach to establishing the phases of bone healing. In BTE, various materials are utilized to support and enhance bone regeneration. Biodegradable polymers like poly-(lactic acid), poly-(glycolic acid), and poly-(ϵ-caprolactone) are commonly used for their customizable mechanical properties and ability to degrade over time, allowing for natural bone growth. PEG is employed in hydrogels to promote cell adhesion and growth. Ceramics, such as hydroxyapatite and beta-tricalcium phosphate (β-TCP) mimic natural bone mineral and support bone cell attachment, withβ-TCP gradually resorbing as new bone forms. Composite materials, including polymer-ceramic and polymer-glasses, combine the benefits of both polymers and ceramics/glasses to offer enhanced mechanical and biological properties. Natural biomaterials like collagen, gelatin, and chitosan provide a natural matrix for cell attachment and tissue formation, with chitosan also offering antimicrobial properties. Hybrid materials such as decellularized bone matrix retain natural bone structure and biological factors, while functionalized scaffolds incorporate growth factors or bioactive molecules to further stimulate bone healing and integration. The current review article provides the critical insights on several biomaterials that could yield to revolutionary improvements in orthopedic medical fields. The introduction section of this article focuses on the statistical information on the requirements of various bone scaffolds globally and its impact on economy. In the later section, anatomy of the human bone, defects and diseases pertaining to human bone, and limitations of natural bone scaffolds and synthetic bone scaffolds were detailed. Biopolymers, bioceramics, and biometals-based biomaterials were discussed in further depth in the sections that followed. The article then concludes with a summary addressing the current trends and the future prospects of potential bone transplants.

Combined release of LL37 peptide and zinc ion from a mussel-inspired coating on porous titanium for infected bone defect repairing

Implant-associated infections impose great burden on patient health and public healthcare. Antimicrobial peptides and metal ions are generally incorporated onto implant surface to deter bacteria colonization. However, it is still challenging to efficiently prevent postoperative infections at non-cytotoxic dosages. Herein, a scaffold based on porous titanium coated with a mussel-inspired dual-diameter TiO2 nanotubes is developed for loading dual drugs of LL37 peptide and Zn2+ with different sizes and characteristics. Benefiting from in-situ formed polydopamine layer and dual-diameter nanotubular structure, the scaffold provides an efficient platform for controllable drugs elution: accelerated release under acidic condition and sustained release for up to 28 days under neutral/alkalescent circumstances. Such combination of dual drugs simultaneously enhanced antibacterial efficacy and osteogenesis. In antibacterial test, LL37 peptide serving as bacteria membrane puncture agent, and Zn2+ acting as ROS generator, cooperatively destroyed bacterial membrane integrity and subsequently damaged bacterial DNA, endowing dual-drug loaded scaffold with remarkable bactericidal efficiency of > 92 % in vitro and > 99 % in vivo. Noteworthily, dual-drug loaded scaffold promoted bone-implant osteointegration under infectious microenvironment, overmatching single-drug load ones. It provides a promising strategy on surface modification of implant for infected bone defect repairing.

Atopic dermatitis treatment: A comprehensive review of conventional and novel bioengineered approaches

Atopic dermatitis (AD) remains a challenging condition, with conventional treatments often leading to adverse effects and limited efficacy. This review explores the diverse landscape of AD treatments, encompassing conventional methods, novel topical and systemic therapies, and emerging bioengineered strategies. While conventional drug administration often requires high dosages or frequent administration, leading to adverse effects, targeted biologics have shown promise. Phototherapy and wet wrap therapy, while helpful, have limitations. Given these factors, the need for modern and effective therapeutic strategies for AD is pressing. Complementary or alternative therapies have garnered significant attention in recent years as a compelling treatment for AD. Among these, functionalized biomaterials and textiles with physicochemical, nanotechnology-based characteristics, or bioengineered features are some of the most common typical adjuvant therapies. The multifunctional-engineered biomaterials, as a new generation of biomedical materials, and stem cells, seem to hold tremendous promise for the treatment of dermatological diseases like AD. Biomaterials have seen great success, especially in various medical fields, due to their unique and adaptable characteristics. These materials, including collagen, PCL, and PLGA, offer unique advantages, such as biocompatibility, biodegradability, controlled drug release, and enhanced drug retention.

Low toxicity of dissolved silver from silver-coated titanium dental implants to human primary osteoblast cells

the controlled release of silver as a biocide from Ag-coated medical implants is desirable. However, the biocompatibility of Ag leachates is poorly understood. This study investigated the toxicity of silver released from the silver plated titanium implants to human primary osteoblast cells; and the effect of cell culture medium on the silver speciation and bioavailability.

METHODS

Ti6Al4V discs were coated with Ag nanoparticles (NPs), silver plus hydroxyapatite (HA) nanoparticles (Ag+nHA), or Ag NPs plus microparticles (Ag+mHA). Primary human osteoblast cells were exposed to the leachates from the various discs for up to 7 days.

RESULTS

the total Ag concentrations released as leachate from the silver-plated titanium discs were 0.7-1.6 mg L-1, regardless of treatment. Cumulative silver release over 7 days was approximately 3 mg L-1 in all treatments. The concentration of total Ag in the cell homogenates from all the Ag-containing treatments was modest, ∼ 0.1 µg mg protein-1 or less at day 7. Cells showed normal healthy morphology with no appreciable leak of LDH or ALP activity into the external media compared to the reference control. Similarly, there was no significant differences (Kruskal Wallis, p > 0.05) in the LDH or ALP activity in the cell homogenate between treatments.

CONCLUSIONS

overall, there was a controlled release of Ag into the external media, but this remained biocompatible with no deleterious effects on the osteoblast cells, which means that the released silver to the peri-implant environment is not toxic making the coating potential for clinical use.

Regulation of Osteogenic and Angiogenic Markers in Alkali-Treated Titanium for Hard Tissue Engineering Applications

Titanium (Ti) and Ti alloys are of great interest in bone and dental tissue engineering applications due to their biocompatibility, corrosion resistance, and close mechanical properties to natural bone. However, the formation of fibrous tissue prevents osteointegration and results in implant loosening. Thus, physical and chemical methods are used to improve the surface properties of Ti. This study aimed to understand the role of alkali treatment conditions, including alkali medium concentration, temperature, rotation speed, and post heat treatment. Our results show that alkali treatment using 5 and 10 molar sodium hydroxide (NaOH) solution allows the formation of web-like microstructure. However, a higher concentration of 15 molar resulted in cracks along the surface. Interaction between the human fetal osteoblast cells and Ti samples showed that heat treatment is necessary for increased cellular proliferation, which was not significantly different at later time points compared with the polished Ti. Alkali heat treatment did not induce inflammatory reactions at later time points. It showed an increase in vascular endothelial growth factor, osteoprotegerin/nuclear factor kappa-Β ligand ratio, and osteocalcin expression, which is evidence for accelerated osteoblast cell maturation and bone remodeling in surface-modified samples. Together, these data show that alkali treatment using 5 or 10 molar of NaOH followed by heat treatment may have a therapeutic effect and assist with bone tissue integration with Ti implant.

Tailoring surface stiffness to modulate senescent macrophage immunomodulation: Implications for osteo-/angio-genesis in aged bone regeneration

The application of biomaterials in bone regeneration is a prevalent clinical practice. However, its efficacy in elderly patients remains suboptimal, necessitating further advancements. While biomaterial properties are known to orchestrate macrophage (MΦ) polarization and local immune responses, the role of biomaterial cues, specifically stiffness, in directing the senescent macrophage (S-MΦ) is still poorly understood. This study aimed to elucidate the role of substrate stiffness in modulating the immunomodulatory properties of S-MΦ and their role in osteo-immunomodulation. Our results demonstrated that employing collagen-coated polyacrylamide hydrogels with varying stiffness values (18, 76, and 295 kPa) as model materials, the high-stiffness hydrogel (295 kPa) steered S-MΦs towards a pro-inflammatory M1 phenotype, while hydrogels with lower stiffness (18 and 76 kPa) promoted an anti-inflammatory M2 phenotype. The immune microenvironment created by S-MΦs promoted the bioactivities of senescent endothelial cells (S-ECs) and senescent bone marrow mesenchymal stem cells BMSCs (S-BMSCs). Furthermore, the M2 S-MΦs, particularly incubated on the 76 kPa hydrogel matrices, significantly enhanced the ability of angiogenesis of S-ECs and osteogenic differentiation of S-BMSCs, which are crucial and interrelated processes in bone healing. This modulation aided in reducing the accumulation of reactive oxygen species in S-ECs and S-BMSCs, thereby significantly contributing to the repair and regeneration of aged bone tissue.

Selective laser melting of titanium matrix composites: An in-depth analysis of materials, microstructures, defects, and mechanical properties

This paper provides an in-depth review of the advancements and challenges associated with Titanium Matrix Composites (TMCs) in Selective Laser Melting (SLM). Material selection, SLM processing parameters, and their influence on the microstructure and properties of TMCs are discussed. The relationship between processing parameters, material characteristics, and the development of defects such as balling, porosity, and cracking is examined. Critical factors influencing the evolution of microstructure and defect formation in TMCs processed by SLM are highlighted. Strengthening mechanisms such as dislocation movements, grain refinement, the Orowan process, and load-bearing capacity are analyzed, and their roles in enhancing hardness, tensile strength, corrosion resistance, and wear resistance are explored. It is indicated by key findings that less than 5 % reinforcement content by volume can significantly enhance mechanical properties, achieving maximum hardness values of approximately 1000 HV and tensile strength close to 1500 MPa. However, this improvement is accompanied by a notable decrease in elongation. The importance of optimizing SLM parameters such as laser power, scan speed, hatch distance, layer thickness, and particle contents to minimize defects and enhance material performance is underscored. Existing research gaps in defect management and material distribution are identified. Future research directions on improving TMCs performance through advanced SLM techniques are suggested.

Optimizing Suitable Mechanical Properties for a Biocompatible Beta-Titanium Alloy by Combining Plastic Deformation with Solution Treatment

The microstructural and mechanical features were investigated for the alloy Ti-36.5Nb-4.5Zr-3Ta-0.16O (wt.%) subjected to thermo-mechanical processing consisting of a series of hot and cold rolling combined with solution treatments with particular parameters. The objective was to find the optimal thermo-mechanical treatment variant to improve the mechanical properties, and namely, to increase the yield tensile strength (YTS) and the ultimate tensile strength (UTS), with a low modulus of elasticity and with an adequate ductility in order to obtain a good biomaterial appropriate for use in hard tissue implants. X-ray diffraction and SEM microscopy served to investigate the microstructural features: the type of formed phases with their morphology, dimensions, and distribution. The experimental alloy presented mainly a β-phase with some α″-Ti martensitic phase in particular stages of the processing scheme. The main mechanical properties were found by applying a tensile test, from which were determined the yield tensile strength [MPa], the ultimate tensile strength [MPa], Young's modulus of elasticity [GPa], and the elongation to fracture (%).

The Effect of Specimen Width on the Deformation Behavior and Formability of cp-Ti Grade 4 Sheets During Uniaxial and Cyclic Bending Under Tension Loading

This study examines the specimen size-dependent deformation behavior of commercially pure titanium grade 4 (cp-Ti grade 4) sheets under tension, with strain paths between uniaxial tension (UT) and plane-strain tension and compares the results with cyclic bending under tension (CBT) data. Specimens of varying widths (11.7, 20, 60, 100, and 140 mm) were tested in both rolling (RD) and transverse (TD) directions. The research employed digital image correlation for full-field strain measurements, finite element simulations, and fracture surface thickness data. Contrary to traditional forming concepts, i.e., the forming limit diagram (FLD) has the lowest major strain at the plane-strain condition, and the fracture forming limit has decreased major strain with increasing (less negative) minor strain, wider specimens exhibited higher major strains at strain localization and fracture under UT. In contrast, CBT findings showed decreased formability with increasing width, i.e., closer to plane-strain deformation, as expected. Strain distribution analyses revealed a transition from nearly uniform deformation in narrow specimens to multiaxial strain states in wider specimens. Thickness measurements along the fracture surface revealed a steeper profile in UT compared to CBT, indicating more localized deformation and necking in UT. In comparison with AA6016-T4, the cp-Ti grade 4 showed greater thickness, suggesting lower susceptibility to localized thinning. Strong anisotropy was observed between the RD and TD, with TD specimens showing higher formability and steeper thickness gradients in UT. Strain fields, along with thickness reduction and adiabatic heating, are used to rationalize the observed width-sensitive deformation behavior of cp-Ti sheets. Notably, CBT improved overall formability compared to UT due to its ability to distribute strain more evenly and delay critical necking. The contrasting trends between simple UT and CBT emphasize the relationship between loading conditions, specimen geometry, and material behavior in determining formability. These findings highlight the ability of the CBT test to create known and desired deformation effects, i.e., lower major strain at failure with increasing specimen width, and more uniform deformation, i.e., consistent thinning across the specimen width, for cp-Ti. Given the observed effects of width in UT, the selection of the testing method is critical for cp-Ti to ensure that results reflect expected material behavior.

Novel biocompatible magnetron-sputtered silver coating for enhanced antibacterial properties and osteogenesis in vitro

Peri-implant infection is a serious complication in orthopedic surgery. This study aimed to reduce the incidence of peri-implant infection by developing a durable and safe antibacterial silver coating. We compared the antibacterial properties and process controllability of various coating techniques to identify the most effective method for silver coating. We refined substrate treatment techniques and coating thicknesses through antibacterial and scratch tests. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) were used to analyze the coating's morphology and composition. Micron-sized magnetron sputtering silver coating samples underwent in vitro antibacterial testing, cytotoxicity testing, silver ion release testing, and osteogenic testing using membrane contact culture, CCK-8 assay, inductively coupled plasma (ICP) detection, and alkaline phosphatase (ALP) activity/osteogenic gene PCR. Magnetron sputtering demonstrated superior antibacterial properties, uniformity, and process controllability compared to alternative techniques. The optimal adhesion strength was achieved with a 0.5 μm coating thickness and a 400 mesh sandpaper pretreatment process, without compromising antibacterial efficacy. The coating showed near-perfect antiseptic results in antibacterial and anti-biofilm tests. Fibroblasts cultured in silver ion precipitation medium exhibited growth rates of 89% on day 30 and 88% on day 90, compared to 95% in the control group. The osteogenic test indicated that the magnetron sputtering silver coating promotes osteogenesis effectively. Our study demonstrated that micron-sized magnetron sputtering silver coating has potential for clinical use to prevent peri-implant infections in the future.

Enhancing Antibacterial Properties of Titanium Implants through Covalent Conjugation of Self-Assembling Fmoc-Phe-Phe Dipeptide on Titania Nanotubes

Bacterial infections and biofilm formation are significant challenges for medical implants. While titanium nanotube engineering improves biocompatibility, it cannot prevent bacterial adhesion and biofilm formation. Optimizing the biomaterial's surface chemistry is vital for its desired functioning in the biological environment. This study demonstrates the covalent conjugating of the self-assembling dipeptide N-fluorenylmethyloxycarbonyl-diphenylalanine (Fmoc-FF) onto titanium nanotube surfaces (TiNTs) without altering the topography. Fmoc-FF peptides, in conjugation with TiNTs, can inhibit biofilm formation, eradicate pre-existing biofilms, and kill bacteria. This functionalization imparts antibacterial properties to the surface while retaining beneficial nanotube topography, synergistically enhancing bioactivity. Surface characterization by XPS, FT-IR, EDS, and SEM confirmed the successful functionalization. Bacterial adhesion experiments showed a significantly improved antibacterial activity of the functionalized TiNT surfaces. This study opens future possibilities for associating biomedical applications such as cell-cell interactions, tissue engineering, and controlled drug delivery of multifunctional self-assembling short peptides with implant materials through surface functionalization.

A two-pronged approach to inhibit ferroptosis of MSCs caused by the iron overload in postmenopausal osteoporosis and promote osseointegration of titanium implant

Postmenopausal osteoporosis (PMOP) is a prevalent condition among elderly women. After menopause, women exhibit decreased iron excretion, which is prone to osteoporosis. To design a specific titanium implant for PMOP, we first analyze miRNAs and DNA characteristics of postmenopausal patients with and without osteoporosis. The results indicate that iron overload disrupts iron homeostasis in the pathogenesis of PMOP. Further experiments confirm that iron overload can cause lipid peroxidation and ferroptosis of MSCs, thus breaking bone homeostasis. Based on the findings above, we have designed a novel Ti implant coated with nanospheres of caffeic acid (CA) and deferoxamine (DFO). CA can bind on the Ti surface through the two adjacent phenolic hydroxyls and polymerize into polycaffeic acid (PCA) dimer, as well as the PCA nanospheres with the repetitive 1,4-benzodioxan units. DFO was grafted with PCA through borate ester bonds. The experimental results showed that modified Ti can inhibit the ferroptosis of MSCs in the pathological environment of PMOP and promote osseointegration in two main ways. Firstly, DFO was released under high oxidative stress, chelating with excess iron and decreasing the labile iron pool in MSCs. Meanwhile, CA and DFO activated the KEAP1/NRF2/HMOX1 pathway in MSCs and reduced the level of intracellular lipid peroxidation. So, the ferroptosis of MSCs is inhibited by promoting the SLC7A11/GSH/GPX4 pathway. Furthermore, the remained CA coating on the Ti surface could reduce the extracellular oxidative stress and glutathione level. This study offers a novel inspiration for the specific design of Ti implants in the treatment of PMOP.

Coalescence Mechanism Induced by Different Wetting States of Ti and Al Droplets on Rough Surfaces

There is currently increasing interest in droplet transportation and coalescence on rough surfaces. However, the relationship among wettability, coalescence mode, and substrate characteristics (roughness and nanopillar height) remains unclear. In this work, two coalescence modes, climbing coalescence and contacting coalescence, are first observed in the dynamic behaviors of Ti and Al droplets on rough substrates. Due to the nonsynchronized wetting state transition of the droplets, the coalescence mode with increasing substrate characteristics differs, transitioning from contacting coalescence to climbing coalescence and then returning to the contacting mode. In general, the mode of coalescence correlates closely with the respective wetting states. Typically, Ti and Al droplets coalesce in the contacting mode when they have the same wetting state, but if they have different wetting states, they coalesce in the climbing mode. Our results emphasize the complicated relationship between the surface structure and the wettability of droplets, which could provide insights into self-assembly, three-dimensional printing, and microfluidic devices.

Recent development and applications of electrodeposition biocoatings on medical titanium for bone repair

Bioactive coatings play a crucial role in enhancing the osseointegration of titanium implants for bone repair. Electrodeposition offers a versatile and efficient technique to deposit uniform coatings onto titanium surfaces, endowing implants with antibacterial properties, controlled drug release, enhanced osteoblast adhesion, and even smart responsiveness. This review summarizes the recent advancements in bioactive coatings for titanium implants used in bone repair, focusing on various electrodeposition strategies based on material-structure synergy. Firstly, it outlines different titanium implant materials and bioactive coating materials suitable for bone repair. Then, it introduces various electrodeposition methods, including electrophoretic deposition, anodization, micro-arc oxidation, electrochemical etching, electrochemical polymerization, and electrochemical deposition, discussing their applications in antibacterial, osteogenic, drug delivery, and smart responsiveness. Finally, it discusses the challenges encountered in the electrodeposition of coatings for titanium implants in bone repair and potential solutions.

Recent advances in materials and manufacturing of implantable devices for continuous health monitoring

Implantable devices are vital in healthcare, enabling continuous monitoring, early disease detection, informed decision-making, enhanced outcomes, cost reduction, and chronic condition management. These devices provide real-time data, allowing proactive healthcare interventions, and contribute to overall improvements in patient care and quality of life. The success of implantable devices relies on the careful selection of materials and manufacturing methods. Recent materials research and manufacturing advancements have yielded implantable devices with enhanced biocompatibility, reliability, and functionality, benefiting human healthcare. This paper provides a comprehensive overview of the latest developments in implantable medical devices, emphasizing the importance of material selection and manufacturing methods, including biocompatibility, self-healing capabilities, corrosion resistance, mechanical properties, and conductivity. It explores various manufacturing techniques such as microfabrication, 3D printing, laser micromachining, electrospinning, screen printing, inkjet printing, and nanofabrication. The paper also discusses challenges and limitations in the field, including biocompatibility concerns, privacy and data security issues, and regulatory hurdles for implantable devices.

The impact of metal implants on the dose and clinical outcome of radiotherapy (Review)

Radiotherapy (RT) is one of the most widely used and effective cancer treatments. With the increasing need for organ reconstruction and advancements in material technology, an increasing number of patients with cancer have metallic implants. These implants can affect RT dosage and clinical outcomes, warranting careful consideration by oncologists. The present review discussed the mechanisms by which different types of metallic implants impact various stages of the RT process, examined methods to mitigate these effects during treatment, and discussed the clinical implications of metallic implants on RT outcomes. In summary, when metallic implants are present within the RT field, oncologists should carefully assess their impact on the treatment.