Osseointegration of titanium with an antimicrobial nanostructured noble metal coating

Analyzing the Surface Topography of Hafnium Nitride Coating on Titanium Screws: An In Vitro Analysis

Background The use of surface coatings to enhance the properties lacking in titanium has attracted significant focus in recent times. Hafnium nitride (HfN) coatings could be explored as promising in the osteoinductive properties of titanium implants. HfN exhibits excellent mechanical attributes, such as hardness and wear resistance, and is often used as a coating on high-end equipment for protection. The findings from this research may carve a new path for the production and optimization of HfN coatings to enhance the longevity and augment properties of implant materials. Thus, the present study was orchestrated to elucidate the surface morphology of HfN coating, ultimately contributing to the advancement of dental implant biomaterials. Materials and methods A total of twenty samples of medical grade commercially pure titanium screws (2 mm diameter and 7 mm length) were procured from G. R. Bioure Surgical System Pvt. Ltd., Ravali, Uttar Pradesh, India, and ten samples were reacted with HfN (0.1 M) (Nano Research Elements, Kurukshetra, Haryana, India) in 100% ethanol and stirred continuously for about 48 hours. Then these screw samples were immersed in the prepared colloidal suspension and sintered for two hours at 400 degrees centigrade. The implant screws were affixed onto metal supports. The magnifications for photomicrographs at ×30, ×200, ×1,500, ×3,000, and ×5,000 were standardized. Elementary semi-quantitative analysis of both dental implants was conducted using energy-dispersive X-ray spectrometry (EDX) coupled with the field emission scanning electron microscope (FE-SEM) equipment (JEOL Ltd., Akishima, Tokyo, Japan). The software used for the analysis of the obtained images is SEM Center. Results The surface analysis using the scanning electron microscope (SEM) showed the coating of HfN over titanium screws. The difference in surface morphology of both the group of implant screws can be visualized under 40.0 and 10.0 mm working distance (WD) for both groups. The surface analysis using the EDX of uncoated titanium screws shows five elements in the spectrum: titanium (Ti), oxygen (O), aluminum (Al), carbon (C), and vanadium (V). The EDX of the HfN-coated screws has two additional metals dispersed in the spectrum, hafnium (Hf). The element characteristics are tabulated with their apparent concentration, k ratio, line type, weight percentage, standard label, and factory label for uncoated titanium screws and HfN-coated titanium screws. Conclusion The study evaluated HfN coating over medical grade commercially pure titanium. The surface topography of coated versus uncoated was visualized. The scanning electron microscope (SEM) images showed a homogenous coating over the titanium surfaces, and the EDX showed elemental dispersion of the coated implant. The study aims to provide a comprehensive understanding of the coating's surface morphology, which will aid in the development of more durable and biocompatible implants. This thereby provides a promising scope for further research of this novel metal coating for use in the biomedical sectors, specifically for dental implants.

Current Progress and Future Perspectives in Contact and Releasing-Type Antimicrobial Coatings of Orthopaedic Implants: A Systematic Review Analysis Emanated from In Vitro and In Vivo Models

Background: Despite the expanding use of orthopedic devices and the application of strict pre- and postoperative protocols, the elimination of postoperative implant-related infections remains a challenge. Objectives: To identify and assess the in vitro and in vivo properties of antimicrobial-, silver- and iodine-based implants, as well as to present novel approaches to surface modifications of orthopedic implants. Methods: A systematic computer-based review on the development of these implants, on PubMed and Web of Science databases, was carried out according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Results: Overall, 31 in vitro and 40 in vivo entries were evaluated. Regarding the in vitro studies, antimicrobial-based coatings were assessed in 12 entries, silver-based coatings in 10, iodine-based in 1, and novel-applied coating technologies in 8 entries. Regarding the in vivo studies, antimicrobial coatings were evaluated in 23 entries, silver-coated implants in 12, and iodine-coated in 1 entry, respectively. The application of novel coatings was studied in the rest of the cases (4). Antimicrobial efficacy was examined using different bacterial strains, and osseointegration ability and biocompatibility were examined in eukaryotic cells and different animal models, including rats, rabbits, and sheep. Conclusions: Assessment of both in vivo and in vitro studies revealed a wide antimicrobial spectrum of the coated implants, related to reduced bacterial growth, inhibition of biofilm formation, and unaffected or enhanced osseointegration, emphasizing the importance of the application of surface modification techniques as an alternative for the treatment of orthopedic implant infections in the clinical settings.

The current applications of nano and biomaterials in drug delivery of dental implant

BACKGROUND AND AIM

Dental implantology has revolutionized oral rehabilitation, offering a sophisticated solution for restoring missing teeth. Despite advancements, issues like infection, inflammation, and osseointegration persist. Nano and biomaterials, with their unique properties, present promising opportunities for enhancing dental implant therapies by improving drug delivery systems. This review discussed the current applications of nano and biomaterials in drug delivery for dental implants.

METHOD

A literature review examined recent studies and advancements in nano and biomaterials for drug delivery in dental implantology. Various materials, including nanoparticles, biocompatible polymers, and bioactive coatings, were reviewed for their efficacy in controlled drug release, antimicrobial properties, and promotion of osseointegration.

RESULTS

Nano and biomaterials exhibit considerable potential in improving drug delivery for dental implants. Nanostructured drug carriers demonstrate enhanced therapeutic efficacy, sustained release profiles, and improved biocompatibility. Furthermore, bioactive coatings contribute to better osseointegration and reduced risks of infections.

CONCLUSION

Integrating current nano and biomaterials in drug delivery for dental implants holds promise for advancing clinical outcomes. Enhanced drug delivery systems can mitigate complications associated with dental implant procedures, offering improved infection control, reduced inflammation, and optimized osseointegration.

Bench-to-bedside: Feasibility of nano-engineered and drug-delivery biomaterials for bone-anchored implants and periodontal applications

Nanotechnology and drug-release biomaterials have been thoroughly explored in the last few years aiming to develop specialized clinical treatments. However, it is rare to find biomaterials associated with drug delivery properties in the current dental market for application in oral bone- and periodontal-related procedures. The gap between basic scientific evidence and translation to a commercial product remains wide. Several challenges have been reported regarding the clinical translation of biomaterials with drug-delivery systems (BDDS) and nanofeatures. Therefore, processes for BDDS development, application in preclinical models, drug delivery doses, sterilization processes, storage protocols and approval requirements were explored in this review, associated with tentative solutions for these issues. The diversity of techniques and compounds/molecules applied to develop BDDS demands a case-by-case approach to manufacturing and validating a commercial biomaterial. Promising outcomes such as accelerated tissue healing and higher antibacterial response have been shown through basic and preclinical studies using BDDS and nano-engineered biomaterials; however, the adequate process for sterilization, storage, cost-effectiveness and possible cytotoxic effects remains unclear for multifunctional biomaterials incorporated with different chemical compounds; then BDDSs are rarely translated into products. The future benefits of BDDS and nano-engineered biomaterials have been reported suggesting personalized clinical treatment and a promising reduction in the use of systemic antibiotics. Finally, the launch of these specialized biomaterials with solid data and controlled traceability onto the market will generate strong specificity for healthcare treatments.

Periosteal topology creates an osteo-friendly microenvironment for progenitor cells

The periosteum on the skeletal surface creates a unique micro-environment for cortical bone homeostasis, but how this micro-environment is formed remains a mystery. In our study, we observed the cells in the periosteum presented elongated spindle-like morphology within the aligned collagen fibers, which is in accordance with the differentiated osteoblasts lining on the cortical surface. We planted the bone marrow stromal cells(BMSCs), the regular shaped progenitor cells, on collagen-coated aligned fibers, presenting similar cell morphology as observed in the natural periosteum. The aligned collagen topology induced the elongation of BMSCs, whichfacilitated the osteogenic process. Transcriptome analysis suggested the aligned collagen induced the regular shaped cells to present part of the periosteum derived stromal cells(PDSCs) characteristics by showing close correlation of the two cell populations. In addition, the elevated expression of PDSCs markers in the cells grown on the aligned collagen-coated fibers further indicated the function of periosteal topology in manipulating cells' behavior. Enrichment analysis revealed cell-extracellular matrix interaction was the major pathway initiating this process, which created an osteo-friendly micro-environment as well. At last, we found the aligned topology of collagen induced mechano-growth factor expression as the result of Igf1 alternative splicing, guiding the progenitor cells behavior and osteogenic process in the periosteum. This study uncovers the key role of the aligned topology of collagen in the periosteum and explains the mechanism in creating the periosteal micro-environment, which gives the inspiration for artificial periosteum design.

Use of a Novel Anti-Infective Noble Metal Alloy-Coated Titanium Orthopedic Nail in Patients with Open Fractures: A Case Series from Malaysia

Fracture-related infection is a serious complication in orthopedic surgery with severe consequences for the patient. We evaluated whether a novel noble metal nail-coating technology can prevent bacterial adhesion and biofilm formation without interfering with bony union. In this retrospective, single-center case series, we described the incidence of fracture-related infections and bony union achievement in patients who had Gustilo type IIIa or IIIb femoral or tibial fractures treated with noble metal alloy-coated titanium nails. Patients were treated between January 2017 and January 2019 at the Sultanah Aminah Hospital, Johor Bahru, Malaysia. Information on fracture-related infections and bone healing assessments was collected from patient records. Additionally, three independent experts retrospectively reviewed patient X-ray images from follow-up visits to further evaluate bony union achievement. Thirty-five patients were included. Infection developed in 3/35 (8.6%) patients; all cases were resolved by antibiotic therapy. Radiographs were available for 32 patients; these confirmed the presence of bone healing in 30/32 (93.8%) patients. However, according to patient records, bony union was achieved in all patients. No safety issues were recorded. This case series suggests that a noble metal alloy-coated titanium nail can prevent infection and facilitate bony union achievement in patients undergoing surgery for severe open fractures.

Recent Advances in the Evaluation of Antimicrobial Materials for Resolution of Orthopedic Implant-Associated Infections In Vivo

While orthopedic implant-associated infections are rare, revision surgeries resulting from infections incur considerable healthcare costs and represent a substantial research area clinically, in academia, and in industry. In recent years, there have been numerous advances in the development of antimicrobial strategies for the prevention and treatment of orthopedic implant-associated infections which offer promise to improve the limitations of existing delivery systems through local and controlled release of antimicrobial agents. Prior to translation to in vivo orthopedic implant-associated infection models, the properties (e.g., degradation, antimicrobial activity, biocompatibility) of the antimicrobial materials can be evaluated in subcutaneous implant in vivo models. The antimicrobial materials are then incorporated into in vivo implant models to evaluate the efficacy of using the material to prevent or treat implant-associated infections. Recent technological advances such as 3D-printing, bacterial genomic sequencing, and real-time in vivo imaging of infection and inflammation have contributed to the development of preclinical implant-associated infection models that more effectively recapitulate the clinical presentation of infections and improve the evaluation of antimicrobial materials. This Review highlights the advantages and limitations of antimicrobial materials used in conjunction with orthopedic implants for the prevention and treatment of orthopedic implant-associated infections and discusses how these materials are evaluated in preclinical in vivo models. This analysis serves as a resource for biomaterial researchers in the selection of an appropriate orthopedic implant-associated infection preclinical model to evaluate novel antimicrobial materials.

Bridging micro/nano-platform and airway allergy intervention

Allergic airway diseases, with incidence augmenting visibly as industrial development and environmental degradation, are characterized by sneezing, itching, wheezing, chest tightness, airway obstruction, and hyperresponsiveness. Current medical modalities attempt to combat these symptoms mostly by small molecule chemotherapeutants, such as corticosteroids, antihistamines, etc., via intranasal approach which is one of the most noninvasive, rapid-absorbed, and patient-friendly routes. Nevertheless, inherent defects for irritation to respiratory mucosa, drug inactivation and degradation, and rapid drug dispersal to off-target sites are inevitable. Lately, intratracheal micro/nano therapeutic systems are emerging as innovative alternatives for airway allergy interventions. This overview introduces several potential application directions of mic/nano-platform in the treatment of airway allergic diseases, including carriers, therapeutic agents, and immunomodulators. The improvement of the existing drug therapy of respiratory allergy management by micro/nano-platform is described in detail. The challenges of the micro/nano-platform nasal approach in the treatment of airway allergy are summarized and the development of micro/nano-platform is also prospected. Although still a burgeoning area, micro/nano therapeutic systems are gradually turning to be realistic orientations as crucial future alternative therapeutic options in allergic airway inflammation interventions.

Effectiveness of Biofunctionalization of Titanium Surfaces with Phosphonic Acid

Surface functionalization of dental implant surfaces has been a developing field in biomaterial research. This study aimed to obtain self-assembled monolayers (SAMs) using carboxyethylphosphonic acid on the surface of titanium (Ti) screws, and assessed the surface characteristics, biomechanical, and cellular behavior on the obtained specimens. This study had three groups, i.e., a control (untreated screws), a test group treated with phosphonic acid, and a third group with treated acid and bone morphogenetic protein (BMP-2) for in vitro analysis of cell lines. The assessed parameters included surface wettability, surface characteristics using scanning electron microscopy (SEM), protein immobilization, and cellular behavior of fibroblasts and mesenchymal stem cells of adipose tissue (MSCat cells). For surface wettability, a Welch test was performed to compare the contact angles between control (67 ± 1.83) and test (18.84 ± 0.72) groups, and a difference was observed in the mean measurements, but was not statistically significant. The SEM analysis showed significant surface roughness on the test screws and the cellular behavior of fibroblasts, and MSCat cells were significantly improved in this group, with fibroblasts having a polygonal shape with numerous vesicles and MSCat cells stable and uniformly coating the test Ti surface. Surface biofunctionalization of Ti surfaces with phosphonic acid showed promising results in this study, but remains to be clinically validated for its applications.

Dental Implant Nano-Engineering: Advances, Limitations and Future Directions

Titanium (Ti) and its alloys offer favorable biocompatibility, mechanical properties and corrosion resistance, which makes them an ideal material choice for dental implants. However, the long-term success of Ti-based dental implants may be challenged due to implant-related infections and inadequate osseointegration. With the development of nanotechnology, nanoscale modifications and the application of nanomaterials have become key areas of focus for research on dental implants. Surface modifications and the use of various coatings, as well as the development of the controlled release of antibiotics or proteins, have improved the osseointegration and soft-tissue integration of dental implants, as well as their antibacterial and immunomodulatory functions. This review introduces recent nano-engineering technologies and materials used in topographical modifications and surface coatings of Ti-based dental implants. These advances are discussed and detailed, including an evaluation of the evidence of their biocompatibility, toxicity, antimicrobial activities and in-vivo performances. The comparison between these attempts at nano-engineering reveals that there are still research gaps that must be addressed towards their clinical translation. For instance, customized three-dimensional printing technology and stimuli-responsive, multi-functional and time-programmable implant surfaces holds great promise to advance this field. Furthermore, long-term in vivo studies under physiological conditions are required to ensure the clinical application of nanomaterial-modified dental implants.

Enhancing Osseointegration of TC4 Alloy by Surficial Activation Through Biomineralization Method

Titanium (Ti) alloys have been applied to biomedical implants for a long time. Although Ti alloys are biocompatible, efforts have been continuously made to improve their bone conductivity and osteogenesis for enhancing their performance. Silk fibroin (SF) is a natural biomaterial with excellent biomedical and mechanical properties, and hydroxyapatite (HAP) nanocomposites derived from SF are promising for producing “artificial bone” owing to their biomedical applicability and strong mechanical functions. Therefore, we built an SF coating on the surface of Ti–6Al–4V alloy, and then the incubated SF-coated Ti alloy were immersed in simulated body fluid to induce mineral deposition of HAP on the alloys. The results from Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) analysis, and Attenuated Total Reflection–Fourier Transform Infrared Spectroscopy (ATR–FTIR) confirmed the deposition of a mineral layer on the SF film surface. The proliferation, adhesion, and differentiation of MG-63 were tested, along with the BMP-2, COX-2, and OPG expression and protein content in the MG-63. Both Ti + SF and Ti + SF + HAP groups exhibited significantly better performance than a control Ti group with regard to the cell adhesion, cell proliferation, and protein expression. Furthermore, the hybrid layer comprising HAP and SF delivered more significant improvement of the osseointegration than the SF alone. It is hoped that the proposed methods can be used for constructing modified surfaces on Ti alloys, as they endowed the implants with good osteogenic potential.

Volatile Iridium and Platinum MOCVD Precursors: Chemistry, Thermal Properties, Materials and Prospects for Their Application in Medicine

Interest in iridium and platinum has been steadily encouraged due to such unique properties as exceptional chemical inertia and corrosion resistance, high biological compatibility, and mechanical strength, which are the basis for their application in medical practice. Metal-organic chemical vapor deposition (MOCVD) is a promising method to fabricate Ir and Pt nanomaterials, multilayers, and heterostructures. Its advantages include precise control of the material composition and microstructure in deposition processes at relatively low temperatures onto non-planar substrates. The development of MOCVD processes is inextricably linked with the development of the chemistry of volatile precursors, viz., specially designed coordination and organometallic compounds. This review describes the synthesis methods of various iridium and platinum precursors, their thermal properties, and examples of the use of MOCVD, including formation of films for medical application and bimetallics. Although metal acetylacetonates are currently the most widely used precursors, the recently developed heteroligand Ir(I) and Pt(IV) complexes appear to be more promising in both synthetic and thermochemical aspects. Their main advantage is their ability to control thermal properties by modifying several types of ligands, making them tunable to deposit films onto different types of materials and to select a combination of compatible compounds for obtaining the bimetallic materials.

[Nanomaterials in the modern dentistry (review)]

Was to study the promising areas for using nanotechnologies in dentistry, existing methods of diagnostics, treatment and prevention of the dental diseases based on the properties of nanoparticles, to review the scientific literature devoted to this problem. In this literature review we use 86 sources: 1 Russian and 85 foreign articles. Analyzed articles were published within the last 5 years. The literature review summarizes and presents up-to-date methods of diagnosing, treating, and preventing dental disease that use nanotechnologies. Development and implementation of nanotechnological treatment are a promising direction for modern dentistry.

Photochemical Surface Modification of Titanium Dioxide Nanotube-Coated Surfaces by Ag-Hydroxyapatite Compositions

Silver-hydroxyapatite coatings prepared from Ag3PO4 microcrystals have been deposited on titanium dioxide nanotubes supported by titanium disks by photodecomposition of predeposited Ag3PO4 microcrystals or their coprecipitate with hydroxyapatite. The SEM-EDS characterization has confirmed excellent film uniformity and consistent deposition over the surface, which is essential for improving osseointegration of tunable antibacterial bone implants.

Anti-microbial coating innovations to prevent infectious diseases (AMiCI): Cost action ca15114

Worldwide, millions of patients are affected annually by healthcare-associated infection (HCAI), impacting up to 80,000 patients in European Hospitals on any given day. This represents not only public health risk, but also an economic burden. Complementing routine hand hygiene practices, cleaning and disinfection, antimicrobial coatings hold promise based, in essence, on the application of materials and chemicals with persistent bactericidal or -static properties onto surfaces or in textiles used in healthcare environments. The focus of considerable commercial investment and academic research energies, such antimicrobial coating-based approaches are widely believed to have potential in reduction of microbial numbers on surfaces in clinical settings. This belief exists despite definitive evidence as to their efficacy and is based somewhat on positive studies involving, for example, copper, silver or gold ions, titanium or organosilane, albeit under laboratory conditions. The literature describes successful delay and/or prevention of recontamination following conventional cleaning and disinfection by problematic microbes such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin resistant enterococci (VRE), among others. However, there is a scarcity of studies assessing antimicrobial surfaces other than copper in the clinical environment, and a complete lack of published data regarding the successful implementation of these materials on clinically significant outcomes (including HCAI). Through its Cooperation in Science and Technology program (COST), the European Commission has funded a 4-year initiative to establish a network of stakeholders involved in development, regulation and use of novel anti-microbial coatings for prevention of HCAI. The network (AMiCI) comprises participants of more than 60 universities, research institutes and companies across 29 European countries and, to-date, represents the most comprehensive consortium targeting use of these emergent technologies in healthcare settings. More specifically, the network will prioritise coordinated research on the effects (both positive and negative) of antimicrobial coatings in healthcare sectors; know-how regarding availability and mechanisms of action of (nano)-coatings; possible adverse effects of such materials (e.g., potential emergence of microbial resistance or emission of toxic agents into the environment); standardised performance assessments for antimicrobial coatings; identification and dissemination of best practices by hospitals, other clinical facilities, regulators and manufacturers.

Silver nanoparticles in dentistry

OBJECTIVE

Silver nanoparticles (AgNPs) have been extensively studied for their antimicrobial properties, which provide an extensive applicability in dentistry. Because of this increasing interest in AgNPs, the objective of this paper was to review their use in nanocomposites; implant coatings; pre-formulation with antimicrobial activity against cariogenic pathogens, periodontal biofilm, fungal pathogens and endodontic bacteria; and other applications such as treatment of oral cancer and local anesthesia. Recent achievements in the study of the mechanism of action and the most important toxicological aspects are also presented.

METHODS

Systematic searches were carried out in Web of Science (ISI), Google, PubMed, SciFinder and EspaceNet databases with the keywords "silver nano* or AgNP*" and "dentist* or dental* or odontol*".

RESULTS

A total of 155 peer-reviewed articles were reviewed. Most of them were published in the period of 2012-2017, demonstrating that this topic currently represents an important trend in dentistry research. In vitro studies reveal the excellent antimicrobial activity of AgNPs when associated with dental materials such as nanocomposites, acrylic resins, resin co-monomers, adhesives, intracanal medication, and implant coatings. Moreover, AgNPs were demonstrated to be interesting tools in the treatment of oral cancers due to their antitumor properties.

SIGNIFICANCE

The literature indicates that AgNPs are a promising system with important features such as antimicrobial, anti-inflammatory and antitumor activity, and a potential carrier in sustained drug delivery. However, there are some aspects of the mechanisms of action of AgNPs, and some important toxicological aspects arising from the use of this system that must be completely elucidated.

Atomic Layer Deposition of a Silver Nanolayer on Advanced Titanium Orthopedic Implants Inhibits Bacterial Colonization and Supports Vascularized de Novo Bone Ingrowth

Joint replacement surgery is associated with significant morbidity and mortality following infection with either methicillin-resistant Staphylococcus aureus (MRSA) or Staphylococcus epidermidis. These organisms have strong biofilm-forming capability in deep wounds and on prosthetic surfaces, with 10³ -10⁴ microbes resulting in clinically significant infections. To inhibit biofilm formation, we developed 3D titanium structures using selective laser melting and then coated them with a silver nanolayer using atomic layer deposition. On bare titanium scaffolds, S. epidermidis growth was slow but on silver-coated implants there were significant further reductions in both bacterial recovery (p < 0.0001) and biofilm formation (p < 0.001). MRSA growth was similarly slow on bare titanium scaffolds and not further affected by silver coating. Ultrastructural examination and viability assays using either human bone or endothelial cells, demonstrated strong adherence and growth on titanium-only or silver-coated implants. Histological, X-ray computed microtomographic, and ultrastructural analyses revealed that silver-coated titanium scaffolds implanted into 2.5 mm defects in rat tibia promoted robust vascularization and conspicuous bone ingrowth. We conclude that nanolayer silver of titanium implants significantly reduces pathogenic biofilm formation in vitro, facilitates vascularization and osseointegration in vivo making this a promising technique for clinical orthopedic applications.

In vivo osseointegration of dental implants with an antimicrobial peptide coating

This study aimed to evaluate the in vivo osseointegration of implants with hydrophobic antimicrobial GL13K-peptide coating in rabbit femoral condyles by micro-CT and histological analysis. Six male Japanese Rabbits (4 months old and weighing 2.5 kg each) were included in this study. Twelve implants (3.75 mm wide, 7 mm long) were randomly distributed in two groups, with six implants in the experimental group coated with GL13K peptide and six implants in the control group without surface coating. Each implant in the test and the control group was randomly implanted in the left or right side of femoral condyles. On one side randomly-selected of the femur, each rabbit received a drill that was left without implant as control for the natural healing of bone. After 3 weeks of healing radiographic evaluation of the implant sites was taken. After 6 weeks of healing, rabbits were sacrificed for evaluation of the short-term osseointegration of the dental implants using digital radiography, micro-CT and histology analysis. To perform evaluation of osseointegration, implant location and group was double blinded for surgeon and histology/radiology researcher. Two rabbits died of wound infection in sites with non-coated implants 2 weeks after surgery. Thus, at least four rabbits per group survived after 6 weeks of healing. The wounds healed without suppuration and inflammation. No implant was loose after 6 weeks of healing. Radiography observations showed good osseointegration after 3 and 6 weeks postoperatively, which proved that the tissues followed a natural healing process. Micro-CT reconstruction and analysis showed that there was no statistically significant difference (P > 0.05) in volume of bone around the implant between implants coated with GL13K peptide and implants without coating. Histomorphometric analysis also showed that the mineralized bone area was no statistically different (P > 0.05) between implants coated with GL13K peptide and implants without coating. This study demonstrates that titanium dental implants with an antimicrobial GL13K coating enables in vivo implant osseointegration at similar bone growth rates than gold-standard non-coated dental implants up to 6 weeks of implantation in rabbit femurs.

TiO2nanotubes enriched with calcium, phosphorous and zinc: promising bio-selective functional surfaces for osseointegrated titanium implants

TiO₂nanotubes enriched with Ca, P, and Zn by reverse polarization anodization, are promising bio-selective functional structures for osseointegrated titanium implants.

A new model of implant-related osteomyelitis in the metaphysis of rat tibiae

Background

Animal models serve as an important tool to understand peri-implant infection. Most of the models use high bacterial loads (>10⁴ colony forming units, CFU) to provide high infection rates. Therefore these animals evolve rather similarly, making comparison between groups and statistical analysis possible. On the other hand, to mimic clinical constellation of surgery-related infections the use of low amounts of bacteria would be more advantageous.

Methods

We developed a metaphyseal rat model of peri-implant bone infection with low amount of bacterial loads (10² and 10³ CFU of Staphylococcus aureus) and investigated osseointegration of the implants coated with hydroxyapatite (HA) and low-dosed HA-silver (HA-Ag). Non-infected implants served as controls. After 6 weeks rats were sacrificed and implants evaluated for osseointegration and infection.

Results

Infection of implanted devices was reliably induced, independently whether 10² or 10³ CFU of S. aureus were inoculated and HA or HA-Ag coated implants were used. No systemic infection was present in any of the animals at the time of sacrifice, and no animal developed acute infection requiring premature sacrifice. All CFU counts of the implant and the bone at sacrifice were significantly higher than the inoculated load (p < .05). All sterilely inserted implants showed excellent osseointegration and no infection.

Conclusions

Our present study of a rat tibia model reliably induced osteomyelitis in the metaphysis with low-doses of bacteria. The addition of low-dosed Ag to the implant coating was not able to reduce the infection rates. The results demonstrate that it is possible to develop a model of implant-related osteomyelitis in rats with low amounts of bacteria to better mimic clinical constellations. No other promoters of infection besides insertion of the screw implant were used in this model.

Multifunctional coatings to simultaneously promote osseointegration and prevent infection of orthopaedic implants

The two leading causes of failure for joint arthroplasty prostheses are aseptic loosening and periprosthetic joint infection. With the number of primary and revision joint replacement surgeries on the rise, strategies to mitigate these failure modes have become increasingly important. Much of the recent work in this field has focused on the design of coatings either to prevent infection while ignoring bone mineralization or vice versa, to promote osseointegration while ignoring microbial susceptibility. However, both coating functions are required to achieve long-term success of the implant; therefore, these two modalities must be evaluated in parallel during the development of new orthopaedic coating strategies. In this review, we discuss recent progress and future directions for the design of multifunctional orthopaedic coatings that can inhibit microbial cells while still promoting osseointegration.

Evaluation of mammalian and bacterial cell activity on titanium surface coated with dicationic imidazolium-based ionic liquids

This work presents a new strategy to protect titanium surfaces against bacterial colonization and biofilm formation using dicationic imidazolium-based ionic liquid coatings.

Spectroscopic and microscopic investigation of the effects of bacteria on dental implant surfaces

The surface morphology and chemical composition of commercially pure titanium dental implants and healing abutments exposed in vitro or in vivo to oral bacteria were studied.

Biomimetic approaches in bone tissue engineering: Integrating biological and physicomechanical strategies

The development of responsive biomaterials capable of demonstrating modulated function in response to dynamic physiological and mechanical changes in vivo remains an important challenge in bone tissue engineering. To achieve long-term repair and good clinical outcomes, biologically responsive approaches that focus on repair and reconstitution of tissue structure and function through drug release, receptor recognition, environmental responsiveness and tuned biodegradability are required. Traditional orthopedic materials lack biomimicry, and mismatches in tissue morphology, or chemical and mechanical properties ultimately accelerate device failure. Multiple stimuli have been proposed as principal contributors or mediators of cell activity and bone tissue formation, including physical (substrate topography, stiffness, shear stress and electrical forces) and biochemical factors (growth factors, genes or proteins). However, optimal solutions to bone regeneration remain elusive. This review will focus on biological and physicomechanical considerations currently being explored in bone tissue engineering.

Biological strategies for improved osseointegration and osteoinduction of porous metal orthopedic implants

The biological interface between an orthopedic implant and the surrounding host tissue may have a dramatic effect upon clinical outcome. Desired effects include bony ingrowth (osseointegration), stimulation of osteogenesis (osteoinduction), increased vascularization, and improved mechanical stability. Implant loosening, fibrous encapsulation, corrosion, infection, and inflammation, as well as physical mismatch may have deleterious clinical effects. This is particularly true of implants used in the reconstruction of load-bearing synovial joints such as the knee, hip, and the shoulder. The surfaces of orthopedic implants have evolved from solid-smooth to roughened-coarse and most recently, to porous in an effort to create a three-dimensional architecture for bone apposition and osseointegration. Total joint surgeries are increasingly performed in younger individuals with a longer life expectancy, and therefore, the postimplantation lifespan of devices must increase commensurately. This review discusses advancements in biomaterials science and cell-based therapies that may further improve orthopedic success rates. We focus on material and biological properties of orthopedic implants fabricated from porous metal and highlight some relevant developments in stem-cell research. We posit that the ideal primary and revision orthopedic load-bearing metal implants are highly porous and may be chemically modified to induce stem cell growth and osteogenic differentiation, while minimizing inflammation and infection. We conclude that integration of new biological, chemical, and mechanical methods is likely to yield more effective strategies to control and modify the implant-bone interface and thereby improve long-term clinical outcomes.

A novel soft tissue model for biomaterial-associated infection and inflammation - bacteriological, morphological and molecular observations

Infection constitutes a major risk for implant failure, but the reasons why biomaterial sites are more vulnerable than normal tissue are not fully elucidated. In this study, a soft tissue infection model was developed, allowing the analysis of cellular and molecular responses in each of the sub-compartments of the implant-tissue interface (on the implant surface, in the surrounding exudate and in the tissue). Smooth and nanostructured titanium disks with or without noble metal chemistry (silver, gold, palladium), and sham sites, were inoculated with Staphylococcus epidermidis and analysed with respect to number of viable bacteria, number, viability and gene expression of host cells, and using different morphological techniques after 4 h, 24 h and 72 h. Non-infected rats were controls. Results showed a transient inflammatory response at control sites, whereas bacterial administration resulted in higher recruitment of inflammatory cells (mainly polymorphonuclear), higher, continuous cell death and higher gene expression of tumour necrosis factor-alpha, interleukin-6, interleukin-8, Toll-like receptor 2 and elastase. At all time points, S. epidermidis was predominantly located in the interface zone, extra- and intracellularly, and lower levels were detected on the implants compared with surrounding exudate. This model allows detailed analysis of early events in inflammation and infection associated to biomaterials in vivo leading to insights into host defence mechanisms in biomaterial-associated infections.

Coatings and surface modifications imparting antimicrobial activity to orthopedic implants

Bacterial colonization and biofilm formation on an orthopedic implant surface is one of the worst possible outcomes of orthopedic intervention in terms of both patient prognosis and healthcare costs. Making the problem even more vexing is the fact that infections are often caused by events beyond the control of the operating surgeon and may manifest weeks to months after the initial surgery. Herein, we review the costs and consequences of implant infection as well as the methods of prevention and management. In particular, we focus on coatings and other forms of implant surface modification in a manner that imparts some antimicrobial benefit to the implant device. Such coatings can be classified generally based on their mode of action: surface adhesion prevention, bactericidal, antimicrobial-eluting, osseointegration promotion, and combinations of the above. Despite several advances in the efficacy of these antimicrobial methods, a remaining major challenge is ensuring retention of the antimicrobial activity over a period of months to years postoperation, an issue that has so far been inadequately addressed. Finally, we provide an overview of additional figures of merit that will determine whether a given antimicrobial surface modification warrants adoption for clinical use.

Osseointegration of bioactive microarc oxidized amorphous phase/TiO2 nanocrystals composited coatings on titanium after implantation into rabbit tibia

The amorphous phase/TiO2 nanocrystals (APTN) composited coatings were prepared on Ti implants for biomedical applications. The Ti implants without and with the APTN composited coatings both do not cause any adverse effects after implantation into the rabbit tibia. The osseointegration of Ti implants after covering the APTN coatings is improved pronouncedly, greatly increasing the interface bonding strength between the implants and newly formed bones. In addition, it is interesting that the newly formed bone tissues appear in the micro-pores of the APTN coatings, promoting the interface bonding between the implants and new bones by the mechanical interlock. Moreover, the Ti implant with the APTN coatings formed at higher applied voltage exhibit higher shear strength and displacement during the pushing out experiment probably due to its better osseointegration.

Dicationic imidazolium-based ionic liquids: a new strategy for non-toxic and antimicrobial materials

Dicationic imidazolium-based ILs: a potent strategy for applications requiring non-toxic materials with antimicrobial activity.