Antibacterial Adhesion Strategy for Dental Titanium Implant Surfaces: From Mechanisms to Application

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.

Calcium Phosphate (CaP) Composite Nanostructures on Polycaprolactone (PCL): Synergistic Effects on Antibacterial Activity and Osteoblast Behavior

Bone tissue engineering aims to develop biomaterials that are capable of effectively repairing and regenerating damaged bone tissue. Among the various polymers used in this field, polycaprolactone (PCL) is one of the most widely utilized. As a biocompatible polymer, PCL is easy to fabricate, cost-effective, and offers consistent quality control, making it a popular choice for biomedical applications. However, PCL lacks inherent antibacterial properties, making it susceptible to bacterial adhesion and biofilm formation, which can lead to implant failure. To address this issue, this study aims to enhance the antibacterial properties of PCL by incorporating calcium phosphate composite (PCL_CaP) nanostructures onto its surface via hydrothermal synthesis. The resulting "PCL_CaP" nanostructured surfaces exhibited improved wettability and demonstrated mechano-bactericidal potential against Escherichia coli and Bacillus subtilis. The flake-like morphology of the fabricated CaP nanostructures effectively disrupted bacteria membranes, inhibiting bacterial growth. Furthermore, the "PCL_CaP" surfaces supported the adhesion, proliferation, and differentiation of pre-osteoblasts, indicating their potential for bone tissue engineering applications. This study demonstrates the promise of calcium phosphate composite nanostructures as an effective antibacterial coating for implants and medical devices, with further research required to evaluate their long-term stability and in vivo performance.

Effect of nanogold incorporation into polymethyl methacrylate denture bases on microbial activity in implant-retained mandibular overdentures

PURPOSE

In this randomized clinical trial, we examined the incorporation of nanogold particles into polymethyl methacrylate denture bases and compared these modified bases with conventional ones in mandibular implant-retained overdentures, focusing on microbiological growth and adhesion characteristics.

METHODS

In this study, twenty-two male patients who were completely edentulous participated in a rehabilitation program involving mandibular overdentures retained by two dental implants placed in the canine area. The subjects were categorized into two equal groups, each comprising eleven patients. Group I received mandibular overdentures fabricated from conventional acrylic denture bases, whereas Group II received mandibular overdentures with bases that had undergone nanogold treatment. Microbial growth and colonization were evaluated around the implant's necks and the fitting surface of each patient's mandibular dentures. Three types of bacteria were studied: Candida albicans, Escherichia coli, and Streptococcus mutans. The mean difference in the counts of bacteria before the denture was inserted and after two, four, and six months has been calculated and analyzed statistically.

RESULTS

Regarding colony count (log 10 CFUs/mmL), there was a significant difference between the research groups. Group II had significantly lower values measured at 2, 4, and 6 months for Candida albicans, Escherichia coli, and Streptococcus mutans, respectively, than group I.

CONCLUSION

The addition of gold nanoparticles to PMMA denture bases was of greater benefit in inhibiting microbial growth than conventional acrylic resin bases.

Emerging Strategies to Prevent Bacterial Infections on Titanium-Based Implants

Titanium and titanium alloys remain the gold standard for dental and orthopedic implants. These materials are heavily used because of their bioinert nature, robust mechanical properties, and seamless integration with bone. However, implant-associated infections (IAIs) remain one of the leading causes of implant failure. Eradicating an IAI can be difficult since bacteria can form biofilms on the medical implant, protecting the bacterial cells against systemic antibiotics and the host's immune system. If the infection is not treated promptly and aggressively, device failure is inevitable, leading to costly multi-step revision surgeries. To circumvent this dire situation, scientists and engineers continue to develop novel strategies to protect the surface of medical implants from bacteria. In this review, details on emerging strategies to prevent infection in titanium implants are reported. These strategies include anti-adhesion properties provided by polymers, superhydrophobic, superhydrophilic, and liquid-infused surface coatings, as well as strategies and coatings employed to lyse the bacteria. Additionally, commercially available technologies and those under preclinical trials are examined while discussing current and future trends.

Insight into antibacterial effect of titanium nanotubular surfaces with focus on Staphylococcus aureus and Pseudomonas aeruginosa

Materials used for orthopedic implants should not only have physical properties close to those of bones, durability and biocompatibility, but should also exhibit a sufficient degree of antibacterial functionality. Due to its excellent properties, titanium is still a widely used material for production of orthopedic implants, but the unmodified material exhibits poor antibacterial activity. In this work, the physicochemical characteristics, such as chemical composition, crystallinity, wettability, roughness, and release of Ti ions of the titanium surface modified with nanotubular layers were analyzed and its antibacterial activity against two biofilm-forming bacterial strains responsible for prosthetic joint infection (Staphylococcus aureus and Pseudomonas aeruginosa) was investigated. Electrochemical anodization (anodic oxidation) was used to prepare two types of nanotubular arrays with nanotubes differing in dimensions (with diameters of 73 and 118 nm and lengths of 572 and 343 nm, respectively). These two surface types showed similar chemistry, crystallinity, and surface energy. The surface with smaller nanotube diameter (TNT-73) but larger values of roughness parameters was more effective against S. aureus. For P. aeruginosa the sample with a larger nanotube diameter (TNT-118) had better antibacterial effect with proven cell lysis. Antibacterial properties of titanium nanotubular surfaces with potential in implantology, which in our previous work demonstrated a positive effect on the behavior of human gingival fibroblasts, were investigated in terms of surface parameters. The interplay between nanotube diameter and roughness appeared critical for the bacterial fate on nanotubular surfaces. The relationship of nanotube diameter, values of roughness parameters, and other surface properties to bacterial behavior is discussed in detail. The study is believed to shed more light on how nanotubular surface parameters and their interplay affect antibacterial activity.

Fighting against biofilm: The antifouling and antimicrobial material

Biofilms are groups of microorganisms protected by self-secreted extracellular substances. Biofilm formation on the surface of biomaterial or engineering materials becomes a severe challenge. It has caused significant health, environmental, and societal concerns. It is believed that biofilms lead to life-threatening infection, medical implant failure, foodborne disease, and marine biofouling. To address these issues, tremendous effort has been made to inhibit biofilm formation on materials. Biofilms are extremely difficult to treat once formed, so designing material and coating bearing functional groups that are capable of resisting biofilm formation has attracted increasing attention for the last two decades. Many types of antibiofilm strategies have been designed to target different stages of biofilm formation. Development of the antibiofilm material can be classified into antifouling material, antimicrobial material, fouling release material, and integrated antifouling/antimicrobial material. This review summarizes relevant research utilizing these four approaches and comments on their antibiofilm properties. The feature of each method was compared to reveal the research trend. Antibiofilm strategies in fundamental research and industrial applications were summarized.

N-Halaminated spermidine-containing polymeric coating enables titanium to achieve dual functions of antibacterial and osseointegration

Titanium (Ti) and its alloys have been widely employed in the treatment of orthopedics and other hard tissue diseases. However, Ti-based implants are bioinert and suffer from bacterial infections and poor osseointegration in clinical applications. Herein, we successfully modified Ti with a porous N-halaminated spermidine-containing polymeric coating (Ti-SPD-Cl) through alkali-heat treatment, surface grafting and chlorination, and it has both excellent antibacterial and osteogenic abilities to significantly enhance osseointegration. The as-obtained Ti-SPD-Cl contains abundant N-Cl groups and demonstrates effective antibacterial ability against S. aureus and E. coli. Meanwhile, due to the presence of the spermidine component and construction of a porous hydrophilic surface, Ti-SPD-Cl is also beneficial for maintaining cell membrane homeostasis and promoting cell adhesion, exhibiting good biocompatibility and osteogenic ability. The rat osteomyelitis model demonstrates that Ti-SPD-Cl can effectively suppress bacterial infection and enhance bone-implant integration. Thus, Ti-SPD-Cl shows promising clinical applicability in the prevention of orthopedic implant infections and poor osseointegration.

Comprehensive Evaluation of Novel Biomaterials for Dental Implant Surfaces: An In Vitro Comparative Study

BACKGROUND

Dental implantology is continually evolving in its quest to discover new biomaterials to improve dental implant success rates. The study explored the potential of innovative biomaterials for dental implant surfaces, including titanium-zirconium (Ti-Zr) alloy, hydroxyapatite-coated titanium (HA-Ti), and porous polyetheretherketone (PEEK), in comparison to conventional commercially pure titanium (CP Ti).

MATERIALS AND METHODS

A total of 186 samples were harvested for the analysis. Biomaterials were thoroughly evaluated in terms of surface topography, chemical composition, biocompatibility, mechanical properties, osseointegration performance, and bacterial adhesion. Study methods and techniques included scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), cell culture variants, tensile tests, hardness measurements, histological analysis, and microbiological testing.

RESULTS

Surface topography examination showed significant disparities between the biomaterials: Ti-Zr had a better roughness of 1.23 μm, while HA-Ti demonstrated a smoother surface at 0.98 μm. Chemical composition evaluation indicated the presence of a Ti-Zr alloy in Ti-Zr, calcium-phosphorus richness in HA-Ti, and high titanium amounts in CP Ti. The mechanical properties assessment showed that Ti-Zr and CP Ti had good tensile strengths of 750 MPa and 320 HV. In addition, bacterial adhesion tests showed low propensities for Ti-Zr and HA-Ti at 1200 and 800 cfu/cm2, respectively.

CONCLUSION

Ti-Zr and HA-Ti performed better than the other biomaterials in surface topography and mechanical properties and against bacterial adhesion. This study emphasizes that multi-parameter analysis is critical for clinical decision-making, allowing for the selection of the currently available biomaterial, which could be conducive to the long-term success of the implant.

Graphene oxide/ε-poly-L-lysine self-assembled functionalized coatings improve the biocompatibility and antibacterial properties of titanium implants

The construction of an antibacterial biological coating on titanium surface plays an important role in the long-term stability of oral implant restoration. Graphene oxide (GO) has been widely studied because of its excellent antibacterial properties and osteogenic activity. However, striking a balance between its biological toxicity and antibacterial properties remains a significant challenge with GO. ε-poly-L-lysine (PLL) has broad-spectrum antibacterial activity and ultra-high safety performance. Using Layer-by-layer self-assembly technology (LBL), different layers of PLL/GO coatings and GO self-assembly coatings were assembled on the surface of titanium sheet. The materials were characterized using scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and contact angle test. The antibacterial properties of Porphyromonas gingivalis (P.g.) were analyzed through SEM, coated plate experiment, and inhibition zone experiment. CCK-8 was used to determine the cytotoxicity of the material to MC3T3 cells, and zebrafish larvae and embryos were used to determine the developmental toxicity and inflammatory effects of the material. The results show that the combined assembly of 20 layers of GO and PLL exhibits good antibacterial properties and no biological toxicity, suggesting a potential application for a titanium-based implant modification scheme.

Surface-Engineered Titanium with Nanoceria to Enhance Soft Tissue Integration Via Reactive Oxygen Species Modulation and Nanotopographical Sensing

The design of implantable biomaterials involves precise tuning of surface features because the early cellular fate on such engineered surfaces is highly influenced by many physicochemical factors [roughness, hydrophilicity, reactive oxygen species (ROS) responsiveness, etc.]. Herein, to enhance soft tissue integration for successful implantation, Ti substrates decorated with uniform layers of nanoceria (Ce), called Ti@Ce, were optimally developed by a simple and cost-effective in situ immersion coating technique. The characterization of Ti@Ce shows a uniform Ce distribution with enhanced roughness (∼3-fold increase) and hydrophilicity (∼4-fold increase) and adopted ROS-scavenging capacity by nanoceria coating. When human gingival fibroblasts were seeded on Ti@Ce under oxidative stress conditions, Ti@Ce supported cellular adhesion, spreading, and survivability by its cellular ROS-scavenging capacity. Mechanistically, the unique nanocoating resulted in higher expression of amphiphysin (a nanotopology sensor), paxillin (a focal adhesion protein), and cell adhesive proteins (collagen-1 and fibronectin). Ti@Ce also led to global chromatin condensation by decreasing histone 3 acetylation as an early differentiation feature. Transcriptome analysis by RNA sequencing confirmed the chromatin remodeling, antiapoptosis, antioxidant, cell adhesion, and TGF-β signaling-related gene signatures in Ti@Ce. As key fibroblast transcription (co)factors, Ti@Ce promotes serum response factor and MRTF-α nucleus localization. Considering all of this, it is proposed that the surface engineering approach using Ce could improve the biological properties of Ti implants, supporting their functioning at soft tissue interfaces and utilization as a bioactive implant for clinical conditions such as peri-implantitis.

Biomaterial engineering surface to control polymicrobial dental implant-related infections: focusing on disease modulating factors and coatings development

INTRODUCTION

Peri-implantitis is the leading cause of dental implant loss and is initiated by a polymicrobial dysbiotic biofilm formation on the implant surface. The destruction of peri-implant tissue by the host immune response and the low effectiveness of surgical or non-surgical treatments highlight the need for new strategies to prevent, modulate and/or eliminate biofilm formation on the implant surface. Currently, several surface modifications have been proposed using biomolecules, ions, antimicrobial agents, and topography alterations.

AREAS COVERED

Initially, this review provides an overview of the etiopathogenesis and host- and material-dependent modulating factors of peri-implant disease. In addition, a critical discussion about the antimicrobial surface modification mechanisms and techniques employed to modify the titanium implant material is provided. Finally, we also considered the future perspectives on the development of antimicrobial surfaces to narrow the bridge between idea and product and favor the clinical application possibility.

EXPERT OPINION

Antimicrobial surface modifications have demonstrated effective results; however, there is no consensus about the best modification strategy and in-depth information on the safety and longevity of the antimicrobial effect. Modified surfaces display recurring challenges such as short-term effectiveness, the burst release of drugs, cytotoxicity, and lack of reusability. Stimulus-responsive surfaces seem to be a promising strategy for a controlled and precise antimicrobial effect, and future research should focus on this technology and study it from models that better mimic clinical conditions.

A Review on Nano Ti-Based Oxides for Dark and Photocatalysis: From Photoinduced Processes to Bioimplant Applications

Catalysis on TiO₂ nanomaterials in the presence of H₂O and oxygen plays a crucial role in the advancement of many different fields, such as clean energy technologies, catalysis, disinfection, and bioimplants. Photocatalysis on TiO₂ nanomaterials is well-established and has advanced in the last decades in terms of the understanding of its underlying principles and improvement of its efficiency. Meanwhile, the increasing complexity of modern scientific challenges in disinfection and bioimplants requires a profound mechanistic understanding of both residual and dark catalysis. Here, an overview of the progress made in TiO₂ catalysis is given both in the presence and absence of light. It begins with the mechanisms involving reactive oxygen species (ROS) in TiO₂ photocatalysis. This is followed by improvements in their photocatalytic efficiency due to their nanomorphology and states by enhancing charge separation and increasing light harvesting. A subsection on black TiO₂ nanomaterials and their interesting properties and physics is also included. Progress in residual catalysis and dark catalysis on TiO₂ are then presented. Safety, microbicidal effect, and studies on Ti-oxides for bioimplants are also presented. Finally, conclusions and future perspectives in light of disinfection and bioimplant application are given.

Response of Human Gingival Fibroblasts and Porphyromonas gingivalis to UVC-Activated Titanium Surfaces

Ultraviolet (UV) photofunctionalization has been demonstrated to synergistically improve the osteoblast response and reduce biofilm formation on titanium (Ti) surfaces. However, it remains obscure how photofunctionalization affects soft tissue integration and microbial adhesion on the transmucosal part of a dental implant. This study aimed to investigate the effect of UVC (100–280 nm) pretreatment on the response of human gingival fibroblasts (HGFs) and Porphyromonas gingivalis (P. g.) to Ti-based implant surfaces. The smooth and anodized nano-engineered Ti-based surfaces were triggered by UVC irradiation, respectively. The results showed that both smooth and nano-surfaces acquired super hydrophilicity without structural alteration after UVC photofunctionalization. UVC-activated smooth surfaces enhanced the adhesion and proliferation of HGFs compared to the untreated smooth ones. Regarding the anodized nano-engineered surfaces, UVC pretreatment weakened the fibroblast attachment but had no adverse effects on proliferation and the related gene expression. Additionally, both Ti-based surfaces could effectively inhibit P. g. adhesion after UVC irradiation. Therefore, the UVC photofunctionalization could be more potentially favorable to synergistically improve the fibroblast response and inhibit P. g. adhesion on the smooth Ti-based surfaces.