Objective: To fabricate TiO₂ nanotube material functionalized by antimicrobial peptide LL-37, and to explore its effects on biological behaviors such as adhesion and migration of human keratinocytes (HaCaT) and its antibacterial properties. Methods: The TiO₂ nanotube array (NT) was constructed on the surface of polished titanium (PT) by anodization, and the antimicrobial peptide LL-37 was loaded on the surface of TiO₂ nanotube (LL-37/NT) by physical adsorption. Three samples were selected by simple random sampling in each group. Surface morphology, roughness, hydrophilicity and release characteristics of LL-37 of the samples were analyzed with a field emission scanning electron microscope, an atomic force microscope, a contact angle measuring device and a microplate absorbance reader. HaCaT cells were respectively cultured on the surface of three groups of titanium samples. Each group had 3 replicates. The morphology of cell was observed by field emission scanning electron microscope. The number of cell adhesion was observed by cellular immunofluorescence staining. Cell counting kit-8 (CCK-8) assay was used to detect cell proliferation. Wound scratch assay was used to observe the migration of HaCaT. The above experiments were used to evaluate the effect of each group on the biological behavior of HaCaT cells. To evaluate their antibacterial effects, Porphyromonas gingivalis (Pg) was respectively inoculated on the surface of three groups of titanium samples. Each group had 3 replicates. The morphology of bacteria was observed by field emission scanning electron microscope. Bacterial viability was determined by live/dead bacterial staining. Results: A uniform array of nanotubes could be seen on the surface of titanium samples in LL-37/NT group, and the top of the tube was covered with granular LL-37. Compared with PT group [the roughness was (2.30±0.18) nm, the contact angle was 71.8°±1.7°], the roughness [(20.40±3.10) and (19.10±4.11) nm] and hydrophilicity (the contact angles were 22.4°±3.1° and 25.3°±2.2°, respectively) of titanium samples increased in NT and LL-37/NT group (P<0.001). The results of in vitro release test showed that the release of antimicrobial peptide LL-37 was characterized by early sudden release (1-4 h) and long-term (1-7 d) slow release. With the immunofluorescence, more cell attachment was found on NT and LL-37/NT than that on PT at the first 0.5 and 2.0 h of culture (P<0.05). The results of CCK-8 showed that there was no significant difference in the proliferation of cells among groups at 1, 3 and 5 days after culture. Wound scratch assay showed that compared with PT and NT group, the cell moved fastest on the surface of titanium samples in LL-37/NT group at 24 h of culture [(96.4±4.9)%] (F=35.55, P<0.001). A monolayer cells could be formed and filled with the scratch in 24 h at LL-37/NT group. The results of bacterial test in vitro showed that compared with the PT group, the bacterial morphology in the NT and LL-37/NT groups was significantly wrinkled, and obvious bacterial rupture could be seen on the surface of titanium samples in LL-37/NT group. The results of bacteria staining showed that the green fluorescence intensity of titanium samples in LL-37/NT group was the lowest in all groups (F=66.54,P<0.001). Conclusions: LL-37/NT is beneficial to the adhesion and migration of HaCaT cells and has excellent antibacterial properties, this provides a new strategy for the optimal design of implant neck materials.
Humans ; Titanium/chemistry* ; Antimicrobial Peptides ; Cathelicidins ; Sincalide ; Anti-Bacterial Agents/pharmacology* ; Nanotubes/chemistry* ; Dental Materials ; Bacteria ; Keratinocytes ; Surface Properties

OBJECTIVES: This study aimed to investigate the effect of new biomimetic micro/nano surfaces on the osteoclastic differentiation of RAW264.7 macrophages by simulating natural osteons for the design of concentric circular structures and modifying graphene oxide (GO). METHODS: The groups were divided into smooth titanium surface group (SS), concentric microgrooved titanium surface group (CMS), and microgroove modified with GO group (GO-CMS). The physicochemical properties of the material surfaces were studied using scanning electron microscopy (SEM), contact-angle measurement, atomic force microscopy, X-ray photoelectron spectroscopy analysis, and Raman spectroscopy. The effect of the modified material surface on the cell biological behavior of RAW264.7 was investigated by cell-activity assay, SEM, and laser confocal microscopy. The effect on the osteoclastic differentiation of macrophages was investiga-ted by tartrate-resistant acid phosphatase (TRAP) immunofluorescence staining and quantitative real-time polymerase chain reaction (qRT-PCR) experiments. RESULTS: Macrophages were arranged in concentric circles along the microgrooves, and after modification with GO, the oxygen-containing groups on the surface of the material increased and hydrophilicity increased. Osteoclasts in the GO-CMS group were small in size and number and had the lowest TRAP expression. Although it promoted the proliferation of macrophages in the GO-CMS group, the expression of osteoclastic differentiation-related genes was lower than that in the SS group, and the difference was statistically significant (P<0.05). CONCLUSIONS Concentric circular microgrooves restricted the fusion of osteoclasts and the formation of sealing zones. Osteomimetic concentric microgrooves modified with GO inhibited the osteoclastic differentiation of RAW 264.7 macrophages.
Graphite/pharmacology* ; Titanium/pharmacology* ; Haversian System ; Macrophages ; Cell Differentiation ; Oxides/pharmacology* ; Surface Properties

Peri-implantitis is one of the most important biological complications in the field of oral implantology. Identifying the causative factors of peri-implant inflammation and osteolysis is crucial for the disease's prevention and treatment. The underlying risk factors and detailed pathogenesis of peri-implantitis remain to be elucidated. Titanium-based implants as the most widely used implant inevitably release titanium particles into the surrounding tissue. Notably, the concentration of titanium particles increases significantly at peri-implantitis sites, suggesting titanium particles as a potential risk factor for the condition. Previous studies have indicated that titanium particles can induce peripheral osteolysis and foster the development of aseptic osteoarthritis in orthopedic joint replacement. However, it remains unconfirmed whether this phenomenon also triggers inflammation and bone resorption in peri-implant tissues. This review summarizes the distribution of titanium particles around the implant, the potential roles in peri-implantitis and the prevalent prevention strategies, which expects to provide new directions for the study of the pathogenesis and treatment of peri-implantitis.
Humans ; Peri-Implantitis/pathology* ; Titanium/pharmacology* ; Dental Implants/adverse effects* ; Osteolysis/pathology* ; Inflammation/chemically induced*

OBJECTIVE: To design and construct a graphene oxide (GO)/silver nitrate (Ag₃PO₄)/chitosan (CS) composite coating for rapidly killing bacteria and preventing postoperative infection in implant surgery. METHODS: GO/Ag₃PO₄ composites were prepared by ion exchange method, and CS and GO/Ag₃PO₄ composites were deposited on medical titanium (Ti) sheets successively. The morphology, physical image, photothermal and photocatalytic ability, antibacterial ability, and adhesion to the matrix of the materials were characterized. RESULTS: The GO/Ag₃PO₄ composites were successfully prepared by ion exchange method and the heterogeneous structure of GO/Ag₃PO₄ was proved by morphology phase test. The heterogeneous structure formed by Ag₃PO₄ and GO reduced the band gap from 1.79 eV to 1.39 eV which could be excited by 808 nm near-infrared light. The photothermal and photocatalytic experiments proved that the GO/Ag₃PO₄/CS coating had excellent photothermal and photodynamic properties. In vitro antibacterial experiments showed that the antibacterial rate of the GO/Ag₃PO₄/CS composite coating against Staphylococcus aureus reached 99.81% after 20 minutes irradiation with 808 nm near-infrared light. At the same time, the composite coating had excellent light stability, which could provide stable and sustained antibacterial effect. CONCLUSION GO/Ag₃PO₄/CS coating can be excited by 808 nm near infrared light to produce reactive oxygen species, which has excellent antibacterial activity under light.
Chitosan ; Silver Nitrate ; Titanium ; Anti-Bacterial Agents/pharmacology* ; Coloring Agents

OBJECTIVE: To review antibacterial/osteogenesis dual-functional surface modification strategy of titanium-based implants, so as to provide reference for subsequent research. METHODS: The related research literature on antibacterial/osteogenesis dual-functional surface modification strategy of titanium-based implants in recent years was reviewed, and the research progress was summarized based on different kinds of antibacterial substances and osteogenic active substances. RESULTS: At present, the antibacterial/osteogenesis dual-functional surface modification strategy of titanium-based implants includes: ① Combined coating strategy of antibiotics and osteogenic active substances. It is characterized in that antibiotics can be directly released around titanium-based implants, which can improve the bioavailability of drugs and reduce systemic toxicity. ② Combined coating strategy of antimicrobial peptides and osteogenic active substances. The antibacterial peptides have a wide antibacterial spectrum, and bacteria are not easy to produce drug resistance to them. ③ Combined coating strategy of inorganic antibacterial agent and osteogenic active substances. Metal ions or metal nanoparticles antibacterial agents have broad-spectrum antibacterial properties and various antibacterial mechanisms, but their high-dose application usually has cytotoxicity, so they are often combined with substances that osteogenic activity to reduce or eliminate cytotoxicity. In addition, inorganic coatings such as silicon nitride, calcium silicate, and graphene also have good antibacterial and osteogenic properties. ④ Combined coating strategy of metal organic frameworks/osteogenic active substances. The high specific surface area and porosity of metal organic frameworks can effectively package and transport antibacterial substances and bioactive molecules. ⑤ Combined coating strategy of organic substances/osteogenic active substancecs. Quaternary ammonium compounds, polyethylene glycol, N-haloamine, and other organic compounds have good antibacterial properties, and are often combined with hydroxyapatite and other substances that osteogenic activity. CONCLUSION The factors that affect the antibacterial and osteogenesis properties of titanium-based implants mainly include the structure and types of antibacterial substances, the structure and types of osteogenesis substances, and the coating process. At present, there is a lack of clinical verification of various strategies for antibacterial/osteogenesis dual-functional surface modification of titanium-based implants. The optimal combination, ratio, dose-effect mechanism, and corresponding coating preparation process of antibacterial substances and bone-active substances are needed to be constantly studied and improved.
Anti-Bacterial Agents/pharmacology* ; Coated Materials, Biocompatible/chemistry* ; Metal-Organic Frameworks/pharmacology* ; Osteogenesis ; Surface Properties ; Titanium/pharmacology* ; Prostheses and Implants

OBJECTIVE: To explore the effects of oral exposure to titanium dioxide nanoparticles (TiO₂ NPs) on the composition and structure of human gut microbiota. METHODS: The particle size, shape, crystal shape and degree of agglomeration in ultrapure water of TiO₂ NPs were characterized. The in vitro human digestive tract microecological simulation system was established by simulating the fluid environment and physical conditions of stomach, small intestine and colon, and the stability of the simulation system was evaluated. The bacterial communities were extracted from human feces and cultured stably in the simulated system. They were exposed to 0, 20, 100 and 500 mg/L TiO₂ NPs, respectively, and the bacterial fluids were collected after 24 h of exposure. The effect of TiO₂ NPs on the composition and structure of human gut microbiota was analyzed by 16S rRNA sequencing technology. Linear discriminant analysis effect size (LEfSe) was used to screen differential bacteria, and the Kyoto encyclopedia of genes and genomes (KEGG) database for functional prediction. RESULTS: The spherical and anatase TiO₂ NPs were (25.12±5.64) nm in particle size, while in ultra-pure water hydrated particle size was (609.43±60.35) nm and Zeta potential was (-8.33±0.22) mV. The in vitro digestive tract microecology simulation system reached a relatively stable state after 24 hours, and the counts of Enterococci, Enterobacte-rium, and Lactobacillus reached (1.6±0.85)×10⁷, (5.6±0.82)×10⁷ and (2.7±1.32)×10⁷, respectively. 16S rRNA sequencing results showed that compared with the control group, the number and evenness of gut microbiota were not significantly affected at phylum, class, order, family and genus levels in TiO₂ NPs groups (20, 100 and 500 mg/L). The relative abundance of some species was significantly changed, and a total of 42 different bacteria were screened between the TiO₂ NPs groups (20, 100 and 500 mg/L) and the control group [linear discriminant analysis(LDA) score>3], represented by Enterobacter, Bacteroidaceae, Lactobacillaceae, Bifidobacteriaceae and Clostridium. Further predictive analysis of gut microbiota function showed that TiO₂ NPs might affect oxidative phosphorylation, energy meta-bolism, phosphonate and phosphonate metabolism, and methane metabolism (P < 0.05). CONCLUSION In human digestive tract microecological simulation system, TiO₂ NPs could significantly change the composition and structure of human gut microbiota, represented by Enterobacter and probiotics, and may further affect a variety of metabolism and function of the body.
Bacteria/genetics* ; Gastrointestinal Microbiome ; Gastrointestinal Tract ; Humans ; Nanoparticles ; Organophosphonates/pharmacology* ; RNA, Ribosomal, 16S ; Titanium/pharmacology* ; Water/pharmacology*

The poor mechanical property and vulnerability to bacterial infections are the main problems in clinic for dental restoration resins. Based on this problem, the purpose of this study is to synthesize silver-titanium dioxide (Ag-TiO₂) nanoparticles with good photocatalytic properties, and add them to the composite resin to improve the mechanical properties and photocatalytic antibacterial capability of the resin. The microstructure and chemical composition of Ag-TiO₂ nanoparticles and composite resins were characterized. The results indicated that Ag existed in both metallic and silver oxide state in the Ag-TiO₂, and Ag-TiO₂ nanoparticles were uniformly dispersed in the resins. The results of mechanical experiments suggested that the mechanical properties of the composite resin were significantly improved due to the incorporation of Ag-TiO₂ nanoparticles. The antibacterial results indicated that the Ag-TiO₂ nanoparticle-filled composite resins exhibited excellent antibacterial activities under 660 nm light irradiation for 10 min due to the photocatalysis, and the Ag-TiO₂ nanoparticle-filled composite resins could also exhibit excellent antibacterial activities after contact with bacteria for 24 h without light irradiation because of the release of Ag ions. In summary, this study provides a new antibacterial idea for the field of dental composite resins.
Anti-Bacterial Agents/pharmacology* ; Composite Resins ; Metal Nanoparticles/chemistry* ; Nanoparticles ; Titanium/pharmacology*

Titanium alloy has good biological properties and is commonly used in orthopedics, but its bone integrity and antibacterial properties are poor, so surface modification is needed to make up for its shortcomings. Chitosan has good biocompatibility and film forming ability, and can be used as a carrier to introduce the target drug to the surface of titanium alloy, which can effectively improve the biological properties of titanium alloy materials and increase its application range. In this paper, the related research of chitosan surface modified titanium alloy materials in recent years is summarized. The modification methods of chitosan coating, the improvement of osteogenesisand antibacterial properties of titanium alloy materials are discussed in order to provide guidance for the clinical application of coating modification of titanium alloy materials.
Alloys ; Anti-Bacterial Agents/pharmacology* ; Chitosan ; Orthopedics ; Surface Properties ; Titanium

Epithelial attachment via the basal lamina on the tooth surface provides an important structural defence mechanism against bacterial invasion in combating periodontal disease. However, when considering dental implants, strong epithelial attachment does not exist throughout the titanium-soft tissue interface, making soft tissues more susceptible to peri-implant disease. This study introduced a novel synthetic peptide (A10) to enhance epithelial attachment. A10 was identified from a bacterial peptide display library and synthesized. A10 and protease-activated receptor 4-activating peptide (PAR4-AP, positive control) were immobilized on commercially pure titanium. The peptide-treated titanium showed high epithelial cell migration ability during incubation in platelet-rich plasma. We confirmed the development of dense and expanded BL (stained by Ln5) with pericellular junctions (stained by ZO1) on the peptide-treated titanium surface. In an adhesion assay of epithelial cells on A10-treated titanium, PAR4-AP-treated titanium, bovine root and non-treated titanium, A10-treated titanium and PAR4-AP-treated titanium showed significantly stronger adhesion than non-treated titanium. PAR4-AP-treated titanium showed significantly higher inflammatory cytokine release than non-treated titanium. There was no significant difference in inflammatory cytokine release between A10-treated and non-treated titanium. These results indicated that A10 could induce the adhesion and migration of epithelial cells with low inflammatory cytokine release. This novel peptide has a potentially useful application that could improve clinical outcomes with titanium implants and abutments by reducing or preventing peri-implant disease.
Amino Acid Sequence ; Animals ; Benzeneacetamides ; chemical synthesis ; pharmacology ; Cattle ; Cell Adhesion ; drug effects ; Cell Movement ; drug effects ; Cells, Cultured ; Cytokines ; metabolism ; Dental Implants ; Enzyme-Linked Immunosorbent Assay ; Epithelial Attachment ; drug effects ; Epithelial Cells ; cytology ; metabolism ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Piperidones ; chemical synthesis ; pharmacology ; Platelet-Rich Plasma ; Receptors, Thrombin ; Surface Properties ; Titanium ; chemistry

OBJECTIVE: To compare the effects of different sized titanium dioxide (titanium dioxide, TiO₂) on the antioxidant function of liver tissues in mice, and study the effect of TiO₂ nanoparticles on the susceptibility of lipopolysaccharide (LPS) on liver tissues. METHODS: Ninety 4-week-old clean-grade male ICR mice were divided into 18 groups, in which the mice were fed for different feed involving ordinary feed, nanometer TiO₂ feed which meant the feed including 1% (mass fraction) TiO₂ nanoparticles, and submicron TiO₂ feed which meant the feed including 1% (mass fraction) TiO₂ submicron particles. Respectively, they were fed for 1 month, 3 months and 6 months. On the second day after the feeding, respectively, 0 and 10 mg/kg LPS were given by gavage. The mice were harvested after 4 h and the body weight and liver weight for calculating the liver coefficient were recorded. Then the liver tissue homogenates were prepared for determining the antioxidant indexes including the total antioxidant capacity (T-AOC), total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-PX), and malondialdehyde (MDA). RESULTS: The change of body weight in mice was only discovered in group fed for 1 month, which showed significant decrease of body weight in treatment groups compared with control group. And there was no significant change of the liver coefficient in each group. Compared with control groups, nanometer TiO₂ groups and submicron TiO₂ group, the activity of T-AOC, T-SOD and MDA of nanometer TiO₂+LPS group and submicron TiO₂+LPS group in which the mice were fed for 1 month and 6 months increased in different degree. And another result was also existing. The MDA activity of liver in different sized treatment groups fed for 3 months decreased. Neither significant difference between the results of different sized TiO₂ treatment groups, nor significant difference among different sized TiO₂ groups and the control groups were observed. CONCLUSION Longterm peroral TiO₂ nanoparticles and TiO₂ submicron particles are more likely to cause damage to the liver in the growing mice, and the damage may be either reductive or oxidative. In addition, small sized TiO₂ can increase the susceptibility of mice liver to LPS and the susceptibility will increase with the increase of exposure time.
Animals ; Antioxidants/pharmacology* ; Glutathione Peroxidase ; Lipopolysaccharides ; Liver ; Male ; Malondialdehyde ; Mice ; Mice, Inbred ICR ; Nanoparticles ; Oxidation-Reduction ; Oxidative Stress ; Superoxide Dismutase ; Titanium/pharmacology*