Titanium and its alloys are routinely used as biomedical implants and are usually considered to be corrosion resistant under physiological conditions. However, during inflammation, chemical modifications of the peri-implant environment including acidification occur. In addition certain biomolecules including lipopolysaccharide (LPS), a component of Gram-negative bacterial cell walls and driver of inflammation have been shown to interact strongly with Ti and modify its corrosion resistance. Gram-negative microbes are abundant in biofilms which form on dental implants. The objective was to investigate the influence of LPS on the corrosion properties of relevant biomedical Ti substrates as a function of environmental acidity. Inductively coupled plasma mass spectrometry was used to quantify Ti dissolution following immersion testing in physiological saline for three common biomedical grades of Ti (ASTM Grade 2, Grade 4 and Grade 5). Complementary electrochemical tests including anodic and cathodic polarisation experiments and potentiostatic measurements were also conducted. All three Ti alloys were observed to behave similarly and ion release was sensitive to pH of the immersion solution. However, LPS significantly inhibited Ti release under the most acidic conditions (pH 2), which may develop in localized corrosion sites, but promoted dissolution at pH 4-7, which would be more commonly encountered physiologically. The observed pattern of sensitivity to environmental acidity of the effect of LPS on Ti corrosion has not previously been reported. LPS is found extensively on the surfaces of skin and mucosal penetrating Ti implants and the findings are therefore relevant when considering the chemical stability of Ti implant surfaces in vivo.
Acids ; chemistry ; Corrosion ; Electrodes ; Hydrogen-Ion Concentration ; Lipopolysaccharides ; pharmacology ; Materials Testing ; Microscopy, Electron, Scanning ; Titanium ; chemistry

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*

Photoreactive heparin was synthesized by reaction of 4-azidoaniline and heparin. An organic layer was introduced on the surface of Ti-O by 3-aminopropylphosphonic acid assembling, and then the modified heparin was immobilized on the surface by UV irradiation. Water contact angle was used to characterize the hydrophilicity, quantitive assay was done by azure staining methods, and blood compatibility was evaluated by platelet adhesion experiment. Water contact angle of heparinized surface was smaller than that of Ti-O film, which indicated more hydrophilic property of heparinized surface. The surface density of heparin increased with the prolonging of irradiation time and the density was 2.1 microg/cm2 when irradiated for 300s. It showed the heparinized surface was effective in resisting platelets from adhesion and aggregation.
Aniline Compounds ; chemistry ; Azo Compounds ; chemistry ; Blood Proteins ; pharmacology ; Fibrinolytic Agents ; pharmacology ; Heparin ; chemistry ; Humans ; Membranes, Artificial ; Propylamines ; chemistry ; Surface Properties ; Titanium ; chemistry

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

To elucidate the adsorption mechanism of CS-A to the surface of titanium, 5 ml solutions of the CS-A were reacted with 2 g of native and 2 g of calcium-treated titanium powder for 48 h at 37 degrees C. Residual CS-A was detected by the carbazole elaborate method. The results showed that no CS-A attached to native titanium. Comparatively, titanium treated with calcium produced a significant adsorption of CS-A. At concentration of 60 micrograms/ml, the adsorption of CA-A to calcium-treated titanium powder attained the maximum, 83 micrograms/g. Only EDTA can liberate the bound CS-A from titanium surface. These findings suggest that calcium ion is necessary for the adsorption of CS-A to titanium.
Adsorption ; Calcium ; Chondroitin Sulfates ; pharmacology ; Static Electricity ; Surface Properties ; Titanium ; chemistry

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

OBJECTIVETo investigate the effects of ambient conditions on the antibacterial activity of inorganic antibacterial agent based on sodium titanium phosphate.

METHODSThe number of live E. Coli ATCC 44113 was counted after the suspension was shaken and incubated in flask with antibacterial agent under ambient conditions.

RESULTThe number of live bacteria increased when the concentration of bacteria increased in the range of 1.2 x 10(2) to 1.2 x 10(8) cfu/ml. The antibacterial activity increased with the increase of ambient temperature in the range of 16 approximately 46 degrees C, showing good antibacterial activity at human body temperature. With the increase of the concentrations of co-existing NaCl and protein, the antibacterial activity was found to decrease at first and level off at 0.01 g/ml and 0.0005 g/ml respectively.

CONCLUSIONThe antibacterial agent has to be used together with organic antibacterial agent in order to achieve good antibacterial effect when the ambient bacterial concentration is high. The antibacterial agent is promising to be used in the preparation of antibacterial cloth because it is highly effective at body temperature and expected to remain antibacterial in perspiration.

Anti-Bacterial Agents ; pharmacology ; Bacteria ; drug effects ; Body Temperature ; Environment ; Microbial Sensitivity Tests ; Sodium ; chemistry ; Titanium ; pharmacology

The functional hemocompatibility between fibrinogen (FIG) and a novel vascular stent material (Ti-O film fixed with albumin and heparin) was investigated as follows: (1) Preparing the new biologic material (Ti-O) film; (2) Coating albumin and heparin on the Ti-O film; (3) Testing platelets (PL) adsorption; (4) Determining FIG adhesion number by use of enzyme linked immunoassay (ELISA); (5) Implanting the films from the test group of Ti-O film and from the comparison group of stainless steel (SS) film into the left and right femoral arteries respectively in 4 dogs. It was proved that albumin and heparin were fixed on Ti-O film. After 6 months, the femoral arteries of the dogs were resected. In the test group of Ti-O film coated with albumin and heparin, few PL adhered to the coat, their form did not change, and no thrombus was found by scanning electron microscopy; the result was better than that of plain Ti-O film, and was much better than that of SS film. Ti-O maintained normal transformation condition of FIG, and no C terminal of gamma chain in FIG was revealed. As it is known whether the hemocompatibility of a biomaterial is good depends upon its adsorption of FIG, and Ti-O has excellent reaction on albumin and heparin by chemical processes. In this study, the Ti-O film coated with albumin and heparin further reduced the absorption of FIG and PL when compared against the plain Ti-O film. So the Ti-O film coated with albumin and heparin has the insistent and permanent anticoagulant character.
Albumins ; chemistry ; Animals ; Coated Materials, Biocompatible ; pharmacology ; Dogs ; Fibrinogen ; chemistry ; Heparin ; chemistry ; Materials Testing ; methods ; Prosthesis Design ; Stents ; Surface Properties ; Titanium ; chemistry

In this study, Ti-O films were synthesized using magnetron sputtering, and were pretreated using NaOH solution for improving surface activity from hydroxyl. The laminin(LN) biomacromolecule was further immobilized to the surface through an anminosilane linker. The surface characteristics of these samples were analyzed by Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, Atomic Force Microscopy and the contact angle method. Finally, human umbilical vein endothelial cells (HUVEC) were in vitro seeded to the modified and unmodified Ti-O films surface for evaluating the cell compatibility. Survey results suggested that the functional group of hydroxyl was presented onto Ti-O film surface after being pretreated, and laminin could be covalently immobilized to Ti-O film surface by anminosilane linker. The in vitro cell culture results reveal that the biological behaviors of ECs on biochemical modified Ti-O film surface are excellent. The adherence, growth and proliferation of ECs on laminin-immobilized surface were obviously improved when compared to control one. It implies that the laminin immobilizing is helpful to increasing the endothelialization of Ti-O films.
Cell Proliferation ; Cells, Cultured ; Coated Materials, Biocompatible ; pharmacology ; Endothelial Cells ; cytology ; Humans ; Immobilized Proteins ; Laminin ; chemistry ; Titanium ; chemistry ; pharmacology ; Umbilical Veins ; cytology

OBJECTIVETo investigate effects of hydroxyapatite (HA) and porous tricalcium phosphate/hydroxyapatite (TCP/HA)-coating titanium on the adhesion behavior of human gingival fibroblasts (HGFs).

METHODSCoatings of HA and duplex phases TCP/HA on titanium (Ti) were formed by ion beam assisted deposition (IBAD) method. Attachment, spreading, extracellular matrix (ECM) production, and focal adhesion plaque formation of HGFs were investigated on commercially pure (CP) titanium, HA-coated CP titanium and porous TCP/HA-coated CP titanium. After incubation of HGFs on these substrates, the number of attached cell, the area of cell spreading, immunostained ECM including fibronectin (FN) and type I collage, and vinculin (presenting the formation of focal adhesion plaque) were quantified by morphometric analysis using immunofluorescence microscope.

RESULTSTCP/HA and HA coatings exhibited that the attached cell number and cell spreading area were greater than those of CP titanium (P < 0.05), and the formation of focal adhesion plaque was earlier than that of uncoated substrate (P < 0.05). The number of attached cell and the formation of type I collagen on TCP/HA were more than those on Ti and HA. After 24-hour incubation on TCP/HA surface, the number of attached cell was 198.1 +/- 27.7 and the fluorescent intensity of type I collagen was 154.10 +/- 31.56. While under the same condition, the corresponding numbers for the CP titanium were 125.1 +/- 29.9 and 132.63 +/- 35.26. The differences between the two groups were significant (P < 0.05).

CONCLUSIONSIn this study, the porous TCP/HA coating significantly facilitated the adherence of human gingival fibroblasts to Ti surface and could improve the biocompatibility of titanium.

Calcium Phosphates ; pharmacology ; Cell Adhesion ; drug effects ; Cells, Cultured ; Coated Materials, Biocompatible ; chemistry ; Durapatite ; pharmacology ; Fibroblasts ; cytology ; drug effects ; Gingiva ; cytology ; Humans ; Materials Testing ; Titanium ; chemistry