Search

Bacterial infection is one of the main reasons for the clinical failure of oral titanium restorations. In this study, biodegradable polymer/TiO2 nanotube nanoarray capsules were constructed on a titanium substrate surface to locally deliver drugs for long-lasting antibacterial properties. Anodization was applied to prepreparation TiO2 nanotube array film on titanium substrate, and then, the upward opening TiO2 nanotubes were sealed with biodegradable polymer (chitosan and polyethylene glycol) through electrochemical deposition. Scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) were used to analyze the characterization of this system. The drug release characteristics and the antibacterial activity demonstrated that the polymer coating significantly reduced burst release and enhanced lasting antibacterial properties. The nanoarray capsules still preserved integrity with a little degradation after 2 days. The strategy described herein provides a versatile route for designing targeted drug delivery systems in orthopaedical and other biomedical fields.

The temperature and strain fields are two key factors in the regulation of fibrous aggregate structure. In this paper, plate specimens of polyamide 6 were prepared by compression molding method. The oriented polyamide 6 plates were systematically analyzed from aspects of mechanical properties, thermal properties, crystal structure and crystal morphology. The maximum tensile strength and elastic modulus of polyamide 6 plate appeared at 120 °C. The stretching process induced the formation of a more thermal stable α-form crystals. With the increase of stretching temperature, α-form crystals transformed into γ-form crystals gradually. The crystal chips transformed into fibrils during the stretching process. The structural evolution model of materials under the temperature and strain fields was established.

Bioceramic hydroxyapatite/sodium titanate coating on sandblasted titanium substrate was fabricated by a three-step process. At first, the sandblasted titanium substrate was coated with a flake-like sodium titanate layer by alkali-heat treatment. In the second step, the alkali-heat treated titanium substrate was hydrothermal treated at 180 °C for 4 h with calcium solutions. In the third step, the hydroxyapatite (HA) coating was deposited onto the hydrothermal treated layer via electrochemical deposition method. The surface topography and roughness of the coatings were determined by field emission scanning electron microscope (FESEM) and a mechanical contact profilometer, respectively. The surface compositions were evaluated by X-ray diffraction (XRD), energy-dispersive X-ray spectrum (EDS), and X-ray photoelectron spectroscopy (XPS). The EDS, XPS, and XRD analysis confirm the presence of element Ca, Ca2+, and CaTiO3 on sodium titanate layer after hydrothermal treatment with Ca(NO3)2 solution, respectively. FESEM micrograph shows the rod/needle-shaped crystallites are highly densely packed on the calcium-ion-containing layer with an average size of ~50 nm in diameter. The results indicate that the sodium titanate layer containing Ca2+ ions possesses higher ability to induce HA formation compared with the pure sodium titanate layer. It is revealed that surface composition plays an important role in the electrochemical deposition of HA. The calcium-ion-containing layer probably makes the nucleation of HA easy and effectively promotes orientated growth of HA on flake-like sodium titanate surface. The sodium titanate layer possesses a lower corrosion current density and a higher corrosion potential than sandblasted-Ti substrate. The sodium titanate layer should act as a barrier to the release of metal ions from metallic substrate to physiological solutions and thus reducing the electrochemical reaction rate.

A composite structure, TiO 2 nanotube array/CdSe nanoparticle/TiO 2 layer, was fabricated by inserting CdSe nanoparticles into anodized TiO 2 nanotube arrays via ultrasonic-assisted cyclic voltammetry electrochemical deposition and subsequently wrapped by a TiO 2 thin layer via TiCl 4 hydrolysis. The films were characterized by X-ray diffraction, field emission scanning electron microscopy, energy dispersive spectroscopy and UV–vis diffuse reflectance spectroscopy. For the film used as the photoanode, linear sweep voltammetry and transient photocurrent were investigated in a three-electrode system under visible light illumination. And the photocatalytic activity was evaluated by the oxidation of glucose in the supporting electrolyte at different potential bias under visible light illumination. The results showed that CdSe nanoparticles are prone to disperse into the nanotube arrays via cyclic voltammetry electrochemical deposition under ultrasonic condition. Increasing cyclic voltammetry cycle increases the loading of CdSe on the TiO 2 nanotube arrays. The CdSe-sensitized TiO 2 nanotube array films exhibit a wide-absorption response in the visible light region. The TiO 2 nanotube array/CdSe/TiO 2 film, prepared by ultrasonic-assisted electrochemical deposition with 50 cyclic voltammetry cycles and subsequently coating a TiO 2 thin layer, exhibits better protection against photocorrosion of CdSe. The TiO 2 NTA/CdSe/TiO 2 film possesses visible light photoelectrocatalytic activity on the degradation of glucose.

The selective laser melting (SLM) technique is a recent additive manufacturing (AM) technique. Several studies have reported success in the SLM-based production of biocompatible orthopaedic implants and three-dimensional bone defect constructs. In this study, we evaluated the surface properties and biocompatibility of an SLM titanium implant in vitro and compared them with those of a machined (MA) titanium control surface. In addition, we evaluated the osseointegration capability of the SLM implants in vivo and compared it with those of MA and Nobel-speedy (Nobel-S) implants. SLM microtopographical surface analysis revealed porous and high roughness with varied geometry compared with a smooth surface in MA Ti samples but with similar favourable wettability. Osteoblast proliferation and alkaline phosphatase activity were significantly enhanced on the SLM surface. Histological analysis of the bone-implant contact ratio revealed no significant difference among SLM, MA, and Nobel-S implants. Micro-CT assessment indicated that there was no significant difference in bone volume fraction around the implant among SLM implants and other types of surface modification implants. The removal torque value measurement of SLM implants was significantly lower that of than Nobel-S implants P < 0.001 and higher than that of MA implants. The study demonstrates the capability of SLM implants to integrate with living bone. The SLM technique holds promise as a new dental implant manufacturing technique.