Surface Modification of Titanium with Hydrothermal Treatment at High Pressure

Enhanced in vitro biocompatibility and osteogenesis of titanium substrates immobilized with dopamine-assisted superparamagnetic Fe3O4 nanoparticles for hBMSCs

Titanium (Ti) is an ideal bone substitute due to its superior bio-compatibility and remarkable corrosion resistance. However, in order to improve the osteoconduction and osteoinduction capacities in clinical applications, different kinds of surface modifications are typically applied to Ti alloys. In this study, we fabricated a tightly attached polydopamine-assisted Fe3O4 nanoparticle coating on Ti with magnetic properties, aiming to improve the osteogenesis of the Ti substrates. The PDA-assisted Fe3O4 nanoparticle coatings were characterized by scanning electron microscopy, energy dispersive spectroscopy, atomic force microscopy and water contact angle measurements. The cell attachment and proliferation rate of the human bone mesenchymal stem cells (hBMSCs) on the Ti surface significantly improved with the Fe3O4/PDA coating when compared with the pure Ti without a coating. Furthermore, the results of in vitro alkaline phosphatase (ALP) activity at 7 and 14 days and alizarin red S staining at 14 days showed that the Fe3O4/PDA coating on Ti promoted the osteogenic differentiation of hBMSCs. Moreover, hBMSCs co-cultured with the Fe3O4/PDA-coated Ti for approximately 14 days also exhibited a significantly higher mRNA expression level of ALP, osteocalcin and runt-related transcription factor-2 (RUNX2). Our in vitro results revealed that the present PDA-assisted Fe3O4 nanoparticle surface coating is an innovative method for Ti surface modification and shows great potential for clinical applications.

Review: physico-chemical modification as a versatile strategy for the biocompatibility enhancement of biomaterials

Physico-chemical modification induced improvement in biocompatibility of materials.

Surface characteristics and osteoblastic cell response of alkali-and heat-treated titanium-8tantalum-3niobium alloy

Purpose

The aim of the present study was to evaluate the biological response of alkali- and heat-treated titanium-8tantalum-3niobium surfaces by cell proliferation and alkaline phosphatase (ALP) activity analysis.

Methods

Commercial pure titanium (group cp-Ti) and alkali- and heat-treated titanium-8tantalum-3niobium (group AHT) disks were prepared. The surface properties were evaluated using scanning electron microscopy, energy dispersed spectroscopy and X-ray photoelectron spectroscopy (XPS). The surface roughness was evaluated by atomic force microscopy and a profilometer. The contact angle and surface energy were also analyzed. The biological response of fetal rat calvarial cells on group AHT was assessed by cell proliferation and ALP activity.

Results

Group AHT showed a flake-like morphology microprofile and dense structure. XPS analysis of group AHT showed an increased amount of oxygen in the basic hydroxyl residue of titanium hydroxide groups compared with group cp-Ti. The surface roughness (Ra) measured by a profilometer showed no significant difference (P>0.05). Group AHT showed a lower contact angle and higher surface energy than group cp-Ti. Cell proliferation on group AHT surfaces was significantly higher than on group cp-Ti surfaces (P<0.05). In comparison to group cp-Ti, group AHT enhanced ALP activity (P<0.05).

Conclusions

These results suggest that group AHT stimulates osteoblast differentiation.

Type I collagen grafting on titanium surfaces using low-temperature glow discharge

To improve the bioactivity of titanium surfaces, glow discharge was used to facilitate collagen grafting on titanium disks. Titanium test specimens were pre-treated by glow discharge fed with a mixture of argon and allylamine (AA) gases. Treated titanium disks were then grafted with type I collagen using glutaraldehyde (GA) as a crosslinking agent. The surfaces of collagen-grafted titanium disks were evaluated using scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS). MG-63 osteoblast-like cells were cultured on the grafted titanium surfaces to examine the effect of collagen grafting in terms of cell morphology. Our results demonstrated that collagen component elements could be detected on the titanium surfaces. Morphology of the cells on the surfaces of collagen-grafted titanium disks indicated differentiation. These findings showed that type I collagen could be successfully grafted onto titanium surfaces using glow discharge technology, with enhanced biofunctionality demonstrated on osteoblastic cells.