Enhancement of Biocompatibility on Bioactive Titanium Surface by Low-Temperature Plasma Treatment

Abstract

The surface of implantable biomaterials directly contacts the host tissue and is critical in determining biocompatibility. To improve implant integration, interfacial reactions must be controlled to minimize nonspecific adsorption of proteins, and tissue-healing phenomena can be controlled. The purpose of this study was to develop a new method of functionalizing titanium surfaces by plasma treatment. The covalent immobilization of bioactive organic molecules and the bioactivities in vitro were assessed by transmission electron microscopy (TEM), atomic force spectroscopy (AFM), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay as indices of cellular cytotoxicity. Argon plasma removed all of the adsorbed contaminants and impurities. Plasma-cleaned titanium surfaces showed better bioactive performances than untreated titanium surfaces. The analytical results reveal that plasma-cleaned titanium surfaces provide a clean and reproducible starting condition for further plasma treatments to create well-controlled surface layers. Allylamine was ionized by plasma treatment, and acted as a medium to link albumin. Cells demonstrated a good spread, and a wide attachment was attained on the Albu-Ti plate. Cell attachment and growth were shown to be influenced by the surface properties. The plasma treatment process plays an important role in facilitating tissue healing. This process not only provides a clean titanium surface, but also leads to surface amination on plasma-treated titanium surfaces. Surface cleaning by ion bombardment and surface modification by plasma polymerization are believed to remove contamination on titanium surfaces and thus promote tissue healing.

Multifunctional Properties of Bulk Nanostructured Metallic Materials

“…The hierarchical textured surfaces obtained via SMAT on pure Ti and Ti-6Al-4V alloy showed enhanced cell attachment, spreading, viability, and alkaline phosphatase activity [280]. Biocompatibility improvement was also reported for CP Ti subjected to low-temperature plasma treatment that not only refined the surface grains to nanosize, but also altered the surface roughness and surface chemical composition [281].…”

“…It should be noted that conventional Co-Cr alloys have high mechanical strength, so surface nanostructuring can be envisaged as a strategy to improve biocompatibility of the material [275]. One technique of particularly high potential is surface mechanical attrition treatment (SMAT) [276][277][278][279][280][281]. SMAT induces large deformation in surfaces by recurring impact of hard spheres.…”

Improved picoliter-sized micro-reactors for high-throughput biological analysis

“…Metallic films, with their distinct opacity toward visible light and adequate bandwidth across the entire visible spectrum, afford a better alternative. In this work, low-cost titanium and aluminum (with oxidized layer) were chosen for their biocompatible properties [29][30][31][32].…”

Enhancement of Biocompatibility on Bioactive Ti-Nb-Based Alloy by High-Density Plasma Modification

“…9) Plasma treatments are commonly used to cleanse the surfaces and to increase the surface energy of biomaterials for use in biologic evolution. [10][11][12][13][14][15][16] The potential of the plasma treatment for sterilizing implants has also been noted. 17) The plasma treatment provides with a simple, all dry and in situ process for chemically tailoring surfaces without compromising the inherent, favorable bulk properties of the biomaterials.…”

“…On the other hand, plasma polymerization of allylamine had been employed in the past several years to provide functional groups for immobilization of albumin on commercial titanium and Ti-6Al-4V alloy surfaces to enhance bioactivity. 16,18) Some researchers reported that higher amounts of protein present on the implant surface can provide better tissue healing and hence better osseointegration. 18) The present authors have developed certain Ti-Nb-based alloys, 2) e.g., Ti-40Nb-1Hf, which has been shown to exhibit excellent properties combination of relatively high strength and low modulus (UTS: 893 MPa, 0.2% Proof stress: 841 MPa and E: 65 GPa), and can be considered quite suitable for implant applications.…”