Photofunctionalization of Titanium: An Alternative Explanation of Its Chemical-Physical Mechanism

Abstract

ObjectivesTo demonstrate that titanium implant surfaces as little as 4 weeks from production are contaminated by atmospheric hydrocarbons. This phenomenon, also known as biological ageing can be reversed by UVC irradiation technically known as photofunctionalization. To propose a new model from our experimental evidence to explain how the changes in chemical structure of the surface will affect the adsorption of amino acids on the titanium surface enhancing osteointegration.MethodsIn our study XPS and AES were used to analyze the effects of UVC irradiation (photofunctionalization) in reversing biological ageing of titanium. SEM was used to analyze any possible effects on the topography of the surface.ResultsUVC irradiation was able to reverse biological ageing of titanium by greatly reducing the amount of carbon contamination present on the implant surface by up to 4 times, while the topography of the surface was not affected. UVC photon energy reduces surface H2O and increases TiOH with many –OH groups being produced. These groups explain the super-hydrophilic effect from photofunctionalization when these groups come into contact with water.SignificancePhotofunctionalization has proven to be a valid method to reduce the amount of hydrocarbon contamination on titanium dental implants and improve biological results. The chemisorption mechanisms of amino acids, in our study, are dictated by the chemical structure and electric state present on the surface, but only in the presence of an also favourable geometrical composition at the atomical level.

Changes in surface characteristics of titanium and zirconia after surface treatment with ultraviolet light or non‐thermal plasma

“…This is attributable to the different characteristics of the materials. Irradiation with UV light and treatment with non‐thermal plasma are capable of improving the wettability and surface energy , which was also shown in the present study as a massive decrease in the size of the contact angles of the water droplets. Although each treatment method was able to turn the non‐hydrophilic surfaces of the titanium and zirconia samples into (super‐)hydrophilic surfaces, non‐thermal plasma in general created the best wettability on titanium, and non‐thermal plasma of argon created the best wettability on zirconia, indicating a high‐grade increase in surface energy on both materials after only a short period (12 min) of time.…”

“…Another reason for the induction of (super‐)hydrophilicity and increased protein binding may be the reduction of carboxyl groups combined with the reduction of hydrocarbons proposed by Roy et al . . In their model, high‐energy photons that are applied to the surface may be able to break the relatively weak bonds between carboxyl groups and titanium, giving the chance to make bonds with the oxide, nitrogen, and sulphur atoms on proteins and subsequently enhance the attachment of cells.…”

“…In a recent study by Roy et al . , carbon present at the surface of pure titanium discs decreased substantially after UV‐C irradiation (UV light spectra 200–280 nm). They also found that UV‐C light was able to increase the amount of titanium hydroxide and decrease the amount of water.…”

Zinc oxide surface functionalization and related effects on corrosion resistance of titanium implants

“…Polyethylene glycol have been used on surface functionalization to obtain anti-infective medical implants because it can reduce the bacterial adhesion [24]. Additionally, amine, thiol and carboxylic acid terminated molecules are relevant in the interaction with proteins from the biological environment, which occurs immediately after implant insertion [25][26][27]. The adsorbed proteins drive the subsequent interaction of the material with cells [28].…”

In Vitro and In Vivo Evaluation of Titanium Surface Modification for Biological Aging by Electrolytic Reducing Ionic Water

“…However, the S-100 treatment could not improve superhydrophilicity such as the UV treatment. This may have been because of the fact that introduction of the hydroxyl groups to the titanium surface by the photocatalytic effect was combined in the principle of acquisition of superhydrophilicity by photofunctionalization, in addition to degradation of carbohydrates by reactive oxygen [14,15]. However, in our preliminary experiment in which the sandblasted surface was treated with S-100 ® , the contact angle decreased to below 5 • , acquiring superhydrophilicity.…”