Effect of gold deposition onto titanium on the adsorption of alkanethiols as the protein linker functionalizing the metal surface

A new method to enhance the biofunctionalization of Ti materials was developed by the immersion of Au-sputtered titanium plates into a solution of alkanethiol with a carboxy group end (HS-C-11-COOH). X-ray photoelectron spectroscopy (XPS) analysis showed that the gold content increased with the Au sputtering time and reached over 98 at% after 100 s. The content of the characteristic alkanethiol elements (S, C, and 0) in the immersed Ti specimens increased with the Au sputtering time, which indicates that the binding of alkanethiol molecules is enhanced by the Au modification on the Ti surface. Qualitative analysis of XPS (Au-S, COO-, and OH- species) and FTIR spectra (peaks assignable to an aliphatic carboxylic acid) for the sample after immersion also supported this. A strong positive correlation between the S and Au content confirms that Au sputtering is an effective method to control the alkanethiol treatment of Ti substrates.