The adsorption of chicken egg albumin on commercially pure titanium has been studied as a function of protein concentration, using X-ray photoelectron spectroscopy (XPS). The adsorption isotherm has been plotted using the increase in N 1s intensity and also by measurement in the decrease in the Ti 2p intensity as the adsorbed film reaches full coverage. It is shown that both sets of data are a good fit to the Temkin isotherm. The influence of the large size of the biomolecule is discussed and the isotherm is modified to take account of the molecular dimension according to the model proposed by Ratner and Paynter. The thicknesses of the adsorbed molecules are measured using atomic force microscopy (AFM) and it is shown that it is only when monolayer coverage has been reached that the molecules begin to take up the characteristic globular shape. Albumin reaches a coverage of 25% of a monolayer in solutions of only 10 ppb by volume, suggesting that it is easily bound to the TiO 2 surface. A complete monolayer is formed at a solution concentration of 100 ppm. The carbon 1s signal is used to estimate the surface free energy at different surface coverages using the model developed by Kinloch, Kodokian and Watts. The transformation from the initial coverage of hydrophobic contamination molecules to the hydrophilic surface presented by the adsorbed albumin film takes place over a range similar to that required to form the monolayer.

This research was to prepare the titanium dioxide nanotube arrays (TiNT arrays) and deposit the Au nanoparticles on its surface using the pulse electrodeposition technique. The Au nanoparticles-TiNT arrays (AuNP-TiNT arrays) were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction, and cyclic voltammetry. The results showed that the Au nanoparticles were uniformly dispersed on the TiNT array surface. The size and loading of Au nanoparticles can be controlled by deposition time, deposition potential, and concentration of HAuCl. The AuNP-TiNT arrays were then used as a working electrode for hydrogen peroxide (HO) detection. Compared with the pure TiNT array electrode, the AuNP-TiNT array electrode had higher sensitivity for the detection of HO and thus provided a simple, promising, and cost-effective sensing platform for the development of enzyme-based biosensors.

No abstract

No abstract

No abstract