Abstract
The adsorptive properties of eight forms of nano-TiO2 were evaluated when they were exposed to the toxic thiol-containing amino acid homocysteine. Homocysteine is an amino acid known to cause cardiovascular toxicity and neurodegenerative disorders. A homocysteine standard solution was combined with dispersions of each TiO2 nanoparticle under physiological conditions, and then a high-performance liquid chromatography fluorescence detection method optimized for quantification of total, unbound homocysteine was utilized. The nano-sized anatase nanoparticle removed 2.92 µg of homocysteine per microgram of nanoparticle, whereas amorphous TiO2 only removed 3.65 ∞ 10−3 µg of homocysteine per microgram of nanoparticle. Other nanoparticles produced values between the anatase and amorphous forms. Surface chemistries are distinguishing characteristics of these nanoparticles and are responsible for their individual physicochemical properties. Variations in results were associated with the unique combinations of size and surface area of each nanoparticle. The aminothiol adsorptive property of TiO2 nanoparticles has potential applications in nanomedicine, biosensing, diagnostics and amino acid tagging.