Comparison of Ti-Based Coatings on Silicon Nanowires for Phosphopeptide Enrichment and Their Laser Assisted Desorption/Ionization Mass Spectrometry Detection.

We created different TiO₂-based coatings on silicon nanowires (SiNWs) by using either thermal metallization or atomic layer deposition (ALD). The fabricated surfaces were characterized by X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), and reflectivity measurements. Surfaces with different TiO₂ based coating thicknesses were then used for phosphopeptide enrichment and subsequent detection by laser desorption/ionization mass spectrometry (LDI-MS). Results showed that the best enrichment and LDI-MS detection were obtained using the silicon nanowires covered with 10 nm of oxidized Ti deposited by means of thermal evaporation. This sample was also able to perform phosphopeptide enrichment and MS detection from serum.