X-ray Photoelectron Spectroscopy as an Effective Biomolecular Binding Site Probe

X-ray photoelectron spectroscopy (XPS) is a versatile surface characterization tool capable of probing adsorbate structure at the topmost 100 Å layers of solid surfaces [1], and can serve as a useful biomolecular binding site probe. Although analysis is performed under conditions where equilibrium is interrupted at the solid-aqueous solution interface, insight into the biomolecular interactions at the interface can still be obtained. In particular, the technique is effective for quantifying the degree of Pb(II) binding to protein structures and antioxidants, important for understanding the metal ion’s interactions with protein structures [2], and developing therapeutic agents for lead poisoning [3], respectively. Also, XPS can effectively be used to measure the relative number of surface binding sites on metal oxide nanoparticulates to which extracellular material can attach, important for evaluating the cytotoxicity of various, 4th period transition metal oxide nanoparticles [4].