Nanoscale chemical composition analysis using peptides targeting inorganic materials.

Chemical composition analysis by scanning probe microscopy (SPM) in water is a method whose introduction has been long-awaited. Here we propose a simple method for performing chemical composition analyses of solid surfaces in water using atomic force microscopes (AFMs) with probes functionalized with peptides targeting inorganic materials. In this work, bicompositional surfaces of gold and titanium oxide were scanned with AFM probes modified with the titanium-binding peptide (TBP). We found that surface chemical composition clearly appeared as contrast in the mapping images of adhesion forces with nanometer-scale resolution. In this Article, we further discuss appropriate designs of the AFM probes and appropriate imaging conditions for the chemical composition analysis based on the results of force measurements of the single TBP-titanium bond.