Identification of peptides capable of inducing the formation of titania but not silica via a subtractive bacteriophage display approach

Abstract

A “subtractive” bacteriophage display biopanning approach has been used to identify 12-mer peptides that are capable of binding selectively to, and inducing the precipitation of, titania but not silica. Unlike the conventional bacteriophage display procedure, this approach consists of two selection steps: i) removal of phage particles containing silica-binding peptides from the phage library (the subtractive step), and then ii) isolation of phage particles bearing peptides that bind strongly to titania. While prior phage display biopanning with silica and titania targets has led to the isolation of polycationic peptides enriched in basic residues, the subtractive biopanning process yielded several acidic peptides enriched in hydroxyl-bearing residues. These peptides were found to induce the precipitation of titania, but not silica, from aqueous precursor solutions at pH 3–8. To our knowledge, this is the first demonstration that a subtractive bacteriophage biopanning process may be used to identify specific peptides possessing the ability to induce the formation of one oxide while lacking the ability to form a second, chemically similar oxide.