Genetically engineered polypeptides for inorganics: A utility in biological materials science and engineering

Adapting molecular biology to materials science we developed peptide-based protocols for the assembly and formation of hybrid materials and systems. In this approach of generating molecular scale biomimetic materials, peptides are designed, synthesized, genetically tailored and, finally, utilized as potential molecular linkers in self-assembly, ordered organization, and fabrication of inorganics for specific technological applications. The potential areas range from molecular and nanoscale functional materials to medical fields, e.g., from diagnosis to biosensors. Here, we describe a selection of inorganic binding polypeptides via directed evolution, post-selection modifications through genetic engineering, and utility in practical applications. The selection of the inorganic binders is accomplished through combinatorial biology based peptide libraries. The diversity of applications is highlighted in three case studies. First, the molecular and nanoscale recognition of the polypeptide is presented via nanosize gold particle immobilization onto a molecular template by gold binding polypeptide. Second, we present that the alkaline phosphatase fused with multiple repeats of gold binding polypeptide can still be enzymatically active when it is immobilized onto a solid substrate. Finally, we present silica biosynthesis in aqueous environment using engineered quartz-binding peptides.