title: Aqueous Peptide-TiO2 Interfaces: Isoenergetic Binding via Either Entropically or Enthalpically Driven Mechanisms.
abstract: A major barrier to the systematic improvement of biomimetic peptide-mediated strategies for the controlled growth of inorganic nanomaterials in environmentally benign conditions lies in the lack of clear conceptual connections between the sequence of the peptide and its surface binding affinity, with binding being facilitated by noncovalent interactions. Peptide conformation, both in the adsorbed and in the nonadsorbed state, is the key relationship that connects peptide-materials binding with peptide sequence. Here, we combine experimental peptide-titania binding characterization with state-of-the-art conformational sampling via molecular simulations to elucidate these structure/binding relationships for two very different titania-binding peptide sequences. The two sequences (Ti-1, QPYLFATDSLIK; Ti-2, GHTHYHAVRTQT) differ in their overall hydropathy, yet via quartz-crystal microbalance measurements and predictions from molecular simulations, we show these sequences both support very similar, strong titania-binding affinities. Our molecular simulations reveal that the two sequences exhibit profoundly different modes of surface binding, with Ti-1 acting as an entropically driven binder while Ti-2 behaves as an enthalpically driven binder. The integrated approach presented here provides a rational basis for peptide sequence engineering to achieve the in situ growth and organization of titania nanostructures in aqueous media and for the design of sequences suitable for a range of technological applications that involve the interface between titania and biomolecules.
authors.affiliation: Institute for Frontier Materials, Deakin University , Geelong, Victoria 3216, Australia.
authors.forename: Anas M
authors.initials: AM
authors.lastname: Sultan
authors.affiliation: Interdisciplinary Biomedical Research Centre, School of Science and Technology, Nottingham Trent University , Clifton Lane, Nottingham NG11 8NS, United Kingdom.
authors.forename: Zayd C
authors.initials: ZC
authors.lastname: Westcott
authors.affiliation: Institute for Frontier Materials, Deakin University , Geelong, Victoria 3216, Australia.
authors.forename: Zak E
authors.initials: ZE
authors.lastname: Hughes
authors.affiliation: Institute for Frontier Materials, Deakin University , Geelong, Victoria 3216, Australia.
authors.forename: J Pablo
authors.initials: JP
authors.lastname: Palafox-Hernandez
authors.affiliation: Laboratory for Atomistic and Molecular Mechanics (LAMM), Department of Civil and Environmental Engineering, Massachusetts Institute of Technology , 77 Massachusetts Ave, Cambridge, Massachusetts 02139, United States.
authors.forename: Tristan
authors.initials: T
authors.lastname: Giesa
authors.affiliation: Interdisciplinary Biomedical Research Centre, School of Science and Technology, Nottingham Trent University , Clifton Lane, Nottingham NG11 8NS, United Kingdom.
authors.forename: Valeria
authors.initials: V
authors.lastname: Puddu
authors.affiliation: Laboratory for Atomistic and Molecular Mechanics (LAMM), Department of Civil and Environmental Engineering, Massachusetts Institute of Technology , 77 Massachusetts Ave, Cambridge, Massachusetts 02139, United States.
authors.forename: Markus J
authors.initials: MJ
authors.lastname: Buehler
authors.affiliation: Interdisciplinary Biomedical Research Centre, School of Science and Technology, Nottingham Trent University , Clifton Lane, Nottingham NG11 8NS, United Kingdom.
authors.forename: Carole C
authors.initials: CC
authors.lastname: Perry
authors.affiliation: Institute for Frontier Materials, Deakin University , Geelong, Victoria 3216, Australia.
authors.forename: Tiffany R
authors.initials: TR
authors.lastname: Walsh
keywords: adsorption; biointerfaces; molecular dynamics simulations; peptides; titania