title: Inhibitory effects of a phage-derived peptide on Au nanocrystal nucleation and growth.
abstract: Peptides have been shown to mediate the reduction and clustering of inorganic ions during biomineralization processes to build nanomaterials with well-defined shape, size, and composition. This precise control has been linked to specific amino acid sequence; however, there is a lack of information about the role of peptides during mineralization. Here, we investigate the nucleation and growth behavior of Au nanocrystals that are mediated by the engineered peptide AYSSGAPPMPPF. Unlike other nanocrystal synthesis schemes, this peptide produces Au nanocrystals from Au(III) ions at very low relative peptide concentrations, at ambient temperature, and in water at neutral pH. Our data show that (i) the peptide AYSSGAPPMPPF actually inhibits nucleation and growth of nanocrystals, (ii) HEPES plays an active chemical role as the reducing agent, and (iii) HAuCl4 accelerates the kinetics of nanoparticle nucleation and growth. Herein, we propose empirical rate laws for nucleation and growth of Au nanocrystals and compare kinetic rate laws for this peptide, citrate, and various other polymer ligands. We find that the peptide belongs to a unique class of nonreducing inhibitor ligands regulating the surface-reaction-limited growth of nanocrystals.
authors.affiliation: National Institute of Standards and Technology, Polymers Division 100 Bureau Drive, Gaithersburg, Maryland 20899, USA. Stanley.s.5@pg.com
authors.forename: Scott K
authors.initials: SK
authors.lastname: Stanley
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Becker
authors.forename: Eric K
authors.initials: EK
authors.lastname: Lin
authors.forename: Wen-li
authors.initials: WL
authors.lastname: Wu
mesh_terms: D000595:Amino Acid Sequence; D001435:Bacteriophages / Q000737:chemistry*; D002021:Buffers; D002712:Chlorides / Q000737:chemistry; D019343:Citric Acid / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D017612:Gold Compounds / Q000737:chemistry; D006531:HEPES; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D053768:Metal Nanoparticles / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry* / Q000302:isolation & purification; D013696:Temperature
chemical_list: D002021:Buffers; D002712:Chlorides; D017612:Gold Compounds; D010455:Peptides; D019343:Citric Acid; D006046:Gold; C024568:gold tetrachloride, acid; D006531:HEPES