Zwitterionic self-assembly of L-methionine nanogratings on the Ag(111) surface.
The engineering of complex architectures from functional molecules on surfaces provides new pathways to control matter at the nanoscale. In this article, we present a combined study addressing the self-assembly of the amino acid L-methionine on Ag(111). Scanning tunneling microscopy data reveal spontaneous ordering in extended molecular chains oriented along high-symmetry substrate directions. At intermediate coverages, regular biomolecular gratings evolve whose periodicity can be tuned at the nanometer scale by varying the methionine surface concentration. Their characteristics and stability were confirmed by helium atomic scattering. X-ray photoemission spectroscopy and high-resolution scanning tunneling microscopy data reveal that the L-methionine chaining is mediated by zwitterionic coupling, accounting for both lateral links and molecular dimerization. This methionine molecular recognition scheme is reminiscent of sheet structures in amino acid crystals and was corroborated by molecular mechanics calculations. Our findings suggest that zwitterionic assembly of amino acids represents a general construction motif to achieve biomolecular nanoarchitectures on surfaces.
Schiffrin
Agustin
A
Department of Chemistry, University of British Columbia, Vancouver, BC, Canada V6T 1Z4.
Riemann
Andreas
A
Auwärter
Willi
W
Pennec
Yan
Y
Weber-Bargioni
Alex
A
Cvetko
Dean
D
Cossaro
Albano
A
Morgante
Alberto
A
Barth
Johannes V
JV
D020816:Amino Acid Motifs; D000596:Amino Acids / Q000737:chemistry; D015180:Electrophoresis, Gel, Two-Dimensional; D006046:Gold / Q000737:chemistry*; D006371:Helium / Q000737:chemistry; D006860:Hydrogen Bonding; D007477:Ions; D008715:Methionine / Q000737:chemistry*; D016252:Microscopy, Scanning Tunneling; D015394:Molecular Structure; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D013499:Surface Properties; D013696:Temperature
D000596:Amino Acids; D007477:Ions; D006371:Helium; D006046:Gold; D008715:Methionine